In situ benzene-1,4-disulfonate ligand synthesis and electric conductivities of four silver 4-sulfobenzoate or benzene-1,4-disulfonate complexes

The reaction of 4,4′-bipyridine (bipy), AgNO3 and 4-sulfobenzoate (4-sb) led to an unprecedented complex, {[Ag2(4,4′-bipy)2(H2O)2]·(1,4-bds)·(2H2O)}n (1), in which benzene-1,4-disulfonate (1,4-bds) was synthesized in situ. This does not happen in the similar 1,2-bis(4-pyridyl)ethylene (bpe) system, where the complex {[Ag2(bpe)2(H2O)2]·(4-sb)·3H2O}n (2) is formed. The same in situ reaction occurred when triphenylphosphine (PPh3) was added into the bipy and silver reaction solution, resulting in the complex [Ag2(PPh3)4(1,4-bds)]. 2DMF (3). Complex 4, {[Ag2(Ph3P)2(4-sb)(H2O)]·(H2O)}n, was synthesized similar to the synthesis of complex 3, without the presence of 4,4′-bipyridine. Complexes 1–4 were characterized by single-crystal X-ray analyses, elemental analyses, IR spectra, TG analyses, fluorescence studies and electric conductivity. Complexes 1 and 2 are cation–anion species. Complexes 3 and 4 are silver triphenylphosphine complexes, where the phenyl embrace interactions play important roles. In 3, the six-fold phenyl embrace (6PEs) connect the molecules into a 1-d hybrid zig-zag infinite chain. Complex 4 is a one-dimensional branch-like polymer containing a 1-d necklace-like backbone made up of an [Ag2(4-sb)(H2O)] unit and PPh3 ‘‘leaves”. Two new coordination modes for the 1,4-bds ligands and one for the 4-sb ligand are observed. Complexes 1–3 are semi-conductors, while complex 4 is an insulator.

The reactions of AgNO3, 4-sulfobenzoate (4-sb) and neutral ligands led to four novel complexes. Two of them occurred with in situ ligand synthesis at room temperature. The structure analyses showed that the neutral ligands largely influence the ultimate networks dramatically, with different functions of guest molecules in the structures. Complexes 1–3 are semi-conductors, while complex 4 is an insulator.Figure optionsDownload as PowerPoint slideResearch highlights
► In situ benzene-1,4-disulfonate synthesis occurred at room temperature.
► The solid electric conductivities of the complexes were investigated.
► Weak interactions play important role in conductivity property.