THE SYNTHESIS AND CRYSTAL STRUCTURE OF A NOVEL MOLYBDENUM-SULFUR CLUSTER COMPLEX, (NH_4)_4[Mo_3(NO)_4S_(13)]·3H_2O

The title compound has been synthesized, the crystal structure of which has been detorminedby the single-crystal X-ray diffraction method. The crystal belongs to triclinic space group C-P1 with the unit cell parameters: a =9.535(2)A, b = 9.740(2)A, c = 15.795(4)A, α = 89.85(2)°, β = 91.80(2)°, γ = 99.37(1)°,ν = 1446.6A~3, Ζ = 2. The structure is refined to R = 0.075, R_w = 0.074 for 1903 reflections. There are diverse bonding modes of molybdenum and sulfur in this eompound. The twosulfur atoms at the center bond to three molybdenum atoms from respective sides and formthe two apices of a trigonal bipyramid. Besides, there are S_2~(-2) ligands and a polysulfur chaincomposed of three sulfur atoms. The coordination number for the three molybdenum atomsis seven. Their coordination polyhedra are somewhat distorted pentagonal bipyramid. Eachof the three NO ligands coordinated to molybdenum gives a linear group of Mo-N-O, whilethe fourth NO ligund bonded with a polysulfur chain forms a bent group of S-N     

A POSSIBLE MECHANISM OF FORMATION OF POLYNUCLEAR MOLYBDENUM CLUSTERS

The reported bi-eapped trinuclear molybdenum cluster anion(Mo_3S_2Cl_9)~(3-) is proposed to be formed first by adding a MoCl_2~(2 ) entity to a dinuclear molybdenum anion (Mo_2Cl_9)~(3-), followed by substitution of two S atoms for the triply bridging Cl atoms. The possible formation of (Mo_3Cl_(11))~- as an intermediate is supported by molecular orbital calculations. It may be possible to construct Mo_4Cl_(13)~ and Mo_5Cl_(15)~~(3 ) by a similar process.     

Theoretical Study of Small Water Clusters of Sulfur Dioxide

The intermolecular clusters of sulfur dioxide with water, SO2(H2O)n (n = 2～5), are studied by using B3LYP density functional theory and MP2 ab initio methods along with the large basis sets (6-311++G(d,p) and aug-cc-pVDZ). The equilibrium geometries, intermolecular binding energies, and anharmonic frequencies of the clusters are calculated and compared with those of pure water clusters and available experiments. SO2 tends to form cyclic hydrogen-bonded complexes with two or three water molecules. In the larger clusters, however, water molecules begin to retain the structure of pure water clusters and segregate from SO2. Infrared absorption assignments for the small clusters are discussed to resolve a possible incorrect assignment in a recent spectroscopic experiment on the clusters.     

Ionic dissociations of chlorosulfonic acid in microsolvated clusters: A density functional theory and ab initio MO study

Ionic dissociation of chlorosulfonic acid (HSO3Cl) in the molecular clusters HSO3Cl-(H2O)n (n = 1-4) and HSO3Cl-NH3-(H2O)n (n = 0-3) was investigated by density functional theory and ab initio molecular orbital theory. The equilibrium structures, binding energies, and thermodynamic properties, such as relative enthalpy and relative Gibbs free energy, and were calculated using the hybrid density func- tional (B3LYP) method and the second order M?ller-Plesset approximation (MP2) method with the 6-311 G** basis set. Chlorosulfonic acid was found to require a minimum of three water molecules for ionization to occur and at least one water molecule to protonate ammonia. The corresponding clusters with fewer water molecules were found to be strongly hydrogen-bonded. The related properties and acid strength of chlorosulfonic acid were discussed and compared to the acid strengths of perchloric acid and sulfuric acid in the context of clusters with ammonia and water. The relative stabilities of these clusters were also investigated.     

A Density Functional Study of Small （NiTi）x Clusters with x=1-3

Systematic studies on the geometry, electronic structure and vibrational properties of small (NiTi)x clusters with x=1-3, within the framework of the density functional theory, were performed in this work. The electronic structure analyses were used to investigate the bonding between the early-late(EL) transition metals in their alloy. The results of our calculations have been used to predict (NiTi)x clusters structure for the ground state and confirm that s-electron density is transferred from Ti atoms to Ni atoms followed by the back donation of electrons through the d-orbital. The study provides a fragment approach based on the isolobal analogy that NiTi molecular fragments play a significant role in forming clusters.     

