1400680-99-0Relevant academic research and scientific papers
Synthesis and oxidation of d6 tungsten pincer complexes: A complete series of tungsten(ii) hydridocarbonyl and halocarbonyl pincer complexes
Wingard, Leah A.,White, Peter S.,Templeton, Joseph L.
, p. 11438 - 11448 (2013/05/22)
Reaction of the neutral PHNP ligand [HN(SiMe2CH 2PPh2)2] with tungsten hexacarbonyl resulted in coordination of PHNP through both phosphorus donor atoms to form the tungsten complex [W(PHNP)(CO)4] (1). Reaction of P HNP with tris(acetonitrile)tricarbonyl tungsten gave both facial and meridional tridentate isomers [W(PHNP)(CO)3] (2-fac and 3-mer). These three d6 tungsten complexes could be interconverted under appropriate conditions. The thermodynamically favored isomer 3 was protonated to form seven-coordinate [W(PHNP)(CO)3H] [BF4] (4). A related series of cationic tungsten(ii) halide complexes was synthesized, [W(PHNP)(CO)3X]+ (6, X = I; 7, X = Br; 8, X = Cl; 9, X = F), by various routes. All of the tungsten(ii) complexes underwent deprotonation at the amine site of the PHNP ligand when triethylamine was added, resulting in neutral seven-coordinate complexes. Variable temperature 1H, 31P{1H}, and 13C{1H} NMR spectroscopy showed fluxional behavior for all the seven-coordinate complexes reported here. Analysis of IR and NMR spectroscopic data showed trends through the series of coordinated halides. Crystal structures of tetracarbonyl 1, meridional tricarbonyl 3, and cationic hydride 4 were determined to confirm the coordination mode of the P HNP ligand.
