Theoretical Studies on the Intermonomer Interaction of F~-·(H_2O)_n (n = 1, 2)

1 INTRODUCTION Hydrogen bond plays an important role in the fields of physics, biology and chemistry. It has cap- tured the interest of chemists for a long time and reports about its theory and experiment have been well represented[1～6]. Concerning its theoretical inves- tigations, most of the emphases are placed on the weak interaction energy of intramolecular hydrogen bond. But studies on its spectrum behavior are rela- tively rare. These years spectrum behavior led by hydrogen bond h…     

Size Dependence of Electronic Excitation Energy in Linear C2nH and C2n－1N

The geometries, bondings, and vibrational frequencies of C2nH (n = 3—9) and C2n-1N(n= 3—9) were in-vestigated by means of density functional theory (DFT). The vertical excitation energies for the X^2Ⅱ→^2Ⅱ transitions of C2nH(n= 3—9) and for the X2∑→^2Ⅱ and the X^2Ⅱ→^2Ⅱ transitions of C2n-1N (n= 3—9) have been calculated by the time-dependent density functional theory(TD-DFT) approach. On the basis of present calculations, the explicit expression for the wavelengths of the excitation energies in linear carbon chains is suggested, namely, λ0 = [1240. 6A/(2 √-3n 6 - √-3n 3）] (1 — Be^Cn), where A = 3. 24463, B =0. 90742, and C=0. 07862 for C2nH, and A=2. 94714, B=0. 83929, and C=0. 08539 for C2n-1N. In consid-eration of a comparison of the theory with the experiment, both the expressions are modified as λ1 = 0. 92 (λ0 100) and λ1 =0. 95(λ0-90) for C2nH and C2n-1N, respectively.     

醇和N,N-二甲基乙酰胺分子间相互作用的FTIR光谱研究

The association between alcohols and N,N-dimethylacetamide in carbon tetrachloride was investigated using FTIR spectroscopy at 298 K.The formation constants for 1∶1 and 1∶2 complexes were calculated using the method of Whetsel and Kagarise.The observed 1∶1 complex values were also verified using the method of Nash.The rate of change in C=O bond moment on complexing with alcohols increased with increasing acidity of alcohols.The formation constant and values of free energy change increased with the increase in carbon chain length of alcohols,which suggested that the degree of complex formation varied with the length of the carbon chain of alcohols.     

Syntheses and Structures of Two Ruthenium(Ⅲ) Complexes [Ru(PPh_3)_2(S_2CNR_2)Cl_2]·CH_2Cl_2(R=Et and ~iPr)

Oxidation reaction of [Ru(PPh3)3Cl2] with tetraethylthiuram disulfide [Et2NCS2]2 or tetra-iso-propylthiuram disulfide [iPr2NCS2]2 afforded ruthenium(Ⅲ) complexes [Ru(PPh3)2(S2CNR2) Cl2]·CH2Cl2(R=Et 1,iPr 2) which were characterized by single-crystal X-ray diffraction.Complex 1 crystallizes in triclinic,space group P with a = 11.5065(6),b = 12.1458(7),c = 18.0034(9) ,α = 109.380(4),β = 95.279(4),γ = 97.969(4)°,V = 2324.8(2) 3 and Z = 2.Complex 2 belongs to the monoclinic system,space group P21/n with a = 12.5752(3),b = 20.7562(5),c = 17.6821(3) ,β = 105.934(1)°,V = 4437.94(17) 3 and Z = 4.Both mononuclear complexes 1 and 2 have an octahedral configuration around the central ruthenium atom which is bonded to one chelated dithiocarbamate ligand,two PPh3 ligands in mutually trans and two chlorides in mutually cis positions.The average Ru-S,Ru-P and Ru-Cl bond lengths are 2.377(2),2.412(2) and 2.369(2)  for 1,and 2.376(2),2.414(1) and 2.383(2)  for 2,respectively.The electrochemical properties of these two complexes were studied in CH2Cl2 solution by cyclic voltammetry.     

Thermal Behavior and Decomposition Kinetics of the Complexes of CuX2 （X=NO3, Br, CI and CIO4） with 3,3＇-Dimethyl-1 -（1 H-1,2,4-triazol-1-yl）-2-butanone

The thermal behaviors of the complexes of Cu(DMTZB)4X2 (DMTZB=3,3‘-dimethyl-1-(1H-1,2,4-triazol-1-yl)-2-butanone, X=NO3 or ClO4) and Cu(DMTZB)2 X2 (X=Br or Cl) in a nitrogen atmosphere were studied under the non-isothermal conditions by simultaneous TG-DTG-DSC, EDS and elemental analysis techniques. The resuits showed that their decomposition proceeded in three different ways mainly depending on the anions in the molecules. The heat effect associated with the decomposition step of DMTZB molecules was also different. The decomposition mechanisms and the kinetic parameters of DMTZB were determined and calculated by jointly using four methods, which showed that its pyrolysis was controlled by D3 mechanism but with different activation energies and pre-exponential factors for different complexes.     

