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Russian Journal of General Chemistry - 相似文献
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Barnes NA Godfrey SM Halton RT Mushtaq I Pritchard RG 《Dalton transactions (Cambridge, England : 2003)》2008,(10):1346-1354
The reactions of the tris-dialkylamino phosphines (Et2N)3P and (nPr2N)3P, and the pyrrolidinyl substituted phosphines (C4H8N)3P and tBuP(NC4H8)2, with I2 and (Ph2Se2I2)2, have been reported. The reactions with diiodine lead to the formation of [R3PI]I adducts, which are essentially ionic, but show a tendency to display long, soft-soft, II interactions in the solid state. The crystal structures of [(Et2N)3PI]I, (1), [(nPr2N)3PI]I, (2), and [(C4H8N)3PI]I, (3), have all been determined, and display II interactions varying between 3.5170(6) and 3.6389(14) A. The analogous reactions with (Ph2Se2I2)2 lead to the formation of phenylseleno-phosphonium salts, [R3PSePh]I. The structures of [(C4H8N)3PSePh]I, (6) and [(C4H8N)2tBuPSePh] I, (7), have been determined and do not display any soft-soft interactions between the selenium and iodine atoms. All of the phosphonium salts represent examples of structures containing tris-dialkylamino phosphine fragments which show no special nitrogen atom, i.e. all three nitrogen atoms are planar. This type of arrangement is usually observed when a C3 symmetric conformation is observed, (which is the case for 1 and 2), but not for the (C4H8N)3P adducts 3 and 6, where the conformation is closer to Cs, although the nitrogen atoms are still essentially planar. The P-N bonds in all the compounds reported herein are short, ranging between 1.599(12) A and 1.643(12) A, and are consistent with the previously reported short P-N bonds in phosphonium salts featuring tris-dialkylamino substituted phosphines. 相似文献
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The reaction of M(η6-1,3,5-Me3C6H3)2, M = Cr, Mo, with the tetrahalides of Groups 4 and 5 elements proceeds with the monoelectronic oxidation of the metal bis-arene to the [M(η6-Me3C6H3)2]+ cation. In the case of MX4, M = Ti, X = Cl, Br, M = V, X = Cl, and of Nb2Cl10 the reduction products are the titanium(III), vanadium(III) halides and the niobium(IV) chloride, isolated as the solvate anions [MCl4(THF)2]− and [NbCl4(CH3CN)]−. The reaction of the tetrachloro complexes MCl4(THF)2, M = Zr, Hf, with Cr(η6-1,3,5-Me3C6H3)2 in THF produces the ionic [Cr(η6-1,3,5-Me3C6H3)2][MCl5(THF)], which has been characterized by single-crystal X-ray diffraction in the case of hafnium. 相似文献
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Nairn AK Archibald SJ Bhalla R Boxwell CJ Whitwood AC Walton PH 《Dalton transactions (Cambridge, England : 2003)》2006,(14):1790-1795
Copper(I) complexes of the ligand cis-1,3,5-tris(cinnamylideneamino)cyclohexane (L) have been prepared from a versatile precursor complex, [Cu(I)(L)NCMe]BF4, which incorporates a labile acetonitrile ligand that can be exchanged to give a range of new Cu(L)X complexes (where X = Cl, Br, NO2, SPh). 1H NMR spectra and X-ray structures of the Cl, Br and NO2 complexes show L coordinated in a symmetric fashion about the copper centre. The complexes have been further characterised using UV/Visible spectroscopy and cyclic voltammetry. CuLCl shows an electrochemically reversible Cu(I/II) redox couple at 0.51 V (vs. Ag/AgCl) while the CuLNO2 complex shows an analogous quasi-reversible wave at 0.41 V (vs. Ag/AgCl). 相似文献
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The stereoselectivity of the Staudinger reactions involving monosubstituted ketenes with electron acceptor substituents was investigated experimentally by determination of the product stereochemistry and theoretically via DFT calculations. The results indicate that imines preferentially attack the less sterically hindered exo-side of the ketenes to generate zwitterionic intermediates. Subsequently, for cyclic imines, the intermediates undergo a conrotatory ring closure directly to produce β-lactams, while for linear imines, the imine moiety of the intermediates isomerizes to more stable intermediates, which further undergo a conrotatory ring closure to afford trans-β-lactams. The steric hindrance and the isomerization, rather than the torquoelectronic effect, play crucial roles in controlling the stereoselectivity in the practical Staudinger reactions involving monosubstituted ketenes with electron acceptor substituents, although the unaccessible borylketene with a powerful electron acceptor group controls the stereoselectivity torquoelectronically, in theory. 相似文献
