Abstract
The synthesis and reaction chemistry of heteromultimetallic transition‐metal complexes are discussed. Complex [(η^2^‐dppf)(η^5^‐C~5~H~5~)Ru‐C≡C‐C~6~H~4~‐4‐PPh~2~] (3) [dppf = 1,1′‐bis(diphenylphosphanyl)ferrocene], accessible by treating [(η^2^‐dppf)(η^5^‐C~5~H~5~)RuCl] (1) with equimolar amounts of HC≡C‐C~6~H~4~‐4‐PPh~2~ (2), gives on treatment with [(cod)RhCl]~2~ (4), [(η^5^‐C~5~Me~5~)RhCl~2~]~2~ (6), and [(tht)AuCl] (8) heterotrimetallic [(η^2^‐dppf)(η^5^‐C~5~H~5~)Ru‐C≡C‐C~6~H~4~‐4‐PPh~2~‐{Rh}] [5, {Rh} = (cod)RhCl; 7, {Rh} = (η^5^‐C~5~Me~5~)RhCl~2~] and [(η^2^‐dppf)(η^5^‐C~5~H~5~)Ru‐C≡C‐C~6~H~4~‐4‐PPh~2~‐AuCl] (9), respectively. Tetra‐ and even pentametallic heteronuclear complexes can be prepared by following consecutive reaction sequences: Treatment of 9 with HC≡CR {10a, R = C~5~H~4~N‐4; 10b, R = C~6~H~4~‐4‐C≡N; 10c, R = bpy (= 2,2′‐__b__i__py__ridyl‐5‐yl); 12a, R = bpy[Re(CO)~3~Cl]} in the presence of HNEt~2~ and [CuI] gave [(η^2^‐dppf)(η^5^‐C~5~H~5~)Ru‐C≡C‐C~6~H~4~‐4‐PPh~2~‐Au‐C≡CR] {11a, R = C~5~H~4~N‐4; 11b, R = C~6~H~4~‐4‐C≡N; 11c, R = bpy; 13, R = bpy[Re(CO)~3~Cl]}. Compound 11c is the key starting material for complexes of higher nuclearity. Treatment of 11c with [(nbd)Mo(CO)~4~] (14) afforded heterotetrametallic {(η^2^‐dppf)(η^5^‐C~5~H~5~)Ru‐C≡C‐C~6~H~4~‐4‐PPh~2~‐Au‐C≡C‐bpy[Mo(CO)~4~]} (15), whereas with [{Ti~2~}M]X [16a, MX = Cu(N≡CMe)PF~6~; 16b, MX = AgOClO~3~] novel heteropentametallic [(η^2^‐dppf)(η^5^‐C~5~H~5~)Ru‐C≡C‐C~6~H~4~‐4‐PPh~2~‐Au‐C≡C‐bpy({Ti~2~}M)]X (17a, M = Cu, X = PF~6~; 17b, M = Ag, X = ClO~4~) is formed. The reaction of 11a with [{Ti~2~}Cu]OTf (16c) produced [(η^2^‐dppf)(η^5^‐C~5~H~5~)Ru‐C≡C‐C~6~H~4~‐4‐PPh~2~‐Au‐C≡C‐4‐C~5~H~4~N({Ti~2~}Cu)]OTf (18). The structures of 9, 11b, 11c, and 12 in the solid state and the electrochemical behavior of selected complexes are also reported.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)