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1.
1 INTRODUCTION Bis(pyrazol-1-yl)methane has been one of the po- pular polydentate nitrogen donor ligands due to its strong chelating coordination to transition metal ions as capping ligand. Coordination behavior of the li- gand is able to yield stable M-N-N-C-N-N six-mem- bered boat conformation[1, 2]. The complexes con- taining bdpm ligand have been widely synthesized and characterized in recent years, and exhibit the striking properties in catalysis, magnetism and so on[3-10]. For exa…  相似文献   

2.
1 INTRODUCTION Owing to their unusual topological properties and economically important applications in many fields, such as catalysis, biology, materials science and mag- netochemistry[1~3], polyoxometalates (POMs) have aroused particular interest for a long time[4~6]. But the investigation in their capability and application are relatively less carried on. Even though some POMs have been put into practice, the mechanism of the function of POMs remains incompletely understood. Thus,…  相似文献   

3.
The reactions of eaq, OH·, CO2·, and N3· radicals with some novel homo nuclear and hetero nuclear peroxo peptide complexes viz: copper peroxo glycylglycine, [Cu(O2)(H2L)2]; molybdenum oxoperoxo glycylglycine, [Mo(O)(O2)2(H2L)2]; Cu,Mo oxoperoxo glycylglycine [CuMo(O)(O2)(L)2] and Cu,Mo, oxo glycylglycine, [CuMo(O)2(L)2] (H2L=glycyl glycine) in aqueous solutions were investigated by pulse radiolysis. Three types of reactions were observed: (1) reduction of Cu(II) to Cu(I) by eaq and CO2·, (2) oxidation of Cu(II) to Cu(III) by N3·, and (3) formation of a radical on H abstraction from the ligand by OH· radical. Rate constants were reported for formation and decomposition of all intermediates. In case of one electron reduced complexes of hetero atoms, CuMo(O)2L2 and CuMo(O)(O2)L2, prepared via the reduction of the corresponding complexes by eaq, formation of a new dimer radical anion complex was observed. It is also noteworthy to mention the possibility of the effect of peroxo ligand on intermediate steps during the formation of Cu clusters. © 1999 John Wiley & Sons, Inc. Int J Chem Kinet 31: 159–168, 1999  相似文献   

4.
1INTRODUCTION Atom transfer radical addition is an efficient me-thod for carbon-carbon bond formation in organic synthesis[1,2].In some of these reactions,a transi-tion-metal catalyst acts as a carrier of the halogen atom in a reversible redox process.The transition-metal-catalyzed has been successfully used to con-trol radical polymerization[3].In the process,the transition-metal species initially abstracts halogen atom X from organic halide to form oxidized species and carbon-centered r…  相似文献   

5.
The complexes, [VO(O(2))(pa)(2)]ClO(4).3H(2)O (1), [VO(O(2))(pa)(2)][VO(O(2))(2)(pa)].3H(2)O (2), [VO(O(2))(pa)(2)][VO(O(2))(ada)].2H(2)O (3) and [VO(O(2))(pa)(pca)].H(2)O (4)[pa = picolinamide, ada = carbamoylmethyliminodiacetate(2-) and pca = 2-pyrazinecarboxylate(1-)], were synthesized. 2 and 3 are new types of peroxovanadium complexes: monoperoxovanadium diperoxovanadate (2) and monoperoxovanadium monoperoxovanadate (3). The complexes were characterized by chemical analysis and IR spectroscopy, and 1, 3 and 4 also by X-ray analysis. The structure of 1 is disordered, with alternating positions of the oxo and peroxo ligands. The peroxo oxygen atoms, O(p), in 1 are involved in weak hydrogen bonds with water molecules and close intramolecular C-HO...(p) bonds [d(HO(p)) approximately 2.0 A]. The supramolecular structure of 1 is formed by a network of hydrogen bonds and strong attractive intermolecular pi-pi interactions between the pyridine rings. The supramolecular architecture in 4 is constructed by (N,O)-H...O hydrogen bonds between the neutral complex molecules and water of crystallization. The peroxo oxygen atoms in 4 form intramolecular C-H...O(p) bonds [d(H...O(p))= 2.303 A]. The pa and pca ligands are ON coordinated via the oxygen atoms of the C(NH(2))=O and COO(-) groups, respectively, and nitrogen atoms of the heterocyclic rings, and ada as a tetradentate O(3)N ligand. The thermal analysis of 4 showed that the loss of water of crystallization and the active oxygen release (T(min)/ degrees C 82, T(max)/degrees C 165) are, under given conditions, individual processes separated by the temperature interval 90-132 degrees C. The solution structures and stability were studied by UV-VIS and (51)V NMR spectroscopies.  相似文献   

