Syntheses and characterization of lead(II) salts with 4,4′-bithiazole ligand:: X-ray crystal structures of [(BTZ)2Pb(NO3)2] and [(BTZ)Pb(SCN)2]n (a new polymeric compound)

Complexes of lead(II) nitrate and lead(II) thiocyanate with 4,4'-bithiazole (BTZ) have been synthesized using a direct reaction of PbX2 (X = nitrate and thiocyanate) and ligand. The complexes have been isolated and characterized by IR spectra and CHN elemental analysis. The structures of [(BTZ)(2)Pb(NO3)(2)](2) and [(BTZ)Pb(SCN)(2)](n) were confirmed by X-ray crystallography. The coordination polyhedron is different in the two complexes. The coordination number of Pb in [(BTZ)(2)Pb(NO3)(2)] is six (four by the chelating BTZ and two oxygen atoms of the two nitrate anions), whereas in [(BTZ)Pb(NCS)(2)](n) it is five with two different Pb environments, PbN3S2 (two by the chelating BTZ and three by SCN- anions) and PbN5 (two by BTZ and three by SCN- anions). The coordination geometry of [(BTZ)(2)Pb(NO3)(2)] and [(BTZ)Pb(NCS)(2)] complexes show a gap around the Pb(II) ion, occupied possibly by a stereoactive lone pair of electrons on lead(II) and coordination around the lead atoms is hemidirected with a significant gap trans to chelating BTZ ligands, nitrate and thiocyanate anions. There is a pi-pi stacking interaction between the parallel aromatic rings belong to adjacent chains in [(BTZ)Pb(NCS)(2)](n) that may help to increase the 'gap' in the coordination geometry around the Pb(II) ion. (C) 2002 Elsevier Science Ltd. All rights reserved.