Trimethylsilyl- and trimethylstannyldimethylphosphane--convenient and versatile reagents for the synthesis of polyfluoroaryldimethylphosphanes.
Trimethylsilyldimethylphosphane (Me3SiPMe2) and the corresponding tin compound (Me3SnPMe2) were used as reagents for the substitution of fluorine by the Me2P group in polyfluoroarenes C6F5X (X = F, H, Cl, CF3) and C5NF5. The reactions occur even under mild conditions (T = 0-20 C), either in benzene or without solvent, to give as a rule 4-X-1-(dimethylphosphano)tetrafluorobenzenes (XC6F4PMe2, 1-4) and 4-(dimethylphosphano)tetrafluoropyridine (C5NF4PMe2, 5), respectively, in yields between 75 and 95%. In the case of C6F6, double substitution is also observed, which affords 1,4-bis(dimethylphosphano)tetrafluorobenzene (6). A very efficient route to the compounds XC6F4PMe2 (X = F, H, Cl, CF3) and C5NF4PMe2 was developed as a one-pot reaction of the corresponding fluoroarenes with tetramethyldiphosphane (P2Me4) and trimethyltin hydride (Me3SnH) at moderate temperatures. This process was tested for C6F6 and perfluorobiphenyl which gave C6F5PMe2 (1) and 4,4'-bis(dimethylphosphano)octafluorobiphenyl (7), respectively. The results, which included kinetic measurements that used the intensities of the 31P signals, revealed the influence of the substrate type on the rate of reaction in the sequence: C5NF5>C6F5CF3> C6F5Cl, C6F5PMe2>C6F5H>C6F6>> C6H5F. Ab initio calculations were carried out on the model reactions of pentafluoropyridine with silylphosphane, phosphane or phosphide to discriminate between possible reaction mechanisms. The novel phosphanes were characterised by spectroscopic investigations (NMR, MS), by preparation of the related thiophosphanes ArFP(=S)Me2 (8-14), their spectroscopic and analytic data and single crystal X-ray diffraction studies on five of these derivatives.
Nuclear magnetic resonance studies on metal complexes. Part I. Dimethylphenylphosphine complexes of platinum(II) and palladium(II)
New complexes of platinum(II) and palladium(II) with dimethylphenylphosphine are described. 1H Nuclear magnetic resonance data for these complexes, and for simple derivatives of dimethylphenylphosphine, e.g., the oxide and sulphide, are given. The phenomenon of “virtual” coupling is discussed briefly and used to study cis/trans isomerism in these complexes. trans-Di-iodobis(dimethylphenylphosphine)palladium(II) is unusual in having a red polymorph in which the palladium is co-ordinated to three iodine atoms and possibly weakly co-ordinated to β-hydrogen atoms on the phenyl rings.
Synthesis and reactions of organolithium and -magnesium compounds of perfluorodiphenyl ethers
Abstract p -C 6 F 5 OC 6 F 4 Li and p -C 6 F 5 OC 6 F 4 MgBr have been prepared. Their stability, benzyne formation and reactions with water, carbon dioxide, cuprous chloride and oxygen, phosphorus tribromide, tin tetrachloride have been studied. Solvent effects of THF, diethyl ether and furan on the synthesis and subsequent reactions of p -C 6 F 5 OC 6 F 4 Li are reported.