Rotation isomers of bis(diethyldithiocarbamato)zinc(II) adduct with pyridine, Zn(EDtc)(2)center dot Py: ESR, C-13 and N-15 CP/MAS NMR and single-crystal X-ray diffraction studies

The adduct of bis(diethyldithiocarbamato)zinc(II) with pyridine, Zn(EDtc)(2 ). Py, was prepared and studied by means of ESR (Cu-63(2+) and Cu-65(2+) we re used as spin labels), solid-state natural abundance C-13 and N-15 CP/MAS NMR spectroscopy and single-crystal X-ray diffraction data analysis. Two r otation isomers of the adduct were unambiguously determined by these three independent methods. It was found that these two isomers have different ori entations of the pyridine ring about the N(Py)-Zn axis. The acute angles of the plane of the pyridine molecules relative to the most weak Zn-S bond ar e equal to 45.6 and 52.7 degrees in the different isomers. Adduct molecules adopt a geometry which is intermediate between the square pyramidal (C-4v) and the trigonal bipyramidal (D-3h). All ESR and NMR resonances of Zn(EDtc )(2). Py were assigned. (C) 1999 Elsevier Science Ltd. All rights reserved.