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V. V. Sharutin O. V. Molokova O. K. Sharutina S. A. Smirnova 《Russian Journal of Inorganic Chemistry》2012,57(9):1252-1258
Bis[??-oxo-tri(2-methylphenyl)antimony] (I) was synthesized via oxidation of tri(2-methylphenyl)antimony by hydrogen peroxide in ether. In the presence of 2-hydroxy-5-bromobenzaldoxime or furfural oxime, the reaction between these reactants (in a 1: 1: 1 molar ratio, respectively) yields (??-oxo)bis[2-hydroxy-5-bromobenzaldoximato-tri(2-methylphenyl)antimony] (II) or (??-oxo)bis[furfural-oximatotri(2-methylphenyl)antimony] (III). The structures of compounds I?CIII was determined by X-ray diffraction. In the centrosymmetric dimeric complex I, the Sb atom has a distorted trigonal-bipyramidal coordination with oxygen atoms in equatorial and axial positions. In II and III, the axial positions are occupied by the bridge oxygen atom and the oxygen atom of the oxime ligand. Bond length values are as follows: Sb-C 2.137(3)?C2.183(3), 2.116(7)?C2.131(7), and 2.105(5)?C2.126(6)?; Sb-O 1.934(2), 2.077(2), 1.973(4)?C2.151(4), and 1.9706(3)?C2.112(6) ? for I, II, and III, respectively. Intramolecular contacts Sb...N (2.953(8), 3.002(9), and 2.951(8) II and III. 相似文献
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《Journal of organometallic chemistry》1995,492(1):C1-C3
The novel tripodal phosphine ligand cis, cis-1,3,5-tris(diphenylphosphino)-1,3,5-tris(methoxycarbonyl)cyclohexane (tdppcyme) (2) has been synthesized. 1H, 13C and 31P NMR spectroscopy shows that in solution the sterically demanding diphenylphosphine groups occupy equatorial positions on the cyclohexane ring. An X-ray crystal investigation confirms this result for the solid state. Treatment of tdppcyme with Mo(η6-C7H8)(CO)3 gives Mo(tdppcyme)(CO)3 (3), with octahedral molybdenum coordination. 相似文献
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《Tetrahedron: Asymmetry》2000,11(20):4171-4178
For the synthesis of the potentially antipsoriatic vitamin D derivative 3 (Ro 65-2299) an efficient and multiselective enzymatic step had been developed in which the easily accessible trans-1,3,5-triacetoxy-cyclohexane 5 was selectively monohydrolyzed in the presence of the cis-isomer 8 to give (1R,3R)-1,3-diacetoxy-5-hydroxy-cyclohexane 6 in high enantiomeric excess (>99%) and yield (84%). Furthermore, for the synthesis of the enantiomer of 3, a simple and efficient enzymatic procedure for the asymmetric acetylation of cis-1,5-dihydroxy-3-(tert-butyldimethylsilanoxy)-cyclohexane 10 in an anhydrous organic solvent providing (1R,3S,5S)-1-acetoxy-3-hydroxy-5-(tert-butyldimethylsilanoxy)-cyclohexane 11 in >99% ee and quantitative yield is described. 相似文献
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Mixed ligand complexes involving four aminoacid dithiocarbamates (RRdtc=glydtc– (R=H; R=H), methdtc– (R=H; R=C3H7S), sardtc– (R=Me; R=H), trydtc– (R=H; R=C9H8N), substituted phosphines [PPh3, Ph2PCH2CH2PPh2(dppe)] and nickel(II) are reported. All are diamagnetic. Thermal analyses of the complexes are in keeping with the proposed formulae. Thermal decomposition of the dithiocarbamate moiety proceeds through the formation of Ni(SCN)2. PPh3 and dppe are lost in the initial decomposition stages. 相似文献
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Conclusions Several complexes of bis[tri(pentafluorophenyl)germyl]eadmium with ligands of the donor type were synthesized.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 702–703, March, 1973. 相似文献
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Carmen Avendaño Carmen de Diego José Elguero 《Monatshefte für Chemie / Chemical Monthly》1990,121(8-9):649-652
Summary A series of seven new tri(hetero)arylmethanes has been prepared by reduction of the corresponding carbinols using a mixture of lithium aluminium hydride/aluminium trichloride. The yields are excellent (77–98%) except in the case of the tri(2-benzothienyl)derivative (41%).1H NMR spectra are discussed.
