Discrete Triangle, Square and Hexametallic Alkynyl Cyano‐Bridged Compounds Based on [ cis ‐Pt(CCR) 2 (CN) 2 ] 2− Building Blocks

Novel mixed bis(alkynyl)bis(cyano)platinate( II ) species [ cis ‐Pt(CCR) 2 (CN) 2 ] 2− ( 1 a : R = t Bu, 1 b : R = Ph) have been prepared and their potential as building blocks in the generation of self‐organized systems with a variable molecular architecture has been studied. The reaction of 1 with the ditopic acceptor species [{ cis ‐Pt(C 6 F 5 ) 2 S} 2 (dppa)] (dppa=diphenylphosphinoacetylene) gave the dianionic cyanide/dppa bridged molecular platinotriangles (NBu 4 ) 2 [(C 6 F 5 ) 2 Pt(μ‐dppa){(μ‐CN) 2 Pt(CCR) 2 }Pt(C 6 F 5 ) 2 ] ( 2 ). X‐ray analysis of 2 a confirmed that the “Pt 2 (C 6 F 5 ) 4 (μ‐dppa)” binuclear moiety is connected to the dianionic “Pt(CCR) 2 (CN) 2 ” unit by two bridging cyanide ligands. Moreover, treatment of 1 with the solvent cationic species [M(cod)(acetone) 2 ] + afforded heterometallic molecular squares Pt 2 M 2 (M=Rh, Ir) containing cyanide bridges and terminal alkynyl ligands, (NBu 4 ) 2 [cyclo{[ cis ‐Pt(CCR) 2 (μ‐CN) 2 ][M(cod)]} 2 ] ( 3 : M=Rh, 4 : M = Ir). The solid‐state structures of phenyl derivatives have been determined by X‐ray crystallography. The terminal alkynyl ligands in these cyanide‐bridged molecular squares 3 and 4 have been used in the assembly of higher multimetallic complexes. Thus, very unusual bis(double‐alkynide)‐cyanide‐bridged hexametallic compounds (NBu 4 ) 2 [{(C 6 F 5 ) 2 Pt(μ‐CCPh) 2 (μ‐CN) 2 } 2 {M(cod)} 2 ] ( 5 b : M=Rh, 6 b : M = Ir) were easily formed by simple reactions of 3 b and 4 b with two equivalents of [ cis ‐Pt(C 6 F 5 ) 2 (thf) 2 ]. An X‐ray diffraction study on complex 5 b indicated that the derivative was formed by a simultaneous migration of one σ‐alkynyl group from each “Pt(CCPh) 2 (μ‐CN) 2 ” corner of the square to both “Pt(C 6 F 5 ) 2 ” units, resulting in bent σ,π‐double‐alkynyl bridging systems. Finally, the novel supramolecular anionic assemblies (NBu 4 ) 4 [cyclo{[ cis ‐Pt(CCR) 2 (μ‐CN) 2 ][SnPh 3 ]} 4 ] 7 have been obtained by self‐assembly of 1 and [SnPh 3 (acetone) 2 ] + .