Keto-stabilized phosphorus ylide gold(I) and gold(III) complexes

Reduction of (imine)Pt(IV) to (imine)Pt(II) complexes with carbonyl-stabilized phosphorus ylides

A novel method is reported for generation of the difficult-to-obtain (imine)Pt(II) compounds that involves reduction of the corresponding readily available Pt(IV)-based imines by carbonyl-stabilized phosphorus ylides, Ph3P=CHCO2R, in nonaqueous media. The reaction between neutral (imino)Pt(IV) compounds [PtCl4[NH=C(Me)ON=CR1R2]2] [R1R2 = Me2, (CH2)4, (CH2)5, (Me)C(Me)=NOH], [PtCl4[NH=C(Me)ONR2]2] (R = Me, Et, CH2Ph), (R1 = H; R2 = Ph or C6H4Me; R3 = Me) as well as anionic-type platinum(IV) complexes (Ph3PCH2Ph)[PtCl5[NH=C(Me)ON=CR2]] [R2 = Me2, (CH2)4, (CH2)5] and 1 equiv of Ph3P=CHCO2R (R = Me, Et) proceeds under mild conditions (ca. 4 h, room temperature) to give selectively the platinum(II) products (in good to excellent isolated yields) without further reduction of the platinum center. All thus prepared compounds (excluding previously described Delta4-1,2,4-oxadiazoline complexes) were characterized by elemental analyses, FAB mass spectrometry, IR and 1H, 13C[1H], 31P[1H] and 195Pt NMR spectroscopies, and X-ray single-crystal diffractometry, the latter for [PtCl2[NH=C(Me)ON=CMe2]2] [crystal system tetragonal, space group P4(2)/n (No. 86), a = b = 10.5050(10) A, c = 15.916(3) A] and (Ph3PCH2CO2Me)[PtCl3(NCMe)] [crystal system orthorhombic, space group Pna2(1) (No. 33), a = 19.661(7) A, b = 12.486(4) A, c = 10.149(3) A]. The reaction is also extended to a variety of other Pt(II)/Pt(IV) couples, and the ylides Ph3P=CHCO2R are introduced as mild and selective reducing agents of wide applicability for the conversion of Pt(IV) to Pt(II) species in nonaqueous media, a route that is especially useful in the case of compounds that cannot be prepared directly from Pt(II) precursors, and for the generation of systematic series of Pt(II)/Pt(IV) complexes for biological studies.

Complexes with S-Donor Ligands. 7. New 1,1-Ethylenedithiolato Complexes of Thallium(I), Gold(I), and Gold(III): Syntheses, Structure, and Molecular Cubic Hyperpolarizabilities

beta-Diketonato complexes [Tl{CH{C(O)R}(2)}] or PPN[Au{CH{C(O)R}(2)}(2)] [where PPN = (Ph(3)P)(2)N] react with an excess of CS(2) to give, respectively, [Tl(2){S(2)C=C{C(O)R}(2)}](n)() [R = Me (1) or Ph (2)] or (PPN)(2)[Au(2){&mgr;-kappa(2)-S(2)C=C{C(O)R}(2)}(2)] [R = Me (3.PPN) or Ph (4.PPN)]. The gold complexes 3.PPN and 4.PPN can also be obtained from PPN[AuCl(2)] and the corresponding thallium 1,1-ethylenedithiolate. PPN[AuCl(4)] reacts with 1 to give PPN[Au{kappa(2)-S(2)C=C{C(O)Me}(2)}(2)] (5) which, in turn, reacts with PhICl(2), Br(2) or I(2) (1:1) to give PPN[AuX(2){kappa(2)-S(2)C=C{C(O)Me}(2)}] [X = Cl (6), Br (7), or I (8)]. By reacting 6 with TlCF(3)SO(3) and 1,10-phenanthroline (phen) in 1:2:1 molar ratio, the cationic complex [Au{kappa(2)-S(2)C=C{C(O)Me}(2)}(phen)]CF(3)SO(3) (9) can be obtained. The crystal structures of 5 and 6.0.5Me(2)CO have been determined. Third-order nonlinearities of 3.PPN, 3.Pr(4)N, 5, and 6 have been evaluated by the Z-scan technique; an increase in nonlinearity upon extending the pi-system is observed, with the anionic dimetallacycle containing two gold and four sulfur atoms in 3 responsible for the largest nonlinearities (approximately 100 x 10(-36) esu).