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1.
About the Preparation of N-Chloro-N-Methylammonium Salts (CH3)nNCl4–n+MF6? (n = 1–3; M = As, Sb) and (CH3)2NClX+MF6? (X = F, Br) Simple one-step methods for the preparation of the methylated chloroammonium salts (CH3)nNCl4–n+MF6? (n = 1–3; M = As, Sb) and for (CH3)2NClX+MF6? (X = F, Br) are reported. Their vibrational and NMR-spectroscopical data are discussed in comparison. 相似文献
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Qing‐Zhu Zhang Ji‐Guo Zhang Shao‐Kun Wang Miao Zhang Chuan‐Pu Liu Yue‐Shu Gu 《中国化学》2001,19(6):566-572
The abstractions of H with (CH3)4‐nSiHn (n = 1–4) have been investigated at high levels of ab initio molecule orbital theory. Geometries have been optimized at the MP‐2 level with 6–31G(d) basis set, and G2MP2 level has been used for the final energy calculations. Theoretical analysis provided conclusive evidence that the main process occurring in each case is the abstraction of H from the Si? H bond leading to the formation of the H2 and silyl radicals; the abstraction of H from C? H bond has higher barrier and is difficult to react in each case. The kinetics of the title reactions have been calculated with variational transition state theory over the temperature range 200–1000 K, and the theoretical rate constants match well with the experimental values. 相似文献
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Alternative Ligands. XXXII [1]. Novel Tetraphosphane Nickel Complexes with Tripod-Ligands of the Type XM′(OCH2PMe2)n(CH2CH2PR2)3 – n (M′ = Si, Ge; n = 0 – 3) Tripod Ligands of the type XM′(OCH2PMe2)n(CH2CH2PMe23 – n (M′ = Si, Ge; n = 0 – 3) ( 1 – 6 , Table 1) have been used together with PPh3 or PMe3 for the preparation of novel tetraphosphane complexes of Nickel. The representatives LNiPPh3 ( 7 – 12 ) are obtained by reaction of Ni(COD)2 (COD = 1,5-cyclooctadiene) with the corresponding ligands and PPh3 in toluene in moderate yields. The synthesis of the derivatives LNiPMe3 ( 13 – 18 ) is partly ( 16 – 18 ) accomplished in analogy to the Ph3P-complexes; compounds 13 – 16 are obtained in higher yields by reaction of Ni(PMe3)4 with the respective ligand. As a rule, 13 – 18 cannot be separated from by-products. The trinuclear complex FSi(CH2CH2PMe2)3[Ni(PMe2CH2CH2)3SiF]3 ( 19 ) is formed together with 18 in the reaction of Ni(COD)2 with 6 and PMe3. The new compounds have been characterized (if possible) by analytical (C, H), but in general by spectroscopic investigations (IR; 1H-, 13C-, 19F-, 31P-NMR; MS). A weak, but significant Ni → Si interaction through the cage is indicated by the following results: (i) Large low-field shifts δδF of 35.2 ppm ( 12 ), 38.3 ppm ( 18 ) and 37.7 ppm ( 19 ); (ii) 6J(PF) coupling constants [or 3J(PNiSiF) through the cage] of 6.0 Hz ( 12 ) and 7.6 Hz ( 18 ) together with a low-field shift δδSi of 12.8 ppm ( 12 ); (iii) NiSi distances of 3.95 Å in 7 and 3.92 Å in 12 , accompanied by a compression of the cage along the Ni ··· Si axis. An additional release from the high charge density on Ni results from π-backbonding to the phosphane ligands. 相似文献
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Triphenylphosphane Nickel(0) Complexes with Isocyanide Ligands — [(RNC)nNi(PPh3)4–n] (n = 1–3) Synthesis and properties of the isocyanide triphenylphosphane nickel(0) complexes [(RNC)Ni(PPh3)3], [(RNC)2Ni(PPh3)2] and [(RNC)3Ni(PPh3)] (R = tBu, Cy, PhCH2, p-TosCH2) are described. I.r. and 31P n.m.r. spectra were recorded and the X-ray crystal structure of [(PhCH2NC)2Ni(PPh3)2] was determined. 相似文献
