New in situ cleavage of both S-S and S-C(sp2) bonds and rearrangement reactions toward the construction of copper(I) cluster-based coordination networks

Solvothermal reaction of 4,4'-dithiodipyridine (dtdp) with CuI at 120 or 160 degrees C results in the formation of three new coordination networks formulated with Cu4I4(tdp)2] (1; tdp = 4,4'-thiodipyridine), Cu5I5(ptp)2] (2), and Cu6I6(ptp)2] 3; ptp = 1-(4-pyridyl)-4-thiopyridine]. The starting dtdp reagent was unprecedentedly converted into two tdp and ptp ligands via new in situ cleavage of both S-S and S-C(sp2) bonds and temperature-dependent in situ ligand rearrangement of dtdp. 1 is a two-dimensional (2D) Cu4I4 cubane-like coordination network of 2-fold interpenetration. While in 2, the Cu8I8 and Cu2I2 cluster units are alternately connected by the mu2-sulfur bridges into one-dimensional inorganic chains along the a axis, which are further joined by the ptp spacers into a three-dimensional (3D) coordination network of 2-fold interpenetration. 3 is a 3D non-interpenetrating coordination network constructed with 2D inorganic (Cu2I2)n layers and the ptp spacers. 1 displays an intense orange-red emission light with a maximum at ca. 563 nm. While luminescence quenching occurs in 2 and 3 by electron transfer of a photoelectron to the electronegative acceptor molecule of ptp.