Mononuclear thiolate complexes of Mo(II) and Mo(III): x-ray crystal structure of trans-[Mo(SBu n) 2(Ph 2PCH 2CH 2PPh 2) 2

Abstract

The complexes trans-[Mo(SR) 2)(diphos) 2] (A) [R = alkyl, C 6F 5 or C 6H 4X-4, where X = H, F, Cl, CH 3, NH 2 or OCH 3; diphos = Ph 2PCH 2CH 2PPh 2 (dppe) or (C 6H 4CH 3-3) 2PCH 2CH 2P(C 6H 4CH 3-3) 2 (dmtpe)] have been prepared by treatment of trans-[Mo(N 2) 2(diphos) 2] with RSH. trans-[Mo(SBu n ) 2(dppe) 2] crystallizes in the monoclinic space group C2/c with a = 25.605(5) Å, b = 12.055(2) Å, c = 19.637(4) Å, β = 107.08(2)° and final R = 0.041. The molecule is centrosymmetric with Mos = 2.363(1) Å and MoR average = 2.511(1) Å. Compounds ( A) are diamagnetic and the 31P NMR chemical shifts and E ox 1 2 values of ( A, R = C 6H 4X-4) show a linear dependence upon the Hammett σ function for X. Chemical oxidation (FeCl 3 or CuCl 2) followed by anion exchange gives the complexes [Mo(SR) 2(dppe) 2][BPh 4], whose ESR spectra show a rhombic signal in frozen solution having hyperfine splitting which is solvent-dependent.