Prof. Dr. Marcel Mayor Department of Chemistry Profiles & Affiliations OverviewResearch Publications Projects & Collaborations Projects & Collaborations OverviewResearch Publications Projects & Collaborations Profiles & Affiliations Projects & Collaborations 29 foundShow per page10 10 20 50 ELUQUINT: Exploring the Limits of Universal Quantum Interferometry Research Project | 2 Project MembersNo Description available 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. 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. NCCR Molecular Systems Engineering - phase 2 Research Project | 30 Project MembersMolecular Systems Engineering is a National Centre of Competence in Research (NCCR) funded by the Swiss National Science Foundation (SNSF), and headed by the University of Basel and the ETH Zurich. This NCCR combines expertise from chemistry, biology, physics, bioinformatics, and engineering. The overreaching aim is to develop tools and devices to monitor and manipulate off-equilibrium (bio)chemical systems. These may find applications in the synthesis of high added-value products, as innovative diagnostic tools and for the restoration of a desired cellular or organ function. Synthetic Nanoscale Objects: Building Blocks for Functional Materials and Devices Research Project | 10 Project MembersThe proposal follows the 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 PhD projects are very different in their aims, they have in common that they address current challenges in nano-technology, supramolecular chemistry, and material science, which are addressed by molecular approaches with tailor-made functional structures. The five subprojects are: (I) "Geländer-type" helical structures and (II) macrocyclic model compounds for molecular junctions, (III) giant conjugated graphene belts geared towards molecule based magnetization experiments. Pre-organized reactants for the assembly of (IV) 2D polymers and molecular fabrics and of (V) optically active nanoscale hybrid architectures.(I) "Geländer-type" helical structures consist of an oligophenylene-axis around which a longer oligomer is helically wrapped, resembling the shape of the banister (Geländer in German) of a helical staircase. The next generation of this appealing molecular design concept is geared towards derivatives with conjugated helical "Geländer", which not only is expected to improve their optical features, but also should enable the assembly of model compounds acting as coil-like molecular wires. (II) macrocyclic model compounds for molecular junctions is focused on model compounds for transport experiments in magnetic fields. A molecular loop of considerable dimension shall increase the influence of the magnetic field on the charge carriers and a variety of rod-like metal complexes shall provide insight into the interplay of the magnetic field with the electronic configuration of the central metal ion. (III) giant conjugated graphene belts are expected to have interesting magnetic properties. These molecular analogues of lithographically fabricated nano-scaled metallic structures shall be assembled by combining macrocyclization approaches from acetylene scaffolding strategies with current chemistry geared towards graphen ribbons. The approach might even make Möbius-shaped graphene belts accessible.(IV) 2D polymers and molecular fabrics shall be obtained by profiting from the perfectly pre-organized arrangement of the molecular building blocks in MOF layers. In a second, alternative approach the organization and intermolecular coupling chemistry at the air/water interface of tailor-made heteroleptic Fe(tpy)2 complexes shall make molecular fabrics available.(V) optically active nanoscale hybrid architectures based on our preliminary findings providing mono-functionalized gold nanoparticles in good yields but of too small dimensions to interact with visible light, a new strategy enabling larger particles by the chemically controlled merging shall be developed. 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. Switching optical antennas via supramolecular translation Research Project | 2 Project MembersOptical antennas are able to efficiently link propagating light fields and nanolocalized excitations and are therefore ideally suited to bridge the gap between the macroscopic world and nanoscopic entities such as individual molecules placed inside the antenna feed gap. Recently, the toolbox of optical antennas has been enriched by the possibility to apply voltages to the antenna via electrical connectors which allows to generate enormous DC electric fields across the antenna gap. Here we propose to realize two-color switchable optical antennas representing reconfigurable functional nanodevices by making use of electric-field induced supramolecular translations, i.e. the nanomechanical motion of ring-like moieties on rod-like molecules (Rotaxanes) placed in the antenna feedgap. Electrically-induced supramolecular translation of the ring moiety will cause selective quenching of one of up to two chromophores whereby its coupling to the antenna resonance will be suppressed. In the final configuration light emission shall even be electrically excited via inelastic electron tunneling and switched via the polarity of the applied voltage. High-end X-ray diffraction