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1.
The structures and stability of pentacoordinate germylenoid PhCH2(OH)CH3GeLiF were first theoretically studied by density functional theory. Two equilibrium structures, the three-membered ring (1a) and the p-complex (1b) structures, were located. Their energy are in the order of 1b > 1a. The Ge-O coordination energies at the B3LYP/6-311+G(d, p) level are 13.6 and 0.2 kJ/mol in 1a and 1b, respectively. The insertion reactions with CH3F indicate that germylenoid PhCH2(OH)CH3GeLiF is more stable than germylene PhCH2(OH)CH3Ge. The insertion barrier of 1a with CH3F is only 3.1 kJ/mol higher than that of PhCH3CH3GeLiF, indicating that the oxygen coordination PhCH2(OH)CH3GeLiF has the same stability as PhCH3CH3GeLiF. 相似文献
2.
The structures and stability of pentacoordinate germylenoid PhCH2(NH2)CH3GeLiF were first theoretically studied by density functional theory. Two equilibrium structures, the three-membered ring and
the p-complex structures, were located. The three-membered ring structure is more stable both in vacuum and in solvents (ether,
THF, and acetone). The Ge–N coordination energies at the B3LYP/6-311+G(d,p) level are 35.8 and 7.9 kJ/mol in the three-membered
ring and the p-complex structures, respectively. The insertion reactions with CH3F indicate that germylenoid PhCH2(NH2)CH3GeLiF is more stable than germylene PhCH2(NH2)CH3Ge. The insertion barrier of PhCH2(NH2)CH3GeLiF with CH3F is higher than that of PhCH3CH3GeLiF, indicating that the amine coordination make PhCH2(NH2)CH3GeLiF more stable. 相似文献
3.
The insertion reactions of the p-complex structure (A) of silylenoid H2SiLiF into C–X bonds of CH3XH
n−1 (X = F, Cl, Br, O, N; n = 1, 1, 1, 2, 3) have been studied using ab initio and DFT methods. The results indicate that the insertions proceed in a
concerted manner, forming H2SiXH
n−1CH3 and LiF. The order of reactivity by A insertion indicates the reaction barriers increase for the same-row element X from right to left in the periodic table, whereas
change very little for the same-family element X. The insertions of A and the three-membered-ring structure of H2SiLiF are similar. Both structures may participate in insertion reactions. 相似文献
4.
The new alkoxysilyl-functionalized alkynes [HC≡CCH2N(H)C(=O)N(H)(CH2)3Si(OEt)3] and [HC≡C(C6H4)–N(H)C(=O)N(H)(CH2)3Si(OEt)3] have been synthesized using literature methods. These have been reacted with Fe3(CO)12, Ru3(CO)12 and Co2(CO)8. With the iron carbonyl only decomposition was observed: with Ru3(CO)12 splitting of the alkynes into their parent components and formation of the complexes (μ-H)Ru3(CO)9[HC=N(CH2)3Si(OEt)3], (μ-H)Ru3(CO)9[C–C(C6H4)NH2] and (μ-H)2Ru3(CO)9[HC–CCH3] occurred. Finally, with Co2(CO)8 formation of complexes Co2(CO)6(HC2R) R=(C6H4)NH2, CH2NH(CO)NH(CH2)3Si(OEt)3, (C6H4)NH(CO)NH(CH2)3Si(OEt)3 containing the intact alkynes could be obtained. 相似文献
5.
The structures and isomerization of silylenoid H2SiLiF are investigated by density functional theory (DFT) at B3LYP/6-311+G(d,p) level. The solvent effects are modeled using
the self-consistent reaction field (SCRF) method with Tomasi’s polarized continuum model (PCM). Five representative solvents,
i.e. benzene, ether, THF, acetone, and DMSO, are chosen for this work. Special attention is paid to THF solvent. The results
indicate that the polarity of solvents has played an important role on the structures and relative stabilities of different
isomers. Contrary to the three-membered ring structure 1, the relative stability of the “classical” tetrahedron structure 4 increases with increasing dielectric constants (ε) of solvents. The σ-complex isomer 3 is most unstable structure. Although the relative energies are reduced with increasing dielectric constants (ε) of solvents, the p-complex structure 2 still has the lowest energy. The effects of solvents on the dipole moments and charge distributions are also discussed. 相似文献
6.
