Reactivity of C10H7+ and C10D7+ with H2 AND D2

We have investigated, both theoretically and experimentally, the reactions of naphthylium C10H7+ and d-naphthylium C10D7+ ions with H2 and D2. Cross sections as functions of the collision energy have been measured for a variety of reaction channels. Theoretical calculations have been carried out at the density functional theory level which utilizes the hybrid functional B3LYP and the split-valence 6-31G* basis set. The key features of the potential energy surfaces and the relevant thermochemical parameters have been calculated and they provide insights on the reaction mechanisms. The bimolecular reactivity of C10H7+ with H2 is dominated by the production of naphthalene cation C10H8+. The reaction is not a direct atom-abstraction process, but instead it proceeds via the formation of a stable intermediate complex C10H9+ of sigma type geometry, with a significant mobility of hydrogen along the ring. This mobility allows the scrambling of the hydrogen atoms and causes the successive statistical fragmentation of the complex into a variety of product channels. Elimination of one H(D) atom appears to be favored over elimination of one H2 or HD molecule. Alternatively, the intermediate complex can be stabilized either by collision with a third body or by emission of a photon.     

Isotope effect in Ni + C2H4 (C2D4) association reaction

The association reactions of atomic nickel with ethene and fully deuterated ethene in carbon dioxide buffer gas at 295 K have been investigated in the pressure range 5–100 torr, using a laser photolysis-laser fluorescence technique. By comparison with results of ab initio quantum chemistry calculations for the complex Ni[C₂H₄], the data are shown to be consistent with reaction on both ground and excited state potential energy surfaces. A simple rate equations treatment is described which shows the form of the pressure dependence of the second-order recombination rate coefficient in this case. Under conditions which are expected to hold for the Ni + C₂H₄ (C₂D₄) reaction, the pressure dependence has the standard Lindemann-Hinshelwood form, with the limiting high pressure rate constant given by an apparent value which reflects the degree to which the participating electronic states are coupled by nonadiabatic transitions. The limiting high pressure behavior of the recombination rate coefficient for Ni + C₂H₄ is not strongly affected by deuterium isotope substitution. However, the effect on the low pressure rate constant is large and consistent with RRKM unimolecular reaction theory. This validates the use of RRKM calculations for estimating the binding energy of the complex from kinetic data. The binding energy of Ni[C₂H₄] is estimated to be 35.2 ± 4.2 kcal mol^?1. © 1994 John Wiley & Sons, Inc.     

Total cross sections for electron scattering from molecules: NH3 and H2O

By developing the semi-empirical formula recently obtained for total cross sections of electron scattering from diatomic molecules in the intermediate- and highenergy range, we calculate the total cross sections for electron scattering from molecules (NH₃ and H₂O) over an incident energy range of 10–1000 eV. The total cross sections have also been calculated by using the complex optical potential and the additivity rule. Compared with other available experimental and calculating data, excellent agreements have been achieved. The developed semi-empirical formula reflects that total cross sections for electron scattering from NH₃ and H₂O in the intermediate- and high-energy range quantitatively depend on the bond length.     

A multiproperty analysis of the OH + H2(D2,HD) potential energy surface

Dynamical and kinetic properties of the OH + H₂(D₂,HD) reaction have been investigated in detail by carrying out extended quasiclassical trajectory calculations on the most recently proposed potential energy surface. Computed values of the reactive properties of H₂, D₂ and HD colliding with OH are compared with measured data and with results obtained on other potential energy surfaces. In most cases the new surface provides excellent estimates of the measured quantities. To better evaluate the accuracy of the proposed surface and the implications of some assumptions made when performing the calculations, the comparison has been extended to available quantum results.     

Molecular orbital studies of hydrogen bonds. IV. Hydrogen bonds in excited states of H2CO with H2O

Ab initio calculations for the interacting system of lower excited states of planar and bent H₂CO with H₂O have been carried out with a minimum basis set, using the recently proposed electron-hole potential method. The blue shifts of the η-π* transition are evaluated as 1100 and 1420 cm^?1 for the singlet and triplet transitions, respectively. In the η-π* states of bent H₂CO, the most stable geometry is one in which an H₂O hydrogen atom is coordinated to the carbon atom.     

