Interaction of zinc and cadmium Bis(benzothiazole-2-thiolates) with nitrogen bases

Abstract

The reactions of polymeric [Zn(C₇H₄NS₂)₂] with pyridine (py), 2,2′-bipyridine (bipy) and 1,10-phenanthroline (phen) lead to the formation of mononuclear adducts which have been characterized by elemental analysis and infrared spectroscopy. The complexes [Zn(C₇H₄NS₂)₂(py)₂]1, [Zn(C₇H₄NS₂)₂(bipy)]2 and [Cd(C₇H₄NS₂)₂(py)₂]3 were structurally characterized by X-ray crystallography. Adducts 1 and 2 have distorted-tetrahedral ZnN₂S₂ cores. The zinc ions are co-ordinated to the two exocyclic S atoms of the benzothiazole-2-thiolates and to two nitrogen atoms from the py or bipy base. The Zn–S and Zn–N bond distances are 2.324(1) and 2.063(4)Å in 1 and 2.310(13) and 2.096(4)Å in 2. The complex [Zn(C₇H₄NS₂)₂(phen)] was found to be isomorphous to 2. Adduct 3 shows a distorted-octahedral CdN₄S₂ unit formed by two bidentate S,N benzothiazole-2-thiolates and two cis pyridine nitrogen atoms. The two exocyclic S atoms are located at the axial positions. The mean Cd–S and Cd–N bonds of the bidentate ligands in 3 are 2.706(10) and 2.422(30)Å and the corresponding mean Cd–N(py) is 2.334(4)Å. The infrared spectra of the adducts in the range 650–200 cm^–1 are discussed in the light of the known structures. The thermal degradation of complexes 1–3 affords ZnS or CdS.