Todisco Stefano, Latronico Mario, Gallo Vito, Re Nazzareno, Marrone Alessandro, Tolbatov Iogann, Mastrorilli Piero
Dipartimento di Ingegneria Civile, Ambientale, del Territorio, Edile e di Chimica (DICATECh), Politecnico di Bari, via Orabona 4, I-70125 Bari, Italy.
Dipartimento di Farmacia, Università di Chieti, Italy.
Dalton Trans. 2020 May 26;49(20):6776-6789. doi: 10.1039/d0dt00923g.
The reaction of the dinuclear phosphinito bridged complex (PHCy2)Pt(μ-PCy2){κ2P,O-μ-P(O)Cy2}Pt(PHCy2) (1) with phenylacetylene affords the η1-alkenyl-μ,η1:η2-alkynyl complex [(η1-trans-(Ph)HC[double bond, length as m-dash]CH)(PHCy2)Pt(μ-PCy2)(μ,η1:η2-PhC[triple bond, length as m-dash]C)Pt{κP-P(O)Cy2}(PHCy2)] (4) displaying a σ-bonded 2-phenylethenyl ligand and an alkynyl (μ-κCα:η2) bridge between the platinum atoms. Complex 4 was shown to form in two steps: initially, the attack of the first molecule of phenylacetylene gives the σ-acetylide complex (PHCy2)(η1-PhC[triple bond, length as m-dash]C)Pt1(μ-PCy2)Pt2(PHCy2){κP-P(OH)Cy2} (5) featuring an intramolecular π-type hydrogen bond between the POH and the C[triple bond, length as m-dash]C triple bond; fast reaction of 5 with a second molecule of phenylacetylene results in the oxidative addition of the terminal C-H bond of the second alkyne to Pt1 that, after rearrangements, leads to 4. When left in solution for two weeks, complex 4 spontaneously isomerizes completely to [(PHCy2)(η1-trans-(Ph)HC[double bond, length as m-dash]CH)Pt(μ-PCy2){κ2P,O-μ-P(O)Cy2}Pt(η1-PhC[triple bond, length as m-dash]C)(PHCy2)] (7) displaying a 2-phenylethenyl ligand and a phenylethynyl group both σ-bonded to the metal. Density functional calculations at the B3LYP/LACV3P++**//DFT/LACVP* level were carried out to study the thermodynamics of the formation of all considered complexes and to trace the mechanism of formation of the observed products.
双核次膦酸桥联配合物(PHCy2)Pt(μ-PCy2){κ2P,O-μ-P(O)Cy2}Pt(PHCy2) (1) 与苯乙炔反应生成η1-烯基-μ,η1:η2-炔基配合物[(η1-反式-(Ph)HC=CH)(PHCy2)Pt(μ-PCy2)(μ,η1:η2-PhC≡C)Pt{κP-P(O)Cy2}(PHCy2)] (4)，该配合物具有一个σ键合的2-苯乙烯基配体以及铂原子之间的一个炔基(μ-κCα:η2)桥。已证明配合物4通过两步形成：最初，第一个苯乙炔分子进攻生成σ-乙炔基配合物(PHCy2)(η1-PhC≡C)Pt1(μ-PCy2)Pt2(PHCy2){κP-P(OH)Cy2} (5)，其在POH和C≡C三键之间存在分子内π型氢键；5与第二个苯乙炔分子的快速反应导致第二个炔烃的末端C-H键向Pt1发生氧化加成，经重排后生成4。当在溶液中放置两周时，配合物4自发地完全异构化为[(PHCy2)(η1-反式-(Ph)HC=CH)Pt(μ-PCy2){κ2P,O-μ-P(O)Cy2}Pt(η1-PhC≡C)(PHCy2)] (7)，其具有一个均通过σ键与金属相连的2-苯乙烯基配体和一个苯乙炔基。在B3LYP/LACV3P++**//DFT/LACVP*水平上进行了密度泛函计算，以研究所有考虑的配合物形成的热力学，并追踪观察到的产物的形成机理。