Weihua Wang Ping Li Xiaojun Tan Qiufen Wang Gengxiu Zheng Yuxiang Bu 《Structural chemistry》2008,19(3):527-533
The geometries and isomerization of the imine silylenoid HN=SiNaF as well as its insertion reactions with some R–H molecules
have been systematically investigated theoretically, where R=F, OH, NH2, and CH3, respectively. The barrier heights for the four insertion reactions are 67.7, 115.6, 153.5, and 271.5 kJ/mol at the B3LYP/6-311+G*
level of theory, respectively. Here, all the mechanisms of the four reactions are identical to each other, i.e., a stable
intermediate has been formed during the insertion reaction. Then, the intermediate could dissociate into the substituted silylene
(HN=SiHR) and NaF with a barrier corresponding to their respective dissociation energies. Correspondingly, the reaction energies
for the four reactions are 71.8, 95.5, 123.3, and 207.6 kJ/mol, respectively, which are linearly correlated with the calculated
barrier heights. Furthermore, the effects of halogen substitutions (F, Cl, and Br) on the reaction activity have also been
discussed. As a result, the relative reactivity among the four insertion reactions should be as follows: H–F > H–OH > H–NH2 > H–CH3. 相似文献
7.
K. Otto I. Oja Acik K. Tõnsuaadu A. Mere M. Krunks 《Journal of Thermal Analysis and Calorimetry》2011,105(2):615-623
Thermal decomposition of precursors for In2S3 thin films obtained by drying aqueous solutions of InCl3 and SC(NH2)2 at the In:S molar ratios of 1:3 (1) and 1:6 (2) was monitored by simultaneous TG/DTA/EGA-FTIR measurements in the dynamic 80%Ar + 20%O2 atmosphere. XRD and FTIR were used to identify the dried precursors and products of the thermal decomposition. The precursors
1 and 2 are complex compounds, while in 2 free SC(NH2)2 is also present. The thermal degradation of 1 and 2 in the temperature range of 30–900 °C consists of four mass loss steps, the total mass loss being 89.1 and 78.5%, respectively.
According to XRD, In2S3 is formed below 300 °C, crystalline In2.24(NCN)3 is detected only in 1 above 520 °C and In2O3 is the final decomposition product at 900 °C. The gaseous species evolved include CS2, NH3, H2NCN, HNCS, which upon oxidation yield also COS, SO2, HCN and CO2. 相似文献
8.
Zakaria Benzekri Sara Sibous Houda Serrar Ali Ouasri Said Boukhris Ali Rhandour Abdelaziz Souizi 《Journal of the Iranian Chemical Society》2018,15(12):2781-2787
In this work, the condensation of aromatic aldehydes with different two-substituted aniline catalyzed by NH3(CH2)5NH3BiCl5 as heterogeneous and recyclable catalyst was reported. It was demonstrated that NH3(CH2)5NH3BiCl5 can act as an efficient and active catalyst and is reusable for six runs without a significant loss of their catalytic activity. Simple preparation of the catalyst, high catalytic activity and good reusability are noteworthy advantages of this catalytic system in the synthesis of benzoxazole, benzimidazole and benzothiazole heterocycles at room temperature under solvent-free conditions. 相似文献
9.
A new molybdophosphate (NH4)8{Mo2VO4[(Mo2VIO6)CH3C(O)(PO3)2]2}·14H2O (1), has been synthesized by the reaction of {Mo2VO4(H2O)6}2+ fragments with 1-hydroxyethylidenediphosphonate (hedp HOC(CH3)(PO3H2)2), and it is characterized by 31P NMR, IR, UV, element analysis, TG and single-crystal X-ray analysis. The structure analysis reveals that the polyoxoanion
can be described as two {(Mo2VIO6)(CH3C(O)(PO3)2} units connected by a {Mo2VO4}2+ moiety. In the structure, the six Mo atoms are arranged into a new “W-shaped” structure, which represents a new kind of molybdophosphate. 相似文献
10.