Syntheses and Structures of Two Ruthenium(III)Complexes [Ru(PPh_3)_2(S_2CNR_2)Cl_2]·CH_2Cl_2(R=Et and ~iPr)

Oxidation reaction of [Ru(PPh_3)_3Cl_2] with tetraethylthiuram disulfide[Et_2NCS_2]_2 or tetra-iso-pmpylthiumm disulfide[~iPr_2NCS_2]_2 afforded mthenium(Ⅲ)complexes[Ru(PPh_3)_2(S_2CNR_2)cl_2]·CH2Cl2(R=Et 1,~iPr 2)which were characterized by single-crystal X-ray diffraction.Complex 1 crystallizes in triclinic,space group Pīwith a=11.5065(6),b=12.1458(7),C=18.0034(9)(A),α=109.380(4),β=95.279(4),γ=97.969(4)°,ν=2324.8(2)(A)~3 and Z=2.Complex 2 belongs to the monoclinic system,space group P21/n with a=12.5752(3),b=20.7562(5),e=17.6821(3)(A),β=105.934(1)°,ν=4437.94(17)(A)~3 and Z=4.Both mononuclear complexes 1 and 2 have an octahedral configuration around the central ruthenium atom which is bonded to one chelated dithiocarbamate ligand,two PPh_3 ligands in mutually tram and two chlorides in mutually cis positions.The average Ru-S,Ru-P and Ru-Cl bond lengths are 2.377(2),2.412(2)and 2.369(2)(A) for 1,and 2.376(2),2.414(1)and 2.383(2)(A) for 2,respectively.The electrochemical properties of these two complexes were studied in CH_2Cl_2 solution by cyclic voltammetry.     

Synthesis,structure and electrochemistry of dithiocarbamato phenthiolate oxo-molybdenum(Ⅳ)complexes[MoO(SΦ)_2(S_2CNEt_2)]

The reaction of Mo(0) complex [Mo(CO)_4(S_2CNEt_2)]~- with phenthiolate [Et_4N]SΦin acetonitrilo in the presence of small amount of air affords a new oxo-molybdenum com-plex [MoO(SΦ)_2(S_2CNEt_2)]~-,which crystallizes in two forms of crystals,[Et_4N][MoO(SΦ)_2(S_2CNEt_2)](1a) and [Et_4N][MoO(SΦ)_2(S_2CNEt_2)]·(CH_3)_2CHOH (1b).The structures of1a and 1b were determined from three-dimensional X-ray data.1a crystallizes in the mo-noclinie,space group C_c with a=12.321(4),b=15.245(4),c=16.087(9);β=98.44(4)°.V=2989~3,Z=4,D_c=1.35 g/cm~3 and R=0.031 for 2434 reflections [I>3(I)].1b crystallizes inthe monoclinic,space group P2_1/n with a=9.861(1),b=20.357(3),c=17.122(5)A;β=92.27(2)°,V=3434.3~3,Z=4;D_c=1.29 g/cm~3 and R=0.051 for 2852 independeut reflections [I>3σ(I)],The structures of 1a and 1b reveal that the anion [MoO(SΦ)_2(S_2CNEt_2)]~- contains asingle oxo ligand coordinating to a molybdenum(Ⅳ) and the geometry around Me(Ⅳ) atomis a distorted square pyramid.Interestingly,the solvate molecule isopropanol of 1b is linkedto oxo group by a hydrogen-bond of 1.928A,leading to the increase of Mo=O bond distance(1.718).Mo—S distances are 2.44 and 2,39.The electrochemical behavior of 1 wasdiscussed also.     

Space Group of Aquaimidazolemaleatozinc, [（H2O）（C3H4N2）（O2CCH=CHCO2Zn）]n

The space group of [(H2O)(C3H4N2)(O2CCH=CHCO2Zn)]n, which was originally described in the acentric Pc space group (Liu et al., Chin. J. Struct. Chem 2004, 23, 160～163),is re-described in the centric P21/c space group.     

