Molecular Devices and Materials (Mayor)Head of Research Unit Prof. Dr.Marcel MayorOverviewMembersPublicationsProjects & CollaborationsProjects & Collaborations OverviewMembersPublicationsProjects & Collaborations Projects & Collaborations 23 foundShow per page10 10 20 50 Synthetische Nanoskalige Objekte: Bausteine für funktionale Materialien und Funktionseinheiten Research Project | 10 Project MembersThe proposal follows the SNF advice of a single project per applicant in division II. It is divided in five subprojects, each being the subject of a PhD thesis. In spite of the different research targets, they have enough overlap enabling the fruitful exchange of knowledge and mutual developments required to build up a joint group identity. All five projects focus on current challenges in nanotechnology, molecular devices, and supramolecular materials, which are addressed by novel strategies and innovative molecular designs of functional structures. The five subprojects are briefly described in the following: (I) «Geländer»-molecules and helical architectures: «Geländer»-molecules consist of two periodically interlinked oligomers which compensate their length mismatch by wrapping the longer one helically around the shorter one, resembling the shape of the banister (Geländer in German) of a spiral staircase. The here promoted new designs profit from right-angled connections resulting in a simplified symmetry of the building blocks which should make longer oligomers synthetically accessible. A second strategy based on o-tetraphenylene building blocks is geared towards helical «plait»-type oligomers. (II) mechanosensitive model compounds for molecular junctions are based on cyclophane-type architectures enabling to tune the extent of the coupling between their subunits mechanically. With small [2.2]paracyclonaphthane derivatives the effect of torque motion shall be explored, while a polycyclic porphyrin hexamer will be assembled with two stacked states with large difference in their expansion. Based on a «upended» porphyrin type structure, even the coupling of the single electrons of two parallel radical planes might be investigated. (III) B-field sensitive macrocyclic model compounds are loop-shaped macrocycles consisting of a conjugated periphery decorated with terminal anchor groups enabling their integration in single molecule junction experiments. The intention is to detect the contribution of the Lorentz force to the molecules transport current. With a compact and twisted OPE type macrocycle, the axial chirality of the immobilized structure might become specifiable in the transport experiment. (IV) synthesis of an armchair carbon nanotube (CNT) is an interesting synthetic strategy for the controlled wet chemical assembly of an armchair CNT. A belt fragment of a CNT shall be obtained from a macrocycle by a reaction sequence, which can subsequently be repeatedly applied to control the length of the CNT. (V) approaches towards molecular textiles are based on the development of a cross-type junction acting a covalent template arranging the precursors at the water/air interface. Upon interlinking within the LB-film and cleavage of the template, textile-type interwoven molecular films should be obtained. The potential of the cross-type junction for superstructures will be investigated as well. Toblerone-Shaped Polymers: Bridging the Gap between Conjugated Polymers and Carbon Nanotubes Research Project | 1 Project MembersElectronic devices fabricated from conjugated polymers are expected to be competitive with those based on inorganic materials because of their low production costs due to high-throughput processing methods. These linear polymers possess tunable optoelectronic and mechanical properties and can be highly soluble. Although, conjugated polymers can be found in prototypes of electronic devices, only a handful of applications found their way to the commercial use. One of the reasons is their relatively low charge carrier mobility. An alternative to conjugated polymers are cylindrical single-walled carbon nanotubes (SWCNTs). Despite their excellent charge transport properties, SWCNTs, however, suffer from low solubility, sample purity, limited tunability of their properties, and, overall, high production costs. Other approaches that would successfully combine the properties of linear polymers and the cylindrical SWCNTs preserving the typical advantages of former and displaying high charge carrier mobility are largely missing.In this research proposal, the synthesis and experimental investigation of nanoprismatic, i.e., toblerone-shaped, polymers and nanoprisms are described for the first time. These ladder structures built by combination of triangular electron acceptor and linear electron donor monomers possess aromatic p-electron surfaces exposed to the exterior of the polymer or nanoprism such that it allows for p-electron communication with adjacent polymer segments or nanoprisms. Such spatial arrangement will result in an improved charge carrier mobility, similar to SWCNT. The choice of the individual monomers allows for tailoring their optoelectronic and material properties. Therefore, successful completion of the proposed research will introduce a new unconventional approach to bridge the conceptual gap between the scientific field of conjugated polymers and SWCNTs unprecedented in the scientific literature. SuperMaMa / Superconducting Mass Spectrometry and Molecule Analysis Research Project | 2 Project MembersSuperMaMa is an EU-FET OPEN Research & Innovation project working on new technologies for mass spectrometry and analysis of lowly charged and neutral high-mass proteins. It comprises the development of neutral and lowly-charged biomolecular beam generation and detection. To this end arrays of superconducting detectors for molecular ions and neutrals will be designed and installed in a converted mass spectrometer, and methods for charge reduction of biomolecular ions in high vacuum devised. The team includes three academic research groups (M. Arndt, U. Vienna; E. Charbon, EPFL; M. Mayor, U. Basel) and two industrial partner (Single Quantum, Delft; MS Vision, Almere). The contribution from UNIBAS is primarily concerned with the development of suitable tags for biomolecules to enable charge manipulation in the gas phase by photochemical methods. QuIET / Quantum Interference Enhanced Thermoelectricity Research Project | 1 Project MembersOur vision is to demonstrate that room-temperature quantum interference effects, measured recently in single molecules, can be exploited in massively-parallel arrays of molecules and used to design ultra-thin-film thermoelectric devices with unprecedented ability to convert waste heat to electricity using the Seebeck effect and to cool at the nanoscale via the Peltier effect. Although the dream of high-performance thermoelectric devices has been discussed for many years, evidence of the room-temperature quantum interference effects needed to realise this dream was achieved experimentally only recently. Building on these indirect demonstrations of quantum interference in single molecules using non-scalable set ups, we anticipate that the next breakthrough will be the implementation of QI functionality these intechnologically-relevant platforms. We shall design molecules with built-in quantum interference functionality, which can be used to engineer the properties of ultra-thin molecular films. Molecules will be designed with robust anchors to metallic and carbon-based nano-gap electrodes, which enhance electron transport and eliminate unwanted phonons.This contacting strategy is