A hexanuclear gold carbonyl cluster.

The hexanuclear gold carbonyl cluster [PPh4](2)[Au-6(CF3)(6)Br-2(CO)(2)] (4) has been obtained by spontaneous self-assembly of the following independent units: CF3AuCO (1) and [PPh4][Br(AuCF3)(2)] (3). The cyclo-Au-6 aggregate 4, in which the components are held together by unassisted, fairly strong aurophilic interactions (Au…Au similar to 310 pm), exhibits a cyclohexane-like arrangement with chair conformation. These aurophilic interactions also result in significant nu(CO) lowering: from 2194 cm(-1) in the separate component 1 to 2171 cm(-1) in the mixed aggregate 4. Procedures to prepare the single-bridged dinuclear component 3 as well as the mononuclear derivative [PPh4][CF3AuBr] (2) are also reported.