Influence of neutral amine ligands on the network assembly of lead(II) 4-sulfobenzoate complexes

Two new lead(II) 4-sulfobenzoate complexes with amine ligands, [Pb(4-sb)(2,2′-bipy)]n (1) and {[Pb(4-sb)(4,4′-bipy)1/2] · (4,4′-bipy)1/2}n (2) (2,2′-bipy = 2,2′-bipyridine; 4,4′-bipy = 4,4′-bipyridine; 4-sb = 4-sulfobenzoate dianion), were synthesized and characterized by single-crystal X-ray analyses, IR, TG, elemental analyses and fluorescent studies. Complexes 1 and 2, in addition to previously reported [Pb(4-sb)(H2O)2]n (3) and {[Pb(4-sb)(phen)] · (H2O)}n (4) where phen is 1,10-phenanthroline, all contain [Pb(4-sb)] building units, while four [Pb(4-sb)] networks in 1–4 are very different, which is significantly influenced by the neutral ligands. The coordination array of complex 1 is a 2-D network in which each 4-sb acts as a η5–μ3 mode while the complex 2 is a 3-D architecture in which each 4-sb performs a η5–μ6 mode. Both coordination modes of 4-sb ligands in 1–2 are novel and first reported in this paper.