scalable from a single junction, with the potential to be replicated billions of times on a single substrate. The ability to exploit quantum interference at room temperature will enable new thermoelectric materials and devices with the ability to scavenge energy with unprecedented efficiency. QuIET is a highly interdisciplinary project that brings together internationally leading scientists from four different countries with proven expertise on synthesis, transport measurements and theoretical modelling. Encapsulation and Covalent Assembly of Nanoparticles Research Project | 1 Project MembersMetal nanoparticles (NPs) are three-dimensional structurally well-defined nanoclusters of around 10-100 atoms, which are best known for their unique size-dependent properties. It has been shown that the properties of a covalent ensemble of a number of NPs are greatly enhanced compared to those of the same number of single components. This, so-called collective, behavior can be useful, once controlled, for constructing NP nanocircuits of electronic devices. To build and study long chains of covalently linked NPs, their encapsulation by two shape- and size-complementary ligands is proposed. A series of bowl-shaped ligands, capable of (1) recognition and (2) covalent encapsulation of spherical NPs, is designed and the synthesis of these ligands is outlined. The ultimate goal is to connect the NP(ligand) 2 building blocks to generate long linear [(ligand)NP(ligand)] n chains and investigate their collective-behavior effect. In addition to standard analytical methods to characterize NPs, high-resolution transmission electron microscopy will be used to provide insight into this unusual phenomenon displayed by covalent NP ensembles. This project is geared towards (1) control over the organization of NPs through their covalent interconnection by chemical means to (2) enhance their electronic properties. The knowledge gained through this investigation can lead to a set of design principles, which can be used in future for making NP-based functional materials. This work can also result in an unprecedented methodology to separate NPs into fractions of extremely low size-distribution. Synthetische Nanoskalige Objekte - Bausteine von funktionalen Materialien und von Funktionseinheiten Research Project | 1 Project MembersThe proposal follows the future SNF rules of one project per applicant in division II. It is divided in five subprojects, each being the subject of a PhD thesis. Even though these five topics have very different aims, they have in common that current challenges in nano-technology are tackled by bottom-up assembly of functional molecular structures by organic synthesis. The five subprojects are: (I) Helical Oligomers, (II) Molecular Junctions, (III) Electrode Functionalization, (IV) Coated Nanoparticles, and (V) Supramolecular Preorganized Reactants. (I) Helical Oligomers: Molecular rods resembling a "molecular screw" will be developed. They consist of two interlinked oligomers with different spacing of the repeat unit, resulting in the helical wrapping of the longer oligomer around the shorter one which acts as axis. These appealing helical architectures are particular interesting due to their chiroptical properties and as model compounds to investigate molecular racemization mechanisms. (II) Molecular Junction: Molecular rods as functional units of carbon nano-tube (CNT) based molecular junctions will be synthesized. Model compounds enabling single molecule electroluminescence experiments with a central Ir(III) terpy as emitting subunit will be investigated. A molecular turnstile responding on the applied electric field shall be assembled and investigated in CNT-junctions. Interestingly the mechanical switching should be detectable in the junction's transport characteristic. (III) Electrode Functionalization: An electrochemically addressable acetylene protection group shall be developed, enabling to differentiate between electrodes by their electrification. The working principle will be investigated in solution as well as on electrodes by in situ functionalization of the deprotected acetylene groups by alkyne-azide "click" chemistry. (IV) Coated Nanoparticles: As continuation of our studies providing mono-functionalized gold particles in good yields, new motives for thioether based olgomers as multidentate macromolecular ligands shall be investigated. The focus is set on making processible gold nanoparticles with diameters of 2 nm and larger in order to increase their attractiveness for sensing applications based on optical read outs. (V) Supramolecular Preorganized Reactants: Supermolecules are used to spatially arrange molecular building blocks which are subsequently covalently interlinked. Examples of various dimensions are investigated ranging from a small (0-d) caged Fe(II) terpy complex to tune its spin state in transport experiments, over mechanically interlinked daisy chain oligomers (1-d) to interwoven 1-d polymers resembling a "molecular textile" (2-d) which shall be obtained by preorganizing the building blocks in metal organic framework. Open-Shell Graphene Fragment in a Shell: Stabilization of Fragile Triangulene Core Research Project | 1 Project MembersGraphene fragments made of exclusively carbon and hydrogen atoms are useful molecular models, which aid and abet our understanding of intrinsic phenomena occurring in graphene. The well-defined structure of these fragments allows us to investigate how the desired properties relate to the structure on a small scale first, before moving to extended two-dimensional carbon networks. Chemistry of graphene fragments is well documented in the literature, with the exception of one class of these hydrocarbon molecules, namely, the "open-shell graphene fragments" . Their unique triangular topology breaks the "alternating-double-bond rule" and, as a result, these molecules contain unpaired delocalized electrons. In general, an increase of the fragment size leads to a higher number of unpaired electrons. The main reason for which the open-shell graphene fragments have not been studied to a great extent is the extremely low stability of systems containing unpaired electrons, the so-called free radicals . The majority of reports on open-shell graphene fragments describe derivatives of the smallest fragment, monoradical phenalenyl (three fused benzene rings), and only a few examples mention its larger homolog, diradical triangulene (six fused benzene rings). In fact, only one derivative of triangulene composed of only carbon and hydrogen atoms has been described so far, however, it could only detected under strictly inert conditions and at low temperatures because of its instability. The objective of the proposed research is to synthesize and characterize a persistent derivative of triangulene and validate its triplet ground state in the solid state for the first time. The unpaired electrons in such open-shell systems can, in principle, serve as information carriers and potentially be used in the design of quantum information processing devices. Polymers Comprising Concave and Chiral Subunits for the Selective Dispersion of Single Walled Carbon Nanotubes (SWCNT) Research Project | 3 Project MembersSingle wall carbon nanotubes are promising materials for future devices due to their outstanding physical properties. In particular their electronic and optical features make them promising functional units in numerous applications. While the correlation between their structure (n,m indices) and physical properties is well understood, their integration into devices and materials suffers from both