- The Hurtley reaction. 1. Synthesis and characterization of copper(I) benzoates containing reactive ortho C-X (X = Cl, Br) bonds and their reactivity toward organocopper(I) compounds: Crystal structure of a thermally stable trinuclear hetero copper(I) cluster, bis(benzoato)mesityltricopper(I)
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A facile, general synthesis of copper(I) carboxylates via the reaction of carboxylic acids with mesityl-copper(I) is described. The 1:1 molar reaction of pentameric mesitylcopper(I) with 2-chloro- or 2-bromobenzoic acids rapidly yields the corresponding reactive copper(I) benzoates [Cu(μ-O2CC6H4Cl-2)]4 (1b) and [Cu(μ-O2CC6H4Br-2)]4 (1c), which are the postulated intermediates in the Hurtley reaction. Reaction at ambient temperature of 1b, 1c, and the parent copper(I) benzoate [Cu(μ-O2CC6H5)]4 (1a) with a further equivalent of mesitylcopper(I) affords the first examples of thermally stable mixed (benzoato)organocopper(I) cluster 2, viz. [Cu3(C6H2Me3-2,4,6)(μ-O 2CC6H4X-2)2] (X = H, 2a; X = Cl, 2b; X = Br, 2c). An X-ray structure determination of 2a (C23H21O4Cu3, monoclinic, space group C2/c, a = 16.926 (2) A?, b = 11.781 (1) A?, c = 10.763 (1) A?, β = 94.48 (1)°, Z = 4, Rw = 0.059 using 1627 reflections) revealed the unique trinuclear geometry of these clusters. In 2a the two benzoato fragments are each bonded as four-electron donors to a pair of copper atoms (Cu-O = 1.862 (av) A?; Cu?Cu = 2.888 (2) A?) while the mesityl fragment is three-center, two-electron bonded to two copper atoms (Cu-C = 1.957 (6) A?; Cu?Cu = 2.421 (2) A?)). Corresponding reactions of benzoic acids with 4-tolylcopper(I) require lower temperatures than those with mesitylcopper(I) and yield the 4-tolyl analogues of 2, e.g. [Cu3(C6H4Me-4)(μ-O2CC 6H4X-2)2] (X = H, 3a; X = Br, 3c).
- Aalten, Henk L.,Van Koten, Gerard,Goubitz, Kees,Stam, Casper H.
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p. 2293 - 2299
(2008/10/08)
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