Preparation and characterization of two chiral Au(CN)2-based coordination polymers containing (1R,2R)-N,N′-dimethylcyclohexanediamine

Abstract

Two chiral heterometallic coordination polymers have been prepared using enantiopure 1R,2R-(N,N′)-bismethylcyclohexanediamine (Me2cydm) as an ancillary ligand along with copper(II) cations and KAu(CN)2. The resultant polymers, Cu(Me2cydm)[Au(CN)2]2 (1) and Cu(Me2cydm)Au(CN)2(ClO4) (2), crystallize in the chiral space groups P21 and C2221, respectively. Polymer 1 consists of 1D zig-zag chains of copper atoms bridged by [Au(CN)2]− groups with pendant [Au(CN)2]− units holding the 1D chains through Au–Au interactions of 3.2799(13) A, generating an overall 2D array. Polymer 2 has both [Au(CN)2]− and ClO4− anions bridging Cu(II) centres in a 2D (4,4) corrugated net motif. Both polymers exhibit weak antiferromagnetic interactions down to 1.8 K with no ordering behaviour. Despite the weak forces holding the 2D sheets in place, the polymers did not exhibit any porosity or vapochromic behaviour, indicating that the structural networks are surprisingly rigid.