Abstrakt: |
The replacement of the PPh3 ligands in “three-bridge” exo-nido-ruthenacarborane 5,6,10-[RuCl(PPh3)2]-5,6,10-(µ-H)3-10-H-exo-nido-7,8-C2B9H8 with diphosphines, viz., 1,3-bis(diphenylphosphino)propane (dppp) or 1,4-bis(diphenylphosphino)butane (dppb) dramatically decreases the barrier to the thermal exo-nido→closo rearrangement affording the chelate closo-complexes 3,3-[Ph2P(CH2)nPPh2]-3-H-3-Cl-closo-3,1,2-RuC2B9H11 (n = 3 or 4) under mild conditions. In the reaction with dppp, the rearrangement is accompanied by the formation of 17-electron paramagnetic closo-ruthenacarborane 3,3-[Ph2P(CH2)3PPh2]-3-Cl-closo-3,1,2-RuC2B9H11, which could be isolated as the main product when the reaction was carried out at 80 °C. [ABSTRACT FROM AUTHOR] |