一氧化碳加到[PtCl(R)(NN)](R =烃基; NN =螯合N,N-配体)上,得到中性五坐标[PtCl(R)(CO)(NN)]或阳离子四-坐标[Pt(R)(CO)(NN)] +配合物,具体取决于N,N-配体的空间拥挤。对于R-芳基,在温和条件下进行迁移插入过程,并获得相应的酰基物质。报道了五配位加合物与亲核试剂的一些反应,并描述了金属上的取代或配位一氧化碳的添加。
Carbon-carbon bond formation in cationic aryl-olefin-platinum(II) complexes
摘要:
Cationic five-coordinate [Pt(3-R1-4-R2-C6H3)(MeCN)(6-Me-py-2-CH=NPh)(C2H4)]+ complexes (R1, R2 = H, Me, OMe) undergo an unexpected rearrangement at 0-degrees-C in chloroform solution, affording, after treatment with aqueous LiCl, the neutral four-coordinate species [Pt(2-Et-4-R1-5-R2-C6H2)Cl(6-Me-py-2-CH=NPh)]. Pt-C(aryl) bond breaking and making is involved in the whole process, resulting in a 1,2-shift of the platinum atom to an adjacent position of the benzene ring. The same compound is obtained, together with products deriving from a typical insertion, when an equimolar amount of ethylene is added to a chloroform solution of [Pt(3-R1-4-R2-C6H3)(MeCN)(6-Me-py-2-CH=NPh)]+ at 0-degrees-C. When higher (>3) ethylene/Pt ratios are used, only the five-coordinate [Pt(3-R1-4-R2-C6H3CH2CH2)Cl(6-Me-py-2-CH= NPh)(C2H4)] complex is isolated. As the experimental data rule out the possibility of a (2-arylethyl)platinum to (2-ethylaryl)platinum rearrangement, different reaction paths are suggested for the two processes. When the two reactions are combined in a "one-pot' sequence, a regiocontrolled double alkylation of the aryl system can be obtained. The behavior of substrates containing bidentate nitrogen ligands having different five-coordination stabilizing effects is examined, and data concerning the reactions of propene and styrene are reported.