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Alternative Ligands. XXX Novel Tripod Ligands XM' (OCH2PMe2)n(CH2CH2PMe2)3?n (M' = Si, Ge; n = 0–3) for Cage Structures Attempts to prepare new tripod ligands XSi(OCH2PMe2)3 [X = CF3 ( 15 ), C6F5 ( 16 ), NMe2 ( 17 ), Cl ( 18 ), F ( 19 ), H ( 20 ), OEt ( 21 ), OMe ( 22 )] prove to be unsuccessful in spite of using different pathways, because the groups X undergo following reactions giving insoluble solids (polyadducts) or form inseparable mixtures, e. g. (RO)nSi(OCH2PMe2)4?n (R = Me, Et). In many cases Si(OCH2PMe2)4 ( 13 ) can be isolated from the reaction mixture. The syntheses of the ligands XSi(CH2CH2PMe2)3 [X = NMe2 ( 6 ), Cl ( 7 ), F ( 8 ), OMe ( 9 ), Vi ( 12 )], Si(OCH2PMe2)4 ( 13 ) und Me3GeOCH2PMe2 ( 14 ) are successful. The compounds MeSi(OCH2PMe2)2CH2CH2NMe2 ( 10 ) and MeSi(OCH2PMe2)2CH2CH2P(CF3)2 ( 11 ) with different donor groups are obtained in good yields. The preparative program includes the synthesis of the known representatives MeSi(OCH2PMe3)3 ( 1 ), MeSi(OCH2PMe2)2CH2CH2PMe2 ( 2 ), MeSi(OCH2PMe2)(CH2CH2PMe2)2 ( 3 ), MeSi(CH2CH2PMe2)3 ( 4 ) and MeGe(OCH2PMe2)3 ( 5 ). Important preparative steps are the substitution of M'Cl (M' = Si, Ge) by Me2PCH2O groups and the photochemically induced or base catalyzed addition of HNMe2, HPMe2 or HP(CF3)2 to SiVi functions. The novel compounds are characterized by analytical and spectroscopic (IR, NMR, MS) investigations. 相似文献
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Alternative Ligands. XXXI. Nickelcarbonyl Complexes of Tripod Ligands of the Type XM′(OCH2PMe2)n(CH2CH2PR2)3–n (M′ = Si, Ge; n = 0–3) The coordinating properties of the tripod ligands RM′(OCH2PMe2)n(CH2CH2PMe2)3–n (M′ = Si, Ge) ( 1–7 ), MeSi(OCH2PMe2)2CH2CH2P(CF3)2 ( 8 ), MeSi(OCH2PMe2)2CH2CH2NMe2( 10 ) as well as of the tetradentate representative Si(OCH2PMe2)4 ( 9 ) have been investigated by the preparation of the novel nickel carbonyl complexes LNiCO ( 11–18 ), Si(OCH2PMe2)4[Ni(CO)2]2 ( 19 ) and (HOCH2PMe2)2Ni(CO)2 ( 20 ). They are obtained in moderate to good yields by the reaction of Ni(CO)4 with the corresponding ligands in toluene (20–111°C) (see Table 1). The new compounds have been characterized by analytical (C, H) and spectroscopic investigations (IR; 1H-, 13C-, 19F, 31P-NMR, MS). The ligand properties are discussed on the basis of spectroscopic data [in particular coordination shifts Δδ = δ(complex)—δ(ligand)] leading to the conclusion that the high electron density on Ni gives rise to a weak, but significant Ni→Si interaction. An important indication comes from the large low field shift ΔδF = 34.5 ppm for the SiF acceptor bridge in 17 . This result is supported by an X-ray diffraction study of 11 giving an NiSi distance of 3.941(2) Å. With the exception of O2…?P3 (Abb. 7) all other O…?P through-cage contacts are longer than the NiSi distance. An additional release from the high charge density on Ni is obtained via π-backbonding to the neighbouring groups OCPMe2, CCPMe2 and CO. 相似文献
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Yoo EJ Feketeová L Khairallah GN White JM O'Hair RA 《Organic & biomolecular chemistry》2011,9(8):2751-2759
