共查询到20条相似文献,搜索用时 812 毫秒
1.
Xiaofei Xue Khalil Hanna Christelle Despas Feng Wu Nansheng Deng 《Journal of molecular catalysis. A, Chemical》2009,311(1-2):29-35
The complex [Rh(CO)2Cl]2 reacts with two molar equivalent of pyridine carboxylic acids ligands Py-2-COOH(a), Py-3-COOH(b) and Py-4-COOH(c) to yield rhodium(I) dicarbonyl chelate complex [Rh(CO)2(L/)](1a) {L/ = η2-(N,O) coordinated Py-2-COO−(a/)} and non-chelate complexes [Rh(CO)2ClL//](1b,c) {L// = η1-(N) coordinated Py-3-COOH(b), Py-4-COOH(c)}. The complexes 1 undergo oxidative addition (OA) reactions with different electrophiles such as CH3I, C2H5I, C6H5CH2Cl and I2 to give penta coordinated Rh(III) complexes of the types [Rh(CO)(CORn)XL/], {n = 1,2,3; R1 = CH3(2a); R2 = C2H5(3a); X = I and R3 = CH2C6H5 (4a); X = Cl}, [Rh(CO)I2L/](5a), [Rh(CO)(CORn)ClXL//] {R1 = CH3(6b,c); R2 = C2H5(7b,c); X = I and R3 = CH2C6H5 (8b,c); X = Cl} and [Rh(CO)ClI2L//](9b,c). The complexes have been characterized by elemental analysis, IR and 1H NMR spectroscopy. Kinetic data for the reaction of 1a–b with CH3I indicate a first order reaction. The catalytic activity of 1a–c for the carbonylation of methanol to acetic acid and its ester is evaluated and a higher turn over number (TON = 810–1094) is obtained compared with that of the well-known commercial species [Rh(CO)2I2]− (TON = 653) at mild reaction conditions (temperature 130 ± 5 °C, pressure 35 ± 5 bar). 相似文献
2.
R. Markovi M. Baranac N. Jurani S. Macura I. Ceki D. Mini 《Journal of Molecular Structure》2006,800(1-3):85-92
The rotational barriers between the configurational isomers of two structurally related push–pull 4-oxothiazolidines, differing in the number of exocyclic CC bonds, have been determined by dynamic 1H NMR spectroscopy. The equilibrium mixture of (5-ethoxycarbonylmethyl-4-oxothiazolidin-2-ylidene)-1-phenylethanone (1a) in CDCl3 at room temperature to 333 K consists of the E- and Z-isomers which are separated by an energy barrier ΔG# 98.5 kJ/mol (at 298 K). The variable-temperature 1H NMR data for the isomerization of ethyl (5-ethoxycarbonylmethylidene-4-oxothiazolidin-2-ylidene)ethanoate (2b) in DMSO-d6, possessing the two exocyclic CC bonds at the C(2)- and C(5)-positions, indicate that the rotational barrier ΔG# separating the (2E,5Z)-2b and (2Z,5Z)-2b isomers is 100.2 kJ/mol (at 298 K). In a polar solvent-dependent equilibrium the major (2Z,5Z)-form (>90%) is stabilized by the intermolecular resonance-assisted hydrogen bonding and strong 1,5-type S · · · O interactions within the SCCCO entity. The 13C NMR ΔδC(2)C(2′) values, ranging from 58 to 69 ppm in 1a–d and 49-58 ppm in 2a–d, correlate with the degree of the push-pull character of the exocyclic C(2)C(2′) bond, which increases with the electron withdrawing ability of the substituents at the vinylic C(2′) position in the following order: COPh COEt > CONHPh > CONHCH2CH2Ph. The decrease of the ΔδC(2)C(2′) values in 2a–d has been discussed for the first time in terms of an estimation of the electron donor capacity of the S fragment on the polarization of the CC bonds. 相似文献
3.
