Reactivity of [trans-PtH(C≡CC5H4N-2) (PPh3)2] toward [cis-Pt(C6F5)2(thf)2]. Synthesis of an Unusual Triplatinum Cluster-Substituted Platinum Complex

Article abstract of DOI:10.1021/om9809062

The complex [trans-PtH(C≡CR)PPh₃)₂] (1) (R = 2-pyridyl) reacts with [cis-Pt(C₆F₅)₂(thf)₂] under mild conditions to afford initially the 1:1 adduct (trans,cis-(PPh₃)₂(H)Pt(μ-1κC ^α:η²αβ: 2κN-C≡CC₅H₄N-2)Pt(C₆F ₅)₂] (2), which finally rearranges to form a mixture of [cis,trans-(PPh₃)(C₆F₅)₂Pt ^-(μ-1κC^α:2κN-C≡CC ₅H₄N-2)Pt⁺(H)(PPh₃)₂] (5) (X-ray) and a tetranuclear cluster [{cis-Pt(C₆F₅)₂(PPh₃)(μ ₃-1κCα:2κCβ:3κN-C₂C ₅H₄N-2)}{Pt₃(C₆F₅) ₂(μ₃3κC^α:η² _α,β:2κN-CH= CHC₅H₄N-2)(PPh₃)₂}] (3). Complex 3, characterized crystallographically, can be described as a formal zwitterionic cationic Pt₃ cluster-substituted alkynyl platinate complex [Pt]^--C≡ CC₅H₄N-2[Pt₃]⁺ (3A), rather distorted. Another important feature in 3 is the presence of a vinyl group capping the Pt₃ framework. Treatment of 2 with the equimolar amount of PPh₃ allows the synthesis not only of 5 but also of the less polar isomeric complex [trans,cis-(PPh₃) ₂(H)Pt(μ-1κCα:2κN-C≡CC₅H ₄N-2)Pt(C₆F₅)₂(PPh₃)] (4).