Bis(diethyldithiocarbamato)pyridinezinc(II) and copper(II) Clathrates with Pyridine: Molecular Structure and EPR and High-Resolution Solid-State (13C, 15N) NMR Spectra

EPR, high-resolution solid-state ((13)C, (15)N) NMR, and X-ray diffraction methods were used to study bis(diethyldithiocarbamato)pyridinezinc(II) and copper(II) clathrates with pyridine, M(Edtc)(2)Py center dot Py. The structural functionalities of the Py molecules in these clathrates were found to be different: one of them is coordinated to the complexing atom, while the other (solvate) is hydrogen-bonded to the sulfur atom of one of the ligands. The heterocycle of the uncoordinated Py molecule was found to be geometrically distorted. The structures of the copper and zinc coordination polyhedra are close to trigonal-bipyramidal: two sulfur atoms and the nitrogen atom of pyridine form the equatorial plane; another two sulfur atoms occupy axial positions at larger distances. EPR spectra of the magnetically diluted copper(II) clathrate exhibit well-resolved SHFS from the nitrogen atom of Py, owing to the contribution of the d(z)(2) orbital to the ground-state wave function of the unpaired electron. The NMR data suggest that the nitrogen atoms of the Edtc(-) ligands are magnetically inequivalent and that the (15)N chemical shift of the uncoordinated Py molecule changes in an unusual fashion. Signal assignment was carried out for the experimental (13)C and (15)N NMR spectra.