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1.
Ksenia V. Zherikova Natalia B. Morozova Ludmila N. Zelenina S. V. Sysoev Tamara P. Chusova I. K. Igumenov 《Journal of Thermal Analysis and Calorimetry》2008,92(3):729-734
Five volatile hafnium(IV) and zirconium(IV) β-diketonates: hafnium(IV) acetylacetonate, hafnium(IV) trifluoroacetylacetonate,
hafnium(IV) pivaloyltrifluoroacetonate, hafnium(IV) 2,2,6,6-tetramethylheptane-3,5-dionate and zirconium(IV) 2,2,6,6-tetramethylheptane-3,5-dionate
were obtained, purified and identified. Thermal behavior of solid compounds was investigated by thermogravimetry (TG) and
differential scanning calorimetry (DSC) in helium atmosphere and in vacuum. DSC method was also used for definition of thermodynamic
characteristics of melting processes. Using the static method with quartz membrane zero-manometer and the flow method the
temperature dependencies of saturated vapor pressure for hafnium(IV) complexes was obtained. The standard thermodynamic characteristics
ΔH
T0 and ΔS
T0 of sublimation and evaporation processes were calculated from the temperature dependences of saturated vapor pressure. 相似文献
2.
本文报道了在焦磷酸盐的碱性水溶液中用O~3氧化Pr(III)和Tb(III),从而得到Pr(IV)-P~2O~7^4^-和Tb(IV)-P~2O~7^4^-的配合物溶液,通过对溶液进行化学分析及吸收光谱的研究,证明了溶液中有Pr(IV)和Tb(IV)的存在,其持征吸收分别为λmax=365nm,摩尔消光系数ε=1205L/mol.cm;/.pr(iv)=257nm,ε=929L/mol.cm.在碱性条件下,Pr(IV)和Tb(IV)的还原反应均为拟一级反应.用动力学方法测定了不同条件下Pr(IV)和Tb(IV)的还原速率常数和半衰期,从而探讨了稳定Pr(IV)和Tb(IV)的条件.同时还测定了在反应条件下Pr(IV)/Pr(III)和Tb(IV)/Tb(III)电对的克式电位。 相似文献
3.
Preparation methods are developed for a number of 7- and 8-coordinated derivatives of Hf(IV) and Zr(IV) with β-diketonate ligands (R1-CO-CH-CO-R2). The complexes obtained are examined by IR spectroscopy, mass spectrometry, and X-ray crystallography. All structures are molecular. The M-O distances fall within 2.09–2.28 Å. In the crystals, the molecules are joined only by van der Waals interactions. It is demonstrated that the series of hafnium(IV) and zirconium(IV) chelates with identical ligands are isostructural, and the introduction of CF3- or tert-butyl groups in the terminal positions of the ligand as well as chlorine substitution for one of the ligands do not essentially affect the basic geometric characteristics of the ligand in the complexes. 相似文献
4.
Luciana S. Guinesi C. A. Ribeiro Marisa S. Crespi A. F. Santos Marisa V. Capela 《Journal of Thermal Analysis and Calorimetry》2006,85(2):301-307
This work aims the evaluation of the kinetic triplets
corresponding to the two successive steps of thermal decomposition of Ti(IV)–ethylenediaminetetraacetate
complex. Applying the isoconversional Wall–Flynn–Ozawa method
on the DSC curves, average activation energy: E=172.4±9.7
and 205.3±12.8 kJ mol–1, and pre-exponential
factor: logA=16.38±0.84 and 18.96±1.21
min–1 at 95% confidence interval could be
obtained, regarding the partial formation of anhydride and subsequent thermal
decomposition of uncoordinated carboxylate groups, respectively.
From E and logA values,
Dollimore and Málek methods could be applied suggesting PT (Prout–Tompkins)
and R3 (contracting volume) as the kinetic model to the partial formation
of anhydride and thermal decomposition of the carboxylate groups, respectively. 相似文献
5.
Irena Bajc Svetozar Milićev Bogdan Volavšek 《Monatshefte für Chemie / Chemical Monthly》1992,123(4):321-324
Summary The microcristalline phase (NH3OH)2TiF6 has been isolated from aqueous solution. It crystallizes in the tetragonal system with cell parameters:a=9.654±0.005 Å,c=11.546±0.010 Å. The hydroxylammonium fluorotitanate was characterized by vibrational spectroscopy and its thermal decomposition studied by DSC and TG analysis. 相似文献
6.