Treatment of a N-arylanilido-imine ligand [ortho-C6H4(NHAr)CHN]2CH2CH2 (Ar = 2,6-Me2C6H3) (LH2) with one equiv. of AlMe3 affords a monometallic complex [C6H4(NHAr)–CHN)]CH2CH2(C6H4(NAr)CHNAlMe2) (1). The monometallic complex 1 reacts with one equiv. of ZnEt2 to give a heterobimetallic complex [C6H4(NAr)–CHNZnEt]CH2CH2[C6H4(NAr)–CHNAlMe2] (2). Both complexes were characterized by 1H and 13C NMR spectroscopy and elemental analyses, and the molecular structures of 1 and 2 were determined by X-ray diffraction analysis. The complexes 1 and 2 both are efficient catalysts for ring-opening polymerization of ε-caprolactone in the presence of benzyl alcohol yielding polymers with narrow polydispersity values and complex 2 initiates the polymerization in a controllable manner. 相似文献
4.
Vinay K. Verma Ashish K. Asatkar Tripti A. Jain Santosh K. Tripathi Rajendra Singh Peter B. Hitchcock Siddhi Nigam Sushil K. Gupta 《Polyhedron》2009,28(13):2591-2598
Two new phenol based macroacyclic Schiff base ligands, 2,6-bis({N-[2-(phenylselenato)ethyl]}benzimidoyl)-4-methylphenol (bpebmpH, 1) and 2,6-bis({N-[3-(phenylselenato)propyl]}benzimidoyl)-4-methylphenol (bppbmpH, 2) of the Se2N2O type have been prepared by the condensation of 4-methyl-2,6-dibenzoylphenol (mdbpH) with the appropriate (for specific reactions) phenylselenato(alkyl)amine. These ligands with Cu(II) acetate monohydrate in a 2:1 molar ratio in methanol form complexes of the composition [(C6H2(O)(CH3){(C6H5)CN(CH2)nSe(C6H5)}{(C6H5)CO}2Cu] (3 (n = 2), 4 (n = 3)) with the loss of phenylselenato(alkyl)amine and acetic acid. In both these complexes, one arm of the ligand molecule undergoes hydrolysis, and links with Cu(II) in a bidentate (NO) fashion, as confirmed by single crystal X-ray crystallography of complex 3. The selenium atoms do not form part of the copper(II) distorted square planar coordination sphere which has a trans-CuN2O2 core. The average Cu–N and Cu–O distances are, respectively, 1.973(3) and 1.898(2) Å. The N–Cu–N and O–Cu–O angles are, respectively, 167.4(11)° and 164.5(12)°. The compounds 1–4 have been characterized by elemental analysis, conductivity measurements, mass spectrometry, IR, electronic, 1H and 77Se{1H} NMR spectroscopy and cyclic voltammetry. The interaction of complex 3 with calf thymus DNA has been investigated by a spectrophotometric method and cyclic voltammetry. 相似文献
5.
Jesús J. Fernndez Nina Gmez-Blanco Alberto Fernndez Digna Vzquez-García Margarita Lpez-Torres Jos M. Vila 《Polyhedron》2009,28(13):2679-2683
Treatment of the Schiff base ligands 4-(NC5H4)C6H4C(H)N[2′-(OH)C6H4] (a), 3,5-(N2C4H3)C6H4C(H)N[2′-(OH)-C6H4] (b) and 3,5-(N2C4H3)C6H4C(H) N[2′-(OH)-5′-tBuC6H3] (c) with palladium (II) acetate in toluene gave the poly-nuclear cyclometallated complexes [Pd{4-(NC5H4)C6H3C(H)N[2′-(O)C6H4]}]4 (1a), [Pd{3,5-(N2C4H3)C6H3C(H)N[2′-(O)-C6H4]}]4 (1b) and [Pd{3,5-(N2C4H3)C6H3C(H)N[2′-(O)-5′-tBuC6H3]}]4 (1c) respectively, as air stable solids, with the ligand acting as a terdentate [C,N,O] moiety after deprotonation of the –OH group. Reaction of the cyclometallated complexes with triphenylphosphine gave the mononuclear species [Pd{4-(NC5H4)C6H3C(H) N[2′-(O)C6H4]}(PPh3)], (2a), [Pd{3,5-(N2C4H3)C6H3C(H) N[2′-(O)C6H4]}(PPh3)], (2b) and [Pd{3,5-(N2C4H3)C6H3C(H)N[2′-(O)-5′-tBuC6H3)}(PPh3)], (2c) in which the polynuclear structure has been cleaved and the coordination of the ligand has not changed [C,N,O]. When the cyclometallated complexes 1b and 1c were treated with the diphosphines Ph2P(CH2)4PPh2 (dppb), Ph2PC5H4FeC5H4PPh2 (dppf) and Ph2P(CH2)2PPh2 (t-dppe) in a 1:2 molar ratio the dinuclear cyclometallated complexes [{Pd[3,5-(N2C4H3)C6H3C(H)N{2′-(O)C6H4}]}2(μ-Ph2P(CH2)4PPh2)], (3b), [{Pd[3,5-(N2C4H3)C6H3C(H) N{2′-(O)-5′-tBuC6H3}]}2(μ-Ph2P(CH2)4PPh2)], (3c), [{Pd[3,5-(N2C4H3)C6H3C(H)N{2′-(O)C6H4}]}2(μ-Ph2P(η5-C5H4)Fe(η5-C5H4)PPh2)], (4b), [{Pd[3,5-(N2C4H3)C6H3C(H) N{2′-(O)-5′-tBuC6H3}]}2(μ-Ph2P(η5C5H4)Fe(η5C5H4)P-Ph2)], (4c) and [{Pd[3,5-(N2C4H3)C6H3C(H)N{2′-(O)-5′-tBuC6H3}]}2(μ-Ph2P(CHCH)PPh2)], (5c) were obtained as air stable solids. 相似文献
6.