P. Schwendt D. Dudášová J. Chrappová M. Drábik J. Marek 《Journal of Thermal Analysis and Calorimetry》2008,91(1):293-297
The compound [Ni(NH3)6][VO(O2)2(NH3)]2 was prepared and characterized by elemental analysis and vibrational spectra. The single crystal X-ray study revealed that
the structure consists of [Ni(NH3)6]2+ and [VO(O2)2(NH3)]− ions. As a result of weak interionic interactions V′···Op (Op-peroxo oxygen), ([VO(O2)2(NH3)]−)2 dimers are formed in the solid-state. The thermal decomposition of [Ni(NH3)6][VO(O2)2(NH3)]2 is a multi-step process with overlapped individual steps; no defined intermediates were obtained. The final solid products
of thermal decomposition up to 600°C were Ni2V2O7 and V2O5. 相似文献
11.
The present research work reports the study on crystal structure, vibrational spectroscopy and thermal analysis of organic-inorganic hybrid compound (C6H5(CH2)2NH3)2CdCl4. Single crystals of bis(phenethylammonium)tetrachlorocadmate (C6H5(CH2)2NH3)2CdCl4 (PEA–Cd) were obtained by diffusion at room temperature. This compound crystallizes in the orthorhombic space group C2cb with unit cell parameters a = 7.4444(2) Å, b = 38.8965(3) Å, c = 7.3737(2) Å and Z = 4. Single crystal structure has been solved and refined to R = 0.036 and wR = 0.092. The structure consists of an extended [CdCl4]2– network and two [C6H5(CH2)2NH3]+ cations to form a two-dimensional perovskite system. The infrared (IR) spectrum of the title compound was recorded at room temperature. Differential scanning calorimetry (DSC) was used to investigate the phase transition; this compound exhibits a reversible single solid-solid phase transition. 相似文献
12.
Fabio Carniato Andrea Secco Giorgio Gatti Leonardo Marchese Enrico Sappa 《Journal of Sol-Gel Science and Technology》2009,52(2):235-241
The reaction of Ru3(CO)12 with 2(diphenylphosphino)ethyl-triethoxysilane (DPTS) in hydrocarbons, leads to the functionalized Ru3(CO)12−n
[Ph2P(CH2)2Si(OEt3)]
n
(n = 1,2) complexes. The complex with two phosphine substituents was chemically anchored on mesoporous silicas, SBA-15 and MCM-41,
in order to obtain two hybrid materials characterized by a different localization of the metal centre on the surface of the
porous supports. A detailed investigation of the cluster, before and after chemical anchoring on the mesoporous silicas, was
pursued. Particular attention was also devoted to the study of the morphological, structural and textural properties of the
metal-functionalised silicas (Ru/SBA-15 and Ru/MCM-41) by infrared spectroscopy (FT-IR), scanning electron microscopy, X-ray
diffraction and N2 physisorption analysis. 相似文献
13.
G. I. Nikishin L. L. Sokova A. O. Chizhov V. D. Makhaev N. I. Kapustina 《Russian Chemical Bulletin》2004,53(10):2200-2204
Solid state reactions of acids RCOOH (R = n-C7H15, BuC(Et)H, n-C9H19, PhCH2, PhCH2CH2, H2C=CH(CH2)8, or MeOOC(CH2)3) with Pb(OAc)4 combined with KCl, NaCl, CdCl2, or NH4Cl in the absence of a solvent and without mechanical activation afford chlorohydrocarbons RCl. The corresponding reactions of acids HOOC(CH2)nCOOH (n = 3–6) give dichloroalkanes Cl(CH2)nCl and γ-butyrolactone (n = 3).__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2105–2109, October, 2004. 相似文献
14.
Sofia Nikolaou Daniela M. Tomazela Marcos N. Eberlin Henrique E. Toma 《Transition Metal Chemistry》2008,33(8):1059-1065
The polymetallic [Ru3O(CH3COO)6(py)2(BPE)Ru(bpy)2Cl](PF6)2 complex (bpy = 2,2′-bipyridine, BPE = trans-1,2-bis(4-pyridil)ethylene and py = pyridine) was assembled by the combination of an electroactive [Ru3O] moiety with a [Ru(bpy)2(BPE)Cl] photoactive centre, and its structure was determined using positive ion electrospray (ESI-MS) and tandem mass (ESI-MS/MS)
spectrometry. The [Ru3O(CH3COO)6(py)2(BPE)Ru(bpy)2Cl]2+ doubly charged ion of m/z 732 was mass-selected and subject to 15 eV collision-induced dissociation, leading to a specific dissociation pattern, diagnostic
of the complex structure. The electronic spectra display broad bands at 409, 491 and 692 nm ascribed to the [Ru(bpy)2(BPE)] charge-transfer bands and to the [Ru3O] internal cluster transitions. The cyclic voltammetry shows five reversible waves at −1.07 V, 0.13 V, 1.17 V, 2.91 V and
−1.29 V (vs SHE) assigned to the [Ru3O]−1/0/+1/+2/+3 and to the bpy0/−1 redox processes; also a wave is observed at 0.96 V, assigned to the Ru+2/+3 pair. Despite the conjugated BPE bridge, the electrochemical and spectroelectrochemical results indicate only a weak coupling
through the π-system, and preliminary photophysical essays showed the compound decomposes under visible light irradiation. 相似文献
15.
