Terdentate (P,N,N) complexes of a new pyridyl azine phosphine Z,E-PPh2CH2(But)CN–NC(Me)C5H4N and its deprotonated derivative (an azo phosphine) with transition metals

Abstract

tert-Butyl diphenylphosphinomethyl ketone hydrazone, Z-PPh₂CH₂C(Bu^t)NNH₂ condensed with 2–acetylpyridine to give Z,E-PPh₂CH₂(Bu^t)CN–NC(Me)C₅H₄N la, which reacts with [M(CO)₄(nbd)](nbd = norbornadiene) to give highly coloured tricarbonyl complexes [[graphic omitted]}](M = Mo 1a, W 1b or Cr 1c). Under mild conditions, la reacted with [PtMe₂(cod)](cod = cycloocta-1,5-diene) to give the dimethylplatinum(II) complex [[graphic omitted]C(Me)C₅H₄N}]2 containing the bidentate azine phosphine ligand. Complex 2 reacted with Mel to give the fac-trimethylplatinum(IV) iodide salt [[graphic omitted]}]3 in which the phosphine is terdentate. Under slightly acidic conditions, la reacted with [PtMe₂(cod)] to give a yellow methylplatinum(II) cation isolated as the PF₆ salt, [[graphic omitted]}]PF₆4a. Deprotonation of this cation with NaOMe gave the deep blue neutral methylplatinum(II) complex [[graphic omitted]}]5a, containing a terdentate azo phosphine ligand. Treatment of [PtCl₂(cod)] with la gave the yellow chloride salt [[graphic omitted]}]Cl 4b, which with NH₄PF₆ gives the corresponding PF₆ salt 4c. Sodium methoxide immediately deprotonates 4b to give the intensely deep blue neutral chloroplatinum(II) complex [[graphic omitted]}]5b. Treatment of [PdCl₂(NCPh)₂] with la gave the yellow chloropalladium(II) chloride salt [[graphic omitted]}]Cl 4d, which on deprotonation with NEt₃, gives the deep purple, neutral chloropalladium(II) complex 5c. Infrared, ³¹P-{¹H}, ¹H, some ¹³C-{¹H} NMR and UV/VIS data are given.