the poor availability of pure samples and the limited processability of these substances. Within this proposal we strive to develop polymeric structures able to selectively disperse SWCNTs with well defined physical features like electronic properties, diameter, n,m-indices and even chirality. For that purpose concave building blocks with favorable p-stacking interactions with bent SWCNT surfaces shall be developed and integrated in various (co)-polymers. These building blocks will be synthesized as racemates which will be separated into pure enantiomers (by separating the diastereomers obtained from both enantiomers). The approach will thus make (co)-polymers of enantiomerically pure building blocks available. These (co)-polymers will be used to disperse HiPco-SWCNTs and the composition of the dispersion (as well as the polymer SWCNT interaction) will be analyzed by optical methods like UV-vis-nIR absorption , nIR photoluminescence-, and Raman spectroscopy. We also aim at developing a process enabling the reversible coating of SWCNTs by polymers. While the dispersing coating provides perfectly processable tubes, the residual insulating coating effects the interaction of the tube with the substrate upon integration. By profiting from the reversibility of Diels-Alder reactions we design coating polymers which can be thermally decomposed into small building blocks. Thereby we hope to provide coatings providing processability which can be removed after integration of the tube in UHV applications. We will correspondingly investigate the polymers thermal decomposition on the SWCNTs in situ, using both desorption mass spectrometry, Raman microscopy and a variety of surface analytical methods to probe the resulting materials. This will also provide feedback for the optimization of the polymer structure for the purpose of obtaining UHV clean chiral vector selected SWCNT materials for further studies. Assembly and investigation of electrochemically triggered molecular muscles Research Project | 2 Project MembersMechanically interlinked supramolecular systems are of interest for the design of systems displaying shape alteration/adaption.1 Particular appealing are systems reacting on an external trigger and thus, catenanes and rotaxanes comprising electrochemically addressable subunits have been assembled and displayed redox state dependant mechanical motions.2 Immobilization of the macrocyclic subunits of rotaxanes comprsing two rings on flexible cantilevers even allowed translating the electrochemically triggered molecular motion into the macroscopic bending of the substrate.3 In order to assemble a molecular muscle, Sauvage presented the design concept of a pseudo-rotaxane.4 By attaching the rotaxane axis at the macrocycle's periphery he obtained a system forming a supramolecular dimer in which the axis of one molecule is penetrating the macrocycle of the other. Functionalization of the subunits with different coordination sites allowed altering the expansion of the structure by varying the coordinating ion. MOLECULAR-SCALE ELECTRONICS: Concepts, Contacts and Stability MOLESCO (Chemistry) Research Project | 1 Project MembersThe MOLESCO network will create a unique training and research environment to develop a pool of young researchers capable of achieving breakthroughs aimed at realising the immense potential of molecular electronics. In part this will involve the major challenges of design and fabrication of molecular-scale devices. To deliver this step-change in capability, MOLESCO will coordinate the activities of internationally-leading scientists from six different countries. MOLESCO has secured the participation of nine private sector partners, including one of Europe's leading industrial electronics-research laboratories (IBM Research-Zurich) as a full partner. A highly-integrated approach to the experimental and theoretical aspects of molecular-scale electronics will deliver the fundamental knowledge and new fabrication strategies needed to underpin future nanotechnologies targeted for electronics applications. MOLESCO represents a highly interdisciplinary and intersectoral collaboration between teams with an extensive portfolio of skills, including molecular synthesis, fabrication of molecular junctions, imaging of molecular junctions with atomic resolution, measurements of charge transport, and electronic structure and transport calculations. Training will be delivered in a series of high-priority actions primarily aimed at providing the researchers with an outstanding career development platform. The network has a strong focus on interdisciplinary training; it is built on several well-established and fruitful collaborations between the partners and seeks to bridge an existing educational gap in the European Research Arena. The development of complementary skills (presentation, management, technology transfer, IP protection, outreach and intersectoral training) will be implemented throughout the lifetime of the project. Specialist professional training in dissemination and outreach will be delivered by our Associate Partner BLP, a professional media production company. 123 123 OverviewMembersPublicationsProjects & Collaborations
Projects & Collaborations 23 foundShow per page10 10 20 50 Synthetische Nanoskalige Objekte: Bausteine für funktionale Materialien und Funktionseinheiten Research Project | 10 Project MembersThe proposal follows the SNF advice of a single project per applicant in division II. It is divided in five subprojects, each being the subject of a PhD thesis. In spite of the different research targets, they have enough overlap enabling the fruitful exchange of knowledge and mutual developments required to build up a joint group identity. All five projects focus on current challenges in nanotechnology, molecular devices, and supramolecular materials, which are addressed by novel strategies and innovative molecular designs of functional structures. The five subprojects are briefly described in the following: (I) «Geländer»-molecules and helical architectures: «Geländer»-molecules consist of two periodically interlinked oligomers which compensate their length mismatch by wrapping the longer one helically around the shorter one, resembling the shape of the banister (Geländer in German) of a spiral staircase. The here promoted new designs profit from right-angled connections resulting in a simplified symmetry of the building blocks which should make longer oligomers synthetically accessible. A second strategy based on o-tetraphenylene building blocks is geared towards helical «plait»-type oligomers. (II) mechanosensitive model compounds for molecular junctions are based on cyclophane-type architectures enabling to tune the extent of the coupling between their subunits mechanically. With small [2.2]paracyclonaphthane derivatives the effect of torque motion shall be explored, while a polycyclic porphyrin hexamer will be assembled with two stacked states with large difference in their expansion. Based on a «upended» porphyrin type structure, even the coupling of the single electrons of two parallel radical planes might be investigated. (III) B-field sensitive macrocyclic model compounds are loop-shaped macrocycles consisting of a conjugated periphery decorated with terminal anchor groups enabling their integration in single molecule junction experiments. The intention is to detect the contribution of the Lorentz force to the molecules transport current. With a compact and twisted OPE type macrocycle, the axial chirality of the immobilized structure might become specifiable in the transport experiment. (IV) synthesis