Ren A. Rozendal Emilie Leone Jürg Keller Korneel Rabaey 《Electrochemistry communications》2009,11(9):1752-1755
Hydrogen peroxide (H2O2) is an important industrial chemical, but its current production methods are highly energy-intensive. This study presents a novel process for the production of H2O2 based on the bioelectrochemical oxidation of wastewater organics at an anode coupled to the cathodic reduction of oxygen to H2O2. At an applied voltage of 0.5 V, this system was capable of producing 1.9 ± 0.2 kg H2O2/m3/day from acetate at an overall efficiency of 83.1 ± 4.8%. As most of the required energy was derived from the acetate, the system had a low energy requirement of 0.93 kWh/kg H2O2. 相似文献
7.
Rajni Sharma Raj Pal Sharma Paloth Venugopalan Miguel Quirs Juan M. Salas J. Yu Y. Du 《Journal of Molecular Structure》2008,885(1-3):7-14
[cis-Co(en)2(N3)2]C7H3ClNO4·1.25H2O (Cocnb) was synthesised and detailed packing analyses were undertaken to delineate the topological complementarity of [cis-Co(en)2(N3)2]+ and a 2-chloro-4-nitro benzoate anion (cnb) for second sphere coordination in the crystal lattice. The complex was completely characterised by elemental analyses, spectroscopic studies (IR, UV/visible, 1H and 13C NMR). The compound crystallizes in the monoclinic (space group C2/c) with a = 21.9843(18), b = 8.7959(7), c = 23.0121(18) Å, β = 116.426(1)°, V = 3984.9(6) Å3, and Z = 8. In the crystal lattice, discrete ions of [cis-Co(en)2(N3)2]+ and cnb are arranged in A–B–A–B pattern (in both a and c directions of the lattice) forming columns of anions and cations. The anionic columns are π stacked and are involved in extensive hydrogen bonding interaction. It appears that the topological feature of [cis-Co(en)2(N3)2]+ is conducive for generating second sphere interactions with aromatic carboxylates. This strategy may be used as a viable method for the capture of aromatic carboxylate anions. 相似文献
8.
Duane Choquesillo-Lazarte María del Pilar Brandi-Blanco Isabel García-Santos Josefa María Gonzlez-Prez Alfonso Castieiras Juan Nicls-Gutirrez 《Coordination chemistry reviews》2008,252(10-11):1241
The available crystal structure information in the CSD database on ternary species prepared by the reaction of diverse copper(II) complexes (CuL) and purine, adenine and guanine or related purine derivatives is considered in order to deepen the intra-molecular interligand interactions affecting the molecular recognition patterns of the ‘metal complex + purine nucleobase’ and closely related systems. The degree of protonation and the possibilities of different tautomeric forms in the purine-like moieties are taken into account. The main conclusion is a general trend to form a CuN(purine-like) coordination bond which can be reinforced by an intra-molecular interligand H-bonding interaction. NH(purines)A (O or Cl acceptor) or NH(amino ligand L)O6(oxo-purines) are commonly observed. In addition, selected examples revealed that the presence of a variety of non-coordinating groups in L or in the purine-like nucleobases can significantly influence the structurally observed molecular recognition pattern. Moreover, examples are known where binuclear cores of the types CuII2(μ2-N3,N9-adeninate)4(aqua)2 or CuI2(μ2-N3,N9-adeninate)2(aqua)2 recognise CuL chelates by means of the expectable pattern (CuN7 coordination bond + N6HO(L) interaction). 相似文献
9.
