A Series of Lead(II) Complexes with pi-pi Stackings: Structural Diversities by Varying the Ligands

Twelve structurally diverse complexes, [Pb-2(pzp)(2)(adip)(NO3)(2)] 1, [Pb(pzp)(glu)] 2, [Pb(pzp)(chdc)]center dot[Pb(pzp)(chdc)]center dot pzp center dot H2O 3, [Pb-2(ndc)(2)(pzp)(2)(H2O)]center dot 0.5H(2)O 4, [Pb(pzp)(1,3-bdc)(H2O)(0.5)]center dot H2O 5, [Pb(pzp)(1,2-bdc)]center dot H2O 6, [Pb-2(ptc)(2)(adip)-(NO3)(2)] 7, [Pb(ptc)(glu)] 8, [Pb(ptc)(chdc)] 9, [Pb(ptc)(dpdc)](2) 10, [Pb(ptc)(1,3-bdc)]-2.5H(2)O 11, and [Pb(ptc)(1,4-bdc)]center dot 0.75H(2)O 12, where H(2)adip = adipic acid, H(2)glu = glutaric acid, H(2)chdc = 1,4-cyclohexanedicarboxylic acid, H(2)ndc = 1,4-naphthalenedicarboxylic acid, 1,4-H(2)bdc = benzene-1,4-dicarboxylic acid, H(2)dpdc = 2,2'-diphenyldicarboxylic acid, 1,3-H(2)bdc benzene-1,3-dicarboxylic acid, 1,2-H(2)bdc = benzene-1,2-dicarboxylic acid, pzp = pyrazino[2,3-f][1,10]phenanthroline, and ptc = 2-phenyl-1H-1,3,7,8,-tetraaza-cyclopenta[l]-phenanthrene, have been hydrothermally synthesized. Compounds 7 and 10 possess dinuclear structures, which are further extended by pi-pi interactions to form supramolecular layers and chains, respectively. 1-6, 8-9, and 11-12 feature chain structures, which are then stacked by pi-pi interactions to result in 2D or 3D supramolecular architectures. The structural differences among such complexes show that the organic acids and neutral chelating ligands have important influences on the structures.