of an armchair carbon nanotube (CNT) is an interesting synthetic strategy for the controlled wet chemical assembly of an armchair CNT. A belt fragment of a CNT shall be obtained from a macrocycle by a reaction sequence, which can subsequently be repeatedly applied to control the length of the CNT. (V) approaches towards molecular textiles are based on the development of a cross-type junction acting a covalent template arranging the precursors at the water/air interface. Upon interlinking within the LB-film and cleavage of the template, textile-type interwoven molecular films should be obtained. The potential of the cross-type junction for superstructures will be investigated as well. Toblerone-Shaped Polymers: Bridging the Gap between Conjugated Polymers and Carbon Nanotubes Research Project | 1 Project MembersElectronic devices fabricated from conjugated polymers are expected to be competitive with those based on inorganic materials because of their low production costs due to high-throughput processing methods. These linear polymers possess tunable optoelectronic and mechanical properties and can be highly soluble. Although, conjugated polymers can be found in prototypes of electronic devices, only a handful of applications found their way to the commercial use. One of the reasons is their relatively low charge carrier mobility. An alternative to conjugated polymers are cylindrical single-walled carbon nanotubes (SWCNTs). Despite their excellent charge transport properties, SWCNTs, however, suffer from low solubility, sample purity, limited tunability of their properties, and, overall, high production costs. Other approaches that would successfully combine the properties of linear polymers and the cylindrical SWCNTs preserving the typical advantages of former and displaying high charge carrier mobility are largely missing.In this research proposal, the synthesis and experimental investigation of nanoprismatic, i.e., toblerone-shaped, polymers and nanoprisms are described for the first time. These ladder structures built by combination of triangular electron acceptor and linear electron donor monomers possess aromatic p-electron surfaces exposed to the exterior of the polymer or nanoprism such that it allows for p-electron communication with adjacent polymer segments or nanoprisms. Such spatial arrangement will result in an improved charge carrier mobility, similar to SWCNT. The choice of the individual monomers allows for tailoring their optoelectronic and material properties. Therefore, successful completion of the proposed research will introduce a new unconventional approach to bridge the conceptual gap between the scientific field of conjugated polymers and SWCNTs unprecedented in the scientific literature. SuperMaMa / Superconducting Mass Spectrometry and Molecule Analysis Research Project | 2 Project MembersSuperMaMa is an EU-FET OPEN Research & Innovation project working on new technologies for mass spectrometry and analysis of lowly charged and neutral high-mass proteins. It comprises the development of neutral and lowly-charged biomolecular beam generation and detection. To this end arrays of superconducting detectors for molecular ions and neutrals will be designed and installed in a converted mass spectrometer, and methods for charge reduction of biomolecular ions in high vacuum devised. The team includes three academic research groups (M. Arndt, U. Vienna; E. Charbon, EPFL; M. Mayor, U. Basel) and two industrial partner (Single Quantum, Delft; MS Vision, Almere). The contribution from UNIBAS is primarily concerned with the development of suitable tags for biomolecules to enable charge manipulation in the gas phase by photochemical methods. QuIET / Quantum Interference Enhanced Thermoelectricity Research Project | 1 Project MembersOur vision is to demonstrate that room-temperature quantum interference effects, measured recently in single molecules, can be exploited in massively-parallel arrays of molecules and used to design ultra-thin-film thermoelectric devices with unprecedented ability to convert waste heat to electricity using the Seebeck effect and to cool at the nanoscale via the Peltier effect. Although the dream of high-performance thermoelectric devices has been discussed for many years, evidence of the room-temperature quantum interference effects needed to realise this dream was achieved experimentally only recently. Building on these indirect demonstrations of quantum interference in single molecules using non-scalable set ups, we anticipate that the next breakthrough will be the implementation of QI functionality these intechnologically-relevant platforms. We shall design molecules with built-in quantum interference functionality, which can be used to engineer the properties of ultra-thin molecular films. Molecules will be designed with robust anchors to metallic and carbon-based nano-gap electrodes, which enhance electron transport and eliminate unwanted phonons.This contacting strategy is scalable from a single junction, with the potential to be replicated billions of times on a single substrate. The ability to exploit quantum interference at room temperature will enable new thermoelectric materials and devices with the ability to scavenge energy with unprecedented efficiency. QuIET is a highly interdisciplinary project that brings together internationally leading scientists from four different countries with proven expertise on synthesis, transport measurements and theoretical modelling. Encapsulation and Covalent Assembly of Nanoparticles Research Project | 1 Project MembersMetal nanoparticles (NPs) are three-dimensional structurally well-defined nanoclusters of around 10-100 atoms, which are best known for their unique size-dependent properties. It has been shown that the properties of a covalent ensemble of a number of NPs are greatly enhanced compared to those of the same number of single components. This, so-called collective, behavior can be useful, once controlled, for constructing NP nanocircuits of electronic devices. To build and study long chains of covalently linked NPs, their encapsulation by two shape- and size-complementary ligands is proposed. A series of bowl-shaped ligands, capable of (1) recognition and (2) covalent encapsulation of spherical NPs, is designed and the synthesis of these ligands is outlined. The ultimate goal is to connect the NP(ligand) 2 building blocks to generate long linear [(ligand)NP(ligand)] n chains and investigate their collective-behavior effect. In addition to standard analytical methods to characterize NPs, high-resolution transmission electron microscopy will be used to provide insight into this unusual phenomenon displayed by covalent NP ensembles. This project is geared towards (1) control over the organization of NPs through their covalent interconnection by chemical means to (2) enhance their electronic properties. The knowledge gained through this investigation can lead to a set of design principles, which can be used in future for making NP-based functional materials. This work can also result in an unprecedented methodology to separate NPs into fractions of extremely low size-distribution. Synthetische Nanoskalige Objekte - Bausteine von funktionalen Materialien und von Funktionseinheiten Research Project | 1 Project MembersThe proposal follows the future SNF rules of one project per applicant in division II. It is divided in five subprojects, each being the subject of a PhD thesis. Even though these five topics have very different aims, they have in common that current challenges in nano-technology are tackled by bottom-up assembly of