CLUSTER SYNTHESIS BY PHOTOLYSIS OF R3PAUN3 .8. SYNTHESIS AND CRYSTAL-STRUCTURE OF [(PH3PAU)5MO(CO)4]PF6.CH2CL2 AND (PH3PAU)3CO(CO)3

Photolysis of a mixture of Ph3PAuN3 and Mo(CO), in THF yields [(Ph3PAu)5Mo(CO)4]+ (1), which can be crystallized from CH2Cl2/diisopropylether as orange 1 . PF6 . CH2Cl2 with the space group P2(1)/c and a = 1 681.4(5), b = 2 215.6(12), c = 2 761.5 (9) pm, beta = 91.54(3)-degrees, Z = 4. The Au5Mo center of cluster 1 forms a capped trigonal bipyramid with the Mo atom in equatorial position and almost equal Mo-Au distances between 279.9(5) and 284.6(7) pm to all five Au atoms. The Au-Au distances range from 272.2(4) to 301.3(4) pm. The Mo(CO)4 group causes three nu(CO) at 1975, 1915 and 1890 cm-1. Reaction of Ph3PAuCo(CO)4 with Ph3PAuPF6 affords the known cluster cation [(Ph3PAu)4Co(CO)3]+ in high yield. It can be degraded with Cl- to the neutral cluster (Ph3PAu)3Co(CO)3 (2). 2 forms air stable, yellow crystals with the space group P2(1)/n and a = 1359.4(4), b = 2 041.0(5), c = 1 853.2(6) pm, beta = 91.47(t)-degrees, Z = 4. The Au3Co core of 2 has a tetrahedral structure with distances Co--Au between 250.4(1) and 254.0(2) pm and Au-Au between 279.5(1) and 285.1(1)pm. Nu(CO) are observed at 1 963, 1 905 and 1891 cm-1. Reaction of 2 with [(Ph3PAu)4Co(CO)3]+ yields the condensed cluster [(Ph3PAu)6AuCo2(CO)6]+.