E. T. de Almeida A. M. Santana A. V. G. Netto Claudia Torres A. E. Mauro 《Journal of Thermal Analysis and Calorimetry》2005,82(2):361-364
The synthesis, characterization and thermal analysis of the novel cyclometallated compounds [Pd2(dmba)2Cl2(μ-bpe)] (1), [Pd2(dmba)2(N3)2(μ-bpe)] (2), [Pd2(dmba)2(NCO)2(μ-bpe)] (3), [Pd2(dmba)2(SCN)2(μ-bpe)] (4), [Pd2(dmba)2(NO3)2(μ-bpe)] (5) (bpe=trans-1,2-bis(4-pyridyl)ethylene; dmba=N,N-dimethylbenzylamine) are described. The thermal stability of [Pd2(dmba)2X2(μ-bpe)] complexes varies in the sequence 1>4>3>2>5. The final residues of the thermal decompositions were characterized as metallic palladium by X-ray powder diffraction. 相似文献
16.
Mohammad El-khateeb Khalil J. Asali Ibrahim Jibril Anas Abuseni Helmar Görls Wolfgang Weigand 《Transition Metal Chemistry》2009,34(4):419-424
A controlled substitution reaction of the chlorine atoms of 1,3,5-benzenetricarbonyl trichloride by the organoiron fragment
(CpFe(CO)2S) has been achieved. The complexes CpFe(CO)2SCO-3,5-C6H3(COCl)2 (1), 1,3-[CpFe(CO)2SCO]2-5-C6H3COCl (2) and 1,3,5-[CpFe(CO)2SCO]3C6H3 (3) were prepared from the reaction of (μ-S
x
)[CpFe(CO)2]2 (x = 3, 4) with 1,3,5-C6H3(COCl)3 in a 1:1, 2:1, or 3:1 metal to ligand molar ratio. The reactions of (1) with amines, thiols, and carboxylic acids produce the trifunctional mono-iron complexes CpFe(CO)2SCO-3,5-C6H3(COY)2 [Y = NR2 (4), SR (5), OCOR (4)]. The X-ray structure determination of (1) is reported. 相似文献
17.
K. Ramalingam R. Thiruneelakandan G. Bocelli L. Righi 《Transition Metal Chemistry》2012,37(3):265-270
The complexes trans-[Ni(4-MP)2(NCS)2]·MeCN (1) and trans-[Ni(3-MP)2(NCS)2] (2) (4-MP = tri(4-methylphenyl)phosphine, 3-MP = tri(3-methylphenyl)phosphine) were prepared and characterized by IR, UV–visible,
NMR spectra, CV, TGA and single crystal X-ray crystallography. Both the complexes have planar geometry and are diamagnetic.
The Ni–P distances in both complexes are relatively short as a result of strong back donation from nickel to phosphorus. The
phenyl rings in the 3-MP analogue (2) show increased pitching with reference to the plane formed by the ipso carbons due to increased steric effects. For complex
(2), the N–Ni–N and P–Ni–P angles are significantly lower than the almost linear N–Ni–N and N–Ni–P angles observed for both
complex (1) and trans-[Ni(PPh3)2(NCS)2]. This observation indicates that the 3-methylphosphine ligand forces complex (2) to distort towards a tetrahedral geometry. IR spectra of both complexes show strong bands around 2,090 cm−1 due to N-coordinated thiocyanate, while the electronic spectra contain d–d transitions around 452 nm. Cyclic voltammograms
show that the irreversible one-electron reduction potentials increase in the following order: trans- [Ni(PPh3)2(NCS)2] < trans- [Ni(3-MP)2(NCS)2] < trans-[Ni(4-MP)2(NCS)2], revealing the electron releasing effect of the methyl groups. The planar complexes exhibit interallogony in coordinating
solvents. 相似文献
18.
