Syntheses and X-ray structures of mixed-metal gold phosphine clusters including an example having a highly asymmetric Re2Au2 skeleton

This study describes the synthesis and single crystal X-ray characterizatio n of three new heteronuclear gold clusters, i.e. (OC)(5)Re-Re(CO)(4)Au(2)dp pfe (1), Au,Co-2(CO)(7)(PPh3)(3) (2), and [Au-Co(CO)(4)](2)(cis-dpen) (3). They were synthesized from reaction of (AuCl)(2)dppfe with NaRe(CO)(5) at r oom temperature, reaction of (PPh3)AuCl with NaCo(CO)(4), and reaction of ( AuCl)(2)-(cis-dpen) with NaCo(CO)(4), respectively. Compound 1 crystallizes in the monoclinic space group P2(1),/n with a=15.331(7), b=23.427(9). c=13 .621(6) Angstrom, beta=112.53(3)degrees and Z = 4. Compound 2 crystallizes in the triclinic space group P (1) over bar with a = 12.838(4), b = 22.406( 6), c = 11.759(4) Angstrom, alpha = 103.15(2), beta = 117.06(2), gamma = 82 .78(2)degrees, and Z = 2. Compound 3 crystallizes in the triclinic space gr oup P1 with a = 10.704(2), b = 17.437(3), c = 10.597(2) Angstrom, alpha = 9 6.73(2), beta = 108.02(2), gamma = 99.53(2)degrees, and Z = 2. In 1, two go ld atoms in the Au(2)dppfe group are bound to one Re atom in the Re-2(CO)(9 ) group. Thus, the total skeleton is highly asymmetric. The metal skeleton of 2 is composed from a butterfly-like Au-4 backbone with a capping Co(CO)( 3) group and the terminal Co(CO)(4) group coordinated to one Au atom. Two g old atoms come close in 3 to cause intramolecular aurophilic interaction. T erminal Co(CO)(4) groups in 2 make an intermolecular pair in a head-to-tail manner in the crystal. (C) 1999 Elsevier Science S.A. All rights reserved.