instrumentation for chemical crystallography Research Project | 7 Project MembersThe determination of the three-dimensional structure of molecules using X-ray diffraction is an invaluable tool of modern chemical research. The prerequisite of such investigations is always the availability of a suitable single crystal. Very high brilliance of the primary X-ray beam in conjunction with an outstanding detector system is the solution in the case where the single crystals obtained are of good quality, but too small for successful structure determination using a conventional X-ray source. The brand new Ga-Metaljet X-ray generator offers a primary beam that is about one order of magnitude more intense than all other X-ray sources that are currently available on the market for laboratory use. The main benefit of this instrument is, that it combines a completely new and innovative setup to produce the X-rays with the well established multilayer optics which results in an extremely intense illumination of very small samples. The anode of this generator consists of a jet of liquid metal inhibiting the problem of the anode melting at higher loads of energy. Together with the single photon counting detectors produced by Dectris in Baden, Switzerland, which market their products under the brand names Pilatus and Eiger, this setup offers the most advanced X-ray detection technology available today. This new solution opens the way for many experiments to be run successfully in house, from small molecule work to macromolecular structures. It is in particular very well suited for small crystals of organic molecules. Its wavelength that is slightly shorter than the wavelength obtained from a Cu-anode makes it possible to collect more data, while the spot separation for long unit cell axes is still ways better than with Mo-radiation. In the following pages it will be demonstrated how this new device increases the possibilities of the investigation and elucidation of the structure of samples for which it would not be possible to measure them successfully using a standard laboratory X-ray source. 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. Picosecond Transient Absorption Setup for Detection of Short-Lived Photoproducts and Excited States in Molecular Systems Research Project | 6 Project MembersMany photophysical and photochemical processes which are relevant for light-to-chemical energy conversion occur on very rapid timescales. Time-resolved UV-Vis absorption spectroscopy has become an indispensable tool in modern photochemistry. Several ongoing Ph. D. theses and postdoctoral research projects in the main applicant's group ask for a transient absorption spectrometer with picosecond time resolution and an appropriate laser source. Among these projects are for example the investigation of photoinduced multi-electron transfer reactions in order to spatially separate multiple electrons from multiple holes, which is of key importance for producing chemical fuels with sunlight as energy input (projects 1 and 2). Similarly, picosecond transient absorption spectrosocopy will permit mechanistic studies of photoinduced proton-coupled electron transfer (PCET) reactions which will greatly further our current fundamental understanding of this important class of reactions (project 3). The activation of small inert molecules such as H 2 O, CO 2 or N 2 will invariably rely on multi-electron, multi-proton chemistry hence the proposed photochemical studies are important in the greater context of solar energy conversion. 123 123 OverviewResearch Publications Projects & Collaborations
Projects & Collaborations 29 foundShow per page10 10 20 50 ELUQUINT: Exploring the Limits of Universal Quantum Interferometry Research Project | 2 Project MembersNo Description available 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. 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. NCCR Molecular Systems Engineering - phase 2 Research Project | 30 Project MembersMolecular Systems Engineering is a National Centre of Competence in Research (NCCR) funded by the Swiss National Science Foundation (SNSF), and headed by the University of Basel and the ETH Zurich. This NCCR combines expertise from chemistry, biology, physics, bioinformatics, and engineering. The overreaching aim is to develop tools and devices to monitor and manipulate off-equilibrium (bio)chemical systems. These may find applications in the synthesis of high added-value products, as innovative diagnostic tools and for the restoration of a desired cellular or organ function. Synthetic Nanoscale Objects: Building Blocks for Functional Materials and Devices Research Project | 10 Project MembersThe proposal follows the 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 PhD projects are very different in their aims, they have in common that they address current challenges in nano-technology, supramolecular chemistry, and material science, which are addressed by molecular approaches with tailor-made functional structures. The five subprojects are: (I) "Geländer-type" helical structures and (II) macrocyclic model compounds for molecular junctions, (III) giant conjugated graphene belts geared towards molecule based magnetization experiments. Pre-organized reactants for the assembly of (IV) 2D polymers and molecular fabrics and of (V) optically active nanoscale hybrid architectures.