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
摘要:
tert-Butyl diphenylphosphinomethyl ketone hydrazone, Z-PPh2CH2C(Bu(t))=NNH2 condensed with 2-acetylpyridine to give Z,E-PPh2CH2(Bu(t))C=N-N=C(Me)C5H4N Ia, which reacts with [M(CO)4(nbd)] (nbd = norbornadiene) to give highly coloured tricarbonyl complexes [M(CO)3{PPh2CH2C(Bu(t))=N-N=C(Me)C5H4N}] (M = Mo 1a, W 1b or Cr 1c). Under mild conditions, Ia reacted with [PtMe2(cod)] (cod = cycloocta-1,5-diene) to give the dimethylplatinum(II) complex [PtMe2{PPh2CH2C(Bu(t))=N-N=C(Me)C5H4N}] 2 containing the bidentate azine phosphine ligand. Complex 2 reacted with Mel to give the fac-trimethylplatinum(IV) iodide salt [PtMe3{PPh2CH2C(Bu(t))=N-N=C(Me)C5H4N}]I 3 in which the phosphine is terdentate. Under slightly acidic conditions, Ia reacted with [PtMe2(cod)] to give a yellow methylplatinum(II) cation isolated as the PF6 salt, [PtMe{PPh2CH2C(Bu(t))=N-N=C(Me)C5H4N}]PF6 4a. Deprotonation of this cation with NaOMe gave the deep blue neutral methylplatinum(II) complex [PtMe{PPh2CH=C(Bu(t))-N=N-C(Me)=C5H4N}] 5a, containing a terdentate azo phosphine ligand. Treatment of [PtCl2(cod)] with Ia gave the yellow chloride salt [PtCl{PPh2CH2C(Bu(t))=N-N=C(Me)C5H4N}]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 [PtCl{PPh2CH=C(Bu(t))-N=N-C(Me)=C5H4N}] 5b. Treatment of [PdCl2(NCPh)2] with Ia gave the yellow chloropalladium(II) chloride salt [PdCl{PPh2CH2C(Bu(t))=N-N=C(Me)C5H4N}]Cl 4d, which on deprotonation with NEt3, gives the deep purple, neutral chloropalladium(II) complex 5c. Infrared, P-31-{H-1}, H-1, some C-13-{H-1} NMR and UV/VIS data are given.
Synthesis of palladium and platinum complexes containing the multidentate ligands PPh2CH2(tBu)NNC(R)Q (R=H, Me; Q=2-pyridine, 2-thiophene, o-BrC6H4). Crystal structure of [PtMe{PPh2CHC(tBu)NNCMe(2-py)-κ3N,N′,P}] and [PdBr{PPh2CH2C(tBu)NNCHC6H4}-κ3C,N,P]
摘要:
The reaction of PPh2CH2C('Bu)=NN=CMe(NC5H4) (1) with [Pt2Me4(mu-SMe2)(2)] gave the six-membered metallacycle [PtMe2(PPh2CHC(Bu-t)NNCMe(2-py)-kappa(2)N,P}] (4) which was converted into [PtMe(PPh2CHC(Bu-t)NNCMe(2-py)-kappa(3)N,N',P}] (5) at elevated temperature. Treatment of the methyl platinum complex 5 with an excess of MeI gave [PtMe2I(PPh2CHC(Bu-t)NNCMe(2-py)-kappa(3)N,N',P}]. A similar reaction of PtMe2(cod) with [PPh2CH2C(Bu-t)=NN=C(HSC4H3] (2) also afforded PtMe2(PPh2CH2C('Bu)NNC(H)SC4H3-kappa(2)N,P} (7). The prolonged heating of 7 led to decomposition rather than the cycloplatination product. The treatment of 2 with PtCl2(cod) in the presence of NEt3 gave the deprotonated platinum(II) complex Pt{PPh2CH=C('Bu)N-N=C(H)SC4H3-kappa(2)N,P}(2)] (8) containing an ene-hydrazone backbone. The cyclopalladated metallacycle [PdBr{PPh2CH2C(Bu-t)-N-N=CHC6H4}-kappa(3)C,N,P] (9) has been prepared by the oxidative addition of the o-halo-substituted phosphino hydrazone derived from PPh2CH2C(Bu-t)=N-N=C(H)(o-BrC6H4) (3) to Pd-2(dba)(3). These new complexes have been characterized by H-1-, C-13-, and P-31-NMR, and elemental analyses. The molecular structures of 4, 5 and 9 have been determined by a single-crystal X-ray diffraction study. (C) 1999 Elsevier Science S.A. All rights reserved.