Bidentate and terdentate (P-N-S) complexes of a new thioether azine phosphine Z,E-PPh2CH2C(But)=N-N=C(Me)CH2S(C6H4Me-4) with molybdenum, tungsten, or platinum

Abstract

Treatment of Z-PPh2CH2C(But)=NNH2 with 4-methylphenylthiomethyl methyl ketone gave the thioether azine phosphine Z,E-PPh2CH2C(But)=N-N=C(Me)CH2S(C6H4Me-4) 1, which with H2O2 gave the corresponding phosphine oxide 2. Treatment of 1 with [Mo(CO)3(η6-cht)] or [W(CO)3(NCEt)3] gave the yellow tricarbonyl complexes fac-[M(CO)3{PPh2CH2C(But)=N-N=C(Me)CH2S(C6H4Me-4)}] 3a (Mo) or 3b (W), respectively. Treatment of 1 with [Mo(CO)4(nbd)] gave the pale yellow tetracarbonylmolbdenum(0) complex [Mo(CO)4{PPh2CH2C(But)=N-N=C(Me)CH2S(C6H4Me-4)}] 4, in which the ligand 1 is bidentate through P and N. Oxidation of either 3a or 4 with 1 equivalent of bromine gave the orange neutral seven-coordinate dicarbonylmolybdenum(II) complex [MoBr2(CO)2{PPh2CH2C(But)=N-N=C(Me)CH2S(C6H4Me-4)}] 5, whereas the tungsten complex 3b with 1 equivalent of bromine gave the seven-coordinate tricarbonyltungsten(II) cation [WBr(CO)3{PPh2CH2C(But)=N-N=C(Me)CH2S(C6H4Me-4)}]+ isolated as the PF6 salt 6. Treatment of 1 with [PtCl2(NCMe)2]gave the yellow dichloroplatinum(II) complex [PtCl2{PPh2CH2C(But)=N-N=C(Me)CH2S(C6H4Me-4)}] 7, in which 1 is bidentate through P and N. When 7 was treated with NH4PF6 in methanol it gave the terdentate salt [PtCl{PPh2CH2C(But)=N-N=C(Me)CH2S(C6H4Me-4)}]PF68a. Deprotonation of 7 with NEt3-NaOH gave the orange neutral chloroplatinum(II) complex [PtCl{PPh2-CH2C(But)N-NC(Me)=CHS(C6H4Me-4)}] 9, containing a terdentate ene-hydrazone phosphine ligand. This neutral complex 9 was reprotonated using HBF4 to give the BF4 salt 8b. Treatment of the phosphine 1 with [PtMe2(cod)] gave the white dimethylplatinum(II) complex [PtMe2{PPh2CH2C(But)=N-N=C(Me)CH2S(C6H4Me-4)}] 10, containing the bidentate azine ligand. Treatment of 10 with MeI gave the white platinum(IV) iodide salt fac-[PtMe3{PPh2CH2C(But)=N-N=C(Me)CH2S(C6H4Me-4)}]I 11a in which the azine is terdentate. When 11a was treated with NH4PF6 in MeOH the PF6 salt 11b was obtained. Treatment of 10 with picric acid gave the yellow methylplatinum(II) picrate salt [PtMe{PPh2CH2C(But)=N-N=C(Me)CH2S(C6H4Me-4)}][OC6H2(NO2)3-2,4,6] 12 and methane. Infrared, 31P–[1H], 1H, and some 13C–[1H] NMRdata are given. Keywords: azine phosphine, thioether, metal-carbonyls, platinum.