Kentaro Takano Hideki Kawasaki Genta Sakane Takashi Shibahara 《Journal of Cluster Science》2007,18(3):684-696
The reaction of a sulfur and oxygen-bridged 8-quinolinolato trinuclear molybdenum cluster [Mo3OS3(qn)3(H2O)3]+ (3; Hqn = 8-quinolinol) with equimolar amounts of acetylene carboxylic acid, 4-pentynoic acid, 5-hexynoic acid, acetic acid,
and pimelic acid gave clusters having μ-carboxylato groups, [Mo3OS3(qn)3(H2O)(μ-HC≡CCOO)] (6), [Mo3OS3(qn)3(H2O)(μ-HC≡C(CH2)2COO)] (7), [Mo3OS3(qn)3(H2O)(μ-HC≡C(CH2)3COO)] (8), [Mo3OS3(qn)3(H2O)(μ-CH3COO)] (4), and [{Mo3OS3(qn)3(C2H5OH)}2(μ-C7H10O4)] (5), respectively. X-ray structural analyses, 1H NMR, and electronic spectra of these clusters made clear that each of the COO− groups of the reagents bridges two Mo atoms in each cluster and that no adduct formation occurred at the sulfurs in the clusters.
The reaction of 3 with a large excess-molar amount (50 times) of acetylene carboxylic acid gave [Mo3OS(μ3-SCH=C(COOH)S)(qn)3(H2O)(μ-HC≡CCOO)] (9) with two molecules of acetylene carboxylic acid, one acting as a carboxylato bridge and the other in adduct formation, as
supported by the electronic and 1H NMR spectra. The corresponding aqua cluster [Mo3OS3(H2O)9]4+ (1), on the contrary, reacts with acetylene carboxylic acid to give adduct [Mo3OS(μ3-SCH=C(COOH)S)(H2O)9]4+ (2).
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
19.
E. G. Il’in A. S. Parshakov V. V. Danilov V. G. Yarzhemskii E. I. Goryunov I. B. Goryunova E. E. Nifant’ev 《Doklady Chemistry》2016,471(1):314-320
The products resulting from the reaction of TiF4 with Ph2P(O)(CH2)2C(O)Me (L') in CH2Cl2 have been studied by 19F{1H} and 31P{1H} NMR spectroscopy. At a twofold excess of L', solution contains cis-TiF4(L')2 (>90%), trans-TiF4(L')2, and fac-[TiF3L3']+, where L' is coordinated via the P=O group, as well as the dimer [(Ti2F7L'2)2]+, where L' is coordinated through the P=O and C=O groups. An equimolar solution contains dimeric and polynuclear complexes containing moieties with three terminal cis fluorine ions, while the other coordination sites are occupied by the P=O groups and F– bridges. At a twofold excess of TiF4, ligand L' coordinates via the P=O and C=O groups and behaves as a bridge along with F– ions. Thermodynamic stability of the structures of the TiF4L'2 isomers and the structure of [(µ-F)(µ-L')2(TiF3)2]+ has been calculated. 相似文献
20.
Aurkie Ray Sambuddha Banerjee Georgina M. Rosair Volker Gramlich Samiran Mitra 《Structural chemistry》2008,19(3):459-465
A nickel(II) and a cobalt(III) complex of two different potentially tetradentate Schiff bases with different binding modes
have been synthesised. The nickel(II) complex [NiL1] · CH3OH (1) was formed, on reacting the metal salt with a perfectly symmetrical N2O2 tetradentate Schiff base ligand H
2
L
1
, which is the 1:2 condensation product of 1,3-diamino propane and 2-hydroxyacetophenone. The cobalt(III) complex [Co(HL2)3] · (ClO4)3 · H2O (2) was synthesised using an asymmetric N2O2 tetradentate Schiff base ligand HL
2
on condensing N,N-dimethyl-1,3-diamino propane with o-vanillin in 1:1 mmol ratio. Although both Schiff bases are N2O2 functionalised, they showed variation in their coordinative property with nickel(II) and cobalt(III) ions. Both the complexes
were characterised by IR spectroscopy and cyclic voltammetry and their single crystal structures clearly indicate that 1 is a mononuclear species whereas 2 is a hydrogen-bonded dimer. 相似文献