Synthesis and structure of hydroxyisoxazolidines and derivatives of hydroxylamine and alkenals

The reactions of N-substituted hydroxylamines with alkenals serve as a method for the synthesis of the corresponding 2-substituted 3(5)-hydroxyisoxazolidines. The reaction pathway is determined by the nature of the substituent attached to the nitrogen atom. Ring-chain isomerism has been detected in these newly obtained compoundsTranslated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1270–1276, September, 1987.     

Investigation of adhesion and mobility of polyurethane and epoxy-rubber glues and adhesives

The values of activation parameters in uncured and cured epoxy resins, rubbers, and blends thereof are investigated. The dependences of activation energy and adhesion strength of epoxy-rubber compositions on rubber content are determined. The correlation of adhesion and activation energy values for polyurethane rubber and epoxy-rubber compositions is shown.     

Mass and NMR spectra of haplophyllidine and perforine and of their derivatives

Conclusions The mass and NMR spectra of haplophyllidine, perforine, and their derivatives have been studied. The influence of the open and cyclic forms of the molecular ion on the nature of the fragmentation has been discussed. The main routes of fragmentation of the compounds considered are due to the presence of substituents at C₈ and C₄.Khimiya Prirodnykh Soedinenii, Vol. 5, No. 4, pp. 273–279, 1969     

Crystal and molecular structure of aroyl- and acetylhydrazones of acet- and benzaldehydes

Aroyl- and acetylhydrazones of acet- (I) and benzaldehydes (IV) and benzoylhydrazones of acet- (II) and benzaldehydes (III) were studied by x-ray structural and quantum-chemical methods in order to establish their structures. Compund (I) was the EEZ structure in the crystal. Calculations and spectral data showed that the EEE form occurs in nonpolar solvents and in the gas phase. According to crystallographic data molecules (I)–(IV) are the E-isomers (relative to the N-N bond) and the hydrazone fragments are planar. Intermolecular N-H...O H-bonds from in the crystals. The data obtained suggest that the majority of acylhydrazones are conformationally rigid on dissolution although exceptions do occur. Apparently the reasons for the difference of acetyl- and benzoylhydrazones in electrocarboxylation reactions are electronic and not steric factors.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 75–81, January, 1991.     

Synthesis and characterization of triazenide and triazene complexes of ruthenium and osmium

Triazenide [M(eta2-1,3-ArNNNAr)P4]BPh4 [M = Ru, Os; Ar = Ph, p-tolyl; P = P(OMe)3, P(OEt)3, PPh(OEt)2] complexes were prepared by allowing triflate [M(kappa2-OTf)P4]OTf species to react first with 1,3-ArN=NN(H)Ar triazene and then with an excess of triethylamine. Alternatively, ruthenium triazenide [Ru(eta2-1,3-ArNNNAr)P4]BPh4 derivatives were obtained by reacting hydride [RuH(eta2-H2)P4]+ and RuH(kappa1-OTf)P4 compounds with 1,3-diaryltriazene. The complexes were characterized by spectroscopy and X-ray crystallography of the [Ru(eta2-1,3-PhNNNPh){P(OEt)3}4]BPh4 derivative. Hydride triazene [OsH(eta1-1,3-ArN=NN(H)Ar)P4]BPh4 [P = P(OEt)3, PPh(OEt)2; Ar = Ph, p-tolyl] and [RuH{eta1-1,3-p-tolyl-N=NN(H)-p-tolyl}{PPh(OEt)2}4]BPh4 derivatives were prepared by allowing kappa1-triflate MH(kappa1-OTf)P4 to react with 1,3-diaryltriazene. The [Os(kappa1-OTf){eta1-1,3-PhN=NN(H)Ph}{P(OEt)3}4]BPh4 intermediate was also obtained. Variable-temperature NMR studies were carried out using 15N-labeled triazene complexes prepared from the 1,3-Ph15N=N15N(H)Ph ligand. Osmium dihydrogen [OsH(eta2-H2)P4]BPh4 complexes [P = P(OEt)3, PPh(OEt)2] react with 1,3-ArN=NN(H)Ar triazene to give the hydride-diazene [OsH(ArN=NH)P4]BPh4 derivatives. The X-ray crystal structure determination of the [OsH(PhN=NH){PPh(OEt)2}4]BPh4 complex is reported. A reaction path to explain the formation of the diazene complexes is also reported.     

