Positional isomeric and N-donor auxiliary chelating ligand effect on engineering crystalline architectures of four lead(II) complexes with diverse fluorescent properties

This work presents an investigation on the positions of the substituent and N-donor auxiliary chelating ligand (bipy/phen) effect on engineering of crystalline architectures of four Pb(II) complexes with a pair of methyl-substituted 3-sulfobenzoic isomers: [Pb(4-msba)(phen)center dot(H2O)] (1), [Pb(4-msba)(bipy)(H2O)]H2O (2), [Pb(5-msba)(phen)(2)]center dot 9H(2)O (3), and [Pb-2(5-msba)(2)(bipy)(2)(H2O)(2)] (4) (4/5-msba=4/5-methyl-3-sulfobenzoate, phen=1,10-phenanthroline and bipy=2,2 '-bipyridine). The lead(II) ions exhibit hemidirected geometry in 1-4. The positions of the methyl as well as the auxiliary chelating ligands influence coordination modes of the sulfonates and thus determine the architectures. As the position of methyl in aromatic ring changes from 4 to 5, the structures change from 2-D sheet-like compounds for 1 and 2 to 0-D dimeric species for 3 and 4. A water cluster (H2O)(18) exists in 3, which further assembles into a water tape with a new pattern T4(3)4(3)10(3)A4. Complex 3 loses crystallinity rapidly in the open air and turns into [Pb(5-msba)(phen)(2)]center dot 2H(2)O (3A). Thermal stabilities and solid state fluorescent properties of 1, 2, 3A, and 4 have been studied.