The Study of Oxygen Transfer Kinetics for MoO_2(S_2CENt_2)_2 in Various Solvents

The reaction kinetics between MoO2 (S2CNEt2)2 and triphenylphos-phine (PPh3) were studied in various organic solvents with the aid of the stopped-flow technique. The linear correlations were found for rate constants or activation energy versus the function of refractive index (n2 - 1)/(2n2 + 1). It was also found that pre-factor increases with the descent of ( n2 - l)/(2n2 - 1) slightly.One step mechanism which supposes the lone pair of electrons on P atom of triphenylphosphine enters directly into the Ⅱ antibonding orbital, which makes the Mo= O bond broken, is suggested.     

Structure and stability for (AlN)_n~+ and (AlN)_n~- (n=1-15) clusters

Using density functional theory (DFT) method with 6-31G* basis set, we have carried out the optimizing calculation of geometry, vibrational frequency and thermodynamical stability for(AIN)n+ and (AIN)n- (n =1-15) clusters. Moreover, their ionic potential (IP) and electron affinity(EA) were discussed. The results show that the electrical charge condition of the cluster has a relatively great impact on the structure of the cluster and with the increase of n, this kind of impactis reduced gradually. There are no AI-AI and N-N bonds in the stable structure of (AIN)n+ or (AIN)n-, and the AI-N bond is the sole bond type. The magic number regularity of (AIN)n+, and (AIN)n- is consistent with that for (AIN)n, indicating that the structure with even n such as 2, 4,6, … is more stable. In addition, (AIN)10 has the maximal ionization power (9.14 eV) and the minimal electron affinity energy (0.19 eV), which manifests that (AIN)10 is more stable than other clusters.     

Solvothermal Synthesis, Crystal Structure and Luminescent Property of a Dy（Ⅲ） Coordination Polymer Constructed by 1,2,4,5-Benzenetetracarboxylic Acid

A three-dimensional coordination polymer {[Dy(H2btec)2/4(btec)3/6(H2O)]·2H2O} n has been synthesized through the reaction of DyCl3·6H2O and 1,2,4,5-benzenetetracarboxylic acid by solvothermal technique, and the crystal structure was determined by X-ray diffraction. The Dy(Ⅲ) coordination polymer crystallizes in monoclinic, space group P21/n with a=10.7063(1), b=7.1491(1), c=17.1197(3), α=90, β=97.10, γ=90°, V=1300.31(3)3 , C10H9DyO11 , Dc=2.389g/cm3 , Z=4, F(000)=892, the final R=0.0165 and wR=0.0448 for I > 2σ(I). The title coordination polymer possesses a three-dimensional framework consisting of nine-coordinate Dy(Ⅲ) centers and two kinds of coordination modes for the 1,2,4,5-benzenetetracarboxylic acid ligands. Every btec4- ligand (deprotonated four protons from 1,2,4,5-benzenetetracarboxylic acid) in the title coordination polymer can clamp three Dy atoms like forceps, which could make the Dy atoms closer in the area of metal-metal interaction. The 3-D framework of the coordination polymer has many channels occupied by the free guest water molecules, and the hydrogen bonds between the coordinated carboxylic groups and guest water molecules could stabilize the crystal structure of the title coordination polymer. In addition, the luminescence properties were also studied.     

Synthesis,Structure and Luminescent Properties of [Zn(btzb)2Cl2]·2H2O[btzb=1,2-Bis(5-tetrazolyl)benzene]

The title compound[Zn(btzb)2Cl2]·2H2O(1·2H2O,btzb=1,2-bis(5-tetrazolyl)benzene)was synthesized in situ by the[2 3] cycloaddition reaction of phthalonitrile with NaN3 in water in the presence of ZnCl2 under refluxing conditions.1·2H2O crystallizes in the monoclinic system,space group P21/c with a=9.0119(18),b=7.5566(15),c=18.076(5)(A),β=114.67(2)°,V=1118.6(4)(A)3,Z=2,Dc=1.784 g/cm3 T=223(2)K,C16H16N16O2Cl2Zn,Mr=600.74,F(000)=608,μ(MoKα)=1.393 mm-1,S=1.081,R=0.0306 and wR=0.0669 for 1896 observed reflections with Ⅰ ＞2σ(Ⅰ).The Zn2 ion of 1 is coordinated by four N atoms from two btzb ligands and two Cl atoms,forming a distorted octahedral coordination geometry.A number of intermolecular hydrogen bonding interactions between molecules 1 and/or the solvated water molecules result in a 3D hydrogen-bonded structure.The luminescent property of 1·2H2O was also investigated.     