Theoretical study of the dehydrogenate reaction of H2S by Sc+(1D)

The reaction Sc⁺(¹D)+H₂S→Sc⁺S+H₂ is theoretically investigated by ab initio MO methods. Two possible reaction channels on the singlet potential surface (PES) and the reaction mechanism are examined and discussed. Three regions of the potential surface were studied, the molecular complex, the S‐H insertion products and the transition states for the reaction. In addition the singlet and triplet PESs of this reaction system are compared in an investigation the chemistry of excited electronic state. © 2001 John Wiley & Sons, Inc. Int J Quant Chem 82: 60–64, 2001     

Isomerization study of C5H5NO molecules

The complex potential energy surface (PES) for the isomerization of C₅H₅NO species, including 18 isomers and 23 interconversion transition states, is probed theoretically at the B3LYP/6‐311++G(d,p) and MP2//B3LYP/6‐311++G(d,p) levels of theory. The geometries and relative energies for various stationary points were determined. The zero‐point vibrational energy (ZPVE) corrections have been made to calculate the reliable energy. We predicted a six‐membered ring structure as a global minima isomer I, which is 118.49 and 131.48 kcal · mol^?1 more stable than the least stable, four‐ and three‐membered ring isomer VIII at B3LYP and MP2//B3LYP levels of theory, respectively. The isomers and interconversion transition states have verified by frequency calculation. The intrinsic reaction coordinates (IRC) calculations have been performed to confirm that each transition state is linked by the desired reactants and products. The isomer stability has been studied using relative energies, chemical hardness, and chemical potential. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007     

Selective Transfer Semihydrogenation of Alkynes with H2O (D2O) as the H (D) Source over a Pd-P Cathode

We reported a selective semihydrogenation (deuteration) of numerous terminal and internal alkynes using H₂O (D₂O) as the H (D) source over a Pd-P alloy cathode at a lower potential. P-doping caused the enhanced specific adsorption of alkynes and the promoted intrinsic activity for producing adsorbed atomic hydrogen (H*_ads) from water electrolysis. The semihydrogenation of alkynes could be accomplished at a lower potential with up to 99 % selectivity and 78 % Faraday efficiency of alkene products, outperforming pure Pd and commercial Pd/C. This electrochemical semihydrogenation of alkynes might proceed via a H*_ads addition pathway rather than a proton-coupled electron transfer process. The decreased amount of H*_ads at a lower potential and the more preferential adsorption of the Pd-P to C≡C π bond than C=C moiety resulted in the excellent alkene selectivity. This method was capable of producing mono-, di-, and tri-deuterated alkenes with up to 99 % deuterium incorporation.     

Structure of hyper-branched polyester polyol BOLTORN H2O-COOH. NMR data

The methods of one- and two-dimensional ¹H and ¹³C NMR spectroscopy have been used to study the structure of hyper-branched polyester polyol BOLTORN H2O-COOH and complex Co₁₂[BH20(COOH)] on its basis. It was shown that both compounds have non-stereoregular structure. Paramagnetic ions Co(II) are coordinated both on the surface of the molecule and near the core.     

BrO-H2O 及 HOBr-H2O复合物偶合方式的理论研究

在6-311++G(d,p)水平上采用四种方法讨论了两种BrO-H₂O和三种HOBr-H₂O复合物的构型性质。在两种BrO-H₂O复合物中，结合能为11.37–13.92 J/mol的复合物2 （电子态为²A′）最稳定，该复合物是通过BrO中的Br原子和水中的O原子结合的。三种HOBr-H₂O复合物中，复合物3和4的结合能约为16.30–21.32 J/mol，三种复合物的稳定顺序为：复合物3 ≈ 复合物4 > 复合物5。     

手性二茂铁基氨基酸配合物(S)-[Zn(FcCH2NHCH(CH2Ph)COO)2·H2O](H2O)的合成及性能

以(S)-N-二茂铁甲基苯丙氨酸钠为配体，与Zn(Ac)₂反应合成了一个新型手性单核配合物(S)-[Zn(FcCH₂NHCH(CH₂Ph)COO)₂·H₂O](H₂O)。X-射线单晶结构分析表明，中心离子Zn(Ⅱ)与2个FcCH₂NHCH(CH₂Ph)COO^-和1个水分子配位，形成树状的骨架构型。该配合物晶体属正交晶系，P2₁2₁2₁空间群。晶胞参数为：a=0.893 4(2) nm；b=1.669 8(4) nm；c=2.588 4(6) nm。电化学测试表明该配合物的氧化和还原峰电位同配体相比向高电位方向移动。室温下，标题化合物呈现出较强的固体双重荧光性能,量子化学计算给出了初步的解释。     

