Structure and properties of silver sulfate complexes derived from dipyridyl methylthio ligands with secondary donor site

Dipyridyl sulphide ligands 4-(pyridin-4-ylmethylthio)pyridine (abbreviated as L1) and 3-(pyridin-4-ylmethylthio)pyridine (abbreviated as L2) have been designed and used as μ-N,N-bridging linkages to construct coordination polymers with free –S–CH2– groups as secondary donor sites. By use solvent control method, coordination polymers {[Ag3SO4(L1)3](Cl)·4.5H2O}∞(1), {[Ag2SO4(L1)2]·6H2O·2CH3OH}∞(2), {[Ag2SO4(L2)2]·H2O}∞(3) and {[Ag4(SO4)2(L2)4]·5H2O}∞(4) with different architectures were obtained. Complexes 1, 3 and 4 feature 1D channel with different sizes and structures. Complex 1 exhibits guest exchange by THF and 1,4-dioxane, and Hg2+ sorption ability from solution due to its relative larger channel and available bonding sites of –S– exposed to the channel region. All complexes have been characterized through single-crystal and powder X-ray diffraction (PXRD), FT-IR spectra, X-ray photoelectron spectroscopy (XPS), elemental and thermogravimetric analyses. The guest exchange and Hg2+ sorption were monitored and identified, and the structure-property relationship of coordination polymers 1–4 are discussed.