444069-41-4Relevant academic research and scientific papers
Electrocatalytic syngas generation with a redox non-innocent cobalt 2-phosphinobenzenethiolate complex
Hong, Lorena E.,Marinescu, Smaranda C.,Orchanian, Nicholas M.,Velazquez, David A.
, p. 10779 - 10788 (2021)
A cobalt complex supported by the 2-(diisopropylphosphaneyl)benzenethiol ligand was synthesized and its electronic structure and reactivity were explored. X-ray diffraction studies indicate a square planar geometry around the cobalt center with a trans arrangement of the phosphine ligands. Density functional theory calculations and electronic spectroscopy measurements suggest a mixed metal-ligand orbital character, in analogy to previously studied dithiolene and diselenolene systems. Electrochemical studies in the presence of 1 atm of CO2and Br?nsted acid additives indicate that the cobalt complex generates syngas, a mixture of H2and CO, with faradaic efficiencies up to >99%. The ratios of H2?:?CO generated vary based on the additive. A H2?:?CO ratio of ～3?:?1 is generated when H2O is used as the Br?nsted acid additive. Chemical reduction of the complex indicates a distortion towards a tetrahedral geometry, which is rationalized with DFT predictions as attributable to the populations of orbitals with σ*(Co-S) character. A mechanistic scheme is proposed whereby competitive binding between a proton and CO2dictates selectivity. This study provides insight into the development of a catalytic system incorporating non-innocent ligands with pendant base moieties for electrochemical syngas production.
Metal complexes (M = Zn, Sn, and Pb) of 2-phosphinobenzenethiolates: Insights into ligand folding and hemilability
Barry, Brian M.,Stein, Benjamin W.,Larsen, Christopher A.,Wirtz, Melissa N.,Geiger, William E.,Waterman, Rory,Kemp, Richard A.
, p. 9875 - 9884 (2013/09/23)
The divalent metal complexes MII{(SC6H 4-2-PR2)-κ2S,P}2 (3-7, and 9-11) (M = Zn, Sn, or Pb; R = iPr, tBu, or Ph), the Sn(IV) complexes Sn{(SC6H4-2-PR2)- κ2-S,P}Ph2Cl (12 and 13) (R = iPr and tBu), and the ionic Sn(IV) complexes [Sn{(SC6H 4-2-PR2)-κ2-S,P}Ph2][BPh 4] (14 and 15) (R = iPr and tBu) have been prepared and characterized by multinuclear NMR spectroscopy and single crystal X-ray diffraction when suitable crystals were afforded. The Sn(II) and Pb(II) complexes with R = Ph, iPr, or tBu (5, 6, 9, and 10) demonstrated ligand folding hinging on the P,S vector - a behavior driven by the repulsions of the metal/phosphorus and metal/sulfur lone pairs and increased M-S sigma bonding strength. This phenomenon was examined by density functional theory (DFT) calculations for the compounds in both folded and unfolded states. The Sn(IV) compound 13 (R = tBu) crystallized with the phosphine in an axial position of the pseudotrigonal bipyramidal complex and also exhibited hemilability in the Sn-P dative bond, while compound 12 (R = iPr), interestingly, crystallized with phosphine in an equatorial position and did not show hemilability. Finally, the crystal structure of 15 (R = tBu) revealed the presence of an uncommon, 4-coordinate, stable Sn(IV) cation.
