1041010-92-7Relevant academic research and scientific papers
Oxidation of Pt-bound bis-hydroxylamine as a novel route to unexplored dinitrosoalkane ligated species
Luzyanin, Konstantin V.,Gushchin, Pavel V.,Pombeiro, Armando J. L.,Haukka, Matti,Ovcharenko, Victor I.,Kukushkin, Vadim Yu.
, p. 6919 - 6930 (2009/02/06)
The reaction of K2[PtCl4] and HO(H)NCMe 2CMe2N(H)OH·H2SO4 (BHA·H2SO4; 2) in a molar ratio 1:2 at 20-25° C in water affords a mixture of [Pt(BHA)2][PtCl4] (5) and [Pt(BHA-H)2] (6) (BHA-H = anionic monodeprotonated form of BHA) which, upon heating at 80-85°C for 12 h or on prolonged keeping at 20-25°C for 2 weeks, is subject to a slow transformation giving [PtCl 2(BHA)] (7). The latter compound is also obtained from the reaction between K[PtCl3(Me2Scombining minus sign belowO)] and 2. The chlorination of [PtCl2(BHA)] (7) in freshly distilled dry chloroform leads to the selective oxidation of one N(H)OH group yielding [PtCl2{HO(H)Ncombining minus sign belowCMe2CMe 2N=O}] (13), while the chlorination in water produces the complex [PtCl2(O=Ncombining minus sign belowCMe2CMe 2Ncombining minus sign below=O)] (14) bearing the unexplored dinitrosoalkane species. Treatment of 14 with 2 equiv of 1,2-bis- (diphenylphosphino)ethane (dppe) in CH2Cl2 results in the liberation of the dinitrosoalkane ligand followed by its fast cyclization giving the α-dinitrone (3,3,4,4-tetramethyl-1,2-diazete-1,2-dioxide) in solution and the solid [Pt(dppe)2](Cl)2. The PtII complexes with hydroxylamino∩oximes [PtCl2{HO(H)Ncombining minus sign belowC(Me)2C(R)=Ncombining minus sign belowOH}] (R = Me 8; R = Ph 9) upon their oxidation with Cl2 in CHCl3 afford the nitrosoalkane derivatives [PtCl2{O=Ncombining minus sign belowCMe2C(R)=Ncombining minus sign belowOH}] (R = Me 16; Ph 17), respectively, while the corresponding chlorination of the bis-chelates [Pt{HO(H)Ncombining minus sign belowCMe2C(R)=Ncombining minus sign belowOH}2] (R = Me 10; Ph 11) gives [Pt{O=Ncombining minus sign belowCMe2C(R)=Ncombining minus sign belowO}2] (R = Me 18; Ph 19). The formulation of 5-19 is based on C, H, and N microanalyses, IR, 1D (1H, 13C{1H}, 195Pt) and 2D ( 1H,1H-COSY,1H,13C-HSQC) NMR spectroscopies, and X-ray diffraction for five complexes (5, 7, and 12-14).
Kinetic and thermodynamic aspects of the regioselective addition of bifunctional hydroxylaminooxime-type HO-nucleophiles to Pt-complexed nitriles
Luzyanin, Konstantin V.,Kukushkin, Vadim Yu.,Kuznetsov, Maxim L.,Ryabov, Alexander D.,Galanski, Markus,Haukka, Matti,Tretyakov, Eugene V.,Ovcharenko, Victor I.,Kopylovich, Maximilian N.,Pombeiro, Armando J. L.
, p. 2296 - 2306 (2008/10/09)
The coupling between coordinated propiononitriles in trans-[PtCl n(EtCN)2] (n = 2, 4) and the 1,2-hydroxylaminooximes HON(H)CMe2C(R)=NOH (R = Ph 1, Me 2) proceeds smoothly in CHCl 3 at ca. 40-45°C and gives trans-[PtCln-{NH=C(Et)ON(H) CMe2C(R)=NOH}2] (n = 2, R = Ph 5, Me 6; n = 4, R = Ph 7, Me 8) in 80-85% isolated yields. The reaction is highly regioselective, and both spectroscopic (IR; FAB+-MS; 1D 1H, 13C{ 1H}, and 195Pt NMR; and 2D 1H,13C HMQC, 1H,13C HMBC, and 1H,15N HMQC NMR) and X-ray data for 6-8 suggest that the addition proceeds exclusively via the hydroxylamine moiety of the 1,2-hydroxylaminooxime species; the existence of an oxime group remote from the nucleophile was also confirmed. Heating of 6 in air leads to its conversion to the unusual nitrosoalkane complex [PtCl 2{HON=C(Me)C(Me)2N=O}] (9), whereas in the case of 5, only the metalfree salt [H3NC(Me)2C(Ph)=NOH] 2(NO3)Cl·H2O (10) was isolated. To compare the kinetic aspects and trends in the addition of both types of nucleophiles (oximes and hydroxylamines; for the latter, see our recent work: Inorg. Chem. 2005, 44, 2944) to coordinated nitriles, a kinetic study of the addition of HON=C(CH2Ph)2 to [Ph3PCH 2-Ph][PtCl5(EtCN)] (11) to give [Ph3PCH 2Ph][PtCl5{NH=C(Et)ON=C(CH2Ph)2}] (12) was performed. The calculated rate constant k2 of 3.9 x 10 -6 M-1 s-1 at -20°C for the addition of the oxime indicates that the hydroxylamine is, by a factor 1.7 × 10 4, more reactive toward the addition to nitriles than the oxime. Results of the synthetic, kinetic, and theoretical (at the B3LYP level of theory) studies have demonstrated that the high regioselectivity of the reactions of the 1,2-hydroxylaminooximes with ligated nitriles is both kinetically and thermodynamically controlled.
