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Titolo:
Experimental and theoretical studies on the course of CO insertion into Pt-C and Pd-C bonds in neutral and cationic complexes, [MR(Cl){P(CH3)(3)}(2)]and [MR{P(CH3)(3)}(2)(s)]+BF4-, (M = Pt, Pd, R = CH3, C6H5, s = coordinated solvent)
Autore:
Kayaki, Y; Tsukamoto, H; Kaneko, M; Shimizu, I; Yamamoto, A; Tachikawa, M; Nakajima, T;
Indirizzi:
Waseda Univ, Grad Sch Sci & Engn, Dept Appl Chem, Shinjuku Ku, Tokyo 1698552, Japan Waseda Univ Tokyo Japan 1698552 Chem, Shinjuku Ku, Tokyo 1698552, Japan Waseda Univ, Grad Sch Sci & Engn, Adv Res Inst Sci & Engn, Shinjuku Ku, Tokyo 1698552, Japan Waseda Univ Tokyo Japan 1698552 Engn, Shinjuku Ku, Tokyo 1698552, Japan RIKEN, Inst Phys & Chem Res, Wako, Saitama 3510198, Japan RIKEN Wako Saitama Japan 3510198 & Chem Res, Wako, Saitama 3510198, Japan Univ Tokyo, Grad Sch Engn, Dept Appl Chem, Bunkyo Ku, Tokyo 1138656, JapanUniv Tokyo Tokyo Japan 1138656 ppl Chem, Bunkyo Ku, Tokyo 1138656, Japan
Titolo Testata:
JOURNAL OF ORGANOMETALLIC CHEMISTRY
fascicolo: 1-2, volume: 622, anno: 2001,
pagine: 199 - 209
SICI:
0022-328X(20010315)622:1-2<199:EATSOT>2.0.ZU;2-D
Fonte:
ISI
Lingua:
ENG
Soggetto:
BETA-HYDRIDE ELIMINATION; REMARKABLE RATE ENHANCEMENT; CIS-TRANS ISOMERIZATION; CARBONYL-INSERTION; GEOMETRICAL ISOMERIZATION; ORGANOPALLADIUM COMPLEXES; UNCATALYZED CIS; AB-INITIO; ALKYLARYLPLATINUM(II) COMPLEXES; PHENYLPLATINUM(II) COMPLEXES;
Keywords:
CO insertion; cis-trans isomerization; palladium; platinum; monoalkyl complexes; ab initio calculations;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
92
Recensione:
Indirizzi per estratti:
Indirizzo: Yamamoto, A Waseda Univ, Grad Sch Sci & Engn, Dept Appl Chem, Shinjuku Ku,Tokyo 1698552, Japan Waseda Univ Tokyo Japan 1698552 uku Ku, Tokyo 1698552, Japan
Citazione:
Y. Kayaki et al., "Experimental and theoretical studies on the course of CO insertion into Pt-C and Pd-C bonds in neutral and cationic complexes, [MR(Cl){P(CH3)(3)}(2)]and [MR{P(CH3)(3)}(2)(s)]+BF4-, (M = Pt, Pd, R = CH3, C6H5, s = coordinated solvent)", J ORGMET CH, 622(1-2), 2001, pp. 199-209

Abstract

Behavior of neutral and cationic cis- and trans-monoorganoplatinum complexes has been examined and compared with that of the corresponding monoorganopalladium complexes. The cis- and trans-monoorganoplatinum complexes havingtwo trimethylphosphine ligands, [PtR(acetone){P(CH3)(3)}(2)]+BF4- (R = CH3and C6H5) (4 and 5), have been prepared by removal of the chloride ligand in neutral complexes, [PdR(Cl){P(CH3)(3)}(2)] (2 and 3) with one equivalentof AgBF4. The cationic platinum complexes retaining the cis configuration of the parent neutral complexes, when prepared at low temperature, were found to be isomerized into the trans complexes 5 above - 10 degreesC for the methyl complex 5a and above - 30 degreesC for the phenyl complex 5b. Treatment of the cationic complexes 4 and 5 with CO gave no CO insertion product but afforded only the GO-coordinated trans-monoorganoplatinum complexes. The reluctance of the organoplatinum complexes toward CO insertion stands in contrast with the ease for the CO insertion of the corresponding organopalladium complexes. For clarifying the reasons of the marked difference between the behavior of the two Group 10 metal complexes the ab initio molecular orbital calculations with the MP2 level have been performed. We have found the transition states for the cis to trans isomerization of the three-coordinated cationic monoalkylplatinum complexes and for the CO insertion into the Pt-CH3 bond, The calculated barriers for the isomerization and CO insertion in the cationic organoplatinum complex are higher than those for the corresponding organopalladium complex in agreement with the experimental results showing the poor reactivity of the solvent-coordinated cationic organoplatinum complexes toward CO insertion compared to the organopalladium complexes. The reason for the difference in the reactivity between the palladiumand platinum complexes can be ascribed to the relativistic effect of the platinum complexes. (C) 2001 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 19/06/18 alle ore 00:49:24