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 °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 μ₂-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.