Coordination chemistry and magnetic properties of copper(II) halide complexes of quinoline

Complexes Cu(quin)(2)X-2 [quin = quinoline, X = Cl (1), Br (2)] have been prepared and characterized via single-crystal X-ray diffraction and variable temperature magnetization measurements. The compounds are isomorphous in the monoclinic space group C2/c and crystallize as square planar complexes linked into chains via short X horizontal ellipsis X contacts. Magnetic susceptibility data were collected over the temperature range 1.8-300 K and were fitted to the one-dimensional Heisenberg antiferromagnetic model yielding J/k(B) = -33.7(5) K (1) and -145(4) K (2) with the larger exchange in the bromide complex a result of greater overlap due to the larger van der Waals contribution. Low temperature data indicate the presence of some short chains in the sample which provide for a paramagnetic contribution (odd length chains) or diamagnetic contribution (even length chains) at the lowest temperatures.