Mechanistic Studies of C-C bond cleavage of nitrites by dinuclear metal cryptates

Document Type

Article

Publication Date

11-16-2009

Department

Department of Chemistry

Abstract

We previously reported that dinuclear copper(II) cryptate [Cu 2L]4+ cleaves the C-C bond of acetonitrile at room temperature to produce a cyanobridged dinuclear cryptate and methanol, whereby the reaction mechanism has not yet become clear. We have now systemically investigated this reaction, and four cryptates, [Cu2L] (ClO 4)4 (1), [Zn2L](ClO4)4 (2), [Cu2L(H2O)2](CF3SO 3)4 (5), and [Cu2L(OH)(OH2)]- (ClO4)3 (6) are reported here. Cryptates 1 and 2 can cleave the C-C bonds of acetonitrile, propionitrile, and benzonitrile at room temperature under open atmospheric conditions to give cyano-bridged cryptates [Cu2L(CN)]-(ClO4)3 (3) and [Zn 2L(CN)](ClO4]3 (4), respectively, and the corresponding alcohol. In contrast, 5 and 6 do not show any C-C bond activation of nitriles, as the interior axial positions of CuII in 5 and 6 are occupied by water/OH-. The C-C bond cleavage of (S)-(+)-2- methylbutyronitrile by 2 produced (R)-(-)2-butanol only; that is, the cleavage reaction proceeds through an SN2 pathway (Walden inversion).

Publication Title

Chemistry - A European Journal

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