Voltammetric determination of stability constants of lead complexes with diallyl disulfide,dimethyl disulfide,and diallyl sulfide

The complexation of Pb~(2+)by diallyl disulfide(DADS), dimethyl disulfide(DMDS) and diallyl sulfide(DAS)has been studied by differential pulse voltammetry. Stability constants,(log b), of the 1:1(PbL) and 1:2(PbL_2) complexes, where L = ligand, were found to be in the range of ca. 3.8–4.2 and 9.4–10.2,respectively. Complex formation is accompanied with a significant decrease in the peak current and the shift of the Pb2+/Pb half-wave potential to a higher one upon the addition of the sulfur containing ligands(L). The formation of 1:1 and 1:2 complexes, i.e., PbL~(2+)and PbL_2~(2+)was observed in the case of the three ligands. The consecutive formation constants of labile lead complexes with DADS, DMDS, and DAS were determined at 298 K by the method of De Ford and Hume. Apparently due to the large size of the lead ion,steric hindrance caused by the greater steric bulk of DADS compared to that of DMDS have little or no effects on the formation constants, so that very similar values were obtained in the case of the two ligands. Also, the possible participation of C=C double bonds in coordination with the metal center in the case of DADS appears to compensate for the steric effects caused by the larger size of this ligand. In agreement with the Jorgensen principle of symbiosis, the second formation constants were found to be approximately six orders of magnitude greater than the first ones.     

Theoretical Study on the Catalytic Activity and Sulfur Resistibility of Amorphous Alloy Ni-B-P

In the present paper,one hundred cluster models NinBP (n=1～6) have been designed and studied by density functional theory (DFT) to get an insight into the local structure,catalytic properties and sulfur resistibility of amorphous alloy Ni-B-P. The configurations in triplet state are found more stable than those in the singlet state. It is found that as the content of Ni in the clusters increases,the value of Fermi level in clusters fluctuated,which shows that the content of Ni can influence the Fermi level to a certain extent. Based on the Fermi level and DOS,we consider the activity of catalyst in hydrogenation reaction is the best in cluster Ni3BP. On the basis of the charge of clusters NinBP (n=1～6),we conclude the amorphous alloy Ni-B-P with high Ni content has better sulfur resistibility and the best hydrogenation activity,strong sulfur resistibility appears in clusters Ni3BP,and the amorphous alloy Ni60B20P20 with similar proportion is expected to prepare in the future.     

DFT Study of Charge Effect on the Odd-even Oscillatory Behavior in Stabilities for Gold Clusters

The comparative study of charge effect on the size-dependence stabilities of gold clusters Aunz(n = 2~12, z = 0/±1) in gas phase is performed at the M06-L/Lanl2 dz level. The lowest-energy structures charged by –1, 0 and +1 are optimized. The result shows that the geometries of the clusters with over 7 atoms tend to be cake-like. From the two- to three-dimensional geometries, the oscillatory behaviors are exhibited in the structural and electronic properties with the most pronounced in energy gap. The amplitude for the positive clusters is bigger than both the neutral and negative clusters. The neutral clusters with even number of even-coordinated atoms are more stable than the neighbors with odd number of even-coordinated atoms, as is completely reversed for the charged clusters. The oscillatory behaviors for the charged clusters are opposite to that for the neutral clusters, as is attributed to the electron-paired effect.     

Synthesis,crystal structure,magnetic properties and second harmonic generation of a new noncentrosymmetric coordination compound:Triaqua(4-amino-6-methoxypyrimidine) cuprate(Ⅱ)sulfate

