106161-02-8Relevant articles and documents
Syntheses of photoactive complexes. Electronic spectra, electrochemistry, and SCF-Xα-DV calculations for bis(phosphine)palladium oxalate and dithiooxalate complexes. Crystal and molecular structures of (dithiooxalato-S,S′)bis(trimethylphosphine)palladium(II) and (1,1-dithiooxalato-S,S′)bis(μ 3-sulfido)-2,2,3,3-tetrakis(trimethylphosphine)-triangulo- tripalladium(II)
Cowan, Robert L.,Pourreau, Daniel B.,Rheingold, Arnold L.,Geib, Steven J.,Trogler, William C.
, p. 259 - 265 (2008/10/08)
The compounds M(S2C2O2)L2 (M = Ni, Pd, Pt; L = P(CH3)3 (PMe3) or L2 = [P(C6H5)2CH2]2 (dppe), [P(C2H5)2CH2]2 (depe)) were prepared from the reaction between K2S2C2O2 and MCl2L2 (M = Ni, Pd, Pt; L = depe, dppe), except for NiCl2(PMe3)2, which was prepared from NiCl2(1,2-dimethoxyethane), K2S2C2O2, and PMe3. In all complexes the dithiooxalate ligand chelates through both sulfur atoms as evidenced by vC-O =1632-1640 cm-1 for the uncomplexed carbonyl groups in the solution IR spectra. Crystals of Pd(S2C2O2)(PMe3)2 belong to the space group Pbca with a = 13.479 (2) ?, b = 12.488 (2) ?, c = 17.542 (2) ?, Z = 8, and V = 2952.7 (7) ?3. Solution of the structure by direct methods led to final values of RF = 2.63 and RwF = 3.23 with 137 least-squares parameters for 2159 unique reflections with Fo > 5σ(Fo). The structure confirmed the square-planar structure about Pd with Pd-P = 2.294 (1) and 2.307 (1) ? and Pd-S = 2.324 (1) and 2.344 (1) ?. All dithiooxalate complexes were photoactive and liberated carbonyl sulfide and products derived from ML2 on photolysis. Thermolysis of Pd(S2C2O2)(PMe3)2 in DMF produced crystals of Pd3(μ3-S)2(S2C2O 2)(PMe3)4 on cooling that belong to the space group P21 with a = 9.580 (2) ?, b = 11.578 (2) ?, c = 13.400 (4) ?, β = 96.93 (2)°, Z = 2, and V = 1475.4 (4) ?3. Solution of the structure by direct methods led to final values of RF = 2.50 and RwF = 2.82 with 245 least-squares parameters for 2523 unique reflections with Fo > 5σ(Fo). The molecular structure consists of a triangle of palladium atoms with Pd(1)-Pd(2) = 3.174 (1) ?, Pd(1)-Pd(3) = 3.038 (1) ?, and Pd(2)-Pd(3) = 3.141 (1) ? capped above and below the plane by sulfurs Pd(1)-S(1) = 2.364 (2) ?, Pd(1)-S(2) = 2.374 (2) ?, Pd(2)-S(1) = 2.356 (2) ?, Pd(2)-S(2) = 2.353 (2) ?, Pd(3)-S(1) = 2.333 (2) ?, and Pd(3)-S(2) = 2.339(2) ?. The coordination geometry, including the capping sulfides, about each palladium is pseudo square planar with Pd(1) and Pd(2) each binding two PMe3 ligands and Pd(3) binding to a dithiooxalate-S,S′ ligand. SCF-Xα-DV calculations for the model complexes Pd(C2O4)(PH3)2 and Pd(S2C2O2)(PH3)2 show a similar orbital energy scheme. The lowest energy and presumably photoactive electronic transitions are to empty C2O42- and S2C2O22- π* orbitals rather than to a ligand to metal charge-transfer transition. Several of the dithiooxalate complexes prepared showed chemically reversible reductions at -1.5 to -1.6 V in CH3CN vs. Ag/AgCl, while all analogous oxalate complexes showed irreversible reductions at -1.5 to -2.1 V.