functional molecular structures by organic synthesis. The five subprojects are: (I) Helical Oligomers, (II) Molecular Junctions, (III) Electrode Functionalization, (IV) Coated Nanoparticles, and (V) Supramolecular Preorganized Reactants. (I) Helical Oligomers: Molecular rods resembling a "molecular screw" will be developed. They consist of two interlinked oligomers with different spacing of the repeat unit, resulting in the helical wrapping of the longer oligomer around the shorter one which acts as axis. These appealing helical architectures are particular interesting due to their chiroptical properties and as model compounds to investigate molecular racemization mechanisms. (II) Molecular Junction: Molecular rods as functional units of carbon nano-tube (CNT) based molecular junctions will be synthesized. Model compounds enabling single molecule electroluminescence experiments with a central Ir(III) terpy as emitting subunit will be investigated. A molecular turnstile responding on the applied electric field shall be assembled and investigated in CNT-junctions. Interestingly the mechanical switching should be detectable in the junction's transport characteristic. (III) Electrode Functionalization: An electrochemically addressable acetylene protection group shall be developed, enabling to differentiate between electrodes by their electrification. The working principle will be investigated in solution as well as on electrodes by in situ functionalization of the deprotected acetylene groups by alkyne-azide "click" chemistry. (IV) Coated Nanoparticles: As continuation of our studies providing mono-functionalized gold particles in good yields, new motives for thioether based olgomers as multidentate macromolecular ligands shall be investigated. The focus is set on making processible gold nanoparticles with diameters of 2 nm and larger in order to increase their attractiveness for sensing applications based on optical read outs. (V) Supramolecular Preorganized Reactants: Supermolecules are used to spatially arrange molecular building blocks which are subsequently covalently interlinked. Examples of various dimensions are investigated ranging from a small (0-d) caged Fe(II) terpy complex to tune its spin state in transport experiments, over mechanically interlinked daisy chain oligomers (1-d) to interwoven 1-d polymers resembling a "molecular textile" (2-d) which shall be obtained by preorganizing the building blocks in metal organic framework. Open-Shell Graphene Fragment in a Shell: Stabilization of Fragile Triangulene Core Research Project | 1 Project MembersGraphene fragments made of exclusively carbon and hydrogen atoms are useful molecular models, which aid and abet our understanding of intrinsic phenomena occurring in graphene. The well-defined structure of these fragments allows us to investigate how the desired properties relate to the structure on a small scale first, before moving to extended two-dimensional carbon networks. Chemistry of graphene fragments is well documented in the literature, with the exception of one class of these hydrocarbon molecules, namely, the "open-shell graphene fragments" . Their unique triangular topology breaks the "alternating-double-bond rule" and, as a result, these molecules contain unpaired delocalized electrons. In general, an increase of the fragment size leads to a higher number of unpaired electrons. The main reason for which the open-shell graphene fragments have not been studied to a great extent is the extremely low stability of systems containing unpaired electrons, the so-called free radicals . The majority of reports on open-shell graphene fragments describe derivatives of the smallest fragment, monoradical phenalenyl (three fused benzene rings), and only a few examples mention its larger homolog, diradical triangulene (six fused benzene rings). In fact, only one derivative of triangulene composed of only carbon and hydrogen atoms has been described so far, however, it could only detected under strictly inert conditions and at low temperatures because of its instability. The objective of the proposed research is to synthesize and characterize a persistent derivative of triangulene and validate its triplet ground state in the solid state for the first time. The unpaired electrons in such open-shell systems can, in principle, serve as information carriers and potentially be used in the design of quantum information processing devices. Polymers Comprising Concave and Chiral Subunits for the Selective Dispersion of Single Walled Carbon Nanotubes (SWCNT) Research Project | 3 Project MembersSingle wall carbon nanotubes are promising materials for future devices due to their outstanding physical properties. In particular their electronic and optical features make them promising functional units in numerous applications. While the correlation between their structure (n,m indices) and physical properties is well understood, their integration into devices and materials suffers from both the poor availability of pure samples and the limited processability of these substances. Within this proposal we strive to develop polymeric structures able to selectively disperse SWCNTs with well defined physical features like electronic properties, diameter, n,m-indices and even chirality. For that purpose concave building blocks with favorable p-stacking interactions with bent SWCNT surfaces shall be developed and integrated in various (co)-polymers. These building blocks will be synthesized as racemates which will be separated into pure enantiomers (by separating the diastereomers obtained from both enantiomers). The approach will thus make (co)-polymers of enantiomerically pure building blocks available. These (co)-polymers will be used to disperse HiPco-SWCNTs and the composition of the dispersion (as well as the polymer SWCNT interaction) will be analyzed by optical methods like UV-vis-nIR absorption , nIR photoluminescence-, and Raman spectroscopy. We also aim at developing a process enabling the reversible coating of SWCNTs by polymers. While the dispersing coating provides perfectly processable tubes, the residual insulating coating effects the interaction of the tube with the substrate upon integration. By profiting from the reversibility of Diels-Alder reactions we design coating polymers which can be thermally decomposed into small building blocks. Thereby we hope to provide coatings providing processability which can be removed after integration of the tube in UHV applications. We will correspondingly investigate the polymers thermal decomposition on the SWCNTs in situ, using both desorption mass spectrometry, Raman microscopy and a variety of surface analytical methods to probe the resulting materials. This will also provide feedback for the optimization of the polymer structure for the purpose of obtaining UHV clean chiral vector selected SWCNT materials for further studies. Assembly and investigation of electrochemically triggered molecular muscles Research Project | 2 Project MembersMechanically interlinked supramolecular systems are of interest for the design of systems displaying shape alteration/adaption.1 Particular appealing are systems reacting on an external trigger and thus, catenanes and rotaxanes comprising electrochemically addressable subunits have been assembled and displayed redox state dependant mechanical motions.2 Immobilization of the macrocyclic subunits of rotaxanes comprsing two rings on flexible cantilevers even allowed translating the electrochemically triggered molecular motion into the macroscopic bending of the substrate.3 In order to assemble a molecular