Metal carbonyl chemistry. Part XVIII. Preparation and reactions of some transition metal derivatives of hexafluorobicyclo[2.2.0]hexa-2,5-diene

Abstract

Hexafluorobicyclo[2.2.0]hexa-2,5-diene reacts with [M(Ph₃P)₄](M = Pt or Pd) to afford air-stable complexes of the type [(C₆F₆)M(PPh₃)₂]. These compounds react further with [Pt(Ph₃P)₄] or [Pd(Ph₃P)₄] to give the compounds [(C₆F₆){Pt(PPh₃)₂}₂] and [(C₆F₆){Pd(PPh₃)₂}₂], respectively; the latter complex is also obtained on thermal decomposition of [(C₆F₆)Pd(PPh₃)₂] in solution at 90 °C. The para-bonded benzene also reacts with an excess of acetylacetonatobis(ethylene) rhodium to give [(C₂H₄)(acac)Rh(C₆F₆)] and [{(C₂H₄)(acac)Rh}₂(C₆F₆)]. The mono-rhodium complex reacts with 1,2-bis(diphenylphosphino)ethane to yield a compound which is thought to be [(C₆F₆)Rh(acac)(Ph₂P·CH₂·CH₂PPh₂)]. Reactions of the para-bonded benzene with carbonyl-metal anions to yield the compounds [(C₆F₅)M(CO)₅](M = Mn or Re) and [(C₆F₅)Fe(CO)₂(π-C₅H₅)] are also described, together with the preparation of the adducts [(RC₆F₆)Mn(CO)₅](R = H, Me, or Ph) obtained by reaction of hexafluorobicyclo[2.2.0]hexa-2,5-diene with [HMn(CO)₅], [MeMn(CO)₅], or [PhMn(CO)₅]. In all complexes described the para-bond is retained.