A concept of chiral, X-type organized π-conjugated oligomers, linked by means of a binaphthalene pincer, is presented. NMR spectroscopy and cyclic and differential pulse voltammetry indicate that these oligomers are in close proximity and influence each other in a through-space manner in their neutral as well as in their oxidized states. The interaction between the oligomers was also confirmed by UV-vis, CD, and emission spectroscopy. The synthetic versatility of this design also enables the development of heterocoupled binaphthalene derivatives BN1-2 and BN1-3, consisting of an electron-neutral oligothiophene or electron-rich oligomer and an electron-poor oligothiazole. Hyper-Rayleigh scattering data show a significant enhancement of the second-order nonlinear hyperpolarizability β for BN1-3 and BN1-2, in contrast with the homocoupled binaphthalene derivatives (BN1-1, BN2-2, and BN3-3). This enhancement provides direct proof for the through-space charge-transfer interaction between the p-type and the n-type oligomers within BN1-3 and BN1-2.
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J Synchrotron Radiat
September 2024
Paul Scherrer Institut, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland.
The ability to freely control the polarization of X-rays enables measurement techniques relying on circular or linear dichroism, which have become indispensable tools for characterizing the properties of chiral molecules or magnetic structures. Therefore, the demand for polarization control in X-ray free-electron lasers is increasing to enable polarization-sensitive dynamical studies on ultrafast time scales. The soft X-ray branch Athos of SwissFEL was designed with the aim of providing freely adjustable and arbitrary polarization by building its undulator solely from modules of the novel Apple X type.
View Article and Find Full Text PDFChemistry
February 2024
Organisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany.
A π-expanded X-type double [5]helicene comprising dihydropyracylene moieties was synthesized from commercially available acenaphthene. X-ray crystallographic analysis revealed the unique highly twisted structure of the compound resulting in the occurrence of two enantiomers which were separated by chiral HPLC, owing to their high conformational stability. The compound shows strongly bathochromically shifted UV/vis absorption and emission bands with small Stokes shift and considerable photoluminescence quantum yield and circular polarized luminescence response.
View Article and Find Full Text PDFMolecules
July 2023
School of Chemistry, South China Normal University, GDMPA Key Laboratory for Process Control and Quality Evaluation of Chiral Pharmaceuticals, Guangzhou Key Laboratory of Analytical Chemistry for Biomedicine, Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, Guangzhou 510006, China.
Organic thioethers play an important role in the discovery of drugs and natural products. However, the green synthesis of organic sulfide compounds remains a challenging task. The convenient and efficient synthesis of 5-alkoxy-3-halo-4-methylthio-2(5)-furanones from DMSO is performed via the mediation of 1,3-dibromo-5,5-dimethylhydantoin (DBDMH), affording a facile route for the sulfur-functionalization of 3,4-dihalo-2(5)-furanones under transition metal-free conditions.
View Article and Find Full Text PDFMolecules
July 2020
School of Chemistry, Trinity Biomedical Sciences Institute, Trinity College Dublin, The University of Dublin, Pearse St, 152-160 Dublin 2, Ireland.
Individual chemical motifs are known to introduce structural distortions to the porphyrin macrocycle, be it in the core or at the periphery of the macrocycle. The interplay when introducing two or more of these known structural motifs has been scarcely explored and is not necessarily simply additive; these structural distortions have a chance to compound or negate to introduce new structural types. To this end, a series of compounds with complementary peripheral (5,15-disubstitution) and core (acidification) substitution patterns were investigated.
View Article and Find Full Text PDFJ Genet
June 2021
Department of Biochemical Engineering, University College London, Bernard Katz Building, London WC1E 6BT, UK.
Transaminases are an industrially important class of enzyme, due to their ability to catalyse amination reactions for production of chiral amines, and are key building blocks of small molecule pharmaceuticals. We analysed the genome of strain GS115 of the methylotrophic yeast , formerly known as , to identify the transaminase genes and propose a systematic nomenclature based on both phylogeny and structuro-functional features. is an increasingly attractive industrial host cell due to its ability to grow to high biomass, up to 60% wet cell weight by volume, using methanol as carbon source and inducer of transgene expression.
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