Axially asymmetric metal alkyls. Part 3. Chemical, electrochemical, and structural studies of group 5A d0,1,2 metallepines [M{(2-CH2C6H4)2}(η-C 5H5)2]z (M = Nb or Ta; z = 1-, 0, or 1+): synthesis of [Nb{2-CH2(C6H4) 2Me-2′}X-(η-C5H5)2] (X = Cl or CO) and [{(η-C5H5)2ClV}2{(2-CH 2C6H4)2}], and electrochemistry of [M(CH2Ph)2-nCln(η-C5H 5)2] (n = 0, M = Nb, or Ta; n = 1, M = V)synthesis of [Nb{2-CH2(C6H4) 2Me-2′}X-(η-C5H5)2] (X = Cl or CO) and [{(η-C5H5)2ClV}2{(2-CH 2C6H4)2}], and electrochemistry of [M(CH2Ph)2-nCln(η-C5H 5)2] (n = 0, M = Nb, or Ta; n = 1, M = V)

Stuart I. Bailey, Lutz M. Engelhardt, Wing Por Leung, Colin L. Raston, Ian M. Ritchie, Allan H. White

Research output: Contribution to journalArticle

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Abstract

Reaction of [MCl2(η-C5H5)2] with the di-Grignard reagent {o-[(thf)nClMgCH2]C6H4}2 in tetrahydrofuran (thf) yields either the bimetallic complex [{(η-C5H5)2ClV}2{(2-CH 2C6H4)2}] (2) or the thermally stable metallepines, [M{(2-CH2C6H4)2}(η-C 5H5)2] [M = Nb (3a) or Ta (3b)]. E.s.r. data on these and the compounds [Nb{2-CH2(C6H4) 2Me-2′}Cl(η-C5H5)2] (7) and [M(CH2Ph)2-nCln(η-C5H 5)2] [n = 1, M = V (8); n = 0, M = Nb (9a) or Ta (9b)], prepared by similar methods, are consistent with each being a d1 complex. Electrochemical reduction and oxidation of (3a) is reversible; the cationic d0 and anionic d2 species have been generated chemically (using AgBF4 and Na[C10H8]) in thf and isolated as salts of [BF4]-, (4a), and [Na(18-crown-6)(thf)2]+, (5), respectively (18-crown-6 = 1,4,7,10,13,16-hexaoxacyclo-octadecane). Electrochemical studies on the other d1 compounds are also reported. Reductive carbonylation of (7) or treating (5) with CF3CH2OH under CO yields [Nb{2-CH2(C6H4) 2Me-2′}(CO)(η-C5H5)2] (6). X-Ray structures of the d0,1,2 niobepines (4a), (3a), and (5) show a large change in CH2-Nb-CH2 angle [106.3(1), 83.0, 80(1)°] in accordance with molecular orbital predictions, and in the Nb-CH2-C angles [102.9, 118.7, and 123(2)°] and the torsion along the biphenyl axis (78.4, 62.4, and 59.6°).

Original languageEnglish
Pages (from-to)1747-1759
Number of pages13
JournalJournal of the Chemical Society, Dalton Transactions
Issue number9
DOIs
Publication statusPublished - 1 Dec 1985
Externally publishedYes

Fingerprint Dive into the research topics of 'Axially asymmetric metal alkyls. Part 3. Chemical, electrochemical, and structural studies of group 5A d<sup>0,1,2</sup> metallepines [M{(2-CH<sub>2</sub>C<sub>6</sub>H<sub>4</sub>)<sub>2</sub>}(η-C <sub>5</sub>H<sub>5</sub>)<sub>2</sub>]<sup>z</sup> (M = Nb or Ta; z = 1-, 0, or 1+): synthesis of [Nb{2-CH2(C6H4) 2Me-2′}X-(η-C5H5)2] (X = Cl or CO) and [{(η-C5H5)2ClV}2{(2-CH 2C6H4)2}], and electrochemistry of [M(CH2Ph)2-nCln(η-C5H 5)2] (n = 0, M = Nb, or Ta; n = 1, M = V)synthesis of [Nb{2-CH2(C6H4) 2Me-2′}X-(η-C5H5)2] (X = Cl or CO) and [{(η-C5H5)2ClV}2{(2-CH 2C6H4)2}], and electrochemistry of [M(CH2Ph)2-nCln(η-C5H 5)2] (n = 0, M = Nb, or Ta; n = 1, M = V)'. Together they form a unique fingerprint.

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