Coordination Chemistry of a Tripodal S2ON Ligand: Syntheses, Structures, and Reactivity of the Molybdenum(VI) and Nickel(II) Complexes of Bis(2-mercaptoethyl)-2-amino-4-methylphenol (H3btap) and Comparison to VVO(btap)
journal contributionposted on 07.10.1998, 00:00 by Charles R. Cornman, Kevin L. Jantzi, Joseph I. Wirgau, Thad C. Stauffer, Jeff W. Kampf, Paul D. Boyle
The tripodal tetradentate ligand H3btap coordinates to VV, MoVI, and NiII via three different bonding modes to yield three complexes with unique ligand-based oxidation chemistry. For VV and MoVI (1), all four of the heteroatom donors are coordinated to the metal ion forming a trigonal bipyramidal complex with the oxovanadium(V) ion, VVO3+, and an octahedral complex with the cis-dioxomolybdenum(VI) ion, [MoO2]2+. Only three of the heteroatom donors of H3btap are used to coordinate to NiII (2), two thiolate sulfurs and the amine nitrogen, yielding a dimeric structure in which each nickel(II) ion has NS3 coordination. The ability of VVO(btap) to form η2-sulfenates, while [MoO2(btap)]- does not form stable η2-sulfenates, has been ascribed to the electron-deficient, π-accepting nature of VVO3+ relative to [MoVIO2]2+. Crystal data for 1 (C11H16NO4S2KMo): space group Pbcn, a = 6.6596(9) Å, b = 13.7446(9) Å, c = 32.992(2) Å, α = β = γ = 90°, Z = 8. Crystal data for 2 (C24H38N2O4S4Ni): space group Pbcn, a = 12.0841(3) Å, b = 14.4948(4) Å, c = 16.7751(4) Å, α = β = γ = 90°, Z = 4.