The chemical preparation, crystal structure and infrared spectroscopic characterization of the triaqua(4-amino-6-methoxypyrimidine) cuprate(II) sulfate, [Cu(C_5H_7N_3)(H_2O)_3]SO_4, is reported. The compound crystallizes in the noncentrosymmetric orthorhombic space group P2_12_12_1 with lattice parameters a = 7.9025(3), b = 11.1189(4), c = 12.9720(4) , V = 1139.81(7) ~3 and Z = 4. The Cu(II) cation is fivecoordinated, in an early half-way between square pyramidal and trigonal bipyramidal fashion, by two nitrogen atoms of the 4-amino-6-methoxypyrimidine ligand and three water oxygen atoms. In the atomic arrangement, the organic ligands and the 5-connected Cu centers are linked with each other to give a 1-D corrugated hybrid chain running along the b-axis direction. The chains are interconnected by the SO_4~(2-) anions via O–H...O, O–H...S, C–H...O and N–H...O hydrogen bonds to form layers spreading parallel to the(011) plane. The vibrational absorption bands were identified by infrared spectroscopy. Quantitative measurements of the second harmonic generation(SHG) of a powdered sample at 1064 nm were performed and a relative efficiency of 5.2 times the KDP standard was observed. Magnetic properties were also defined to characterize the complex. Magnetic measurements revealed that this material had a onedimensional antiferromagnetic character. The magnetic parameters were g = 2.11 and 2J/k B = -36 K.     

S掺杂纳米多孔碳的光催化活性:表面化学和孔隙率的重要性(英文)

This minireview summarizes our recent findings on the photoactivity of S-doped nanoporous carbons. The materials were either synthesized from the sulfur-containing polymers or obtained by heat treatment of commercial carbon with hydrogen sulfide. Their surface was extensively charac terized from the points of view of its surface chemistry, porosity, morphology, and electronic properties. The carbons showed enhanced activity towards oxidation of arsine and removal of diben-zothiophenes from model diesel fuel. The latter were oxidized to various oxygen containing intermediates and the cleavage of C–C bonds in aromatic ring was detected when carbon with adsorbed species was exposed to UV or visible light. Irradiation resulted in generation of photocurrent in a broad range of wavelength. The presence of sulfur led to the reduction of oxygen and contributed to an increased capacitive performance. We link these effects to the presence of reduced sulfur in the small pores which enhances the dispersive interactions via inducing a positive charge to carbon atoms, to sulfur in oxygenated forms which contribute to Faradaic reactions and increase the polar interactions, and to the hydrophobicity of a surface in small pores where oxygen can be reduced by excited electrons from chromophoric-like sulfur containing groups.     

Syntheses and Characterization of Half—Sandwich Zirconium Complexes with Dichalcogenolate o—Carborane Ligands

Metallocene complex Cp2^ttZrCl2(Cp^tt=η^5-1,3-^tBu2C5H3)(1)has been prepared from the reaction of LiCp^tt with ZrCl4 in good yield.Reactions of 1 with dilithium dichalcogenolate o-carboranes afforded new type of half-sandwich compounds with dichalcogenolate o-carboranyl ligands,[Li(THF)4][Cp^ttZr(E2C2B10H10)2](E=S,2a;E=Se,2b)in which only one cyclopentadienyl ring ligand existed.Complexes 1 and 2a were structurally characterized by X-ray analyses.In complex 2a,the Zr(IV)ion is η^5-bound to one 1,3-ditert-cyclopentadienyl ring and σ-bound to four μ2-sulfur atoms of two dithio-carboranes.the zirconium atom and four sulfur atoms form a distorted pyramid.The coordination sphere around the zirconium atom resembles in a piano stool structure with four legs of sulfur stoms and the fulcrum at the zirconium stom.     

Synthesis,Crystal Structure and Antimicrobial Activity of a New Ternary Copper(Ⅱ) Complex with p-Chlorophenoxyacetic Acid and 2-Amino Benzothiazole

