Copper(II) complexes of picolinamide incorporating both tricyanomethanido and 2-(aminomethyl)pyridine moieties
Reaction of picolinamide (pca) with potassium tricyanomethanide (tcm) and copper(II) perchlorate in 1-propanol gave [Cu(pca)2(tcm)2] (1a and 1b) while addition of 2-(aminomethyl)pyridine (2-ampy) provided [Cu(pca)(2-ampy)(tcm)](ClO4) (2). These compounds have been characterized by IR, powder X-ray diffraction, single crystal X-ray diffraction, combustion analysis, and temperature-dependent magnetic susceptibility. Compound 1a crystallized in the monoclinic space group C2/c whereas 1b and 2 crystallized in the triclinic space group Pī. In 1a, the copper complexes stack alternately with semi-coordinated tcm ions creating layers, further stabilized by hydrogen bonding to neighboring layers. In 1b, the tcm ions are coordinated to complete the octahedral coordination sphere around the copper ions and form staggered layers parallel to the ab face diagonal. In 2, stacks of copper complexes form bilayers, held together by hydrogen bonding between tcm ions and amino groups, parallel to the a axis. Variable temperature magnetic susceptibility data were collected on 1 and 2 from 1.8–310 K. The data were fit to the Curie–Weiss law which showed no significant magnetic exchange as expected based upon the crystal structures [1 − Curie constant = 0.419(2) emu-K/mol-Oe, θ = −0.10(6)°; 2 – Curie constant = 0.438(1) emu-K/mol-Oe, θ = 0.05(3)°].
