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1.
1.  It has been shown that in the presence of (2-methylenecyclopropane)bis(triphenyl-phosphine) nickel (Kt-1) and of a series of triphenylphosphine Ni(O) complexes the catalytic conversion of methylenecyclopropane (MCP) proceeds with the formation of identical di- and trimerization products. It is postulated that the mechanism of di- and trimerization of MCP on all Ni(O) phosphine complexes is similar, with the formation of Kt-1 as a general intermediate.
2.  Complexes of Ni(I) and Ni(II) which have been studied were found to be inactive in MCP conversion.
Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1591–1594, July, 1988.  相似文献   

2.
1.  Rhodium complexes [RhCl(COD)]2, RhCl(PPh3)3, and RhCl3 immobilized on silica gel modified by aminophosphine groups catalyze the transfer of hydrogen from 2-propanol to cyclohexanone, styrene, and 2-cyclohexenone and the isomerization of allylbenzene in an argon atmosphere.
2.  The reduction of cyclohexanone to cyclohexanol is promoted by alkali. The reaction rate is proportional to the amount of catalyst, 2-propanol concentration, and cyclohexanone. The reaction rate decreases at high ketone concentrations.
3.  Styrene is reduced to ethylbenzene extremely slowly. Under these conditions, allylbenzene is not reduced, but rather undergoes isomerization with the predominant formation of trans-propenylbenzene.
4.  The reduction of 2-cyclohexenone to cyclohexanol occurs by the initial reduction of the C=C bond and the subsequent reduction of the C=O group.
Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1223–1228, June, 1988.  相似文献   

3.
1.  The complexes ArNiXL2 and HNiXL2 (X is halide, L is tertiary phosphine) in the presence of zinc catalyze the condensation of bromobenzene with styrene (stilbene formation).
2.  The yield of stilbene and 1,3-diphenylbutene, the dimerization product of styrene, in the presence of pyridine is lowered according to the substitution of phenyl groups on the phosphorus ligand L by alkyl (ethyl, cyclohexyl) groups.
3.  Change of triphenylphosphine to phenylethylphosphines and tricyclohexylphosphine in the hydride complex HNi(X)(PR3)2, the catalytic activity of which falls in the order X=Cl–Br–>I–, favors the dimerization of styrene in the absence of pyridine.
Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 782–786, April, 1989.  相似文献   

4.
1.  New cationic o-tolyl and o-fluorophenyl complexes of Ni containing Ph3P, MeCN, or THF ligands have been synthesized.
2.  Reaction of these compounds with potassium carboxylates gave the novel o-tolyl and o-fluorophenylbis(triphenylphosphinyl)nickel carboxylates.
3.  According to19F NMR data o-tolylbis(triphenylphosphinyl)nickel p-fluorobetizoate contained a highly polarized Ni-O bond.
Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 166–170, January, 1988.  相似文献   

5.
1.  New catalysts, Pd-Sn compounds, were synthesized and fixed to macroporous anion exchangers. They are active in hydrogenation and isomerization reactions of 1-hexene.
2.  The catalytic properties of the Pd-Sn systems depends on the structure of the fixed compound (cluster, complex), the nature and state of the exchanger functional groups (Cl-or OH-form), and the reaction conditions (pH, PH2).
3.  The cluster [Pd4(SnCl2)2(SnCl3)8]5– on the highly basic anion exchanger AV-17-2P (Cl-form) catalyzes mainly the hydrogenation reaction, while the complex [Pd(SnCl3)4]2– catalyzes the isomerization reaction.
4.  The complex [Pd(SnCl3 4)]2–, fixed to the weakly basic anion exchanger AN-221 (OH-form), is active in the isomerization and hydrogenation of 1-hexene under mild conditions.
Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 773–776, April, 1989.  相似文献   

6.
In conclusion, let us note the principal results of the calculation.
1.  On a clean Ni(100) surface, only molecular adsorption of water is realized. Partial dissociation of H2O is thermodynamically allowed process; however, dissociation of water is impossible because of kinetic limitations.
2.  Modification of the nickel surface by oxygen stabilizes the donor-acceptor pair (H2O/O) on the surface and removes the kinetic limitation in decomposition of water, through a substantial reduction of the activation energy of dissociation.
3.  The promoting role of oxygen is manifested in an increase in the nonuniformity of electron density on the nickel surface in the vicinity of the [Ni]–OH2 bond, which makes it possible to open up a new channel of the reaction in which a high degree of energy compensation in the water dissociation reaction is possible.
Institute of Catalysis, Siberian Branch, Russian Academy of Sciences. Translated from Zhurnal Strukturnoi Khimii, Vol. 33, No. 2, pp. 35–41, March-April, 1992.  相似文献   

