Structural conversion of a cyclic D-Penicillaminato tripalladium(II) complex by pyridine or 2-pyridinethiol

摘要

Structural conversion of a tripalladium(II) complex with a chair-type Pd3S3 metallacycle, [Pd-3(D-pen-N,O,S)(3)] (1; H(2)pen = penicillamine), triggered by the coordination of pyridine (py) or 2-pyridinethiol (Hpyt) was reported. Treatment of 1 with py in water produced a tripalladium(II) complex with a boat-type Pd3S3 metallacycle, [Pd-3(D-pen-N,O,S)(D-pen-N,S)(2)(py)(2)] 2, in which two of three Pd II centers are each coordinated by a py ligand through N atom. On the other hand, similar treatment of 1 with Hpyt induced a ring-expansion to form a cyclic tetrapalladium(II) complex with a twist-boat-type Pd4S4 metallacycle, [Pd-4(D-Hpen-N,S)(D-pen-N,S)(3)(Hpyt-S)(2)(pyt-N,S)] 3, in which two of four Pd II centers are bridged by a deprotonated pyt(-) ligand through N and S atoms and the remaining two Pd II centers are each coordinated by a protonated Hpyt ligand through an S atom. The H-1 NMR spectral monitoring of each reaction solution showed that the structural conversion to 2 is considerably slower than that to 3.