Copper(I) alkoxides: preparation and structural characterisation of triphenylmethoxocopper(I) and of an octanuclear form of t-butoxocopper(I)

Artikel i vetenskaplig tidskrift, 2000

Two copper(I) alkoxides, the novel compound triphenylmethoxocopper(I) and an octanuclear form of t-butoxocopper(I), have been prepared from mesitylcopper(I) and the relevant alcohol. [Cu-4(OCPh3)(4)]. 2C(6)H(5)CH(3) (1) and [Cu-8((OBu)-Bu-t)(8)] (2) have been characterised by means of crystal structure determination. Compound 1 contains two crystallographically independent triphenylmethoxocopper(I) molecules, each with a planar Cu-4 core. The Cu4O4 unit is butterfly-shaped with the oxygen ligands situated alternately approximately 0.4 Angstrom above and below the plane through the copper atoms, and the triphenylmethyl groups spread out over both sides of the Cu4O4 core. The copper(I) centres are two-coordinated with distances of 1.83(1)-1.86(1) Angstrom and O-Cu-O angles of 169.4(5)degrees. [Cu-8((OBu)-Bu-t)(8)] (2) can be described as being composed of two approximately planar Cu4O4 cores, each with the t-butyl groups bent away in the same direction from the Cu4O4 plane. These units are related to one another by a centre of symmetry and with weak Cu-O interactions of 2.493(5) and 2.536(5) Angstrom, involving four of the eight coppers, thus yielding an octanuclear Cu8O8 core. These four copper(I) centres thus attain T-shaped three-coordination by oxygen, whereas the remaining four are approximately linearly coordinated. The short Cu-O bond lengths in 2 range from 1.844(5) to 1.888(5) Angstrom.