Syntheses and structures of the heterometallic clusters [(Ph3PAu)3Re(CO)4], [(Ph3PAu)4Re(CO)4], [(Ph3PAu)6AuRe2(CO)8], and [(Ph3PAu)6Re(CO)3]

The reaction of HRe₃(CO)₁₂]²⁻ with an excess of Ph₃PAuCl in CH₂Cl₂ yields (Ph₃PAu)₄Re(CO)₄]⁺ as the main product, which crystallizes as (Ph₃PAu)₄Re(CO)₄]PF₆ · CH₂Cl₂ (1 · CH₂Cl₂) after the addition of KPF₆.The crystal structure determination reveals a trigonal bipyramidal Au₄Re cluster with the Re atom in equatorial position.If (Ph₃PAu)₄Re(CO)₄]⁺ is reacted with PPh₄Cl, a cation Ph₃PAu]⁺ is eliminated as Ph₃PAuCl, and the neutral cluster (Ph₃PAu)₃Re(CO)₄] (2) is formed.It combines with excess (Ph₃PAu)₄Re(CO)₄]⁺ to afford the cluster cation, (Ph₃PAu)₆AuRe₂(CO)₈]⁺. It crystallizes from CH₂Cl₂ as(Ph₃PAu)₆AuRe₂(CO)₈]PF₆ · 4CH₂Cl₂ (3 · 4CH₂Cl₂). In (Ph₃PAu)₃Re(CO)₄] the metal atoms are arranged in form of a lozenge while in (Ph₃PAu)₆AuRe₂(CO)₈]⁺ two Au₄Re trigonal bipyramids are connected by a common axial Au atom.The treatment of (Ph₃PAu)₄Re(CO)₄]⁺ with KOH and Ph₃PAuCl in methanol yields the cluster cation (Ph₃PAu)₆Re(CO)₃]⁺, which crystallizes with from CH₂Cl₂ as (Ph₃PAu)₆Re(CO)₃]PF₆ · CH₂Cl₂ (4 · CH₂Cl₂). The metal atoms in this cluster form a pentagonal bipyramid with the Re atom in the axial position.