School of Chemistry - Research Publications
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ItemA photo-switchable molecular capsule: sequential photoinduced processes(ROYAL SOC CHEMISTRY, 2022-11-30)The metastable trilacunary heteropolyoxomolybdate [PMo9O31(py)3]3- - {PMo9}; py = pyridine) and the ditopic pyridyl bearing diarylethene (DAE) (C25H16N2F6S2) self-assemble via a facile ligand replacement methodology to yield the photo-active molecular capsule [(PMo9O31)2(DAE)3]6-. The spatial arrangement and conformation of the three DAE ligands are directed by the surface chemistry of the molecular metal oxide precursor with exclusive ligation of the photo-active antiparallel rotamer to the polyoxometalate (POM) while the integrity of the assembly in solution has been verified by a suite of spectroscopic techniques. Electrocyclisation of the three DAEs occurs sequentially and has been investigated using a combination of steady-state and time-resolved spectroscopies with the discovery of a photochemical cascade whereby rapid photoinduced ring closure is followed by electron transfer from the ring-closed DAE to the POM in the latent donor-acceptor system on subsequent excitation. This interpretation is also supported by computational and detailed spectroelectrochemical analysis. Ring-closing quantum yields were also determined using a custom quantum yield determination setup (QYDS), providing insight into the impact of POM coordination on these processes.
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ItemHoch fluoreszierende Pyridiniumbetaine für die Lichtsammlung(Wiley, 2017-10-23)Abstract Die Ergebnisse experimenteller und theoretischer Untersuchungen der Eigenschaften von Pyridiniumenolaten werden vorgestellt, und ihre potenzielle Nutzbarkeit in Lichtsammelanwendungen, insbesondere lumineszierenden Solarkonzentratoren (LSCs), wird demonstriert. Synthesen, Strukturen, photophysikalische Charakterisierung und wellenfunktionsbasierte quantenchemische Studien für fünf Cyclobetaine werden präsentiert und die Leistungsfähigkeit einer LSC‐Apparatur, die eines dieser Cyclobetaine enthält, wird mit dem aktuellen Stand der Technik verglichen.
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ItemHighly Fluorescent Pyridinium Betaines for Light Harvesting(WILEY-V C H VERLAG GMBH, 2017-10-23)We report the findings of our experimental and theoretical investigations into the properties of pyridinium enolates and their potential utility in light-harvesting applications, such as in luminescent solar concentrators (LSCs). We present the synthesis, structures, photophysical characterization, and wavefunction-based quantum-chemical studies of five cyclobetaines. The performance of an LSC device incorporating one of these cyclobetaines is shown to be comparable to state-of-the-art devices.
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ItemNichtwässrige mikrowellengestützte Synthesen von Deca‐ und Hexamolybdovanadaten(Wiley, 2017-07-10)Abstract Ein neuer Ansatz zur Synthese von Heterohexa‐ und Heterodecametallaten unter nichtwässrigen, mikrowellengestützten Reaktionsbedingungen wurde entwickelt. Die zwei neuartigen Molybdovanadate wurden isoliert und im festen sowie gelösten Zustand mittels Einkristall‐Röntgenbeugung, FT‐IR‐, UV/Vis‐ und multinuklearer NMR‐Spektroskopie sowie ESI‐MS charakterisiert. Die relativen Stabilitäten der möglichen Strukturisomere beider Polyoxometallatsysteme wurden mithilfe von dispersionskorrigierten DFT‐Rechnungen untersucht.
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ItemNon-Aqueous Microwave-Assisted Syntheses of Deca- and Hexa-Molybdovanadates(Wiley, 2017-07-10)We report a new approach for the synthesis of heterohexa‐ and heterodecametalates via the use of non‐aqueous, microwave‐assisted reaction conditions. The two novel molybdovanadates have been isolated and characterized in the solid and solution states using single‐crystal X‐ray diffraction, FT‐IR, UV/Vis, multinuclear NMR spectroscopy, and ESI‐MS. The relative stabilities of the possible structural isomers were probed using dispersion‐corrected DFT calculations for both polyoxometalate systems.
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ItemNo Preview AvailableA Heteroaromatically Functionalized Hexamolybdate(MDPI - Open Access Publishing, 2015-05-08)A new heteroaromatic thiophene containing organoimido functionalized hexamolybdate has been synthesized and characterized in both solid form and solution. Structural analysis shows successful introduction of the organoimido ligand through replacement of one terminal oxo site on [Mo6O19]2− to yield the singly functionalized hexamolybdate. Spectroscopic and theoretical analysis indicates charge transfer between the inorganic and organic components, with a significantly red-shifted lowest lying transition of 399 nm vs. the parent Lindqvist ion of 325 nm. Additional characterization includes, thermal gravimetric analysis (TGA), infrared (IR), cyclic voltammetry (CV), nuclear magnetic resonance (NMR) and time-dependent density functional theory (TD-DFT) studies.