Complexes of tert-butyl diphenylphosphinomethyl ketone N-phenylhydrazone, Z-PPH2CH2C(But)=NNHPH, with molybdenum, palladium or platinum: Crystal structure of cis-[PdCl2{Z-PPH2CH2C(Bu t)=NNHPH}2]

Article abstract of DOI:10.1016/0020-1693(95)04806-5

tert-Butyl diphenylphosphinomethyl ketone N-phenylhydrazone, Z-PPh₂CH₂C(Bu^t)=NNHPh (1), was prepared by heating the phosphino N,N-dimethylhydrazone, Z-PPh₂CH₂C(Bu^t)=NNMe₂ with PhNHNH₂ in ethanol in the presence of acetic acid as catalyst. This phosphine was converted into the corresponding phosphine oxide 2a and phosphine sulfide 2b. Treatment of [Mo(CO)₄(nbd)] (nbd=norbornadiene) with 1 equiv. of 1 gave the tetracarbonylmolybdenum(0) complex [Mo(CO)₄{PPh₂CH₂C(Bu^t)=NNHPh}] (3) in which 1 is bidentate; [Mo(CO)₄(nbd)] with 2 equiv. of 1 gave the bis(phosphine)molybdenum(0) complex cis-[Mo(CO)₄{PPh₂CH₂C(Bu ^t)=NNHPh}₂] (4) in which 1 is monodentate through P. Treatment of [PdCl₂(NCPh)₂] or [PtCl₂(cod)] (cod=cycloocta-1,5-diene) with 2 equiv. of 1 gave the complexes cis-[MCl₂{PPh₂CH₂C(Bu^t)=NNHPh} ₂] (M=Pd (5a), Pt (5b)). The crystal structure of 5a was determined. Treatment of [PtCl₂(NCMe)₂] with 2 equiv. of the phosphine 1 gave trans-[PtCl₂{PPh₂CH₂C(Bu ^t)=NNHPh}₂] (5c). Dehydrochlorination of the platinum(II) dichloride 5b or 5c with Et₃N gave the neutral cis-[Pt{PPh₂CH₂C(Bu^t)=NNPh}₂] (6), containing two six-membered chelate rings. Treatment of the π-2-methylallyl complex [{(η³-2-MeC₃H₄)PdCl}₂] with 2 equiv. of the phosphine 1 gave the neutral complex [(η³-2-MeC₃H₄)PdCl{PPh₂CH ₂C(Bu^t)=NNHPh}] (7) in which 1 is monodentate through P. Dehydrochlorination of 7 with aqueous NaOH solution gave the π-methylallylpalladium(II) chelate complex [(η³-2-MeC₃H₄)Pd{PPh₂CH ₂C(Bu^t)=NNPh}] (8) containing an amidepalladium bond. Treatment of 1 with LiBuⁿ followed by PPh₂Cl gave the diphosphine Z-PPh₂CH₂C(Bu^t)=NN(Ph)PPh₂ (9) which with 0.5 equiv. of [{(η³-2-MeC₃H₄)PdCl}₂] followed by NH₄PF₆ gave the π-methylallylpalladium(II) PF₆ salt [(η³-2-MeC₃H₄) Pd-{PPh₂CH₂C(Bu^t)=NN(Ph)PPh ₂}]PF₆ (10). Crystals of 5a are monoclinic, space group P2₁/c, with a=12.900(2), b=40.083(6), c=10.8779(11) A, β=111.891(7)^o and Z=4, final R=0.0535 for 7558 observed reflections with F>4.0σ(F).