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1.
The newly discovered crystal structures of CH3(OCH2CH2)OCH3(LiCF3SO3)2, monoglyme:(LiTf)2, and CH3(OCH2CH2)3OCH3(LiCF3SO3)2, triglyme:(LiTf)2, are briefly described. The coordination of lithium cations and the CF3SO3− anions in these structures is compared with the cation and anion coordination in the crystalline phase of high molecular weight P(EO)3LiCF3SO3. Comparison is also made with the previously reported crystalline phase of CH3(OCH2CH2)2OCH3LiCF3SO3, diglyme:LiTf. A tendency to form trans-gauche-trans conformations for the bond order -O-C-C-O- is noted in adjacent ethylene oxide sequences interacting with a five-coordinate lithium ion. 相似文献
2.
In the system LiSO3CF3/RbSO3CF3 four different quasi‐ternary phases occur: Li0.7Rb0.3SO3CF3, Li0.55Rb0.45SO3CF3, LiRb2(SO3CF3)3, and Li0.2Rb0.8SO3CF3. These have been identified, and characterized by means of X‐ray powder diffractometry and DSC. LiSO3CF3 is trimorphic, LiRb2(SO3CF3)3 is dimorphic and RbSO3CF3 exists in four different modifications. The cation dynamics has been studied using 7Li‐NMR line shape analysis and 7Li‐spin lattice relaxation (T1) measurements. The pure and mixed trifluoromethylsulfonates in the system LiSO3CF3/RbSO3CF3 are solid electrolytes. Their ionic conductivities below 475 K increase with the rubidium content. Above this temperature, the conductivity of β‐LiRb2(SO3CF3)3 exceeds the one of δ‐RbSO3CF3. 相似文献
3.
Rate constant ratios, kd/kc for the disproportionation/combination reaction have been measured as 0.07 ± 0.02 when an H is removed from the CH2 position of the CF3CH2CHCH3 radical and as 0.24 ± 0.03 when the H is removed from the CH3 position in the reaction with the CF3 radical. For the self‐reaction between two CF3CH2CHCH3 radicals, kd/kc has been measured as 0.27 ± 0.03 when the H is removed from the CH2 position and as 0.47 ± 0.04 when the H is removed from the CH3 position. The branching fraction, corrected for the number of hydrogens at each site, is 0.70 favoring the methyl position when the acceptor radical is CF3 and 0.54 when CF3CH2CHCH3 is the acceptor radical. Branching fraction results show that the CF3 substituent on the CF3CH2CHCH3 radical hinders disproportionation when CF3 is the acceptor radical. When the accepting radical is CF3CH2CHCH3 the CF3 substituent may slightly impede the disproportionation reaction, but the branching ratio is nearly statistical. The effect of substituents on the donor radical, CF3CH2CHX, will be discussed for the series X = H, CF3, Cl, and CH3 when the acceptor radical is CF3. © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 33: 549–557, 2001 相似文献
4.
PMR studies show that CH3CdOC(CH3)3 is formed more rapidly than symmetrical alkoxide from (CH3)2Cd and (CH3)3COH. Spectra of CH3CdOC(CH3)3 in different solvents show that this product is less solvated that (CH3)2Cd. An interpretation based on exchange of methyl groups in various cases is proposed. 相似文献
5.
The maximum monolayer dispersion (the threshold) for WO3 on γ-Al2O3 calcined at 500°, 550°, 600°, and 640°C has been determined quantitatively by XRD (amount of crystalline phase) and XPS (intensity ratios Iw4f/IAl2). The results show that if the amount of WO3 loaded is lower than the maximum monolayer dispersion, WO3 will react with γ-Al2O3 to form surface compound due to mutual ionic interaction, and will be dispersed on γ-Al2O3 surface as monolayer then. In case the amount is higher than this value, the residual crystalline WO3 will remain. The maximum monolayer dispersion (threshold) is 0.21 g and 0.20 g WO3/100 m2 γ-Al3O3 by XRD and XPS respectively. It agrees with the value (0.189 g WO3/100 m2 or 4.90 × 10?18 W atoms/m2) calculated from the model on assumption that the WO3 is dispersed as a closed-packed monolayer on γ-Al2O3 surface. Inasmuch as WO3/γ-Al2O3 system is stable up to higher temperature, e.g. 700°C, than MoO3/γ-Al2O3 system, WO3 seems unfavorable to form new bulk compound with γ-Al2O3 at that temperature. However, Al2(MoO4)3 forms perceptibly in MoO3/γ-Al2O3 system at 500°C. Besides, the size of residual crystalline WO3 in WO3/γ-Al2O3 is much smaller than that of MoO3 in MoO3/γ-Al2O3. It might be the reason that WO3/γ-Al2O3 catalyst is superior to MoO3/γ-Al2O3 in hydrodesulfurization (HDS) or hydrodenitrogenation (HDN) in some cases. 相似文献
6.
