Metathesis Approach to Linkage of Two Tetraplatinum Cluster Units: Synthesis, Characterization, and Dimerization of [Pt4(μ-OCOCH3)7(μ-OCO(CH2)nCH=CH2)] (n = 0–3)
Reaction of [Pt 4 (μ-OCOCH 3 ) 8 ] (1) with 1 equiv of acrylic acid led to the selective monosubstitution of one of the four in-plane acetates in 1, affording [Pt 4 (μ-OCOCH 3 ) 7 (μ-OCOCH=CH 2 )] (2a), whereas treatment with excess amounts of acrylic acid resulted in a full-substitution of four in-plane acetates, yielding [Pt4(μ-OCOCH3)4(μ-OCOCH=CH2) 4 ] (3). Similarly, monosubstituted heptaacetate complexes [Pt 4 (μ-OCOCH3) 7 {μ-OCO(CH) n CH=CH 2 }] (2b-2d: n = 1-3) were prepared. Catalytic intermolecular coupling reactions of 2c and 2d assisted by Grubbs' catalysts gave the desired dimers [{Pt 4 -(μ-OCOCH 3 ) 7 } 2 {μ-OCO(CH 2 ),,CH=CH(CH2) n (μ-OCO)} (6c: n = 2; 6d: n = 3).