Thermodynamics of bolaform electrolytes. IV. Enthalpies and partial molal heat capacities in H2O,D2O,and dimethylsulfoxide

The partial molal heats of solution ΔH _s ^o and the partial molal heat capacities of solution ΔC _p ^o of the bolaform salts [Et₃N(CH₂)_nNEt₃]Br₂ and [allyl₃N(CH₂)_nNallyl₃]Br₂ have been obtained at infinite dilution in dimethylsulfoxide (DMSO). A comparison of these data with the results of previous thermodynamic studies of the same solutes in aqueous solvents has been carried out. The observed differences have been interpreted in terms of solute-induced solvent structural effects occurring in aqueous solvent media. Partial molal heat capacities of the bolaform salts at infinite dilution in DMSO, H₂O, and D₂O have been calculated from ΔC _p ^o data and previously reported values of the heat capacities of the crystalline state. The data clearly show that the structure-promoting capabilities of these salts in aqueous solvents increase with increasing hydrocarbon content. A comparison of contributions to partial molal heat capacities of methylene groups in the bolaform and R₄N⁺ series of salts reveals that similarities exist between the solvation effects of CH₂ groups in the normal alkyl chain of the R₄N⁺ cations and in the bridging alkyl chain of the bolaform cation.     

Nonempirical analysis of unusual chemical bonds. II. AlH2BH4 and AlH2C3H5

Ab initio computations have been performed on the compounds AlH₂BH₄ and AlH₂C₃H₅ in order to achieve a better understanding of the peculiar characteristics of the metal to ligand bond. Our results suggest a bidentate coordination for the tetrahydroborate complex and an η³ coordination for the allyl complex. Due to the nonrigidity of the BH and allyl complexes, possible interconversion paths between different coordination modes have also been analyzed.     

Molecular calculations with the nonempirical ab initioMODPOT,VRDDO, and MODPOT/VRDDO procedures. XI. Theoretical study of the [C6H5OH ⃛OC6H5]− molecular complex: Ab initioMODPOT/VRDDO calculations and electrostatic molecular potential contour maps

The transport of C₆H₅O^? (or similarly charged moieties) through a lipoidal membrane may possibly be facilitated by forming complexes with the neutral compound. Thus, theoretical studies were performed on the model [C₆H₅OH ?OC₆H₅]^? molecular complex to obtain some information concerning the possible molecular and electronic structure of such complexes. Ab initio MODPOT /VRDDO SCF calculations were carried out on the neutral-anion dimer [C₆H₅OH ?OC₆H₅] to optimize the equilibrium geometry. Electrostatic molecular potential contour maps have been generated from the ab initio MODPOT /VRDDO results in the molecular plane and in the plane perpendicular to the molecular plane and intersecting the hydrogen bond O ?H? O. Difference maps have also been generated showing the change of potential on complex formation. There is a decrease of electrostatic interactions of the phenoxide anion upon complex formation with the neutral phenol. Counterpoise corrections for basis set size could not be made since calculation of the phenoxide anions in the basis set of the phenol plus the phenoxide anion led to an excited state for the phenoxide anion. This behavior is somewhat similar to that occurring in the stabilization method for excited states of negative ions as the size of the basis set is increased.     

In vitro antitumor and antibacterial assay of organotin(IV) complexes of 2,3-methylenedioxybenzoic acid; X-ray crystal structure of [(C2H5)2Sn(C8H5O4)2]

New organotin(IV) compounds containing the carboxylate ligand 2,3-methylenedioxybenzoic acid (HL) have been synthesized with the general formula R₂SnL₂ (R = Me, Et, n-Bu, Ph and n-Oct) and R₃SnL (R = n-Bu). All compounds have been studied in the solution state by multinuclear NMR (¹H, ¹³C and ¹¹⁹Sn) by using the non-coordinating solvent and also in solid sate by FTIR, mass spectrometry and X-ray crystallography. Spectroscopic data have shown that methylenedioxy moiety does not coordinate with tin atom and the coordination site is actually -COO group, as is proved by X-ray structure determination. The solid state structure of compound (2) has been determined by X-ray crystallography which shows that the complex (2) has distorted octahedral geometry. These complexes have been evaluated in vitro against crown gall tumor and antibacterial activity. Interesting results were noticed during the bio-activity screenings, which proved their in vitro biological potential and possible use as drugs.     

