W2Cl4(NR2)2(PR′ 3)2 molecules - 9. New mixed valent WIII/WIV face-sharing bioctahedral complexes with chelating bis(diphenylphosphino)propane and dialkylamido ligands

Article abstract of DOI:10.1016/S0277-5387(97)00216-7

The triply-bonded ditungsten(III) species trans,trans-W₂Cl₄(NBuⁿ₂) ₂(dppp) (1) and a new mixed-valent W^III/W^IV complex (dppp)ClW(μ-Cl)₃WCl₂(NBuⁿ₂) (3) have been isolated from the reaction of W²Cl₄ (NBuⁿ₂)₂(NHBu_n2) ₂ with 1,3-bis(diphenylphosphino)propane (dppp). A complex similar to 3, (dppp)ClW(μ-Cl)₃WCl₂(NEt²) (2), has also been prepared. Both 2 and 3 are characterized by a W⁷⁺₂ core and they adopt face-sharing bioctahedral geometry with a chelating dppp ligand. The W - W distances in 2 and 3 are both 2.660(1) A and each of them shows an EPR signal at g = 1.88. The structure of 1 contains a W⁶⁺₂ core with a W - W distance of 2.3055(8) A. It has a bridging dppp ligand and a trans,trans stereochemistry.