We study the properties of photoinduced metal-nitrosyl linkage isomers in sodium nitroprusside (SNP) as a function of particle size. By embedding the molecular complex at various concentrations into mesopores of silica xerogels the size of the particles can be adjusted. The ground state is characterized by X-ray diffraction, absorption and infrared spectroscopy. The physical properties of the photoswitched molecules were analysed by steady-state low-temperature absorption, infrared spectroscopy and by nanosecond transient absorption spectroscopy. The electronic structure as well as the activation energies of the metastable linkage isomers are independent of the particle size down to single isolated molecules, indicating that the SNP complexes are quasi-free inside the pores of the gel.
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http://dx.doi.org/10.1039/c2cp23607a | DOI Listing |
Dalton Trans
December 2024
Inorganic Chemistry I, Ruhr-Universität Bochum, Universitätsstraße 150, 44801 Bochum, Germany.
In biological systems, nitrite reductase enzymes (NIRs) are responsible for reduction of nitrite (NO) to nitric oxide (NO). These NIRs have mostly Cu- or Fe-containing active sites, surrounded by amine-containing ligands. Therefore, mononuclear Cu complexes with N-donor ligands are highly relevant in the development of NIR model systems and in the mechanistic investigation of the nitrite reduction reaction.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States.
A monocationic dicopper(I,I) nitrite complex [Cu(μ-κ:κ-ON)DPFN][NTf] () (DPFN = 2,7-bis(fluoro-di(2-pyridyl)methyl)-1,8-naphthyridine, NTf = N(SOCF)), was synthesized by treatment of a dicopper acetonitrile complex, [Cu(μ-MeCN)DPFN][NTf] (), with tetrabutylammonium nitrite ([BuN][NO]). DFT calculations indicate that is one of three linkage isomers that are close in energy and presumably accessible in solution. Reaction of the μ-κ:κ-ON complex with -TolSH produces nitrous acid (HONO) and the corresponding dicopper thiolate species via an acid-base exchange reaction.
View Article and Find Full Text PDFJ Agric Food Chem
December 2024
College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, China.
Rebaudioside M2 (RebM2) is characterized as 13-[(2--β-d-glucopyranosyl-3--β-d-glucopyranosyl-β-d-glucopyranosyl)oxy] ent-kaur-16-en-19-oic acid-[(2--β-d-glucopyranosyl-6--β-d-glucopyranosyl-β-d-glucopyranosyl) ester], an isomer of rebaudioside M with a 1 → 6 sugar linkage. The product was found in the biotransformation of rebaudioside D (RebD) catalyzed by a glycosyltransferase from (UGT). Herein, guided by consensus engineering and molecular dynamics simulations, a variant UGT with enhanced activity and thermostability was obtained.
View Article and Find Full Text PDFChem Sci
December 2024
Applied Chemistry Program, Graduate School of Advanced Science and Engineering, Hiroshima University 1-4-1 Kagamiyama Higashihiroshima 739-8527 Japan
Chem Sci
December 2024
Department of Chemistry, Indian Institute of Technology Ropar Rupnagar 140001 Punjab India
Nakano reported that the antiaromatic indenofluorene (IF) isomers are diradicaloid molecules having varying degrees of open-shell character, with indeno[1,2-]fluorene displaying a weaker diradical character index ( = 0.072). Unlike 6,12-trimethylsilylethynyl disubstituted [1,2-]IF, the 6,12-aryl disubstituted [1,2-]IF derivatives did not show any experimental evidence of diradical properties.
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