Cleavage of C−S Bonds with the Formation of a Tetranuclear Cu(I) Cluster

The treatment of a ligand, 2,6-bis((4-(pyridin-2-yl)pyrimidin-2-ylthio)methyl)-4-chlorophenol (ClPPT2), with cuprous
chloride under a weak base condition led to the formation of a neutral CuI4-centered cluster [Cu4(PPT2)4], whose
X-ray diffraction analysis indicated that C−S bonds of the ligand were cleaved in the course of the reaction. To
explain the C−S bond cleavage, a reasonable mechanism has been proposed. In support of it, four additional
ligands, 2,6-bis((4-(pyridin-2-yl)pyrimidin-2-ylthio)methyl)-4-methylphenol (MePPT2), 2,6-bis((4-(pyridin-3-yl)pyrimidin-2-ylthio)methyl)-4-methylphenol (MePPT3), 2,6-bis((4-(pyridin-3-yl)pyrimidin-2-ylthio)methyl)-4-chlorophenol (ClPPT3),
and 5-((4-(pyridin-3-yl)pyrimidin-2-ylthio)methyl)-2-hydroxybenzaldehyde (HBPPT2) were further tested to undertake
the analogous reaction, and the cleaved products in these experiments were detected by electrospray ionization
mass spectrometry techniques to clarify the process.