A novel ternary complex of Cu(pcpa)2(aben)2 (pcpa=p-chlorophenoxyacetic acid anion,aben=2-amino benzothiazole) was synthesized by the reaction of copper acetate,2-amino benzothiazole and p-chlorophenoxyacetic acid.Elemental analysis,IR,UV and X-ray single-crystal diffraction were carried out to determine the composition and crystal structure.The crystal crystalli-zes in the monoclinic system,space group C2/c with a=25.795(4),b=7.384(3),c =17.741(6),β=107.47(2)°,C30H24Cl2CuN4O6S2,Mr=735.09,V=3223.2(18) 3,Z=4,Dc=1.515 Mg/m3,λ(MoKα)=0.71073 ,μ=1.022 mm-1,F(000)=1500,the final R=0.0464 and wR=0.1244.A total of 3218 unique reflections were collected,of which 2228 with I 2σ(I) were observed.The Cu(II) atom is four-coordinated with two carboxylate oxygen atoms of the two pcpa ligands and two nitrogen atoms in thiazole rings of two aben ligands.The analysis of crystal structure shows intermolecular and intramolecular hydrogen bonds between amino-nitrogen atoms of the two aben ligands and carboxylate oxygen atoms of the two pcpa ligands.The antimicrobial properties of the title complex and its two free ligands were tested against representative bacterial and fungal strains.Results show that the antibacterial activity of the complex is less than or equal to that of 2-amino benzothiazole,but for yeasts and moulds,it exhibits excellent inhibitory effect better than that of its two free ligands.     

Theoretical Investigation of Hydrogen Sulfide Adsorption on the Surface of F Functionalized Carbon and Carbon Silicon Nanotubes (7,0) in the Gas Phase and Water

In order to develop a sensor for the detection of toxic H_2S molecule,the interactions of C–NT and CSi–NT with H_2S molecule were investigated by density functional theory calculations. The effects of F functionalization and water on the adsorption of H_2S gas on C–NT and CSi–NT surfaces were investigated. The studied nanotubes can interact with the H_2S molecule effectively and so adsorptions of H_2S on studied nanotubes are exothermic and possible from the energetic viewpoint. Replacing the C atoms of C–NT with Si atoms may be a good strategy for improving the sensitivity of C–NT towards H_2S. F functionalization and water cause an increase and decrease in the absolute adsorption energy(Ead) values of H_2S on the studied nanotubes,respectively. There are good linearity dependencies between Ead and orbital energy values of studied nanotubes. The Ead and orbital energy values of studied nanotubes can be considered as important parameters to propose suitable nanotubes with increased potential of H_2S adsorption.     

Theoretical Study on the Structures and Magnetic Properties of Metal String Complexes Containing Rigid Equatorial Ligands[Ni_3(L)_4(NCS)_2](L=dzp~-,mpmpa~-,mppda~-,mptpa~-)

Density functional theory at the BP86 level was used to investigate the influence of equatorial ligands on the Ni–Ni interactions and magnetic coupling properties of metal string complexes [Ni_3(L)_4(NCS)_2](L represents the rigid equatorial ligands; L = dzp-(1), mpmpa-(2), mppda-(3), mptpa-(4)). The following conclusions can be drawn.(1) With increasing the radius of the connecting atom in the cental ring in equatorial ligands, the two pyridine rings bend down, resulting in the decreasing distance between the two pyridine-nitrogen atoms and the Ni–Ni distance. Therefore, the strength order of the Ni–Ni interaction is 4 2 3 1. The Ni–Ni interactions in 2 and 4 are stronger than those in Ni_3(dpa)_4(NCS)_2 containing no-rigid equatorial ligands.(2) The calculated-Jab is 4 2 3 1. There are two types of magnetic exchange pathways in these complexes: the σ-type pathway through the Ni_3~(6+) chains and the δ-type pathway through the equatorial ligands. The magnetic coupling through the metals is the dominant part. Hence, the magnetic coupling strength increases with increasing the Ni–Ni interaction. Modifying the radius of the connecting atom may be one of the means to fine tuning of magnetic coupling strength of this kind of metal string complexes.     

Mononuclear and Dinuclear Yttrium Complexes Supported by Pyrrolide Ligands: Syntheses,Structures and Catalytic Behaviors towards the Ring-opening Polymerization of ε-Caprolactone

