The structure of N-meso-(6,8,8,14,16,16-hexamethyl-1,5,9,13-tetraazacyclohexadeca-5,13-diene)nickel(II) chloro(isothiocyanato)zincate(II)

A yellow compound which was crystallised from a solution of (6,8,8,14,16,16-hexamethyl-1,5,9,13-tetraazacyclohexadeca-5,13-diene)bis(isothiocyanato)nickel(II) in aqueous zinc(II) chloride has cations with singlet ground state nickel(II) in square-planar coordination by the nitrogen atoms of the macrocycle. The asymmetric unit has two similar cations. The N4 group of one cation is near coplanar (r.m.s. displacements ±0.009(1) Å, with Ni displaced by 0.048(1) Å from this plane) while the other cation has significant tetrahedral twisting of the N4 group (r.m.s. displacements of N atoms ±0.126(2) Å, with Ni displaced by 0.027(2) Å from this plane). The mean Ni–N distances are Ni–Namine = 1.950(6) and Ni–Nimine = 1.897(6) Å. Both cations have N-meso configurations with saddle conformations, with the substituted chelate rings in boat conformations tilted to one side of the NiN4 ‘plane’ and the unsubstituted chelate rings tilted to the other side, one in a boat conformation and the other with the central methylene group disordered, the components forming boat {s.o.f. 0.70(1) and 0.74(1) for the two cations} and chair conformation chelate rings. The counter-ions have tetrahedrally coordinated zinc(II) ions, one as [ZnCl2(NCS)2]2− ions and the other with one ligand site with disordered Cl− {s.o.f. 0.78(1)} and NCS− ligands, i.e. with disordered [ZnCl2(NCS)2]2− and [ZnCl(NCS)3]2− ions, with an overall composition of [Ni(trans-Me6[16]diene)][ZnCl1.9(NCS)2.1].

The yellow crystals formed when (6,8,8,14,16,16-hexamethyl-1,5,9,13-tetraazacyclohexadeca-5,13-diene)bis(isothiocyanato)nickel(II) reacts with aqueous zinc(II) chloride have a structure with N-meso cations with trans imine groups. One anion is [ZnCl2(NCS)2]2−, the other is disordered [ZnCl2(NCS)2]2−/[ZnCl3(NCS)]2− with the overall composition [Ni(trans-Me6[16]diene)][ZnCl1.91(NCS)2.09].Figure optionsDownload as PowerPoint slide