Tomachinskaya L. A. Kolotilova Yu. Yu. Chernii V. Ya. Volkov S. V. 《Theoretical and Experimental Chemistry》2003,39(2):104-108
We have used cyclic voltammetry to study the electrochemical properties of novel bis(-diketonate)phthalocyanine complexes of Zr(IV) and Hf(IV) in dichloromethane. We found three waves for the studied complexes that can be attributed to one-electron processes MPc(L)0/1–
2, MPc(L)1+/0
2 and MPc(L)2+/1+
2. We have shown that the electrochemical behavior of the complexes depends on the nature of the substituents in axial ligands and does not depend on the nature of the metals. We have analyzed the stability of the one-electron oxidation products of the complexes relative to disproportionation. 相似文献
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8.
Suraj P. Narula Sajeev Soni Meenu Puri Rishi D. Anand Jugal K. Puri 《Phosphorus, sulfur, and silicon and the related elements》2013,188(7):1647-1654
Si(NHC6H5-nFn)4.xTiCl4 [n = 2–5; x = 3,4] are obtained from the disproportionation reactions between (CF3CH2O)3SiNHC6H5-nFn (n = 2–5) and TiCl4 in petroleum ether (40–60°C) at 0°–10°C. These complexes are characterized by elemental analyses and IR, 1H, and 19F NMR spectroscopy. Unlike the reported5 complex Si(NHC6H4F-o)4.3TiCl4, these are non-ionic in nature. All complexes give double adducts with CH3NO2 and CH3CN within 24 h. 相似文献
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11.
Sharma Neeraj Sood Anoop K. Bhatt Sarvjeet S. Kalia Shashi B. Chaudhry Subhash C. 《Transition Metal Chemistry》1998,23(5):557-560
Complexes of composition [VCl(acac)2(OAr1–4)] and [V(acac)2(OAr1–4)2] (HOAr1=HOC6H4NO2–4, HOAr2= HOC6H4OMe-4, HOAr3=HOC6H4But-4 and HOAr4= HOC6H2But-2,6–Me-4; acac=2,4–pentanedionato ion) have been synthesized by the reaction of [VCl2(acac)2] with the respective phenols or their trimethylsilyl derivatives. The complexes have been characterized by physicochemical and spectroscopic techniques. They are non-electrolytes in nitrobenzene. Room temperature magnetic moments in the 1.71–1.82B range are consistent with the VIV system. The reactions of [VCl(acac)2(OAr2)] and [VCl(acac)2(OAr3)] with chloride acceptors have been studied by conductance techniques and the formation of ionic complexes of the types [V(acac)2(OAr2,3)][MCl4] (M=Fe, Al or Sb) and [V(acac)2(OAr2,3)][MCl6] (M=P or Sb) is indicated by the conductance composition curves. Several of these complexes have been isolated and characterized. 相似文献
12.
《Journal of organometallic chemistry》1986,307(3):319-325
The new toluene-3,4-dithiolate chelates CpMCl(S2C6H3CH3-4) (Cp = η5-C5H5; M = Ti (III), Zr (IV)) can be prepared by the reactions of CpTiCl3 (I) or CpZrCl3 (II) with equimolar amounts of (LiS)2C6H3CH3-4. I and II react with an excess of (LiS)2C6H3CH3-4, via III and IV, to give the fivefold-coordinated anions which can be isolated as the tetraethylammonium salts NEt4[CpM(S2C6H3CH3-4)2] (M = Ti (V), Zr (VI). 1H NMR studies of III and V under variable temperatures indicate in both complexes the presence of only one sterically-promoted conformation of the five-membered TiS2C2 chelate rings. 相似文献
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16.
《Journal of organometallic chemistry》1988,346(1):C31-C34
It is shown that photolysis of [PtMe4(bipy)] using incident radiation with λ 436 or 473 nm occurs with high quantum efficiency of 0.8–1.0 to give homolysis of a methylplatinum bond; this has allowed a study of the chemical reactions of the [PtMe3(bipy)] radical. 相似文献
17.
《Polyhedron》1986,5(11):1733-1740
Reaction of protonated 2,2′-bipyridine (bpy) with octacyanometalates(IV and V), [M(CN)8]n− (M = Mo or W, n = 3 or 4), gave the following complexes: {(bpyH)3[M(CN)8]·4H2O}, {(bpyH)3(H3O)[M(CN)8]·H2O}, {(bpyH2)2[W(CN)8]·3H2O} and {(bpyH2)K2[W(CN)8]·2H2SO4·7H2O}. These salts were characterized by electron absorption and reflectance spectrometry, IR, Raman and ESR spectrometry, thermo gravimetry and differential thermal analysis, cyclic voltammetry and potentiometry. The solubility of the salts in water and some polar organic solvents has been measured. The intensively coloured salts of molybdenum(IV) and tungsten(IV) have been discussed in terms of the bpyH+-[M(CN)8]4− ion pairs, which exhibit an outer-sphere electron transfer between adjacent redox sites. 相似文献
18.
