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Displacement of norbornadiene (NBD) from Pt(CF3)2(NBD) by weak donor ligands L, and reactions of cis-Pt(CF3)2L2 with water and acids

1989; Elsevier BV; Volume: 364; Issue: 1-2 Linguagem: Inglês

10.1016/0022-328x(89)85349-5

1872-8561

Trevor G. Appleton, Ron D. Berry, John R. Hall, Donald W. Neale,

Organic Light-Emitting Diodes Research

The NBD ligand in Pt(CF3)2(NBD) has been replaced under mild conditions by a number of neutral S-, N-, and O-donor ligands to form cis-Pt(CF3)2L2 complexes (L2 =N,N,N′,N′-tetramethylethylenediamine (tmen), bipyridine (bipy), ethylenediamine (en); L = pyridine (py), NH3, dimethylsulfoxide (DMSO), CH3CN, C6H5CN,N,N-dimethylformamide (DMF)). Reaction with DMSO produces predominantly the isomer cis-Pt(CF3)2(DMSO-S)(DMSO-O), with cis-Pt(CF3)2(DMSO-S)2 a minor component, as a result of steric constraints. Water or methanol attacks the CF3 groups, producing fluoride ion. The fluorine atoms of cis-Pt(CF3)2L2 (L2 = bipy, tmen; L = py) are susceptible to electrophilic attack by H+. Reaction with aqueous HCl or HClO4 converts one CF3 group into a coordinated CO group. With HCl, simultaneous protonation and displacement of the N-donor ligands occurred, yielding cis-Pt(CF3)(CO)Cl2−. With HClO4, the complexes cis-Pt(CF3)(CO)L2+ are initially generated, with subsequent displacement of the tmen and py (but not bipy) ligands to form cis-Pt(CF3)(CO)(OH2)2+. The remaining CF3 group is not attacked by H+. Reaction of Pt(CF3)2(NBD) with halide ions in acetone initially produced the binuclear complexes [(CF3)2Pt(μ-X)2Pt(CF3)2]2− (X = I, Cl) containing bridging halide. With larger amounts of halide ion the expected cis-Pt(CF3)2X22− complexes were not obtained, and instead cis-Pt(CF3)(CO)X2− and fluoride ion were formed. When the complexes [(CF3)2Pt(μ-X)2Pt(CF3)2]2− were kept in the presence of NBD, cis-Pt(CF3)(CO)X2− and Pt(CF3)2(NBD) were formed. When X = I, these two complexes then reacted together to yield cis-Pt(CF3)2I(CO)− and Pt(CF3)I(NBD).