Borate ligand derived from CS<inf>2</inf> unveiling ruthenium dithioformate and trithia-borinane complexes

The reactivity of κ2-N,S-chelated ruthenium borate complexes, [Ph3P(κ2-N,S-L)Ru{κ3-H,S,S′-H2B(L)2}], (L = C5H4NS, C7H4NS2) 1 and 3 with borate ligand derived from CS2 has been investigated. The thermolysis of [Ph3P(κ2-N,S-C5H4NS)Ru{κ3-H,S,S′-H2B(C5H4NS)2}], 1 with Na[BH3(SCHS)] led to the formation of ruthenium dithioformate complexes, [PPh3(κ3-H,S,S′-H2B(C5H4NS)}Ru{(η2-SCHS)}], trans-2 and [PPh3(κ3-H,S,S′-H2B(C5H4NS)}Ru{(η2-SCHS)}], cis-2. Further, to study the reactivity of the same borate ligand derived from CS2, we have performed the reaction of [Ph3P(κ2-N,S-C7H4NS2)Ru{κ3-H,S,S′-H2B(C7H4NS2)2}], 3 with Na[BH3(SCHS)] that yielded ruthenium dithioformate, [Ph3P(κ2-N,S-C5H4NS)Ru{(η2-SCHS)}], cis-4 and 1,3,5-trithia-2-borinane, [PPh3Ru{κ3-H,S,S′-H2B(NC7H4S2)2}]{(SCH2)2SBH}], 5 complexes. All these studies show that cis-4 is analogous to trans-2 and cis-2. The solid-state X-ray structure of 5 shows that the ruthenium center is stabilized by diborate, phosphine and six-membered ruthenacycle [RuSBNCS] ring that is fused with a {C2S3B} ring. The synthesized complexes have been thoroughly characterized by various spectroscopic techniques and single-crystal X-ray diffraction analysis of trans-2, cis-2 and 5. Density functional theory (DFT) calculations further provided an insight into the electronic structures of the complexes.