A. A. S. Elkhaldy A. R. Hussien A. M. Abu Shanab M. A. Wassef 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3):589-597
Abstract Reactions of O,O′-dialkyl and alkylene dithiophosphoric acids with bis (cyclopentadienyl) titanium(IV) and zirconium (IV) dichloride in a 1:1 molar ratio in refluxing benzene proceeds with elimination of HCl and formation of the substituted derivatives, Cp2MCl[S2P(OR)2] (where R = Et, Pr-n, Pr-i, Bu-i and Ph), Cp2MCl[S2POGO] (where G = ?CH2CMe2CH2?, ?CH2CEt2CH2? and ?CMe2CMe2?), (M = Ti and Zr). The complexes are dark red and yellow solids, soluble in common organic solvents and monomeric in nature. These have been characterized on the basis of elemental analyses, molecular weight determinations, IR, and NMR (1H, 13C, and 31P). GRAPHICAL ABSTRACT 相似文献
19.
Mala Anchal Srivastava Akhilesh K. Pandey Om P. Sengupta Soumitra K. 《Transition Metal Chemistry》2000,25(6):613-616
Bis(cyclopentadienyl)titanium(IV) and zirconium(IV) chlorides react with bis(hydrazones) derived from 1,1-diacetylferrocene in anhydrous THF in the presence of base to give complexes of the type [(Cp2MCl)2L] [M = Ti or Zr; LH2 = ferrocenyl bis(hydrazones)]. Tentative structures are proposed for these complexes based upon elemental analyses, electrical conductance, magnetic moment and spectroscopic data. 相似文献
20.
Treatment of titanyl sulfate in dilute sulfuric acid with 1 equiv of NaL(OEt) (L(OEt)(-) = [(eta(5)-C(5)H(5))Co{P(O)(OEt)(2)](3)](-)) in the presence of Na(3)PO(4) and Na(4)P(2)O(7) led to isolation of [(L(OEt)Ti)(3)(mu-O)(3)(mu(3-)PO(4))] (1) and [(L(OEt)Ti)(2)(mu-O)(mu-P(2)O(7))] (2), respectively. The structure of 1 consists of a Ti(3)O(3) core capped by a mu(3)-phosphato group. In 2, the [P(2)O(7)](4-) ligands binds to the two Ti's in a mu:eta(2),eta(2) fashion. Treatment of titanyl sulfate in dilute sulfuric acid with NaL(OEt) and 1.5 equiv of Na(2)Cr(2)O(7) gave [(L(OEt)Ti)(2)(mu-CrO(4))(3)] (3) that contains two L(OEt)Ti(3+) fragments bridged by three mu-CrO(4)(2-)-O,O' ligands. Complex 3 can act as a 6-electron oxidant and oxidize benzyl alcohol to give ca. 3 equiv of benzaldehyde. Treatment of [L(OEt)Ti(OTf)(3)] (OTf(-) = triflate) with [n-Bu(4)N][ReO(4)] afforded [[L(OEt)Ti(ReO(4))(2)](2)(mu-O)] (4). Treatment of [L(OEt)MF(3)] (M = Ti and Zr) with 3 equiv of [ReO(3)(OSiMe(3))] afforded [L(OEt)Ti(ReO(4))(3)] (5) and [L(OEt)Zr(ReO(4))(3)(H(2)O)] (6), respectively. Treatment of [L(OEt)MF(3)] with 2 equiv of [ReO(3)(OSiMe(3))] afforded [L(OEt)Ti(ReO(4))(2)F] (7) and [[L(OEt)Zr(ReO(4))(2)](2)(mu-F)(2)] (8), respectively, which reacted with Me(3)SiOTf to give [L(OEt)M(ReO(4))(2)(OTf)] (M = Ti (9), Zr (10)). Hydrolysis of [L(OEt)Zr(OTf)(3)] (11) with Na(2)WO(4).xH(2)O and wet CH(2)Cl(2) afforded the hydroxo-bridged complexes [[L(OEt)Zr(H(2)O)](3)(mu-OH)(3)(mu(3)-O)][OTf](4) (12) and [[L(OEt)Zr(H(2)O)(2)](2)(mu-OH)(2)][OTf](4) (13), respectively. The solid-state structures of 1-3, 6, and 11-13 have been established by X-ray crystallography. The L(OEt)Ti(IV) complexes can catalyze oxidation of methyl p-tolyl sulfide with tert-butyl hydroperoxide. The bimetallic Ti/ Re complexes 5 and 9 were found to be more active catalysts for the sulfide oxidation than other Ti(IV) complexes presumably because Re alkylperoxo species are involved as the reactive intermediates. 相似文献