The fixed charge zwitterionic sulfur betaines dimethylsulfonioacetate (DMSA) (CH(3))(2)S(+)CH(2)CO(2)(-) and dimethylsulfoniopropionate (DMSP) (CH(3))(2)S(+)(CH(2))(2)CO(2)(-) have been synthesized and the structures of their protonated salts (CH(3))(2)S(+)CH(2)CO(2)H···Cl(-) [DMSA.HCl] and (CH(3))(2)S(+)(CH(2))(2)CO(2)H···Pcr(-) [DMSP.HPcr] (where Pcr = picrate) have been characterized using X-ray crystallography. The unimolecular chemistry of the [M+H](+) of these betaines was studied using two techniques; collision-induced dissociation (CID) and electron-induced dissociation (EID) in a hybrid linear ion trap Fourier transform ion cyclotron resonance mass spectrometer. Results from the CID study show a richer series of fragmentation reactions for the shorter chain betaine and contrasting main fragmentation pathways. Thus while (CH(3))(2)S(+)(CH(2))(2)CO(2)H fragments via a neighbouring group reaction to generate (CH(3))(2)S(+)H and the neutral lactone as the most abundant fragmentation channel, (CH(3))(2)S(+)CH(2)CO(2)H fragments via a 1,2 elimination reaction to generate CH(3)S(+)=CH(2) as the most abundant fragment ion. To gain insights into these fragmentation reactions, DFT calculations were carried out at the B3LYP/6-311++G(2d,p) level of theory. For (CH(3))(2)S(+)CH(2)CO(2)H, the lowest energy pathway yields CH(3)S(+)=CH(2)via a six-membered transition state. The two fragment ions observed in CID of (CH(3))(2)S(+)(CH(2))(2)CO(2)H are shown to share the same transition state and ion-molecule complex forming either (CH(3))(2)S(+)H or (CH(2))(2)CO(2)H(+). Finally, EID shows a rich and relatively similar fragmentation channels for both protonated betaines, with radical cleavages being observed, including loss of ˙CH(3). 相似文献
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Xiu‐Li Dong Zheng‐Yu Zhou Lai‐Jin Tian Gang Zhao 《International journal of quantum chemistry》2005,102(4):461-469
The hydrogen bonding complexes HO(H2O)n (n = 1–3) were completely investigated in the present study using DFT and MP2 methods at varied basis set levels from 6‐31++G(d,p) to 6‐311++G(2d,2p). For n = 1 two, for n = 2 two, and for n = 3 five reasonable geometries are considered. The optimized geometric parameters and interaction energies for various complexes at different levels are estimated. The infrared spectrum frequencies and IR intensities of the most stable structures are reported. Finally, thermochemistry studies are also carried out. The results indicate that the formation and the number of hydrogen bonding have played an important role in the structures and relative stabilities of different complexes. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005 相似文献
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Preparation of Mixed Potassium Hexabromochloro Osmates(IV), K2OsBrnCl6–n (n = 1…5), and Potassium Hexabromochloro Rhenates(IV), K2ReBrnCl6–n (n = 1…5) Solutions of mixed hexabromochloro osmates and rhenates which were separated by ion column chromatography are extracted by tridodecylamine in ether. The potassium salts are precipitated from the extractions with potassium acetate and following further purification are characterized spectrophotometrically and by powder X-ray methods. 相似文献
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Perfluoromethyl-Element-Ligands. XVII. Formation of Adducts of MenE(CF3)3?n Ligands with BX3 Compounds (Me = CH3; E = P, As, Sb; n = 0–3; X = H, CH3, Hal) The ligands MenE(CF3)3?n (Me = CH3; E = P, As, Sb; n = 0–3) have been prepared (partly using new methods) and studied by n.m.r. spectroscopy (1H, 19F, 31P, 13C). In order to deduce their relative donor strength their reactions with the Lewis acids “BH3”, BMe3, BMe3, Me2BBr, and BX3 (X = F, Cl, Br) have been studied. Control of adduct formation occurs by n.m.r. spectroscopy (1H, 19F). The following series of decreasing basicity or acidity are obtained: 相似文献