Sukhjinder Singh Madanmohan Singh Gill Rajendar D. Verma 《Journal of fluorine chemistry》1985,27(2):133-142
V(SO3CF3)3, VO(SO3CF3)2 and VO(SO3CF3)3 have been prepared by reacting V(O2CCF3)3, VO(O2CCF3)2 and VOC13 with HSO3CF3. The i.r. data suggest a bridging bidentate nature for SO3CF3 groups. The diffuse reflectance spectrum of V(SO3CF3)3 suggests hexacoordination of vanadium, whilst that of VO(SO3CF3)2 is comparable to either five or six coordinated oxovanadium (IV) systems. The magnetic moments of V(SO3CF3)3 and VO(SO3CF3)2 are slightly lower than the spin-only values. Thermal decomposition of these triflates is simple. All the three triflates form coordination complexes with pyridine, 2, 2′-bipyridyl and triphenylphosphine oxide. 相似文献
7.
Synthesis and Structures of Novel Ring Compounds of Bismuth with Tris(trimethylsilyl)silyl and ‐stannyl Substituents – [(Me3Si)3Si]4Bi4 and [(Me3Si)3Sn]6Bi8 A bicyclo[3.3.0]octane‐like core consisting of eight bismuth atoms is found in the novel octabismuthane Bi8[Sn(SiMe3)3]6. It is prepared like Bi4[Si(SiMe3)3]4 by reduction of BiBr3 with Li(thf)3E(SiMe3)3 (E = Si, Sn) together with (Me3Si)6E2. Both bismuth ring compounds have been characterized by single crystal X‐ray crystallography. 相似文献
8.
A series of gold(III) cations of the type cis-[CH3)2AuL2]+ X? where L Ph3, PMePh2, PMe2Ph, PMe3, AsPh3, AsPh3, SbPh3, H2NCH2CH2NH2, Ph2PCH2CH2-PPh2, Ph2AsCH2CH2AsPh2, and o-C6H4(AsMe2)2 and X BF4?, PF6?, ClO4?, and F3CSO3? has been prepared. In addition, the cis complexes [(CH3)(CD3)-Au(PPh3)2]F3CSO3, [(C2H5)2Au(PPh3)2]F3CSO and [(n-C4H9)2Au(PPh3)2]F3-CSO3 have been synthesized. All have been characterized by PMR, Raman and infrared spectroscopy. These [R2AuL2]X compounds yield only ethane, butane, or octane via reductive elimination, and no disproportionation is observed. The alkane eliminations have been studied in CHCl3, CH3Cl2, and CH3COCH3 solution as a function of temperature, concentration of the complex, and concentration of added ligand L. Elimination is fastest when L is bulky (PPh3 > PMePh2 > PMe2Ph > PMe3), decreases in the sequence SbPh3 > AsPh3 > PPh3, is slow with chelating ligands, is inhibited by excess ligand, and there is small anion effect as X is varied. As R is varied, the rate of elimination decreases Bu ? Et > Me. An intramolecular dissociative mechanism is proposed which involves rapid elimination of alkane from an electron deficient dialkylgold(III) complex with nonequivalent gold—carbon bonds and produces the corresponding [AuL2]X complex. 相似文献
9.
Synthesis, Properties, and Structure of cis-Dihydrido Azido Tris(triphenylphosphino) Iridium cis-IrH2(N3)(PPh3)3 is formed from IrCl3(PPh3)3 and NaN3 in alcohol. The solvent transfers the hydride ions whereby aldehyde is formed. The creme-colored cis-IrH2(N3)(PPh3)3 is a diamagnetic low-spin complex. Exposure to light yields H2 and Ir(N3)(PPh3)3 in a reversible process. The cis position of the hydrido ligands is confirmed by the i.r. and H-N.M.R. spectra. Cis-IrH2(N3)(PPh3)3 crystallizes in the monoclinic system with the space group P21/c. The crystal structure exhibits isolated octahedral complexes, in which one hydrido ligand is located trans to the azido group. The other one being trans to one of the phosphine ligands. 相似文献
10.
Cyclothiazeno Complexes of Tungsten with Phosphoraneiminato and t-Butoxy Ligands The cyclothiazeno complex [WCl3(N3S2)]2 reacts with the silylated phosphaneimine Me3SiNPPh3 in THF solution forming the cyclothiazenophosphoraneiminato complex [Cl2W(N3S2)(NPPh3)]n which forms green crystals of [Cl2W(N3S2)(NPPh3)(Py)] ( 1 ) when pyridine is added. The corresponding reaction with Me3SiNPMe3 leads to the methyl derivative which is analogous to 1 and which is obtained as dark green crystals along with the tetrakis(phosphoraneiminato) complex of the crystal composition [W(NPMe3)4]Cl2 · 2 [Cl2W(N3S2)(NPMe3)(Py)] · 2 CH2Cl2 ( 2 ). According to the crystal structure analyses the phosphoraneiminato ligands NPR3– cause as a result of the short WN bonds of approximately 180 pm a strong trans influence on one of the WN bonds of the planar WN3S2 rings and alternatingly long SN bonds. With LiOCMe3 [WCl3(N3S2)]2 reacts forming the centrosymmetrically dimeric cyclothiazeno alkoxy complex [(Me3CO)4W(N3S2)Li2Cl]2 ( 3 ) the ion ensemble of which is linked via the lithium and the chlorine atoms. 相似文献
11.
