Homo- and hetero-binuclear complexes containing the anion [Rh(C5Me5){PO(OMe)2}2(pyrazolate)]– as ligand. Crystal structure of [(C5Me5)Rh{µ-PO(OMe)2}2(µ-C3H3N2)-Ru(C6H6)]ClO4·CH2Cl2

Abstract

The neutral rhodium(III) complex [Rh(C₅Me₅)I{PO(OMe)₂}{P(OH)(OMe)₂}] reacts with pyrazole-type ligands [HL = pyrazole (Hpz), 3-methylpyrazole, or 3,5-dimethylpyrazole] in the presence of AgClO₄ yielding cationic complexes of the general formula [Rh(C₅Me₅){PO(OMe)₂}{P(OH)(OMe)₂}(HL)]ClO₄. They react with Na₂CO₃ in aqueous solutions with formation of the neutral complexes [Rh(C₅Me₅){PO(OMe)₂}₂(HL)]. Addition of NaH in tetrahydrofuran to the cationic complexes or thallium acetylacetonate in MeOH to the neutral compounds affords the corresponding bimetallic derivatives [(C₅Me₅)Rh{PO(OMe)₂}₂LM](M = Na or Tl). These complexes react with halide compounds such as [{M(ring)Cl₂}₂][M(ring)= Rh(C₅Me₅), Ir(C₅Me₅), Ru(C₆H₆), Ru(C₆H₅Me), Ru(MeC₆H₄Prⁱ-p) or Ru(C₆Me₆)], [MBr(CO)₅], [(PtMe₃I)₄] or [{Rh(µ–Cl)(cod)}₂](cod = cycloocta-1,5-diene) to give cationic or netural complexes of the type [(C₅Me₅)Rh{µ-PO(OMe)₂}₂(µ-L)-M(ring)]ClO₄ or [(C₅Me₅)Rh{PO(OMe)₂}₂(µ-L)ML_n][ML_n= Re(CO)₃, Mn(CO)₃, PtMe₃ or Rh(cod)]. The crystal structure of [(C₅Me₅)Rh{µ-PO(OMe)₂}₂(µ-pz)Ru(C₆H₆)]ClO₄·CH₂Cl₂ has been determined by X-ray diffraction methods: monoclinic, space group P2₁/c, a= 11.179(1), b= 17.039(1), c= 18.186(2)Å, β= 94.85(1)° and Z= 4. The complex cation consists of one rhodium and one ruthenium atom bridged by two phosphonate and one pyrazolate anion. An η⁵-C₅Me₅ and an η⁶-C₆Me₆ group complete the co-ordination spheres of the metals, which show no direct intermetallic interaction.