Synthesis and Dimer Cleavage Reactions of the N₂S Thiolate Bridged Dimer [(mmp-dach)₂Ni₂]Cl₂

The facile synthesis of a monoderivatized N2S ligand based on the cyclic diamine diazacycloheptane provides a tridentate donor which coordinates nickel(II), yielding a dithiolate bridged nickel dimer with a hinge angle of 135.7° and acute N−Ni−N bite angles of ca. 80°. Dimer splitting occurs on reaction with iodoacetamide, producing an S-alkylated octahedral complex. Cyanide also cleaves the dimer, resulting in a cyanide-bound N2S square planar monomer with two nucleophilic sites, thiolate-S and cyanide-N. Molecular structures of the dimeric cation, [(mmp-dach)2Ni2]Cl2, the iodoacetamide derivative, [(dtp-dach)Ni(MeCN)2]Cl2, and an S-oxygenate, [(smp-dach)Ni(CN)], are reported.