Reduktion von Tri(hetero)arylcarbinolen zu Tri(hetero)arylmethanen
Zusammenfassung Durch die Reduktion der entsprechenden Carbinole mit Lithium-aluminiumhydrid/Aluminiumchlorid wurden sieben neue Tri(hetero)arylmethane in sehr guten Ausbeuten (77–98%) hergestellt. Eine Ausnahme bildet das Tri-(2-benzothienyl)-Derivat mit 41%. Die1H-NMR-Spektren werden diskutiert.相似文献
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Masaaki Yoshifuji Hiroaki Takahashi Kazuho Shimura Kozo Toyota Ken Hirotsu Kengo Okada 《Heteroatom Chemistry》1997,8(5):375-382
Dibenzocycloheptenylidene(2,4,6-tri-t-butylphenyl)-phosphine and fluorenylidene(2,4,6-tri-t-butylphenyl)-phosphine were prepared by the reactions of lithium silylphosphide with benzosuberenone and fluorenone, respectively. The reactions of the phosphines with sulfur were carried out to compare the results with those of the corresponding diphenyl derivative, and the new findings are discussed in terms of steric hindrance based on the results of the X-ray crystallographic analyses for dibenzocycloheptenylidenephosphine and its sulfide and the computational structure for the fluorenyl derivative. © 1997 John Wiley & Sons, Inc. Heteroatom Chem 8: 375–382, 1997 相似文献
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《Electrochemistry communications》2002,4(1):30-35
Polarographic (direct current, dc, and differential pulse, DP) studies of the electroreduction of the s-triazine derivatives ametryn (2-methylthio-4-ethylamino-6-isopropylamino)-1,3,5-triazine), dimethametryn (2-methylthio-4-ethylamino-6-(1,2-dimethylpropyl) amino-1,3,5-triazine) and simetryn (2-methylthio-4,6-di(ethylamino)-1,3,5-triazine) were made in the acidity range from 2.25 M H2SO4 to pH 6.5. Above this last pH value no signals were obtained. In DP polarography, two main reduction peaks were observed, accompanied by a pre-peak due to the adsorption of the herbicides on the electrode. The main peaks corresponded to two-electron irreversible reduction processes, at pH values higher than the protonation pK of the triazine ring (ca. 4). In this pH range, the protonation of the triazine ring preceding the reduction process is responsible for decrease in limiting current. At pH<pK the herbicides suffer a cleavage of the –SCH3 group via two different intermediates related by a chemical reaction, whose extension depends on the herbicide. 相似文献
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Reactions of [ReOCl3(PPh3)2] with a potentially tridentate Schiff base derived from (2-formylphenyl)diphenylphosphine and 2-aminophenol, HL1P, (HL1P = Ph2PC6H4-2-HCN(C6H4-2-OH)) result in a rapid decomposition of the Schiff base and the formation of a large number of hitherto non-identified metal-containing species, while from similar reactions with the analogoue phosphine oxide HL1PO, (HL1PO = Ph2P(O)C6H4-2-HCN(C6H4-2-OH)) products of the compositions [ReOCl2(PPh3)(L1PO)] (1) and [Re(NC6H4-2-OH)Cl3(PPh3)2] (2) could be isolated. The structure of 2 is an experimental proof of the preceding, metal-induced cleavage of the C–N double bond. A subsequent reaction of the released 2-aminophenol forms the final phenylimido ligand.Reduction of HL1P with NaBH4 gives the phosphine amine H2L2P (H2L2 = Ph2P(C6H4-2-CH2NH(C6H4-2-OH))) in good yield. Reactions of H2L2P with common oxorhenium(V) complexes result in the formation of the stable rhenium(V) complex [ReOCl2(HL2P)] (3) with a facially coordinated HL2P? ligand. 相似文献
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Chinwon Rim 《Tetrahedron letters》2009,50(7):745-422
Efficient syntheses of tripodal thioethers have been achieved by ionic thiol-ene reactions of 1,3,5-triacryloylhexahydro-1,3,5-triazine (TAT) with a variety of commercially available thiols. The reactions are complete within minutes and give the products in high yields (63−96%) and high purity without a complex workup. The thiol-ene reactions tolerate a wide range of functionality, including hydroxy, amino, carboxylate, and trimethoxylsilyl groups. The amino acid cysteine is also an excellent substrate for this reaction. 相似文献
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cis-Oligo(phenylenevinylene)s (OPVs) are synthesized by Suzuki-Miyaura coupling of arylboronic acids with (Z)-bromoalkenes in over 96% geometrical purity. On the other hand, trans-oligo(phenylenevinylene)s can be synthesized by Hiyama coupling of aryl iodide with (E)-alkenylsilanes in almost perfect purities. Effect of pi-conjugation chain length on photoisomerization behavior of OPVs is described. 相似文献
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《Journal of organometallic chemistry》1986,310(1):127-134
[Pd2(μ-Cl)2Cl2L2] (L = PEt3, PBu3 or PMe2Ph) reacts with AlMe3 in ether, THF or a mixture of these solvents depending on L to give [Pd2(μ-Cl)2Me2L2] in high yield, which has been characterized by IR and NMR spectroscopy as well as elemental analysis. Treatment of [Pd2(μ-Cl)2Me2L2] with CO yields [Pd2(μ-Cl)2(COMe)2L2], while its reaction with L leads to trans-[PdClMeL2]. The preparative method and the characteristic data of these complexes are discussed in comparison with the earlier work on the analogous aryl and aralkyl complexes. 相似文献