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51.
Thekku Veedu Sreevidya Gilad Golden Noam Saper Jared Feldman Mark Botoshansky Menahem Kaftory 《Structural chemistry》2011,22(5):1105-1112
Abstract
The preparation and crystal structure of six molecular compounds consist of light-stable host molecules [(1-cyclohexyl-4-hydroxybenzene, 1,1,6,6-tetraphenyl-2,4-hexadiyne-1,6-diol, 4-((10-[4-(ethoxycarbonyl)phenoxy]decyl)oxy)benzene, 1,2,4,5-benzenetetracarboxylic acid, resorcinol] and light-sensitive guest molecules [(5-chloro-2(1H)-pyridone or 5-nitro-2(1H)-pyridone] are described in light of their failure to undergo [4 + 4] photodimerization in the solid-state upon irradiation with UV light. Unlike in many cases were pyridone and its derivatives undergo such dimerization in the solid-state due to the packing arrangement in the crystalline form in which the geometric requirement for photodimerization meet, the compounds described here failed to pack in ways to enable such photodimerization. The distances between the potentially reactive atoms ranged from 4.620 to 8.408 ? which are too long to react. 相似文献52.
MM. D. Letouz J. Duflos G. Queguiner P. Pastour 《Journal of heterocyclic chemistry》1973,10(6):1075-1076
This communication describes the synthesis of 7-one (7H) cyclohepta[b]pyridine and some derivatives (6,8-dimethyl; 8-methyl; 8-ethyl….). These compounds have been obtained by condensation of ketones with 2,3-diformylpyridine. 相似文献
53.
Tamer Andrea Mark Botoshansky Elisheva Genizi Moris S. Eisen 《Journal of organometallic chemistry》2007,692(5):1074-1080
The reaction between the chelating amino bisphenole ligand (ONOO)H2 (1) and (ONNO)H2 (2) with an excess of NaH gives the corresponding bis-sodium salts 3 and 4 quantitatively.The salts were reacted with thorium tetrachloride at room temperature to obtain the corresponding (ONOO)ThCl2 (5) and (ONNO)ThCl2 (6) complexes.However, ThCl4 and UCl4 react with (3) at higher temperatures to give the corresponding isomorphous homoleptic complexes (ONOO)2Th (7) and (ONOO)2U (8).We have also synthesized and characterized a thorium salicylaldiminato complex L3ThCl (11) , in order to study the effect of the bridged ligand on the molecular structure. 相似文献
54.
Boaz Turner Mark Botoshansky Yoav Eichen 《Angewandte Chemie (International ed. in English)》1998,37(18):2475-2478
A 1,3,5- alternate conformation of the pyrrole rings is adopted by the calix[6]pyrrole 1 in the crystal (see picture). Compound 1 was synthesized in a two-step process and although it crystallizes in the form of the adduct 1 ⋅3CH3COCH3⋅H2O⋅CHCl3, there are no solvent molecules in the cavity (cross section ca. 60Å2) of this macrocycle which possesses alternating dimethyl and diphenyl substitutents at the meso positions. 相似文献
55.
Wang J Gurevich Y Botoshansky M Eisen MS 《Journal of the American Chemical Society》2006,128(29):9350-9351
The tetrachloride salt of uranium reacts with 1 equiv of the lithium ligand Li2[(C5Me4)2SiMe2] in DME to form the complex [eta5-(C5Me4)2SiMe2]UCl2.2LiCl.2DME (1), which undergoes a rapid hydrolysis in toluene to yield the dimeric bridged monochloride, monooxide complex [{[eta5-(C5Me4)2SiMe2]UCl}2(mu-O)(mu-Cl)*Li*1/2DME]2 (2). Metathesis of 2 with BuLi in DME gives the mono-bridged dibutyl complex {[eta5-(C5Me4)2SiMe2]UBu}2(mu-O) (3). Complex 2 was characterized by solid-state X-ray analysis. Complex 3 was found to be an active catalyst for the disproportionation metathesis of TMSCCH (TMS = SiMe3) and the cross-metathesis of TMSCCH or TMSCCTMS with various terminal alkynes. The metathesis of TMSCCH gives TMSCCTMS and HCCH, whereas the cross-metathesis of TMSCCH or TMSCCTMS with terminal alkynes (RCCH) yields TMSCCTMS, TMSCCR, and HCCH. In addition, TMSCCCH3 also was found to react with tBuCCH, yielding TMSCCBut and CH3CCH. A plausible mechanism for the catalytic process is presented. 相似文献
56.
Dr. Yuri Tulchinsky Dr. Sebastian Kozuch Dr. Prasenjit Saha Assaf Mauda Dr. Gennady Nisnevich Dr. Mark Botoshansky Dr. Linda J. W. Shimon Prof. Mark Gandelman 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(19):7099-7110
Comprehensive studies on the coordination properties of tridentate nitrenium‐based ligands are presented. N‐heterocyclic nitrenium ions demonstrate general and versatile binding abilities to various transition metals, as exemplified by the synthesis and characterization of RhI, RhIII, Mo0, Ru0, RuII, PdII, PtII, PtIV, and AgI complexes based on these unusual ligands. Formation of nitrenium–metal bonds is unambiguously confirmed both in solution by selective 15N‐labeling experiments and in the solid state by X‐ray crystallography. The generality of N‐heterocyclic nitrenium as a ligand is also validated by a systematic DFT study of its affinity towards all second‐row transition and post‐transition metals (Y–Cd) in terms of the corresponding bond‐dissociation energies. 相似文献
57.
58.
The objective of this study was to determine if topical anesthesia to the larynx and pharynx affects vocal fold motion during dynamic voice evaluation with transnasal flexible endoscopy. Transnasal dynamic laryngeal examinations of 10 patients with no voice complaints were evaluated by five blinded fellowship-trained laryngologists. Each patient was examined before and after application of topical anesthetic. Reviewers rated briskness of right and left vocal fold movement and longitudinal tension on a visual analogue scale. Statistical comparisons were made between individual subject scores before and after anesthetic application. Inter-rater reliability was also assessed. No statistical difference was observed between subject scores before and after anesthetic application. Average intraclass correlation coefficients were 0.643 and 0.591 for pre- and postanesthesia scores, respectively. Application of topical anesthesia to the larynx and pharynx does not affect vocal fold motion. 相似文献
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