Preparation and characterization of diarylphosphazene and diarylphosphinohydrazide complexes of titanium, tungsten and ruthenium and phosphorylketimido complexes of rhenium

Reaction of the proligand Ph2PN(SiMe3)2 (L1) with WCl6 gives the oligomeric phosphazene complex [WCl4(NPPh2)]n, 1 and subsequent reaction with PMe2Ph or NBu4Cl gives [WCl4(NPPh2)(PMe2Ph)] (2) or [WCl5(NPPh2)][NBu4] (3), respectively. DF calculations on [WCl5(NPPh2)][NBu4] show a W=N double bond (1.756 A) and a P-N bond distance of 1.701 A, which combined with the geometry about the P atom suggests, there is no P-N multiple bonding. Reaction of L1 with [ReOX3(PPh3)2] in MeCN (X = Cl or Br) gives [ReX2(NC(CH3)P(O)Ph2)(MeCN)(PPh3)](X = Cl, 4, X = Br, 5) which contains the new phosphorylketimido ligand. It is bound to the rhenium centre with a virtually linear Re-N-C arrangement (Re-N-C angle = 176.6 degrees, when X = Cl) and there is multiple bonding between Re and N (Re-N = 1.809(7) A when X = Cl). The proligand Ph2PNHNMe2(L2H) reacts with [(C5H5)TiCl3] to give [(C5H5)TiCl2(Me2NNPPh2)] (6). An X-ray crystal structure of the complex shows the ligand (L2) is bound by both nitrogen atoms. Reaction of the proligands Ph2PNHNR2[R2 = Me2 (L2H), -(CH2CH2)2NCH3 (L3H), (CH2CH2)2CH2 (L4H)] with [{RuCl(mu-Cl)(eta6-p-MeC6H4iPr)}2] gave [RuCl2(eta6-p-MeC6H4iPr)L] {L = L2H (7), L3H (8), L4H (9)}. The X-ray crystal structures of 7-9 confirmed that the phosphinohydrazine ligand is neutral and bound via the phosphorus only. Reaction of complexes 7-9 with AgBF4 resulted in chloride ion abstraction and the formation of the cationic species [RuCl(6-p-MeC6H4iPr)(L)]+ BF4- {(L = L2H (10), L3H (11), L4H (12)}. Finally, reaction of complex 6 with [{RuCl(mu-Cl)(eta6-p-MeC6H4iPr)}2] gave the binuclear species [(eta6-p-MeC6H4iPr)Cl2Ru(mu2,eta3-Ph2PNNMe2)TiCl2(C5H5)], 13.     

Ti-V基储氢合金及其氢化物的物相结构与组分优化设计

Ti-V基储氢合金在室温、常压下即可表现出良好的储氢特性,且质量储氢容量明显高于传统AB₅型储氢合金,从而在氢气的精制和回收、运输和储存及热泵等方面有较早的应用。 此外,在混合气体分离、核反应堆中处理氢的同位素、镍氢电池及燃料电池负极材料等方面也得到了广泛的研究与关注。 基于目前Ti-V基储氢合金的研究现状,概述了该类合金的优势、限制性因素(包括成因)及改性手段。 此外,为了进一步理解Ti-V基合金储氢机理、构建合金组分与储氢特性之间的对应关系,本工作重点围绕Ti-V基储氢合金及其氢化物的结构、组分优化设计展开综述,并对其未来研究方向做出展望。     

Glycolate and Thioglycolate Complexes of Rhenium and Their Oxidative Elimination of Ethylene and of Glycol