Competition between C-C and C-H Activation in Reactions of Neutral Nickel Atom with Cycloalkanes （n = 3-7）

A theoretical investigation of the reaction mechanisms for C-H and C-C bond activation processes in the reaction of Ni with cycloalkanes C,,H2. （n = 3-7） is carried out. For the Ni ＋ CnH2, （n = 3, 4） reactions, the major and minor reaction channels involve C-C and C-H bond activations, respectively, whereas Ni atom prefers the attacking of C-H bond over the C-C bond in CnH2n （n = 5=7）. The results are in good agreement with the experimental study. In all cases, intermediates and transition states along the reaction paths of interest are characterized, It is found that both the C-H and C-C bond activation processes are proposed to proceed in a one-step manner via one transition state. The overall C-H and C-C bond activation processes are exothermic and involve low energy barriers, thus transition metal atom Ni is a good mediator for the activity of cycloalkanes CnH2n （n = 3 -7）.     

Syntheses,Structures, and Photoluminescent Properties of Two 2D Coordination Polymers Based on 1,3-Di(2,4-dicarboxyphenyl) Benzene and 1,3-Di(4-pyridyl)propane

Two new 2D coordination polymers, [Zn(HL)(Hbpp)]n(1) and [Cd(HL)(Hbpp)(H2O)]n(2)(H4L = 1,3-di(2,4-dicarboxyphenyl) benzene, bpp = 1,3-di(4-pyridyl)propane), have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction analysis, elemental analysis, TGA and IR spectroscopy. Complex 1 crystallizes in monoclinic, space group P21/n, with a = 13.1031(6), b = 14.7315(7), c = 15.0041(7) A, β = 91.202(1)°, V = 2895.6(2) A3, Dc = 1.532g/cm3, Mr = 667.97, F(000) = 1376.0, μ = 0.909 mm–1, Z = 4, the final R = 0.0481 and wR = 0.1304 for 7027 observed reflections with I 2σ(I). Complex 2 also belongs to the monoclinic space group P21/n, with a = 13.6326(4), b = 14.6432(4), c = 14.9395(5) A, β = 93.132(1)o, V = 2977.84(16) A3,Dc = 1.613 g/cm3, Mr = 1445.98, F(000) = 733.0, μ = 0.794 mm–1, Z = 2, the final R = 0.0283 and w R = 0.0784 for 7230 observed reflections with I 2σ(I). Both complexes 1 and 2 form 2D net structures, which are further linked to form 3D supramolecular net structures via intermolecular hydrogen bonds and aromatic π-π stacking interactions.     

The Syntheses and crystal structures of trans-dichlorobis (10-thiabenzo-15-crown-5)-palladium(Ⅱ)and trans-dichlorobis-(10-selenabenzo-15-crown-5)palladium(Ⅱ)

The preparation and X-ray crystal structures of the adducts of 10-thiabenzo-15-crown-5 and 10-selenabenzo-15-crown-5 with PdCl2 are reported. [PdCl2(C14H20O4S)2] (1): or-thorhombic, space group Pbca with cell dimensions of a=17.285(5), 6=8.354(3), c=21.689(4) A, K=3131.9 A3, Z=4;R=0.0330 for 2301 reflections with I > 3o(I), [PdCl2(C14H2oO4Se)2] (2): monoclinic, space group P21/n with cell dimensions of a=18.928(4), b=8.912(3), c=9.813(2) A, β=96.90(2)0, V=1643.4 A3, Z=2; R=0.0289 for 2617 reflections with I> 3σ(I), Both complexes are monomeric, square-planar palladiurn(Ⅱ) compounds with the Pd(Ⅱ) ion situating on a crystal-lographic inversion centre, and the crown ligands all adopt the axial coordination with the Pd-S bond of 2.3233(7) A and the Pd-Se bond of 2.4357(3) A. Their complexing characteristics are discussed in brief.     

Synthesis, Structure and Physical Property of a New 3D Lead Coordination Polymer:[Pb2(L)2(dea)]n·nH2O

A new 3D Pb(Ⅱ) coordination polymer [Pb2(L)2(dea)]n·nH2O has been hydrothermally prepared by using the long flexible decanedioic acid (H2dea) and the N-donor chelating ligand 2-(1H-l,3,7,8-tetraazacyclopenta[l]phenanthren-2-yl)naphthol (HL). Single-crystal X-ray determi- nation shows that the complex crystallizes in the monoclinic system, space group C2/c with a = 25.453(5), b = 7.5035(15), c = 27.340(6),β= 114.84(3)°, V = 4738.6(16)3, Z = 8, C28H22N4O4Pb, Mr = 685.69, Dc = 1.922 g/cm3, F(000) = 2656, μ(MoKa) = 7.166 mm-1, R = 0.0282 and wR = 0.0687. Two L ligands bridge two Pb(Ⅱ) atoms to form a dimmer, and the neighboring dimers are further linked by the dea ligands to yield a 3D structure. The IR and TG of the compound have been investigated in detail.     