(I) "Geländer-type" helical structures consist of an oligophenylene-axis around which a longer oligomer is helically wrapped, resembling the shape of the banister (Geländer in German) of a helical staircase. The next generation of this appealing molecular design concept is geared towards derivatives with conjugated helical "Geländer", which not only is expected to improve their optical features, but also should enable the assembly of model compounds acting as coil-like molecular wires. (II) macrocyclic model compounds for molecular junctions is focused on model compounds for transport experiments in magnetic fields. A molecular loop of considerable dimension shall increase the influence of the magnetic field on the charge carriers and a variety of rod-like metal complexes shall provide insight into the interplay of the magnetic field with the electronic configuration of the central metal ion. (III) giant conjugated graphene belts are expected to have interesting magnetic properties. These molecular analogues of lithographically fabricated nano-scaled metallic structures shall be assembled by combining macrocyclization approaches from acetylene scaffolding strategies with current chemistry geared towards graphen ribbons. The approach might even make Möbius-shaped graphene belts accessible.(IV) 2D polymers and molecular fabrics shall be obtained by profiting from the perfectly pre-organized arrangement of the molecular building blocks in MOF layers. In a second, alternative approach the organization and intermolecular coupling chemistry at the air/water interface of tailor-made heteroleptic Fe(tpy)2 complexes shall make molecular fabrics available.(V) optically active nanoscale hybrid architectures based on our preliminary findings providing mono-functionalized gold nanoparticles in good yields but of too small dimensions to interact with visible light, a new strategy enabling larger particles by the chemically controlled merging shall be developed. 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. Switching optical antennas via supramolecular translation Research Project | 2 Project MembersOptical antennas are able to efficiently link propagating light fields and nanolocalized excitations and are therefore ideally suited to bridge the gap between the macroscopic world and nanoscopic entities such as individual molecules placed inside the antenna feed gap. Recently, the toolbox of optical antennas has been enriched by the possibility to apply voltages to the antenna via electrical connectors which allows to generate enormous DC electric fields across the antenna gap. Here we propose to realize two-color switchable optical antennas representing reconfigurable functional nanodevices by making use of electric-field induced supramolecular translations, i.e. the nanomechanical motion of ring-like moieties on rod-like molecules (Rotaxanes) placed in the antenna feedgap. Electrically-induced supramolecular translation of the ring moiety will cause selective quenching of one of up to two chromophores whereby its coupling to the antenna resonance will be suppressed. In the final configuration light emission shall even be electrically excited via inelastic electron tunneling and switched via the polarity of the applied voltage. High-end X-ray diffraction instrumentation for chemical crystallography Research Project | 7 Project MembersThe determination of the three-dimensional structure of molecules using X-ray diffraction is an invaluable tool of modern chemical research. The prerequisite of such investigations is always the availability of a suitable single crystal. Very high brilliance of the primary X-ray beam in conjunction with an outstanding detector system is the solution in the case where the single crystals obtained are of good quality, but too small for successful structure determination using a conventional X-ray source. The brand new Ga-Metaljet X-ray generator offers a primary beam that is about one order of magnitude more intense than all other X-ray sources that are currently available on the market for laboratory use. The main benefit of this instrument is, that it combines a completely new and innovative setup to produce the X-rays with the well established multilayer optics which results in an extremely intense illumination of very small samples. The anode of this generator consists of a jet of liquid metal inhibiting the problem of the anode melting at higher loads of energy. Together with the single photon counting detectors produced by Dectris in Baden, Switzerland, which market their products under the brand names Pilatus and Eiger, this setup offers the most advanced X-ray detection technology available today. This new solution opens the way for many experiments to be run successfully in house, from small molecule work to macromolecular structures. It is in particular very well suited for small crystals of organic molecules. Its wavelength that is slightly shorter than the wavelength obtained from a Cu-anode makes it possible to collect more data, while the spot separation for long unit cell axes is still ways better than with Mo-radiation. In the following pages it will be demonstrated how this new device increases the possibilities of the investigation and elucidation of the structure of samples for which it would not be possible to measure them successfully using a standard laboratory X-ray source. 