The synthesis and structural characterization of bulkier variations of the very common organometallic compound MSi(SiMe3)3, namely MSi(SiMe3)(SiPh3)2 3 and MSi(SiPh3)3 [M = Li ( 1 ), K ( 5 )] are presented, which can be synthesized via a step by step exchange of SiMe3 groups by bulkier SiPh3 groups. This synthetic route is high selective and is performed in good yields via the silanes Si(SiMe3)2(SiPh3)2 ( 2 ) and Si(SiMe3)(SiPh3)3 ( 4 ). Additionally, the corresponding silanes HSi(SiMe3)(SiPh3)2 ( 6H ) and HSi(SiPh3)3 ( 7H ) are obtained via the reaction of 3 and 5 with aqueous HCl, respectively. Oxidation of 6H with CCl4 gives the chlorsilane Cl‐Si(SiMe3)(SiPh3)2 ( 6Cl ). The bulkiest chlorsilane Cl–Si(SiPh3)3 ( 7 ) is obtained by the reaction of 5 with ECl2 (E = Sn, Pb). 相似文献
12.
Formation of Tri-tert.-butyl-nonaphosphane (3); P9(CMe3)3 P9(CMe3)3 1 is formed by the reaction of “Na3P/K3P” with (Me3C)PCl2 [maximum yield 20% with regard to (Me3C)PCl2]. The molar ratio of the reactants used on this synthesis is Na/K:P4:(Me3C)PCl2 is 4:1:2. The method of preparation is described. 相似文献
13.
《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1990,46(5):793-796
The stretching vibrations of the SnC3Cl group in the infrared spectrum of SnPh3Cl have been reassigned on the basis of an SnC3 group belonging to the C3ν point group which is replaced by D3h in SnPh3Cl2TMN (TMN = tetramethylammonium). The important shift (108 cm−1) of νsSnC3 from SnPh3Cl to SnPh3Cl2 TMN is due to a “C3ν point group inversion” (νsSnC3 is higher in frequency than νasSnC3 in the i.r. spectrum of SnPh3Cl). 相似文献
14.
The MnS-La2S3 phase diagram has been constructed where the incongruently melting compound Mn2La6S11 is formed. Complex sulfide Mn2La6S11 is characterized by monoclinic structure; its incongruent melting temperature is 1535 K. Eutectic coordinates are 31 mol % La2S3, 1490 K. The extent of the ??-La2S3 based solid solutions at 1570 K is 8 mol % MnS; at 770 K, ??-La2S3 dissolves 3 mol % MnS. The MnS-Gd2S3 system is a eutectic with limited solid solutions. Eutectic coordinates are 35.5 mol % Gd2S3, 1640 K. Solubility in ??-Gd2S3 is 28 mol % MnS at 1570 K, in ??-Gd2S3 is 13 mol % MnS at 1170 K, and in MnS is 1 mol % Gd2S3. Thermochemical equations have been composed for eutectic and eutectoid phase transformations. A MnS-Nd2S3 phase diagram has been predicted. 相似文献
15.
Quantum chemical calculations at various levels of theory (BP86, B3LYP, MP2, CCSD(T), CBS‐QB3) of the beryllium complexes [BeCl2(NHPH3)], [BeCl2(NHPH3)2], [BeCl3(py)]?, [BeCl2(NH3)], [BeCl2(NH3)2], [BeCl3(py)]? and [BeCl3(NH3)]? as well as the boron compounds [BCl3(py)] and [BCl3(NH3)] show that BeCl2 is a very strong Lewis acid. The theoretically predicted bond dissociation energy at CBS‐QB3 of Cl2Be‐NH3 (De = 32.5 kcal/mol)is even higher than that of Cl3B‐NH3 (De = 28.6 kcal/mol). Even the second ammonia molecule in [BeCl2(NH3)2] still has a strong bond with De = 24.2 kcal/mol. The theoretically predicted bond strengths for the phosphaneimine ligands in [BeCl2(NHPH3)2] are De = 46.7 kcal/mol for the first ligand and De = 29.8 kcal/mol for the second. The anion BeCl3? is a moderately strong Lewis acid which has bond energies of De = 14.1 kcal/mol in [BeCl3(py)]? and De = 14.2 kcal/mol in [BeCl3(NH3)]?. The higher bond energy of [BeCl2(NH3)] compared with [BCl3(NH3)] comes from less deformation energy for BeCl2 than for BCl3. The intrinsic attraction between BeCl2 and NH3 calculated with frozen geometries of the complex geometry is ~5 kcal/mol less than the attraction between BCl3 and NH3. The bonding analysis with the EDA method shows that the attractive energy of the beryllium complexes comes manly from electrostatic attraction. The larger contribution of the electrostatic term is the most significant difference between the nature of the donor‐acceptor bonds of the beryllium and boron complexes. 相似文献
16.