Aurkie Ray Dipali Sadhukhan Georgina M. Rosair Carlos J. Gmez-García Samiran Mitra 《Polyhedron》2009,28(16):3542-3550
A new tetradentate N2O2 donor Schiff base ligand [OHC6H4CHNCH2CH2CH(CH2CH3)NCHC6H4OH = H2L ] was obtained by 1:2 condensation of 1,3-diaminopentane with salicylaldehyde and has been used to synthesise an unusual copper(II) complex whose asymmetric unit presents two structurally different almost linear trinuclear units [Cu3(μ-L)2(ClO4)2] [Cu3(μ-L)2(H2O)(ClO4)2] (1). The ligand and the complex were characterised by elemental analysis, FT-IR, 1H NMR and UV–Vis spectroscopy in addition electrochemical and single crystal X-ray diffraction studies were performed for the complex. The magnetic properties of 1 reveal the presence of strong intra-trimer (J1 = −202(3) cm−1 and J2 = −233(3) cm−1) as well as very weak inter-trimer (zJ′ = −0.11(1) cm−1) antiferromagnetic interactions. 相似文献
10.
Xin Zhou Qing-Jiang Pan Tao Liu Ming-Xia Li Hong-Xing Zhang 《Journal of Molecular Structure》2008,863(1-3):91-98
A comprehensive calculations were carried out to get a deep insight into the ground- and excited-state electronic structures and the spectroscopic properties for a series of [Pt(4-X–trpy)CCC6H4R]+ complexes (trpy = 2,2′,6′,2″-terpyridine; X = H, R = NO2 (1), Cl (2), C6H5 (3) and CH3 (4); R = Cl, X = CH3 (5) and C6H5 (6)). MP2 (second-order Møller–Plesset perturbation) and CIS (single-excitation configuration interaction) methods were employed to optimize the structures of 1–6 in the ground and excited states, respectively. The investigation showed that substituted phenylacetylide and trpy ligands only give rise to a small variation in geometrical structures but lead to a sizable difference in the electronic structures for 1–6 in the ground and excited states. The introduction of electron-rich groups into the phenylacetylide and/or terpyridyl ligands produces two different low-lying absorptions for 1 and 2–6, i.e., Pt(5d) → π*(trpy) metal-to-ligand charge transfer (MLCT) mixed with π → π*(CCPh) intraligand charge transfer (ILCT) for 1 and Pt(5d)/π(CCPh) → π*(trpy) charge transfer (MLCT and LLCT) for 2–6. Remarkable electronic resonance on the whole Pt–CCPh–NO2 moiety for 1 may be responsible for the difference. Solvatochromism calculation revealed that only LLCT/MLCT transitions showed the solvent dependence, consistent with the experimental observations. 相似文献
11.