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. Picosecond Transient Absorption Setup for Detection of Short-Lived Photoproducts and Excited States in Molecular Systems Research Project | 6 Project MembersMany photophysical and photochemical processes which are relevant for light-to-chemical energy conversion occur on very rapid timescales. Time-resolved UV-Vis absorption spectroscopy has become an indispensable tool in modern photochemistry. Several ongoing Ph. D. theses and postdoctoral research projects in the main applicant's group ask for a transient absorption spectrometer with picosecond time resolution and an appropriate laser source. Among these projects are for example the investigation of photoinduced multi-electron transfer reactions in order to spatially separate multiple electrons from multiple holes, which is of key importance for producing chemical fuels with sunlight as energy input (projects 1 and 2). Similarly, picosecond transient absorption spectrosocopy will permit mechanistic studies of photoinduced proton-coupled electron transfer (PCET) reactions which will greatly further our current fundamental understanding of this important class of reactions (project 3). The activation of small inert molecules such as H 2 O, CO 2 or N 2 will invariably rely on multi-electron, multi-proton chemistry hence the proposed photochemical studies are important in the greater context of solar energy conversion. 123 123
ELUQUINT: Exploring the Limits of Universal Quantum Interferometry Research Project | 2 Project MembersNo Description available
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.
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.
NCCR Molecular Systems Engineering - phase 2 Research Project | 30 Project MembersMolecular Systems Engineering is a National Centre of Competence in Research (NCCR) funded by the Swiss National Science Foundation (SNSF), and headed by the University of Basel and the ETH Zurich. This NCCR combines expertise from chemistry, biology, physics, bioinformatics, and engineering. The overreaching aim is to develop tools and devices to monitor and manipulate off-equilibrium (bio)chemical systems. These may find applications in the synthesis of high added-value products, as innovative diagnostic tools and for the restoration of a desired cellular or organ function.
Synthetic Nanoscale Objects: Building Blocks for Functional Materials and Devices Research Project | 10 Project MembersThe proposal follows the 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 PhD projects are very different in their aims, they have in common that they address current challenges in nano-technology, supramolecular chemistry, and material science, which are addressed by molecular approaches with tailor-made functional structures. The five subprojects are: (I) "Geländer-type" helical structures and (II) macrocyclic model compounds for molecular junctions, (III) giant conjugated graphene belts geared towards molecule based magnetization experiments. Pre-organized reactants for the assembly of (IV) 2D polymers and molecular fabrics and of (V) optically active nanoscale hybrid architectures.(I) "Geländer-type" helical structures consist of an oligophenylene-axis around which a longer oligomer is helically wrapped, resembling the shape of the banister (Geländer in German) of a helical staircase. The next generation of this appealing molecular design concept is geared towards derivatives with conjugated helical "Geländer", which not only is expected to improve their optical features, but also should enable the assembly of model compounds acting as coil-like molecular wires. (II) macrocyclic model compounds for molecular junctions is focused on model compounds for transport experiments in magnetic fields. A molecular loop of considerable dimension shall increase the influence of the magnetic field on the charge carriers and a variety of rod-like metal complexes shall provide insight into the interplay of the magnetic field with the electronic configuration of the central metal ion. (III) giant conjugated graphene belts are expected to have interesting magnetic properties. These molecular analogues of lithographically fabricated nano-scaled metallic structures shall be assembled by combining macrocyclization approaches from acetylene scaffolding strategies with current chemistry geared towards graphen ribbons. The approach might even make Möbius-shaped graphene belts accessible.(IV) 2D polymers and molecular fabrics shall be obtained by profiting from the perfectly pre-organized arrangement of the molecular building blocks in MOF layers. In a second, alternative approach the organization and intermolecular coupling chemistry at the air/water interface of tailor-made heteroleptic Fe(tpy)2 complexes shall make molecular fabrics available.(V) optically active nanoscale hybrid architectures based on our preliminary findings providing mono-functionalized gold nanoparticles in good yields but of too small dimensions to interact with visible light, a new strategy enabling larger particles by the chemically controlled merging shall be developed.