Selenium dioxide and osmium tetroxide are effective reagents and catalysts for olefin oxidation, although, owing to their toxicity, reservations remain as to their applicability.^[1] We are therefore seeking more easily handled metal oxides that are soluble in organic solvents and that are as effective as osmium tetroxide in carrying out stereospecific cis hydroxylation of olefins. The rhenium(VII ) oxide 1 , which has meanwhile become readily accessible, is a favorable candidate.^[2]     

The chemical transport of molybdenum and tungsten and of their dioxides and sulfides

Experiments have been made and an extensive thermodynamic discussion has taken place concerning the chemical transport of Mo, W, MoO₂, WO₂, MoS₂ and WS₂ in the presence of iodine. Efforts have been made to find the species via which Mo and W can migrate within the gas phase.Results: In each case the transport proceeds via the oxide iodides MoO₂J₂ and WO₂J₂ respectively, as already known for the dioxides. Thus the chemical transport of Mo, W, MoS₂ and WS₂ needs not only J₂ but also H₂O, usually liberated from the wall of the quartz ampoule.By means of J₂ + H₂O, the metals can be transported into the high temperature region of the ampoule (e.g., 1050 → 1150°C), whereas the transport of the sulfides proceeds in the opposite direction (e.g., 900 → 700°C).For the sulfide-transport the influence of the ratio of the transport agents $\text{J}{}_2\text{H}{}_2\text{O}$ has been discussed.The water content of the quartz glass out of which the ampoules are made is an important source for water, influencing the reactions.The addition of graphite which considerably lowers the H₂O partial pressure prevents any transport of the metals or the sulfides, which proves that the use of J₂ alone as a transport agent is insufficient in these cases.The gaseous iodides MoJ_x and WJ_z are without any importance under the experimental conditions used for the transport of the metals, their dioxides and sulfides.The partial pressures of MoO₂(OH)₂ and WO₂(OH)₂ under the experimental conditions chosen may usually be neglected. But in the system $\text{MoO}{}_2\text{H}{}_2\text{O}$ the transport via MoO₂(OH)₂ (1000 → 800°C) has been observed.The synthesis of MoO₂ and WO₂, starting with the elements or with powder of metal and trioxide is promoted by the addition of J₂. The reaction steps involved are discussed.     

Simultaneous spectrophotometric determination of molybdenum and selenium,and of molybdenum and tellurium

A method is reported for the extraction of molybdenum-phenylfluorone by chloroform. The extraction is complete whether perchlorate ions are present or not but the extractions in the presence of perchlorate ions gave a somewhat more sensitive procedure for the spectrophotometric determination of molybdenum in the solvent phase as the molybdenum-phenylfluorone complex.A procedure is reported for the simultaneous determination of molybdenum and selenium, and molybdenum and tellurium. The method involves first the formation and solvent extraction of the molybdenum-phenylfluorone complex by chloroform in the presence of perchlorate ions, followed by determination of selenium in the remaining aqueous phase as selenium-diethyldithiocarbamate complex after solvent extraction with 2-ethyl-1-hexanol in the presence of perchlorate ions. A similar procedure is reported for the simultaneous determination of molybdenum and tellurium except that in the determination of molybdenum, the phenylfluorone complex is extracted by chloroform in the absence of perchlorate ions. Tellurium is determined in the remaining aqueous phase as tellurium-diethyldithiocarbamate complex after solvent extraction by 2-ethyl-1-hexanol solvent extraction in the presence of perchlorate ions.     

Protonation of amino and hydroxypyrimidines. NMR-spectra and structures of mono and dications

Proton-NMR. spectra of amino- and hydroxypyrimidines including biologically important bases have been measured in four solvents: CF₃COOH, CF₃COOH? SO₂, FSO₃H and FSO₃H? SbF₅–SO₂ at 27° and ?55°C. In CF₃COOH mono-cations are formed, whereas in FSO₃H and FSO₃H? SbF₅–SO₂ double protonation occurs. In each case the structures of the protonated species are derived from the chemical shifts of CH, NH and OH protons and proton-proton spin coupling constants. A combination of the measurements described leads to a complete assignment of all proton resonances of the protonated pyrimidines. This approach is also recommended for the structural determination of heterocyclic compounds.     

