Stereochemistry of metal complexes of the macrocycle 3,3,7,7,11,11,15,15-octamethyl-1,9-dithia-5,13-diazacyclohexadecane. Crystal structure analysis of 3,3,7,7,11,11,15,15-octamethyl-1,9-dithia-5,13-diazacyclohexadecanepalladium(II) dichloride dihydrate

Abstract

Crystals of the title compound are monoclinic, space group Pn, with a= 10.533(3), b= 14.994(5), c= 17.214(4)Å, β= 96.58(2)°, and Z= 4. In the asymmetric unit there are two independent [PdL]²⁺ cations separated by, and hydrogen-bonded to, two independent chains of hydrogen-bonded water and chloride ions. The cations have different configurations, c,c,c and c,c,t(N); the Pd atoms have distorted square-planar geometry [Pd–S 2.290(5)–2.297(6) and Pd–N 2.05(2)–2.14(2)Å] with one Cl^– ion in each case in a distant axial position (Pd ⋯ Cl 3.20 and 3.68 Å). The solid-state structures allow us to rationalize the effect of trace amounts of water on the isomer population of the title compound when dissolved in non-polar solvents, in which the two major species present also have the ligand in the c,c,c and c,c,t(N) configurations.