The synthesis and properties of tris(diphosphine)- and bis(triphosphine)-chromium (III) cations and analogues with arsenic and sulphur donor ligands
Abstract
The reaction of [Cr(thf)6][BF4]3(thf = tetrahydrofuran) with bidentate (L2) and tridentate (L3) ligands in thf produces [Cr(L2)3][BF4]3[L2= Ph2PCH2CH2PPh2, Me2PCH2CH2PMe2, o-C6H4(PMe2)2, o-C6H4(AsMe2)2, cis-Ph2AsCHCHAsPh2, or cis-MeSCH
CHSMe] and [Cr(L3)2][BF4]3[L3= PhP(CH2CH2PPh2)2, McAs(CH2CH2CH2AsMe2)2, MeC(CH2PPh2)3, MeC(CH2AsMe2)3, or S(CH2CH2CH2SMe)2] respectively. On the basis of their i.r. and electronic spectra all contain octahedral chromium(III) CrE63+(E = P, As, or S) type cations. [Cr(Me2PCH2CH2PMe2)3][BF4]3 undergoes a reversible electrochemical one-electron reduction in dimethyl sulphoxide solution.