Theoretical study on the hydrolysis mechanism of N,N-dimethyl-N′-(2′,3′-dideoxy-3′-thiacytidine)formamidine

The hydrolysis mechanisms of N,N-dimethyl-N′-(2′,3′-dideoxy-3′-thiacytidine)formamidine (FA-3TC) in the gas phase and in aqueous solution were studied by use of the density functional theory B3LYP/6-31 G(d, p) method. Two possible reaction pathways in the title reaction were considered. In one pathway water attacks the C=N double bond first (path A) while in the other water attacks the C—N single bond first (path B). The calculated results indicate that the first step in both pathways is the rate-limiting process and path A is more favorable than path B in the gas phase. The effect of solvent water on the title reaction was assessed at the B3LYP/6-31 G(d, p) level of theory based on the po-larizable continuum model (CPCM). In water the first mechanism (path A) is also favored.     

Crystal and Molecular Structure of Copper (Ⅱ) Dimeric Complex of S-Methyl-β-N-(Pyridine N-Oxide-2-ylmethylidene) Dithiocarbazate with Acetonitrile

The crystal and molecular structure of copper(Ⅱ) dimeric complex of S-methyl-B-N-(pyridine N-oxide-2-ylmethylidene) dithiocarbazate with acetonitrile, [CuL (CH3CN)]2 (ClO4)2, was determined by X-ray diffraction. The complex crystalizes in monoclinic system with space group P21/n, a= 7. 685(2), 6=20.160(6), c= 10. 847(5) A ,B = 107.89(3), Z=2,Dc=1.788 g/cm3, F(000) = 835. 8, u= 18. 17 cm-1(Moka,R= 0. 057.Each Cu(Ⅱ) ion in the complex is surrounded by a distorted square pyramidal. The basal plane is comprised of S, N and O atoms of one ligand together with a N atom of the solvent--acetonitrile, while the axial position is occupied by the S atom of the other ligand. The bond length of Cu-S(bridging) is 3. 038A . and Cu-Cu distance is 3. 700A.     

Crystal and Molecular Structures of Two Derivatives of 1, 3a, 5-Trisubstituted-3a ,4,5,11-Tetrahydro-1,2,4-Oxadiazolino[5,4-d] [1, 5]Benzothiazepine

The structures of two derivatives of the title compound [C24H22N2OS, Mr = 386. 5 for (1); C25H22N2O3S, Mr = 430. 5 for (2)] were determined by using X-ray single-crystal strcuture analysis method. The final discrepancies are R = 0. 071 and 0. 077, respectively, for the reflections measured on a four-circle diffractometer. The space group for compound (1) is P bca with a=1. 6639(4), b=2.0286(3), c= 1.1742(1) nm, V = 3. 964(1) nm3, F(000) = 1632 e, Z=8; and (2) belongs to P21/n space group, and the cell dimensions are a=1. 1115(4), b=0. 8932(7), c=2. 186(3) nm, β=97. 52 (1)°? V=2.151(4) nm3, F(000) = 904 e, Z=4.The molecular backbones are very similar, each is a tricyclic system. The central seven-membered ring is in a twisted-boat conformation, and is cis-fused to 1,2,4-oxa-diazolino ring, while the latter moiety is in an envelope form. There are conjugated but non-coplanar effects in each structure. All bond lengths and angles in the molecules are normally acceptable. The crystal structure on the whol     

Preparation,Crystal Structure and Theoretical Calculation of N-（Pyrimidin-2-yl）-N＇-methoxycarbonyl-thiourea

The compound, N-（pyrimidin-2-yl）-N＇-methoxycarbonyl-thiourea, has been synthesized. The single crystal structure has been determined by an X-ray diffractometer. The crystal belongs to triclinic with space group P-1 and a=0.72152（4） nm, b=0.8056（4） nm, c=0.90772（5） nm, α= 105.141（4）°, β=94.588（4）°, γ= 115.415（4）°, F（000）= 220, the unit cell volume V=0.45704（4） nm^3, the molecule number in one unit cell Z=2, the absorption coefficient μ=0.333 mm^-1, the calculated density Dc= 1.542 g/cm^3. The theoretical investigation of the title compound was carried out with B3LYP/6-311G, HF/6-311G and MP2/6-311G methods, and the atomic charges and natural bond orbital analysis were also discussed.