Four-, six- and eight-coordinated lead(II) complexes with amine- or amide-type tripodal ligands

Three novel lead(II) complexes, [Pb(L1)](ClO4)2 (1) (L1 = tris(2-benzylaminoethyl)amine), [Pb(L2)2](ClO4)2 (2) (L2 = tris(4-phenyl-3-aza-2-oxobutyl)amine) and [Pb2(L3)2](ClO4)4 (3) (L3 = tris[3-aza-2-oxo-4-(2-pyridyl)butyl]amine) were synthesized and structurally characterized. All three complexes show different stoichiometries as well as coordination numbers of four in 1, eight in 2 and six in 3, respectively. Complex 1 displays a typical tripodal-type 1:1 (M:L) structure and 2 shows a sandwich-type 1:2 structure. The octa-dentate lead(II) ion in 2 is at the center of a dicapped trigonal prism. Complex 3 is revealed as a unique dinuclear 2:2 complex, in which two hexa-dentate lead(II) ions are linked by two carbonyl μ–O atoms forming a Pb2(μ–O)2 parallelogram-type moiety.