THE SYNTHESIS OF [AUCO(CO)(4)](2)(MU-DPPFE) (DPPFE = 1,1'-BIS(DIPHENYL PHOSPHINO)FERROCENE) AND THE P-AU-CO-CO(AXIAL) SKELETAL PAIR FORMATION BETWEEN NEIGHBORING MOLECULES IN THE CRYSTAL

The title compound has been synthesized by reacting (AuCl)(2)(mu-dppfe ) with LiCo3(CO)(10) in THF at room temperature. The IR spectrum of th is product in the nu(CO) region has shown that each of the three peaks observed for a solution sample splits into a doublet in the solid. Si ngle crystal X-ray analysis has revealed that the P-Au-Co-CO(axial) sk eleton makes a pair in a head-to-tail manner with neighboring molecule s. The Au-Au separation in the pair is 5.6220(8) A, which is far beyon d the regime of the normal aurophilic interaction. By comparing the re sults with those of analogous Mn compound, that is, [AuMn(CO)(5)](2)(m u-dppfe), it has been concluded that the pair formation between the ne ighboring molecules is responsible for nu(CO) splitting of [AuCo(CO)(4 )](2)(mu-dppfe). (C) 1998 Elsevier Science S.A. All rights reserved.