7.
1.  Perfluoro-tert-butanol forms H bonds of the OH...OC-M type with transition metal carbonyl complexes: CpM(CO)3 (Cp=5-C5H5 and 5-Et5C5, M=Mn, Re), MezM(CO)3 (Mez = 6-Me3H3C6, M=Cr, Mo, W), (5-C5H5)M(CO)2PR3 (R=Ph, i-Pr, M=Mn, Re) at low temperatures in liquid xenon and at 20C in CCl4.
2.  For isostructural complexes, the basicity of the O atom of the CO group increases on substitution of one of the CO groups by a phosphine ligand, introduction of alkyl substituents in the ring, and in going from Mn to Re.
3.  Hexacarbonyls M(CO)6 (M=Cr, Mo, W) do not form an H bond with perfluro-tert-butanol.
Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 562–568, March, 1988.  相似文献   

8.
1.  The competitive kinetics method was used to show that hydrogen abstraction from propylene by telomeric CCl3[CH2CH(CH3)]n radicals (n=1, 2) proceeds at 140°C with rate constants 2.5·103 and 1.8·103 liters/mole·sec, respectively.
2.  The polar effect upon the abstraction of hydrogen atoms from propylene by telomer radicals is less pronounced than upon the abstraction of a chlorine atom from CCl4.
Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 894–897, April, 1988.  相似文献   

9.
1.  Platinum hydrides are the active donors of the hydride ion with respect to Ph3 \mathop C? Ph_3 \mathop C\limits^ \oplus .
2.  The phosphine complexes of Ni, Pd, and Pt exhibit catalytic activity in the ionic hydrogenolysis of alcohols, the Pt complexes being the most active.
  相似文献   

10.
1.  A series of C-functional derivatives of (3)-1,2-dicarbaundecaborate was synthesized and some of their properties were studied.
2.  Apparent ionization constants of acids of the (3)-1,2-dicarbaundecaborate series were measured and it was found that they are very weak carboxylic acids.
3.  Upon reaction with excess LiA1H4, under mild conditions the carbonyl, *20c \CH(OH) / \begin{array}{*{20}c} \backslash \\ {CH(OH)} \\ / \\ \end{array} , and CH2OH groups of dicarbaundecaborate ketones and alcohols are reduced to CH2 and CH3 groups, respectively.
4.  The effect of Grignard reagent on ketones and esters of the dicarbaundecarbprate series was studied and it was established that the composition of reaction products depends both on the steric hindrance of the carbonyl group and on the electron-donating effect of the (3)-1,2-dicarbaundecaborate substituent.
  相似文献   

11.
1.  According to1H and31P NMR spectra, the cationic complexes [Rh(PMe3)4]X (X=Cl, BPh4) exist in solution (H2O, MeOH, MeCN) as fluxional five-coordinate species [Rh(PMe3)4. (solvent)]X.
2.  The synthesized complexes [Rh(PMe3)4O2]Cl and [Rh(PMe3)4O2]BPh4 have trigonal bipyramidal structure in solution according to31P and1H NMR spectroscopy.
Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1036–1040, May, 1989.  相似文献   

12.
1.  The structures and stability constants of outer-sphere adducts of Co(HBpz3)2 with aromatic nitro compounds have been determined.
2.  The process of outer-sphere solvation of Co(HBpz3)2 has been shown to lie outside the framework of a simple donor-acceptor model for adduct formation.
Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1756–1759, August, 1988.  相似文献   

13.
1.  The rate constants were calculated for the abstraction of hydrogen from HCCl3 and of bromine from BrCCl3 by CCl3(CH2CHX)n radicals.
2.  The reactivity of CCl3(CH2CH2)n radicals (n=1, 2) depends on the position of the CCl3 group and the chain transfer step makes the major contribution to the chain transfer constants in the telomerization of ethylene with HCCl3 and BrCCl3.
3.  The reactivity of CCl3(CH3CHX) n . radicals (X=H, Me, Cl) in reactions involving replacement with C-H and C-Hal bond cleavage depends on the nature of X.
Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1402–1404, June, 1988.  相似文献   