muscle, Sauvage presented the design concept of a pseudo-rotaxane.4 By attaching the rotaxane axis at the macrocycle's periphery he obtained a system forming a supramolecular dimer in which the axis of one molecule is penetrating the macrocycle of the other. Functionalization of the subunits with different coordination sites allowed altering the expansion of the structure by varying the coordinating ion. MOLECULAR-SCALE ELECTRONICS: Concepts, Contacts and Stability MOLESCO (Chemistry) Research Project | 1 Project MembersThe MOLESCO network will create a unique training and research environment to develop a pool of young researchers capable of achieving breakthroughs aimed at realising the immense potential of molecular electronics. In part this will involve the major challenges of design and fabrication of molecular-scale devices. To deliver this step-change in capability, MOLESCO will coordinate the activities of internationally-leading scientists from six different countries. MOLESCO has secured the participation of nine private sector partners, including one of Europe's leading industrial electronics-research laboratories (IBM Research-Zurich) as a full partner. A highly-integrated approach to the experimental and theoretical aspects of molecular-scale electronics will deliver the fundamental knowledge and new fabrication strategies needed to underpin future nanotechnologies targeted for electronics applications. MOLESCO represents a highly interdisciplinary and intersectoral collaboration between teams with an extensive portfolio of skills, including molecular synthesis, fabrication of molecular junctions, imaging of molecular junctions with atomic resolution, measurements of charge transport, and electronic structure and transport calculations. Training will be delivered in a series of high-priority actions primarily aimed at providing the researchers with an outstanding career development platform. The network has a strong focus on interdisciplinary training; it is built on several well-established and fruitful collaborations between the partners and seeks to bridge an existing educational gap in the European Research Arena. The development of complementary skills (presentation, management, technology transfer, IP protection, outreach and intersectoral training) will be implemented throughout the lifetime of the project. Specialist professional training in dissemination and outreach will be delivered by our Associate Partner BLP, a professional media production company. 123 123
Synthetische Nanoskalige Objekte: Bausteine für funktionale Materialien und Funktionseinheiten Research Project | 10 Project MembersThe proposal follows the SNF advice of a single project per applicant in division II. It is divided in five subprojects, each being the subject of a PhD thesis. In spite of the different research targets, they have enough overlap enabling the fruitful exchange of knowledge and mutual developments required to build up a joint group identity. All five projects focus on current challenges in nanotechnology, molecular devices, and supramolecular materials, which are addressed by novel strategies and innovative molecular designs of functional structures. The five subprojects are briefly described in the following: (I) «Geländer»-molecules and helical architectures: «Geländer»-molecules consist of two periodically interlinked oligomers which compensate their length mismatch by wrapping the longer one helically around the shorter one, resembling the shape of the banister (Geländer in German) of a spiral staircase. The here promoted new designs profit from right-angled connections resulting in a simplified symmetry of the building blocks which should make longer oligomers synthetically accessible. A second strategy based on o-tetraphenylene building blocks is geared towards helical «plait»-type oligomers. (II) mechanosensitive model compounds for molecular junctions are based on cyclophane-type architectures enabling to tune the extent of the coupling between their subunits mechanically. With small [2.2]paracyclonaphthane derivatives the effect of torque motion shall be explored, while a polycyclic porphyrin hexamer will be assembled with two stacked states with large difference in their expansion. Based on a «upended» porphyrin type structure, even the coupling of the single electrons of two parallel radical planes might be investigated. (III) B-field sensitive macrocyclic model compounds are loop-shaped macrocycles consisting of a conjugated periphery decorated with terminal anchor groups enabling their integration in single molecule junction experiments. The intention is to detect the contribution of the Lorentz force to the molecules transport current. With a compact and twisted OPE type macrocycle, the axial chirality of the immobilized structure might become specifiable in the transport experiment. (IV) synthesis of an armchair carbon nanotube (CNT) is an interesting synthetic strategy for the controlled wet chemical assembly of an armchair CNT. A belt fragment of a CNT shall be obtained from a macrocycle by a reaction sequence, which can subsequently be repeatedly applied to control the length of the CNT. (V) approaches towards molecular textiles are based on the development of a cross-type junction acting a covalent template arranging the precursors at the water/air interface. Upon interlinking within the LB-film and cleavage of the template, textile-type interwoven molecular films should be obtained. The potential of the cross-type junction for superstructures will be investigated as well.
Toblerone-Shaped Polymers: Bridging the Gap between Conjugated Polymers and Carbon Nanotubes Research Project | 1 Project MembersElectronic devices fabricated from conjugated polymers are expected to be competitive with those based on inorganic materials because of their low production costs due to high-throughput processing methods. These linear polymers possess tunable optoelectronic and mechanical properties and can be highly soluble. Although, conjugated polymers can be found in prototypes of electronic devices, only a handful of applications found their way to the commercial use. One of the reasons is their relatively low charge carrier mobility. An alternative to conjugated polymers are cylindrical single-walled carbon nanotubes (SWCNTs). Despite their excellent charge transport properties, SWCNTs, however, suffer from low solubility, sample purity, limited tunability of their properties, and, overall, high production costs. Other approaches that would successfully combine the properties of linear polymers and the cylindrical SWCNTs preserving the typical advantages of former and displaying high charge carrier mobility are largely missing.In this research proposal, the synthesis and experimental investigation of nanoprismatic, i.e., toblerone-shaped, polymers and nanoprisms are described for the first time. These ladder structures built by combination of triangular electron acceptor and linear electron donor monomers possess aromatic p-electron surfaces exposed to the exterior of the polymer or nanoprism such that it allows for p-electron communication with adjacent polymer segments or nanoprisms. Such spatial arrangement will result in an improved charge carrier mobility, similar to SWCNT. The choice of the individual monomers allows for tailoring their optoelectronic and material properties. Therefore, successful completion of the proposed research will introduce a new unconventional approach to bridge the conceptual gap between the scientific field of conjugated polymers and SWCNTs unprecedented in the scientific literature.
