COPPER(II) CHLORIDE ADDUCTS WITH NICOTINIC AND ISONICOTINIC-ACID N-OXIDES

CuLnCl2 complexes are formed by interaction of nicotinic (n = 4) or isonicotinic (n = 1) acidd N-oxide and CuCl2 solutions in ethanol-triethylorthofromate. The 1:4 CuCl2 adduct with nicotinic acid N-oxide seems to be a dimer of the [L3ClCuL2CuClL3]Cl2 type, with both terminal and briging, exclusively NO oxygen-bonded ligand groups. This compound exhibits a subnormal ambient temperature magnetic moment (1.20 βB) and temperature-dependent paramagnetic behavior. The 1:1 CuCl2 adduct with isonicotinic acid N-oxide is apparently polymeric ([CuLcl2]x), with the ligand functioning as tridentate, bridging, coordinating through all three (NO and COO) of its oxygens. This formulation is supported by the magnetic evidence, i.e., normal ambient temperature μeff of 2.06 μB, and measurable antiferromagnetic exchange at lower temperatures. © 1978.