14.
1.  Using seven independent methods it was found that the concentration of the active centers on the surface of-Al2O3, which are responsible for the dehydration, is (9±1)×1017 centers/m2. The catalytically active centers are identical with adsorption centers.
2.  A method of calculating the stochiometry, concentration, and thermodynamics of the surface association reactions has been developed.
3.  The first reaction step proceeds according to the associative bimolecular substitution mechanism, with the formation of an associative intermediate compound. The association enthalpy and entropy have been calculated.
  相似文献   

15.
1.  Oxidation of o-organosilyl-substituted phenols with potassium ferricyanide in an alkaline medium in an oxygen atmosphere led to the formation of siloxydiphenyls and bis(l-R2-3-R1-5-R3-2,5-cyclohexadien-4-one) peroxides.
2.  The silyl-substituted peroxides were isolated preparatively. Their thermal decomposition occurred by a homolytic mechanism with cleavage of the O-O bond.
  相似文献   

16.
1.  The catalytic properties of iron nitride (Fe2N) and carbonitride (Fe2C0.29N0.71) in the reactions of amination and dehydrogenation of alcohols were compared.
2.  In the course of the amination and dehydrogenation reactions on a nitride catalyst, there is an elution of part of the introduced nitrogen from the surface with the formation of the structure of the lower nitride.
3.  For related structures of the nitride and carbonitride, a correlation was detected between the catalytic activity and the average magnetic moment of the iron atom in the alloy.
  相似文献   

17.
1.  The heats of the reactions of xenon difluoride with fluoro complexes of RE(III) have been determined experimentally by the methods of DTA and mass spectrometry. The values of ArH for the thermolysis of MI 3MIVF7 to MI 3MIIIFI 6 and F2have been found.
2.  The values of the enthalpy changes according the transition of KHF2, the melting of KHF2, and the melting of XeF2 have been refined and found to be equal to 41.4±1.25, 26.7±2.60, and 19.0 ± 2.0 kJ/mole, respectively.
3.  The series of the thermodynamic stability of the fluoro complexes of RE(IV) toward the elimination of a fluoride ion has been established.
Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1012–1018, May, 1989.  相似文献   

18.
The photoluminescence (PL) of zircon is characterized by a broad structureless spectral band down to 4.6 K, which does not enable correct interpretation of the nature of the luminescence centres (LC). By applying step-like thermal treatment, a radiation treatment and timeresolved spectroscopy, seven pure bands were separated and their individual spectral-kinetic properties were determined.The yellow PL is connected with three LC:
1.  Intrinsic defects of the (SiOm)n– type, which are generated by radioactive decay of U and Th;
2.  Impurity defects (MeOm)n– (Me–Mo, V) associated with charge compensators, probably the Fe3+ and Ti3+ (clusters of these LC generate a yellow-orange shoulder);
3.  Impurity defects (UO2)2+.
  相似文献   

19.
1.  The condensation of 1,2-hydroxylamino oximes with biacetyl leads to 1-hydroxy-2-acetyl-2,4,5,5-tetrasubstituted 3-imidazoline 3-oxides.
2.  When 1-hydroxy-2-acetyl-2,5,5-trimethyl-4-phenyl-3-imidazoline 3-oxide is oxidized the CH3CO group is cleaved to give the 5H-imidazole 1,3-dioxide.
3.  Stable nitroxyl radicals were obtained when the 1-hydroxy-2-oximiaoethyl-2,4,5,5-tetrasubstituted 3-imidazoline 3-oxides are oxidized.
  相似文献   

20.
1.  Methanol, containing 10–20 mole % of CH3I, is carbonylated to methyl acetate in the presence of impregnated Eh-zeolite NaX catalyst at 230–250° and atmospheric pressure.
2.  The specific (per gram of Rh) rate of methyl acetate formation is antibatic to the Rh content in the catalyst, it increases with increase in the methanol contact time, and shows little change in the range 230–250°.
3.  The rate of forming the sole secondary product, namely dimethyl ether, decreases with increase in the amount of Rh and the methanol contact time.
4.  CH2I is an astoichiometric component of the reaction.
  相似文献   

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