Nina Gmez-Blanco Jesús J. Fernndez Alberto Fernndez Digna Vzquez-García Margarita Lpez-Torres Antonio Rodríguez Jos M. Vila 《Polyhedron》2009,28(16):3533-3613
Reaction of the Schiff base ligand derived from 4-pyridinecarboxaldehyde NC5H4C(H)N[2′,4′,6′-(CH3)C6H2], (1), with palladium(II) acetate in toluene at 60 °C for 24 h gave [Pd{NC5H4C(H)N[2′,4′,6′-(CH3)C6H2]}2(OCOCH3)2], (2), with two ligands coordinated through the pyridine nitrogen. Treatment of the Schiff base ligand derived from 4-pyridinecarboxaldehyde N-oxide, 4-(O)NC5H4C(H)N[2′,4′,6′-(CH3)C6H2], (4), with palladium(II) acetate in toluene at 75 °C gave the dinuclear acetato-bridged complex [Pd{4-(O)NC5H3C(H)N[2′,4′,6′-(CH3)C6H2]}(OCOCH3)]2, (5) with metallation of an aromatic phenyl carbon. Reaction of complex 5 with sodium chloride or lithium bromide gave the dinuclear halogen-bridged complexes [Pd{4-(O)NC5H3C(H)N[2′,4′,6′-(CH3)C6H2]}(Cl)]2, (6) and [Pd{4-(O)NC5H3C(H)N[2′,4′,6′-(CH3)C6H2]}(Br)]2, (7), after the metathesis reaction. Reaction of 6 and 7 with triphenylphosphine gave the mononuclear species [Pd{4-(O)NC5H3C(H)N[2′,4′,6′-(CH3)C6H2]}(Cl)(PPh3)], (8) and [Pd{4-(O)NC5H3C(H)N[2′,4′,6′-(CH3)C6H2]}-(Br)(PPh3)], (9), as air stable solids. Treatment of 6 and 7 with Ph2P(CH2)2PPh2 (dppe) in a complex/diphosphine 1:2 molar ratio gave the mononuclear complexes [Pd{4-(O)NC5H3C(H)N[2′,4′,6′-(CH3)C6H2]}(PPh2(CH2)2PPh2)][Cl], (10), and [Pd{4-(O)NC5H3C(H)N[2′,4′,6′-(CH3)C6H2]}(PPh2(CH2)2PPh2)][PF6], (11), with a chelating diphosphine. The molecular structure of complex 9 was determined by X-ray single crystal diffraction analysis. 相似文献
12.
A crystallographic investigation of anion–π interactions and hydrogen bonds on the preferred structural motifs of molybdenum(VI) complexes has been carried out. Two molybdenum(VI) network polymers MoO2F4·(Hinca)2 (1) and MoO2F3(H2O)·(Hinpa) (2), where inca = isonicotinamide and inpa = isonipecotamide, have been synthesized, crystallographically characterized and successfully applied to alcohol oxidation reaction. Complex 1 crystallizes in the monoclinic space C2/c: a = 16.832(3) Å, b = 8.8189(15) Å, c = 12.568(2) Å, β = 118.929(3)°, V = 1560.1(5) Å3, Z = 4. Complex 2 crystallizes in the triclinic space P-1: a = 5.459(2) Å, b = 9.189(4) Å, c = 12.204(5) Å, α = 71.341(6)°, β = 81.712(7)°, γ = 77.705(7)°, V = 564.8(4) Å3, Z = 2. Complex 1 consists of hydrogen bonding and anion–π interactions, both of which are considered as important factors for controlling the geometric features and packing characteristics of the crystal structure. The geometry of the sandwich complex of [MoO2F4]2− with two pyridine rings indicates that the anion–π interaction is an additive and provides a base for the design and synthesis of new complexes. For complex 2, the anions and the protonated inpa ligands form a 2D supramolecular network by four different types of hydrogen contacts (N–HF, N–HO, O–HF and O–HO). The catalytic ability of complexes 1 and 2 has also been evaluated by applying them to the oxidation of benzyl alcohol with TBHP as oxidant. 相似文献
13.
Tao Hong Li Chuan Ming Wang Shi Wen Yu Xiang Yi Liu Hui Fu Xiao Guang Xie 《Journal of Molecular Structure》2009,915(1-3):105-111
The reaction of ground-state Y with 2-butyne has been investigated in detail using B3LYP method. Four pathways for elimination of H2 were identified. Two isomers, Y(HCCC)CH3 and Y(H2CCCCH2) were assigned to the observed product, YC4H4. The calculated PESs suggest that the concerted H2-elimination leading to Y(H2CCCCH2) + H2 product is the most favorable pathway. For the elimination of CH3, combining the results of this work with our previous study on Y + propyne reaction, a general mechanism for the reactions of Y with 2-alkynes bearing RCCCH3 structure was established: Y + RCCCH3 → π-complex → TS(H-migration) → HY(CH2CC)R → TS (CC insertion) → (CH2)HYCCR → TS(H-migration) → H3CYCCR → CH3 + YC2R. Such mechanism was found to be always energetically more favorable than the direct sp–sp3 CC bond insertion mechanism. Further, such mechanism can also be applied to the elimination of CH4 and it can be described as: Y + CH3CCCH3 → π-complex → TS (H-migration) → HY(H2CCC)CH3 → TS(CC insertion) → (H2CCC)HYCH3 → TS(H-migration) → CH4 + YC3H2. 相似文献
14.
