Lewis Base Adducts of Lead(II) Compounds. I. Polymer Isomerism in Some 1-2 Adducts of Lead(II) Halides With Pyridine Bases

Abstract

Recrystallization of lead(II) halides, PbX2 (X = C1, Br, I), from n- methylpyridine, n = 3, 4, yields crystalline 1 : 2 adducts; these have all been shown by single-crystal X-ray structure determination to contain the lead in an essentially octahedral six-coordinate environment, two of the coordination sites being occupied by monodentate pyridine base moieties and four by bridging halogen, yielding infinite polymeric arrays. For X = Cl, Br, n = 3, the nitrogen atoms lie cis in the coordination sphere; for the other complexes, they are trans. In the two cis complexes, distortion from ideal orthogonal geometry is more substantial than in the trans, possibly indicative of the presence of a sterically active 'lone pair'.