Rotational inelasticity in high-energy H2H2 collisions

Rotational cross sections for transitions in the H₂H₂ system have been calculated for energies up to ≈ 2.0 eV and for rotor levels up to j = 11 in the effective potential approximation. The cases of para H₂-para H₂, ortho H₂-ortho H₂ and ortho H₂-para H₂ are considered. Correlations and trends in the cross sections have been examined, and it is shown that the high-energy collisions are dominated by coupling effects. The results of this analysis also suggest that the collision process may be profitably viewed as a diffusion of probability among the levels.     

Synthesis, characterization, properties and crystal structure of heterometallic 1D coordination polymers {[CuLZn·CuLZn(H2O)]·H2O}n

Copper-zinc heterometallic 1D chain coordination polymer has been synthesized and characterized by elemental analysis, and IR spectra etc. The crystal structure was determined by single-crystal X-ray diffraction analyses. The title complex is 1D chain coordination polymer with the chemical formula {[CuLZn·CuLZn(H₂O)]·H₂O}_n, where H₄L=N-(2-hydroxybenzamido)-N′-(3-carboxylsalicylidene)ethylenediamine. Its structural unit is comprosed of two tetranuclear cycles formed by two dissymmetrical tetranuclear units. These units polymerized each other to form 1D chain coordination polymer.     

Synthesis,Crystal Structure and Magnetic Properties of a 1‐D Polymer, [Cu(NITpPy)2(H2TCB)(H20)]·2H2O

A novel complex [Cu(NnpPy)₂(H_lTCB)(H₁O)]·2H₂O (NITpPy = 2‐(pyrid‐4′‐yl)‐4,4,5,5‐tetramethyl‐1, 3‐dioxoimidazoline; H₂TCB = 1, 5‐dicarboxybenzene carboxylic‐2, 4‐diacid) has been synthesized and characterized by X‐ray crystallography analysis. The crystal structure consists of infinite chains of Cu‐(NITpPy)₂(H₂O) units linked by H₂TCB ligands. The complex crystallizes in triclinic system with space group PI. Crystal data: a = 1.0594(2) nm, b = 1.3830(3) nm, c = 1.5551(3) nm, a = 67.75(3)°, β = 89.83(3)°, γ = 70.54(3)°. The variable magnetic susceptibility studies lead to magnetic coupling constant values of J₁= ?11.18 cm‐¹ (Cu—Rad) and J₂ = ?4.06 cm^?1 (Cu—Cu).     

Synthesis and crystal structure of nitrosoruthenium aquadiammine complex, [Ru(NO)(NH3)2Cl2(H2O)]Cl·H2O

The reaction between [RuNO(NH₃)₂(NO₂)₂OH] and an excess of 3 M HCl leads to denitration of the starting complex and precipitation of [Ru(NO)(NH₃)₂Cl₃]. Crystals of the tittle complex have been obtained by evaporation of the mother liquor at ambient temperature. The crystal structure of the product has been determined. The linear nitroso group and a water molecule are coordinated in the trans positions, three nitrogen atoms from NO and NH₃ ligands occupy the coordination octahedron face.     

Addition of H2 Across a Cobalt–Phosphorus Bond

Addition of H₂ across the cobalt–phosphorus bond of (PPP)CoPMe₃ ( 3 ) is demonstrated, where PPP is a monoanionic diphosphine pincer ligand with a central N‐heterocyclic phosphido (NHP^?) donor. The chlorophosphine Co^II complex (PP^ClP)CoCl₂ ( 2 ) can be generated through coordination of the chlorophosphine ligand (PP^ClP, 1 ) to CoCl₂. Subsequent reduction of 2 with KC₈ in the presence of PMe₃ generates (PPP)CoPMe₃ ( 3 ), in which both the phosphorus and cobalt centers have been reduced. The addition of 1 atm of H₂ to complex 3 cleanly affords (PP^HP)Co(H)PMe₃ ( 4 ), in which H₂ has ultimately been added across the metal–phosphorus bond. Complex 4 was characterized spectroscopically and using computational methods to predict its geometry.