Variations in the copper(I)-copper(I) distances in multinuclear clusters with identical coordination geometries. Short metal-metal contacts induced by oligomerization

Abraham, Santosh P and Samuelson, Ashoka G and Chandrasekhar, Jayaraman (1993) Variations in the copper(I)-copper(I) distances in multinuclear clusters with identical coordination geometries. Short metal-metal contacts induced by oligomerization. In: Inorganic Chemistry, 32 (26). pp. 6107-6111.

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Abstract

Factors contributing to the variations in the Cu(I)-Cu(I) distances in two clusters with identical ligand and coordination geometries have been analyzed. While the hexamer, 4, exhibits metal-metal distances in the range 2.81-3.25 Angstrom, shorter contacts are found in the corresponding tetramer, 3 (2.60-2.77 Angstrom). EHT calculations reveal relatively little attractive interactions in the corresponding Cu-4(4+) and Cu-6(6+) cores. Introduction of the ligands lowers the reduced overlap populations between the metals further. MNDO calculations with model electrophiles have been carried out to determine the bite angle requirements of the ligands. These are satisfactorily met in the structures of both 3 and 4. The key geometric feature distinguishing 3 and 4 is the Cu-S-Cu angle involving the bridging S- unit. In 4, the corresponding angles are about 90 degrees, while the values in 3 are smaller (70-73 degrees). Wider angles are computed to be energetically favored and are characterized by an open three-center bond and a long Cu-Cu distance. The bridging angles are suggested to be primarily constrained by the mode of oligomerization. Implications of these results for the stability and reactivity of these clusters and for short metal-metal distances in d(10) systems in general are discussed.

Item Type:	Journal Article
Publication:	Inorganic Chemistry
Publisher:	American Chemical Society
Additional Information:	Copyright of this article belongs to American Chemical Society.
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry Division of Chemical Sciences > Organic Chemistry
Date Deposited:	26 Apr 2011 10:19
Last Modified:	26 Apr 2011 10:19
URI:	http://eprints.iisc.ac.in/id/eprint/36455

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