SuperMaMa / Superconducting Mass Spectrometry and Molecule Analysis Research Project | 2 Project MembersSuperMaMa is an EU-FET OPEN Research & Innovation project working on new technologies for mass spectrometry and analysis of lowly charged and neutral high-mass proteins. It comprises the development of neutral and lowly-charged biomolecular beam generation and detection. To this end arrays of superconducting detectors for molecular ions and neutrals will be designed and installed in a converted mass spectrometer, and methods for charge reduction of biomolecular ions in high vacuum devised. The team includes three academic research groups (M. Arndt, U. Vienna; E. Charbon, EPFL; M. Mayor, U. Basel) and two industrial partner (Single Quantum, Delft; MS Vision, Almere). The contribution from UNIBAS is primarily concerned with the development of suitable tags for biomolecules to enable charge manipulation in the gas phase by photochemical methods.
QuIET / Quantum Interference Enhanced Thermoelectricity Research Project | 1 Project MembersOur vision is to demonstrate that room-temperature quantum interference effects, measured recently in single molecules, can be exploited in massively-parallel arrays of molecules and used to design ultra-thin-film thermoelectric devices with unprecedented ability to convert waste heat to electricity using the Seebeck effect and to cool at the nanoscale via the Peltier effect. Although the dream of high-performance thermoelectric devices has been discussed for many years, evidence of the room-temperature quantum interference effects needed to realise this dream was achieved experimentally only recently. Building on these indirect demonstrations of quantum interference in single molecules using non-scalable set ups, we anticipate that the next breakthrough will be the implementation of QI functionality these intechnologically-relevant platforms. We shall design molecules with built-in quantum interference functionality, which can be used to engineer the properties of ultra-thin molecular films. Molecules will be designed with robust anchors to metallic and carbon-based nano-gap electrodes, which enhance electron transport and eliminate unwanted phonons.This contacting strategy is scalable from a single junction, with the potential to be replicated billions of times on a single substrate. The ability to exploit quantum interference at room temperature will enable new thermoelectric materials and devices with the ability to scavenge energy with unprecedented efficiency. QuIET is a highly interdisciplinary project that brings together internationally leading scientists from four different countries with proven expertise on synthesis, transport measurements and theoretical modelling.
Encapsulation and Covalent Assembly of Nanoparticles Research Project | 1 Project MembersMetal nanoparticles (NPs) are three-dimensional structurally well-defined nanoclusters of around 10-100 atoms, which are best known for their unique size-dependent properties. It has been shown that the properties of a covalent ensemble of a number of NPs are greatly enhanced compared to those of the same number of single components. This, so-called collective, behavior can be useful, once controlled, for constructing NP nanocircuits of electronic devices. To build and study long chains of covalently linked NPs, their encapsulation by two shape- and size-complementary ligands is proposed. A series of bowl-shaped ligands, capable of (1) recognition and (2) covalent encapsulation of spherical NPs, is designed and the synthesis of these ligands is outlined. The ultimate goal is to connect the NP(ligand) 2 building blocks to generate long linear [(ligand)NP(ligand)] n chains and investigate their collective-behavior effect. In addition to standard analytical methods to characterize NPs, high-resolution transmission electron microscopy will be used to provide insight into this unusual phenomenon displayed by covalent NP ensembles. This project is geared towards (1) control over the organization of NPs through their covalent interconnection by chemical means to (2) enhance their electronic properties. The knowledge gained through this investigation can lead to a set of design principles, which can be used in future for making NP-based functional materials. This work can also result in an unprecedented methodology to separate NPs into fractions of extremely low size-distribution.
Synthetische Nanoskalige Objekte - Bausteine von funktionalen Materialien und von Funktionseinheiten Research Project | 1 Project MembersThe proposal follows the future SNF rules of one project per applicant in division II. It is divided in five subprojects, each being the subject of a PhD thesis. Even though these five topics have very different aims, they have in common that current challenges in nano-technology are tackled by bottom-up assembly of functional molecular structures by organic synthesis. The five subprojects are: (I) Helical Oligomers, (II) Molecular Junctions, (III) Electrode Functionalization, (IV) Coated Nanoparticles, and (V) Supramolecular Preorganized Reactants. (I) Helical Oligomers: Molecular rods resembling a "molecular screw" will be developed. They consist of two interlinked oligomers with different spacing of the repeat unit, resulting in the helical wrapping of the longer oligomer around the shorter one which acts as axis. These appealing helical architectures are particular interesting due to their chiroptical properties and as model compounds to investigate molecular racemization mechanisms. (II) Molecular Junction: Molecular rods as functional units of carbon nano-tube (CNT) based molecular junctions will be synthesized. Model compounds enabling single molecule electroluminescence experiments with a central Ir(III) terpy as emitting subunit will be investigated. A molecular turnstile responding on the applied electric field shall be assembled and investigated in CNT-junctions. Interestingly the mechanical switching should be detectable in the junction's transport characteristic. (III) Electrode Functionalization: An electrochemically addressable acetylene protection group shall be developed, enabling to differentiate between electrodes by their electrification. The working principle will be investigated in solution as well as on electrodes by in situ functionalization of the deprotected acetylene groups by alkyne-azide "click" chemistry. (IV) Coated Nanoparticles: As continuation of our studies providing mono-functionalized gold particles in good yields, new motives for thioether based olgomers as multidentate macromolecular ligands shall be investigated. The focus is set on making processible gold nanoparticles with diameters of 2 nm and larger in order to increase their attractiveness for sensing applications based on optical read outs. (V) Supramolecular Preorganized Reactants: Supermolecules are used to spatially arrange molecular building blocks which are subsequently covalently interlinked. Examples of various dimensions are investigated ranging from a small (0-d) caged Fe(II) terpy complex to tune its spin state in transport experiments, over mechanically interlinked daisy chain oligomers (1-d) to interwoven 1-d polymers resembling a "molecular textile" (2-d) which shall be obtained by preorganizing the building blocks in metal organic framework.
