The bis(tosylimido)osmium(VI) porphyrins [Os(VI)(Por)(NTs)(2)] [Por = tetraphenylporphyrinato (TPP), meso-tetrakis(p-tolyl)porphyrinato (TTP), meso-tetrakis(4-chlorophenyl)porphyrinato (4-Cl-TPP), meso-tetrakis(4-methoxyphenyl)porphyrinato (4-MeO-TPP); Ts = tosyl] were prepared from the reactions of [Os(II)(Por)(CO)(MeOH)] with excess PhI=NTs in dichloromethane. The X-ray crystal structure of [Os(VI)(TPP)(NTs)(2)] has been determined. Crystal data for [Os(VI)(TPP)(NTs)(2)]: triclinic, space group P&onemacr; (No. 2), a = 10.836(3) Å, b = 12.067(4) Å, c = 19.647(6) Å, alpha = 94.05(3) degrees, beta = 93.88(3) degrees, gamma = 104.65(3) degrees, V = 2469(1) Å(3), Z = 2, R (R(w)) = 0.030 (0.038), goodness-of-fit = 1.19. The mean Os=NTs distance is 1.800 Å. The Os-N-S angles average 155.8 degrees. Reaction of [Os(VI)(TPP)(NTs)(2)] with triphenylphosphine gives Ph(3)P=NTs and [Os(II)(TPP)(PPh(3))(2)].
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http://dx.doi.org/10.1021/ic980256u | DOI Listing |
Nat Microbiol
January 2025
Department of Molecular Microbiology, John Innes Centre, Norwich, UK.
Examples of long-range gene regulation in bacteria are rare and generally thought to involve DNA looping. Here, using a combination of biophysical approaches including X-ray crystallography and single-molecule analysis for the KorB-KorA system in Escherichia coli, we show that long-range gene silencing on the plasmid RK2, a source of multi-drug resistance across diverse Gram-negative bacteria, is achieved cooperatively by a DNA-sliding clamp, KorB, and a clamp-locking protein, KorA. We show that KorB is a CTPase clamp that can entrap and slide along DNA to reach distal target promoters up to 1.
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January 2025
Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, PR China. Electronic address:
Chemical investigation on the secondary metabolites of Aspergillus aculeatus led to the identification of ten modified fusicoccane-type diterpenoids aculeanoids A-J (1-10). Their structures and absolute configurations were characterized by comprehensive spectroscopic analysis, DP4+ analysis, Mo(OAc)-induced ECD, single-crystal X-ray diffractions, and ECD calculations. Compounds 1-4 belong to a rare class of 17-nor fusicoccane diterpenoids, with only one previously reported example.
View Article and Find Full Text PDFInorg Chem
January 2025
Department of Materials Chemistry, Faculty of Engineering, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553, Japan.
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View Article and Find Full Text PDFChemistry
January 2025
Indian Institute of Technology Madras, Department of Chemistry, Chennai, Chennai, INDIA.
A series of significantly bulky mono- and di-substituted cyclic alkyl-amino carbene (cAAC)- functionalized cyclopentadiene ring (Cp) compounds were synthesized. The functionalization of the Cp ring with cAAC ligands makes them significantly bulkier, while retaining their ligation properties. These compounds display interesting fluorescence properties.
View Article and Find Full Text PDFActa Crystallogr C Struct Chem
February 2025
Institute of Applied Chemistry, Shanxi University, Wucheng, Taiyuan, Shanxi 030006, People's Republic of China.
Three bisferrocene-based bis(acylthiourea) positional isomers, namely, 1,2-bis(ferrocenylcarbonylthioureido)benzene (1), 1,3-bis(ferrocenylcarbonylthioureido)benzene (2) and 1,4-bis(ferrocenylcarbonylthioureido)benzene (3), all [Fe(CH)(CHNOS)], have been synthesized via facile nucleophilic addition reactions of 2.3 equivalents of ferrocenoyl isothiocyanate with o-, m- and p-phenylenediamine, respectively. The structures of the three new synthesized isomers were fully characterized by H NMR, C NMR, IR and UV-Vis spectroscopy, elemental analyses and cyclic voltammetry.
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