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.
Switching optical antennas via supramolecular translation Research Project | 2 Project MembersOptical antennas are able to efficiently link propagating light fields and nanolocalized excitations and are therefore ideally suited to bridge the gap between the macroscopic world and nanoscopic entities such as individual molecules placed inside the antenna feed gap. Recently, the toolbox of optical antennas has been enriched by the possibility to apply voltages to the antenna via electrical connectors which allows to generate enormous DC electric fields across the antenna gap. Here we propose to realize two-color switchable optical antennas representing reconfigurable functional nanodevices by making use of electric-field induced supramolecular translations, i.e. the nanomechanical motion of ring-like moieties on rod-like molecules (Rotaxanes) placed in the antenna feedgap. Electrically-induced supramolecular translation of the ring moiety will cause selective quenching of one of up to two chromophores whereby its coupling to the antenna resonance will be suppressed. In the final configuration light emission shall even be electrically excited via inelastic electron tunneling and switched via the polarity of the applied voltage.
High-end X-ray diffraction instrumentation for chemical crystallography Research Project | 7 Project MembersThe determination of the three-dimensional structure of molecules using X-ray diffraction is an invaluable tool of modern chemical research. The prerequisite of such investigations is always the availability of a suitable single crystal. Very high brilliance of the primary X-ray beam in conjunction with an outstanding detector system is the solution in the case where the single crystals obtained are of good quality, but too small for successful structure determination using a conventional X-ray source. The brand new Ga-Metaljet X-ray generator offers a primary beam that is about one order of magnitude more intense than all other X-ray sources that are currently available on the market for laboratory use. The main benefit of this instrument is, that it combines a completely new and innovative setup to produce the X-rays with the well established multilayer optics which results in an extremely intense illumination of very small samples. The anode of this generator consists of a jet of liquid metal inhibiting the problem of the anode melting at higher loads of energy. Together with the single photon counting detectors produced by Dectris in Baden, Switzerland, which market their products under the brand names Pilatus and Eiger, this setup offers the most advanced X-ray detection technology available today. This new solution opens the way for many experiments to be run successfully in house, from small molecule work to macromolecular structures. It is in particular very well suited for small crystals of organic molecules. Its wavelength that is slightly shorter than the wavelength obtained from a Cu-anode makes it possible to collect more data, while the spot separation for long unit cell axes is still ways better than with Mo-radiation. In the following pages it will be demonstrated how this new device increases the possibilities of the investigation and elucidation of the structure of samples for which it would not be possible to measure them successfully using a standard laboratory X-ray source.
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.
Picosecond Transient Absorption Setup for Detection of Short-Lived Photoproducts and Excited States in Molecular Systems Research Project | 6 Project MembersMany photophysical and photochemical processes which are relevant for light-to-chemical energy conversion occur on very rapid timescales. Time-resolved UV-Vis absorption spectroscopy has become an indispensable tool in modern photochemistry. Several ongoing Ph. D. theses and postdoctoral research projects in the main applicant's group ask for a transient absorption spectrometer with picosecond time resolution and an appropriate laser source. Among these projects are for example the investigation of photoinduced multi-electron transfer reactions in order to spatially separate multiple electrons from multiple holes, which is of key importance for producing chemical fuels with sunlight as energy input (projects 1 and 2). Similarly, picosecond transient absorption spectrosocopy will permit mechanistic studies of photoinduced proton-coupled electron transfer (PCET) reactions which will greatly further our current fundamental understanding of this important class of reactions (project 3). The activation of small inert molecules such as H 2 O, CO 2 or N 2 will invariably rely on multi-electron, multi-proton chemistry hence the proposed photochemical studies are important in the greater context of solar energy conversion.