The syntheses, structures and catalytic activities of two yttrium complexes supported by pyrrolide ligands are reported. Treatment of Y(N(Si Me3)2)3 with one equivalent of H3bptd(H3bptd = 1,9-bis(2-pyrrolyl)-2,5,8-triazanona-1,8-diene) in THF gave a complex of composition [Y(bptd)(THF)]2(1). Reaction of Y(N(Si Me3)2)3 with one equivalent of H3tpa(H3tpa = tris(pyrrolyl-?-methyl)amine) in THF generated [Y(tpa)(THF)3](2) in good yield. Complexes 1and 2 have been characterized by single-crystal X-ray diffraction, elemental analyses and NMR spectroscopy. Complex 1 is dinuclear. The two metal centers are doubly bridged by two amine nitrogen atoms to form a Y–N–Y–N four-membered rhombus ring. The geometries of Y3+ ions in 1and 2 are well described as pentagonal bipyramid and capped octahedron, respectively. The ring-opening polymerization reactions of ?-caprolactone initiated by 1 and 2, respectively, were investigated. They both exhibited good catalytic activity for the polymerization of ?-caprolactone. All of the obtained polymers have high molecular weights and relatively narrower PDIs. The polymers generated by 2 possessed polydispersity close to 1.1. The good catalytic activities of 1 and 2 reveal their potential applications in polymer industry.     

Design criteria for tetradentate phenanthroline-derived heterocyclic ligands to separate Am(Ⅲ) from Eu(Ⅲ)

To design novel phenanthroline-derived soft ligands for selectively separating minor actinides from lanthanides, four tetradentate phenanthroline-derived heterocyclic ligands(BTPhen, BPyPhen, BPzPhen, and BBizPhen) were constructed and their complexation behaviors with Am(ⅡI) and Eu(ⅡI) were systematically investigated by density functional theory(DFT) coupled with relativistic small-core pseudopotential. In all the 1:1-type species, the metal ion is in the center of the cavity and coordinates with two nitrogen atoms(N1 and N1′) of the phenanthroline skeleton and the other two nitrogen atoms(N2 and N2′) of the auxiliary groups. The bond lengths of Am–N are comparable to or even shorter than those of Eu–N bonds because the ionic radii of Am(ⅡI) are larger than those of Eu(ⅡI). Additionally, the negative ΔΔGAm/Eu value for the reaction of [M(H2O)4-(NO3)3] + L → ML(NO3)3 + 4H2 O indicates that the complexation reaction of Am(ⅡI) is more energetically favorable than that of Eu(ⅡI); this can be considered as an important design criterion to screen phenanthroline-derived ligands for MA(ⅡI) extraction. According to this criterion, the selectivity of tetradentate phenanthroline-derived ligands for separating Am(ⅡI) over Eu(ⅡI) follows the order of BTPhen BBizPhen BPyPhen BPzPhen.     

硫化态三组元NiMoP/γ-Al2O3催化剂的TPR表征及噻吩HDS活性的研究

A series of sulfided tertiary NiMoP/γ-Al2O3 catalysts with different contents of MoO3 were prepared by using molybdophosphoric acid of Keggin structure(H3PMo12O40) and nickel nitrate as origins of active phase components of molybdenum, phosphorus and nickel, and characterized by TPR technique, with their HDS activity being investigated with thiophene as a model substrate. For the sulfided Mo-0 catalyst containing no nickel as promoter, the only hydrogen sulfide evolution peak Ⅰ　is observed at 462 K and attributed to the hydrogenation of the so-called edge sulfur atoms chemisorbed on coordinatively unsaturated(cus) Mox+ sites on the MoS2 phase(MoS2 slab). With the introduction of nickel into the active phase of the sulfided Mo-0 catalyst and with the increase of the molybdenum loading, a new hydrogen sulfide evolution peak Ⅱ gradually develops at the low temperature side of the peak Ⅰ, at the same time accompanied by both the increase of the area ratio of the peak Ⅱ to the peak Ⅰ and the shift of the hydrogen sulfide evolution maximum rate to lower temperatures, which may imply the existence of two kinds of active centers related to molybdenum and nickel respectively and the synergic action between the two centers above. It should be noted that for the sulfided NiMoP/γ-Al2O3 catalysts, the thiophene HDS rate and the quantity of hydrogen sulfide evolved during TPR process increase monotonously with the atomic ratio of molybdenum to nickel in the form of ［n(Ni)+n(Mo)］/n(Ni). On the basis of the results here, the conclusion may be reached that the two kinds of vacancies can be formed on the edge of Ni-Mo-S slab due to the loss of S during TPR process and vacancies or sites related to the H2S evolution peak II should be regarded as the mainly active reaction centers of thiophene HDS.     