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Ohne Zusammenfassung 相似文献
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Volker Jonas Gernot Frenking Manfred T. Reetz 《Journal of computational chemistry》1992,13(8):919-934
The performance of effective core potentials (ECP) and model potentials (MP) has been studied by calculating the geometries and reaction energies of isodesmic reactions for the molecules Ti(CH3)nCl4 ? n (n = 0–4) at the Hartree–Fock level of theory. The results are compared with data from all electron calculations and experimental results as far as available. The all electron calculations were performed with a 3-21G basis set from Hehre and a (53321/521/41) basis set from Huzinaga. For the ECP calculations the potentials developed by Hay and Wadt, and for the MP calculations, the model potentials developed by Sakai and Huzinaga, are employed. © 1992 by John Wiley & Sons, Inc. 相似文献
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Qi Ying Xia He Ming Xiao Xue Hai Ju Xue Dong Gong 《International journal of quantum chemistry》2004,100(3):301-308
Computations on the systems of (H2GaN3)n (n = 1–4) are performed using the density functional theory (DFT)/B3LYP method with different basis sets. (H2GaN3)2 possessing D2h symmetry is found to exhibit the planar Ga2N2 ring structure. (H2GaN3)3 involving a six‐membered Ga3N3 ring is found to exhibit two minima with very similar binding energies (ca. −235 ∼ −231 kJ · mol−1). One minimum is the newly found boat‐like conformation possessing Cs symmetry. Another minimum possessing C3v symmetry is the chair‐like conformation. (H2GaN3)4 occurs in several structures with Ga4N4 eight‐membered ring structures that correspond to minima with slight energy differences among them. The structural changes of the clusters are large compared with the monomer. Frequency calculations are carried out on each optimized structure, and their infrared (IR) spectra are discussed. Thermodynamic properties demonstrate that the systems of H2GaN3 occur at dimer–trimer–tetramer equilibrium, and the trimer is the main component. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004 相似文献
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Řeřicha R. Stokr J. Jakoubková M. Svoboda P. Chvalovský V. 《Colloid and polymer science》1976,254(10):932-932
Ohne Zusammenfassung 相似文献
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采用量子化学的QCISD(T)/6-311 G(d,p)//BHandHLYP/6-311G(d,p)方法研究了氟代甲烷CH4-nFn(n=1~3)与CH3自由基氢抽提反应的微观动力学性质.并利用Polyrate程序分别计算了3个反应在200~3000K范围内的速率常数.计算结果表明,R1a,R2a和R3三个反应路径的反应能量分别为-12.7,-9.5和11.8kJ/mol,相应的能垒依次为67.0,62.2和67.5kJ/mol.在437K时,kCVT/SCT分别为6.72×10-19,8.01×10-18和8.82×10-20cm3/(molecule.s).计算结果还表明,在低温段反应的量子隧道效应显著,在计算温度范围内变分效应对反应速率常数的影响可以忽略. 相似文献
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An ab initio Hartree–Fock–Slater procedure was applied to the calculation of the electronic structure of polysulfanes, H2Sn (n = 1–4) and the ions HS and S. Charge densities, overlap populations, and deprotonation energies are calculated; the latter appear well correlated with the first and second acidity constants. 相似文献