Alper Tolga olak Ferda olak Demet Akduman Okan Zafer Yeilel Orhan Büyükgüngr 《Solid State Sciences》2009,11(11):1908-1918
In this study, three novel Cu(II)-pyridine-2,5-dicarboxylate (pydc) complexes with 4-methylimidazole (4-Meim), [Cu(pydc)(H2O)(4-Meim)2]·H2O (1), imidazole (im), {[Cu(μ-pydc)(im)2]·2H2O}n (2), and 3,4-dimethylpyridine (dmpy), [Cu(μ-pydc)(H2O)(dmpy)]n (3) have been synthesized. Elemental and thermal analyses, magnetic susceptibilities, IR and UV/vis spectroscopic studies have been performed to characterize the complexes. The molecular structures of mononuclear (1) and polynuclear (2 and 3) complexes have been determined by the single crystal X-ray diffraction technique. In 1 and 2, Cu(II) ions have distorted square planer geometry, while 3 has distorted octahedral coordination. The pyridine-2,5-dicarboxylate exhibits three different coordination modes namely bidentate (1), tridentate (2) and tetradentate (3). The complex 1 is further constructed to form three-dimensional framework by hydrogen bonding, C–Hπ and ππ stacking interactions. The adjacent chains of 2 and 3 are then mutually linked via hydrogen bonding, ππ and C–Hπ interactions, which are further assembled to form three-dimensional framework. 1 exhibits the magnetic moment value of 1.70 BM, which corresponds to one of the unpaired electron, while the polynuclear complexes 2 and 3 exhibit 1.58 and 1.46 BM, which is lower than the spin only value for one unpaired electron, indicates to antiferromagnetic effect. The first thermal decomposition process of all the complexes is endothermic dehydration. This stage is followed by partial (or complete) decomposition of the neutral and pydc ligands. In the later stage, the remained organic residue exothermically burns. The final decomposition products which identified by IR spectroscopy were the CuO. 相似文献
15.
Four new coordination polymers of cobalt(II) and nickel(II) with functionalized dicarboxylate ligands, namely, [CoIIL1(2,2′-bpy)(H2O)] (1), [NiIIL1(2,2′-bpy)(H2O)]·H2O (2), [CoII2(L2)2(2,2′-bpy)2(H2O)] (3) and [NiII2(L2)2(2,2′-bpy)2(H2O)] (4), where H2L1 = 2,5-dibenzoylterephthalic acid, H2L2 = 4,6-bis(4-methylbenzoyl)isophthalic acid and 2,2′-bpy = 2,2′-bipyridine, were synthesized and characterized by elemental analysis, IR spectra and thermogravimetric analysis. Complex 1 exhibits a zigzag chain with a C–Hπ interaction between the phenyl ring proton and the phenyl ring of an adjacent chains to form a 2D supramolecular sheet. Complex 2 contains two helical chains which extend into 2D via a C–Hπ interaction between the pyridine ring proton and the pyridine ring. Complexes 3 and 4 are isomorphous with helical chains that extend in the same direction and further link to one another by supramolecular forces into a 2D structure. Moreover, magnetic and luminescence properties have been investigated for 1 and 2, respectively. 相似文献
16.
E. Germn I. Lpez-Corral A. Juan G. Brizuela 《Journal of molecular catalysis. A, Chemical》2008,290(1-2):23-29
The adsorption of cyclopentene (c-C5H8) on Ni(1 1 1) was studied using DFT and semiempirical calculations. Preferred site and geometry calculations were carried out considering a Ni(1 1 1) surface and a unit cell of 64-atoms. The tetrahedral threefold hollow position was identified as the most favorable site, with a surface-molecule minimum distance of 1.83 Å. A bending structure is adopted when the molecule is adsorbed where the carbon atoms of the double bond are closer to the surface forming an angle of 160° among non-equivalents carbon atoms. The metal surface was represented by a two-dimensional slab with an overlayer of c-C5H8/Ni of 1/9 ratio. We also computed the density of states (DOS) and the crystal orbital overlap populations (COOP) corresponding to CC, CNi, CH, and NiNi bonds. We found that both NiNi bonds interacting with the ring, and the CC bond are weakened after adsorption, this last bond is linked significantly to the surface. The hydrogen atoms belonging to the saturated carbon atoms also participate in the adsorbate–surface bonding. The main interactions include the 4s, 3pz and 5dz2 bands of nickel and 2pz bands of the carbon atoms of the double bond. 相似文献
17.