Syntheses and properties of NCN-bridged tri- and tetranuclear complexes of cobalt and rhodium

The reaction of [Cp¹CoI₂]₂ (1b) with 2 equiv of NaNCNH affords the 16-membered macrocyclic NCNH-bridged tetracobalt(III) complex [Cp¹CoI(μ₂-NCNH-N,N′)]₄ (2b), while that with 2 equiv of Na₂NCN yields the C₃-elongated cubane-like NCN-bridged tetracobalt(III) complex [Cp¹Co(μ₃-NCN-N,N,N′)₃(CoCp¹)₃(μ₃-NCN-N,N,N)] (4b). Treatment of [Cp¹RhCl₂]₂ (1c) with 2 equiv of NaNCNH gives the C₃-elongated cubane-like tetrarhodium(III) complex [Cp¹Rh(μ₃-NCN-N,N,N′)₃(RhCp¹)₃(μ₃-NCN-N,N,N)] (4c) via the macrocyclic complex [Cp¹RhCl(μ₂-NCNH-N,N′)]₄ (2c). On the other hand, the reaction of [Cp¹CoCl]₂ (7) with Na₂NCN affords the anionic bis(NCN)-capped tricobalt(II) complex Na[(Cp¹Co)₃(μ₃-NCN-N,N,N)₂] (6). The molecular structures of complexes 2b · CH₂Cl₂ and 4c · 2C₆H₆ have been confirmed by X-ray analyses. The electrochemical properties of these types of NCN-bridged group 9 metal complexes have also been examined.     

Synthesis and characterization of norverapamil and quantification of verapamil and nor-verapamil in plasma

Verapamil is a calcium channel blocking agent which has found widespread use in the management of supraventricular tachyarrhythmias, angina pectoris, hypertrophic cardiomyopathy and hypertension. It is converted to its biologically active metabolite nor-verapamil in liver by cytochrome P450. In present communication, synthesis and characterization of nor-verapamil and development of reverse phase high performance liquid chromatographic method for the quantification of nor-verapamil along with verapamil in plasma has been carried out. The characterization of nor-verapamil was carried out using GC-MS, FT-IR and NMR spectroscopy. The separation was carried out with an isocratic JASCO RP-HPLC system using 5 μm KYA TECH HiQ Sil C₁₈ HS column (250 mm × 4.6 mm internal diameter) as a stationary phase and methanol: water: 0.01 M orthophosphoric acid: triethylamine [70: 30: 2: 0.5, v/v/v/v] as mobile phase. The flow rate was maintained at 1.0 mL/min and UV detection at 222 nm. The calibration for verapamil and nor-verapamil were found to be linear over concentration range of 50–300 ng/mL with correlation coefficient (n = 6) of 0.9995 and 0.9997, respectively. This method was validated according to USFDA guidelines. The method was found to be simple, accuare, precise sensitive and selective for the determination of verapamil and nor-verapamil in plasma and thus useful in bioequivalence studies of verapamil.     

Preconcentration and determination of ultratraces of lead and bismuth

The recovery and preconcentration of Pb(II) and Bi(III) by coupling ion-exchange and precomplexation with 1,2-dihydroxy-3,5-benzenedisulphonic acid and 3,3',4'-trihydroxyfuchsone-2'-sulphonic acid has been investigated. Metal recoveries at 0.1-mg l . concentrations are better than 99% in the presence of cationic, anionic and non-ionic detergents, or an organic sequestering agent such as NTA, and at high ionic strength. Experiments with radiotracers show total recovery even at 15-ng l . concentrations. In the light of the results the procedure is proposed as a simple and rapid analytical method to preconcentrate Pb(II) and Bi(III).     

Properties and structure of compositions of polyethylene and san-copolymer

Some strength-deformation and rheological properties of compositions of PE and SAN-copolymer obtained by three methods were studied. Light-microscopy analyses were made. It was established that the structural characteristics and the properties of the mixtures depend on the method of production rather than on composition.