Diphenyl-bis(P-trimethylphosphinimino)-phosphonium Chloride The reaction of Na⊕(CH3)3Si? N? P(C6H5)2? N? Si(CH3)3? III with (CH3)3PCI2 results in the elimination of NaCI and (CH3)3SiCI and the formation of (CH3)3P = N? P(C6H5)2? N = P(CH3)3 ⊕CI? VII . The mechanism of the reaction is discussed. (CH3)3P = N? P(C6H5)2 = N? Si(CH3)3 V can be obtained as an intermediate. This intermediate, when synthesized by an other independent route, is found to react with (CH3)3PCI2 to give the same product VII . 相似文献
17.
[(Ph3Sn)3VO4]·CH3CN and [(Ph3Sn)3VO4]·2 DMF, Triphenyltin Vanadates with Novel Chain Structures The reaction of Na3VO4 with Ph3SnCl in a water/CH2Cl2 mixture leads to the formation of [(Ph3Sn)3VO4] ( 1 ). Recrystallization of 1 from toluene/CH3CN gives pale yellow crystals of [(Ph3Sn)3VO4]·CH3CN ( 2 ). 2 crystallizes as coordination polymer which consists of infinite chains composed of corner‐sharing VO4 tetrahedra and Ph3SnO2 trigonal bipyramides. Additionally the VO4 groups are connected to two terminal SnPh3‐Groups containing tin atoms in a tetrahedral environment. [(Ph3Sn)3VO4]·2 DMF ( 3 ) which is obtained from Na3VO4 and Ph3SnCl in a water/DMF mixture contains a polymeric chain structure similar to 2 and additionally one of the terminal SnPh3 groups is coordinated to a DMF solvent molecule. 相似文献
18.
Solubility of lanthanum oxide was measured by thermal analysis. The solubility in alkali cryolites is rather high, because of chemical reactions between lanthanum oxide and cryolites. In Li3AlF6-La2O3, alumina precipitates, in the other systems the mixed oxide LaAlO3 is formed. In La2O3-Li3AlF6 the eutectic point is at 9.5 mol% La2O3 and 755 °C. The eutectic points in La2O3-Na3AlF6 and La2O3-K3AlF6 are at 11.5 mol% La2O3, and at 937 and 934 °C, respectively. 相似文献
19.
《Journal of Coordination Chemistry》2012,65(3):121-126
Abstract Thirty compounds of the type (ZC6H4)3PM(CO)5 where Z is 3-CH3, 4-CH3, 3-CH3O, 4-CH3O, 3-CF3, 4-CF3, 4-Cl, 4-F, 4-CH3S, or 4-(CH3) C and M is Cr, Mo, or W are reported, in addition to [4-(CH3)3SiC6H4]3 PW(CO)5 and [(2-CH3C6H4)n(C6H5)3–n P] M(CO)5 where n is 1 or 2 and M is Cr, Mo, or W. Phosphorus-31 NMR and infrared data are presented. In general, the compounds containing the more effective electron withdrawing substituents on the tertiary arylphosphines exhibit the larger 31P coordination chemical shifts, the higher carbonyl stretching frequencies, and the larger phosphorus-31-tungsten-183 coupling constants. 相似文献
20.
The reaction between liquid F3SiI and red HgS mainly yields the disilylsulfane (F3Si)2S and, in smaller amounts, hitherto unknown (F3SiS)2SiF2. These fluorosilylsulfanes have different thermal stabilities. (F3Si)2S is a versatile precursor for F3Si derivatives, and at ambient temperature it is stable, while (F3SiS)2SiF2 decomposes rapidly. F3SiSH has been obtained, along with F3SiBr, by selective cleavage of one of the Si–S bonds in (F3Si)2S with HBr in the liquid phase and was for the first time unambiguously characterized. Contrary to previous reports, (F3Si)2O rather than (F2SiS)2 is formed when SiF4 is passed over SiS2 at 1298 K in a quartz tube. Raman and infrared spectra of (F3Si)2S, F3SiSH and its deuterated derivative F3SiSD have been measured and assigned to vibrational fundamentals. Multinuclear NMR spectra have been recorded. 相似文献