Syntheses and crystal structures of two copper(II) chloride complexes with 2,3-dimethyl-2,3-butanediol

Abstract

The crystal and molecular structures of the complexes [CuCl 2(H 2pin)] 2 (H 2pin = 2,3-dimethyl-2,3-butanediol = pinacol) (1) and [CuCl 2(H 2pin)]·H 2pin (2) have been determined. The compound (1) crystallizes in the orthorhombic space group Pbcn with a = 20.710(2), b = 11.401(6), c = 17.469(4), and Z = 8. The dimeric [CuCl 2(H 2pin)] 2 molecules consist of two five-coordinated Cu(II) ions with two different CuO 2Cl 2Cl′ chromophores. The symmetry around one copper atom can be described as a distorted square based pyramid, and around the other as a distorted trigonal bipyramid. The dimers are held together by hydrogen bonds. The compound (2) crystallizes in the monoclinic space group C2/c with a = 18.878(18), b = 12.115(3), c = 7.541(2), β = 104.94(5), and Z = 4. The structure of (2) is a polymer. The copper atom is surrounded by two oxygen atoms of one H 2pin molecule and by two chloride ions (Cu-Cl = 2.223 Å). Two extra chloride ions from adjacent CuCl 2(H 2pin) units are at the distance of 3.223 Å. The coordination number of copper(II) ion is 4 + 2 with an elongated rhombic octahedral symmetry. The second H 2pin molecule is not coordinated to copper atom, but has an anti conformation and connects CuCl 2(H 2pin) units together by hydrogen bonds.