The separation of cis- and trans-1,3-cyclohexanediol isomers by copper complexation. Crystal structures of cis-1,3-cyclohexanediol and copper(II) chloride cis-1,3-cyclohexanediol complex

摘要

A 1:1 complex between copper(II) chloride and cis -1,3-cyclohexanediol has been synthesized and its crystal structure determined. The structure is composed of two different dinuclear [CuCl2(c-13chd)](2) units in which the copper(II) ions are surrounded by the two oxygen atoms of the diol and the two halide ions in a distorted cis-square planar arrangement in both cases. A fifth coordination site is occupied by a halide ion in one dinuclear unit for both copper ions and an 0 atom belonging to the adjacent CuCl2(c-13chd) moiety in the other dinuclear unit for both copper ions, thus forming a distorted square pyramidal geometry for the metals in all cases. The ability of CuCl2 to preferentially form acomplexwith cis-1,3-cyclohexanediol renders it amenable to the separation of the cis- and trans-isomers of 1,3-cyclohexanediol as the trans-isomer is not able to form such a complex with CuCl2 and neither are any mixed complexes formed. The crystal structure of cis-1,3-cyclohexanediol is also reported for comparative purposes. (C) 2002 Elsevier Science Ltd. All rights reserved. [References: 26]