THE SYNTHESIS AND CRYSTAL STRUCTURE OF A NOVEL TETRANUCLEAR COPPER (Ⅰ) CLUSTER COMPLEX, Cu_4(α-C_(10)H_7CSS_2)_4·1/2CS_2

The title compound has been synthesized by the reaction of sodium α-dithionaphthoatewith CuCl_2 in an alkaline aqueous solution or by the reaction of α-dithionaphthoic acid withCuCl_2 in an organic solvent, The crude product was recrystallized in a mixture of CS_2 andC_2H_5OH. The crystals obtained are red and stable in air. The structure of the title compound is determined by a single-crystal X-ray diffractionanalysis. The crystal belongs to monoclinic space group C_(2h)~5- P(2_1/a) with unit cell parameters:a= 16.453(3)A, b=12.651(4)A, c=23.182(7)A, β=100.5(2)°, V=4744.6A~3,Z=4. Thestructure was refined to R=0.06 for 4707 reflections. In the molecule, Cu_4 cluster has a distorted tetrahedral configuration. Surrounding thistetrahydron are four α-perthionaphthoate ligands, coordinated to copper through the sulfuratoms. One of the sulfur atoms in each ligand forms sulfur bridge with copper atoms,while the other is coordinated to only one copper. The three Cu--S bonds formed by thethree sulfur atoms with a given copper atom are approximately coplanar. Each group--C--S_2 with Cu atom on a vertex of the tetetrahedron forms a five-member ring. Thesefive-member rings are also approximately cooplanar. The molecule possesses an approachingS_4 point symmetry. The mechanism for the formation of the title compound involves a redox reaction.which is discussed in this paper.     

Crescent aromatic oligothioamides as highly selective receptors for copper(Ⅱ) ion

A series of crescent aromatic oligothioamides(4, 6, 8, 15, and 18) bearing different number of sulfur atoms were designed and synthesized via thionation of their corresponding aromatic oligoamides(3, 5, and 7) using Lawesson's reagent. The X-ray structure of a trimeric analogue(13) revealed the presence of intramolecular three-center hydrogen bonds that are responsible for the rigidification of the molecular backbone. The extraction by these novel receptors toward some representative heavy metal cations(Zn2+, Cd2+, Co2+, Ni2+, Pb2+, and Cu2+) and alkali and alkaline earth metal cations(Li+, Na+, K+, Rb+, Cs+, Ca2+, and Sr2+) demonstrated high efficiency(83.5%–96.4%) and superior selectivity for Cu2+ over other selected metal cations. Particularly, the extractability was correlated to both the number of sulfur atoms and orientation of thiocarbonyl groups as revealed in the order: 6 4 18 15. This is in stark contrast to the oligoamides that only gave much lower extractability(5.9%–16.4%), suggestive of the importance of replacement of carbonyl oxygen atoms with sulfur atoms in the extraction of Cu2+. The complexation behavior of 4, 6, and 8 with Cu2+ was also examined by UV-Vis and NMR techniques.     

Synthesis and Crystal Structure of Bis{2-bromo- 4-chloro-6-[（2-isopropylammonioethylimino）- methyl]phenolato}bisthiocyanatozinc（Ⅱ）

A Schiff base zinc(Ⅱ) complex [Zn(C12H16BrClN2O)2(NCS)2] was prepared and characterized by elemental analysis,IR and single-crystal X-ray diffraction. The crystal belongs to the triclinic system,space group P1 with a=8.414(1),b=9.124(1),c=22.212(3),α=79.177(2),β=86.296(2),γ=89.899(2)o,V=1671.3(4)3,Z=2,Dc=1.631 g/cm3,Mr=820.79,λ(MoKα)= 0.71073,μ=3.444 mm-1,F(000)=824,R=0.0646 and wR=0.1179. A total of 7371 unique reflections were collected,of which 3904 with I > 2σ(I) were observed. The complex crystallizes with two half-molecules per asymmetric unit and each mononuclear molecule is centrosymmetric. The Zn atom lying at the inversion centre is six-coordinated in a slightly distorted octahedral geometry by two phenolate O atoms and two imine N atoms from two Schiff base ligands,as well as two N atoms from two thiocyanate anions. In the crystal structure,the combination of π-π stacking interactions and intermolecular hydrogen bonds (N–H…Br,N–H…O,N–H…N,C–H…O,C–H…S and C–H…Cl) leads to a three-dimensional network.