Open-Shell Graphene Fragment in a Shell: Stabilization of Fragile Triangulene Core Research Project | 1 Project MembersGraphene fragments made of exclusively carbon and hydrogen atoms are useful molecular models, which aid and abet our understanding of intrinsic phenomena occurring in graphene. The well-defined structure of these fragments allows us to investigate how the desired properties relate to the structure on a small scale first, before moving to extended two-dimensional carbon networks. Chemistry of graphene fragments is well documented in the literature, with the exception of one class of these hydrocarbon molecules, namely, the "open-shell graphene fragments" . Their unique triangular topology breaks the "alternating-double-bond rule" and, as a result, these molecules contain unpaired delocalized electrons. In general, an increase of the fragment size leads to a higher number of unpaired electrons. The main reason for which the open-shell graphene fragments have not been studied to a great extent is the extremely low stability of systems containing unpaired electrons, the so-called free radicals . The majority of reports on open-shell graphene fragments describe derivatives of the smallest fragment, monoradical phenalenyl (three fused benzene rings), and only a few examples mention its larger homolog, diradical triangulene (six fused benzene rings). In fact, only one derivative of triangulene composed of only carbon and hydrogen atoms has been described so far, however, it could only detected under strictly inert conditions and at low temperatures because of its instability. The objective of the proposed research is to synthesize and characterize a persistent derivative of triangulene and validate its triplet ground state in the solid state for the first time. The unpaired electrons in such open-shell systems can, in principle, serve as information carriers and potentially be used in the design of quantum information processing devices.
Polymers Comprising Concave and Chiral Subunits for the Selective Dispersion of Single Walled Carbon Nanotubes (SWCNT) Research Project | 3 Project MembersSingle wall carbon nanotubes are promising materials for future devices due to their outstanding physical properties. In particular their electronic and optical features make them promising functional units in numerous applications. While the correlation between their structure (n,m indices) and physical properties is well understood, their integration into devices and materials suffers from both the poor availability of pure samples and the limited processability of these substances. Within this proposal we strive to develop polymeric structures able to selectively disperse SWCNTs with well defined physical features like electronic properties, diameter, n,m-indices and even chirality. For that purpose concave building blocks with favorable p-stacking interactions with bent SWCNT surfaces shall be developed and integrated in various (co)-polymers. These building blocks will be synthesized as racemates which will be separated into pure enantiomers (by separating the diastereomers obtained from both enantiomers). The approach will thus make (co)-polymers of enantiomerically pure building blocks available. These (co)-polymers will be used to disperse HiPco-SWCNTs and the composition of the dispersion (as well as the polymer SWCNT interaction) will be analyzed by optical methods like UV-vis-nIR absorption , nIR photoluminescence-, and Raman spectroscopy. We also aim at developing a process enabling the reversible coating of SWCNTs by polymers. While the dispersing coating provides perfectly processable tubes, the residual insulating coating effects the interaction of the tube with the substrate upon integration. By profiting from the reversibility of Diels-Alder reactions we design coating polymers which can be thermally decomposed into small building blocks. Thereby we hope to provide coatings providing processability which can be removed after integration of the tube in UHV applications. We will correspondingly investigate the polymers thermal decomposition on the SWCNTs in situ, using both desorption mass spectrometry, Raman microscopy and a variety of surface analytical methods to probe the resulting materials. This will also provide feedback for the optimization of the polymer structure for the purpose of obtaining UHV clean chiral vector selected SWCNT materials for further studies.
Assembly and investigation of electrochemically triggered molecular muscles Research Project | 2 Project MembersMechanically interlinked supramolecular systems are of interest for the design of systems displaying shape alteration/adaption.1 Particular appealing are systems reacting on an external trigger and thus, catenanes and rotaxanes comprising electrochemically addressable subunits have been assembled and displayed redox state dependant mechanical motions.2 Immobilization of the macrocyclic subunits of rotaxanes comprsing two rings on flexible cantilevers even allowed translating the electrochemically triggered molecular motion into the macroscopic bending of the substrate.3 In order to assemble a molecular muscle, Sauvage presented the design concept of a pseudo-rotaxane.4 By attaching the rotaxane axis at the macrocycle's periphery he obtained a system forming a supramolecular dimer in which the axis of one molecule is penetrating the macrocycle of the other. Functionalization of the subunits with different coordination sites allowed altering the expansion of the structure by varying the coordinating ion.
MOLECULAR-SCALE ELECTRONICS: Concepts, Contacts and Stability MOLESCO (Chemistry) Research Project | 1 Project MembersThe MOLESCO network will create a unique training and research environment to develop a pool of young researchers capable of achieving breakthroughs aimed at realising the immense potential of molecular electronics. In part this will involve the major challenges of design and fabrication of molecular-scale devices. To deliver this step-change in capability, MOLESCO will coordinate the activities of internationally-leading scientists from six different countries. MOLESCO has secured the participation of nine private sector partners, including one of Europe's leading industrial electronics-research laboratories (IBM Research-Zurich) as a full partner. A highly-integrated approach to the experimental and theoretical aspects of molecular-scale electronics will deliver the fundamental knowledge and new fabrication strategies needed to underpin future nanotechnologies targeted for electronics applications. MOLESCO represents a highly interdisciplinary and intersectoral collaboration between teams with an extensive portfolio of skills, including molecular synthesis, fabrication of molecular junctions, imaging of molecular junctions with atomic resolution, measurements of charge transport, and electronic structure and transport calculations. Training will be delivered in a series of high-priority actions primarily aimed at providing the researchers with an outstanding career development platform. The network has a strong focus on interdisciplinary training; it is built on several well-established and fruitful collaborations between the partners and seeks to bridge an existing educational gap in the European Research Arena. The development of complementary skills (presentation, management, technology transfer, IP protection, outreach and intersectoral training) will be implemented throughout the lifetime of the project. Specialist professional training in dissemination and outreach will be delivered by our Associate Partner BLP, a professional media production company.