Charles W. Bock Joseph D. Larkin Stephen S. Hirsch J.B. Wright 《Journal of Molecular Structure》2009,915(1-3):11-19
Computed reaction enthalpies, free energies, and activation barriers in vacuo are presented for the nucleophilic detoxification of the organophosphorus compounds (H)(HO)P(O)F, (H)(H3CO)P(O)F and (H3C)(CH(CH3)2O)P(O)F via the reaction R1OH + (R2)(R3O)P(O)F → (R2)(R3O)P(O)(OR1) + HF for a wide variety of R1OH nucleophiles. Density functional theory at the B3LYP/6-311++G(d,p) computational level was employed for all the calculations. A multi-step Wright-type reaction mechanism [J. B. Wright, W.E. White, J. Mol. Struct. (THEOCHEM) 454 (1998) 259], which proceeds via a proton transfer from the nucleophile to the fluorine atom through the phosphinyl oxygen atom, was consistently found to have a lower activation barrier in the gas-phase than for the corresponding mechanism that operates via a proton transfer from the nucleophile directly to the fluorine atom. Of the nucleophilic agents investigated, peroxybenzoic acid and o-iodosobenzoic acid had the lowest classical activation barrier for the Wright-type mechanism. 相似文献
18.
Excitation spectra of Na fluorescence in mixtures with CF4 display a new band shifted by the energy of one-vibrational quantum of the IR active ν3-mode of CF4 (1281 cm−1) from Na 3d states. This band is attributed to a Na(3s)CF4(ν3 = 0) → Na(3d)CF4(ν3 = 1) transition and its intensity is explained by coupling with Na(4p)CF4(v3 = 0) resonance state which lies 180 cm−1 below in energy. An analogous satellite of the Na 6p state combined with the same vibration and lying close to the Na 7p state is reported and discussed. 相似文献
19.
The syntheses, physical characterization and crystal structures of two new molecular copper(II) complexes of composition [Cu(C5H5N)2(C7F5O2)2] (1) and [Cu(C5H5N)2(C7F5O2)2(H2O)] (2) (C5H5N = py = pyridine and C7F5O2− = pfb = pentafluorobenzoate) are reported. Single-crystal X-ray structure determinations revealed that in 1, the Cu2+ ion, which lies on a crystallographic inversion centre, is coordinated to two py molecules and two oxygen atoms from two monodentate pfb anions, resulting in a trans-CuN2O2 square planar geometry. In 2, the Cu2+ ion is also coordinated to two py and two pfb species in addition to a water molecule in the apical site of a distorted CuN2O3 square pyramid. In the crystal packing, both 1 and 2 show segregated aromatic π-π stacking interactions in which (py + py) and (pfb + pfb) ring-pairings are seen, but no (py + pfb) pairings occur. Crystal data: 1: C24H10CuF10N2O4, Mr = 643.88, space group , a = 8.0777 (3) Å, b = 8.0937 (3) Å, c = 10.5045 (5) Å, α = 90.916 (3)°, β = 93.189 (2)°, γ = 118.245 (3)°, V = 603.36 (4) Å3, Z = 1. 2: C24H12CuF10N2O5, Mr = 661.90, space group , a = 7.5913 (5) Å, b = 15.6517 (6) Å, c = 21.1820 (14) Å, α = 95.697 (4)°, β = 94.506 (2)°, γ = 91.492 (4)°, V = 2495.2 (3) Å3, Z = 4. 相似文献
20.
The synthesis and crystal structures of five new analogues of the supramolecular copper(II) organophosphonate [CuII(phen)2Cl][(C6H5PO(OH)2)((OH)O2PC6H5)] (1) are presented. The structures contain substituted phenylphosphonic acids, and are of the general formula [CuII(phen)2Cl][(XPO(OH)2)((OH)O2PX)] · Z, where X = o-CH3(C6H5) (2); X = p-CH3(C6H5), Z = H2O · 2CH3CH2OH (4); X = o-NO2(C6H5), m-NO2(C6H5) (5); X = m-NO2(C6H5) (6); X = C10H7 (7). 相似文献