6.
ComplexationofMolybdenum(Ⅵ)withR-andS-malicAcid,TheCrystalStructureof(NH_4)_4[(MoO_2)_4O_3(R-mal)_2]·6H_2OZhouZhao-Hui;YanWen-Bi?..  相似文献   

7.
K_6[(VO)_2(C_2O_4)_5]·4H_2O的晶体属单斜晶系,空间群为C2/c。a=16.149(5),b=7.304(2),c=23.591(5),β=94.62(2)°,Z=4。晶体结构用直接法解出并经全矩阵最小二乘法修正至R=0.085。晶体中的络阴离子是双核的,每个VO~(2+)被两个草酸根所螯合,且呈顺式排布。另有一个草酸根将两个VO~(2+)连接在一起,该草酸根的C—C键中点位于对称心上。  相似文献   

8.
1 INTRODUCTION Many crown ethers have been synthesized[1, 2] and widely used[3~5]. The amide-type acyclic poly- ethers with versatile molecular structures offer many advantages over the traditional crown ethers, such as their potential activity for ion-selective electrodes[6] and the extraction of metal ions[7], so they have attracted much scientific attention[8~10]. In an effort to investigate the effect of skeleton of acyclic polyether on the extractability of metal ions, and to find …  相似文献   

9.
1 INTRODUCTION Coordination polymers are a family of materials composed of 1D chains, 2D sheets, and 3D networks of metal-organic building blocks connected via co- valent and hydrogen bonds. Recently, they have re- ceived increasing attention for their fascinating struc- tures and topological features[1~4]. The complex as ligands approach is one of the best strategies to de- sign and synthesize polynuclear species, and a good example of ‘complex ligand’ is represented by mono- nuclear…  相似文献   

10.
The reaction of 2-(1-naphthyl)benzothiazoline with palladium(II) acetate leads to helical mononuclear and orthometalated tetranuclear products. The molecular structures of mononuclear palladium(II) [Pd(H1-nabz)(2)] (1) (H(2)1-nabz = 2-N-(1-naphthylmethylideneamino)benzenethiolate), tetranuclear palladium(II) [Pd(4)(1-nabz)(4)] (2) and tetranuclear platinum(II) [Pt(4)(1-nabz)(4)] (3) have been determined by single-crystal X-ray diffraction method. Crystal data for complex 1 are as follows: a = 14.208(3) ?, b = 18.227(4) ?, c = 14.398(8) ?; beta = 94.55(3) degrees; V = 3717.0(23) ?(3); space group = P2(1)/n, Z = 4. Crystal data for the complex 2 are as follows: a = b = 15.798(3) ?, c = 23.728(4) ?; V = 5921.7(20) ?(3); space group = I4(1)/a, Z = 16 for the Pd(1-nabz) unit. Crystal data for the complex 3 are as follows: a = b = 15.496(2) ?, c = 24.348(3) ?; V = 5846.3(20) ?(3); space group = I4(1)/a, Z = 16 for the Pt(1-nabz) unit. The mononuclear palladium(II) complex reveals short ortho-hydrogen.palladium distances of 2.66(7) and 2.48(7) ?. These short distances and (1)H NMR studies provide a M.H-C interaction which can be regarded as a three-center four-electron interaction. The molecular structures of 2 and 3 confirm the formation of unusual tetranuclear compounds featuring a rare C,N,S-tridentate ligand derived from orthometalation of pendant side arm. The structural and chemical properties of the mononuclear palladium(II) complex 1 clearly suggest that 1 is a potential intermediate in the formation of the tetranuclear complex 2 by orthometalation reactions.  相似文献   

11.
A new complex of N,N'-bis(p-nitrophenyl)-2,2'-(p-phenylene-dioxy) diacetamide DMF monohydrate, C25H25N5O9H2O (Mr = 557.52), has been synthesized and its structure was determined by X-ray crystallography method.The crystal belongs to monoclinic system, space group P21/c with a = 7.2812, b = 25.5894, c = 14.3434 (A), β = 91.110(1)o, V = 2672.0(2) (A)3, Dc = 1.386 g/cm3, F(000) = 1168, μ = 0.109 mm-1 and Z = 4.The final R = 0.0493 and wR = 0.1173 for 3389 observed reflections with I > 2σ(I).The asymmetric unit of the title complex consists of monomeric N,N'-bis(p-nitrophenyl)-2,2'-(p-phenyleneioxy)diacetamide 1, one DMF and one water molecule, which are incorporated during recrystallization.The molecules are linked into a three-dimensional network by π…π interactions as well as intermolecular interactions among DMF, water molecule and 1.  相似文献   

12.
1 INTRODUCTION The development of supramolecular complexes has recently attracted considerable attention due to the fundamental interest in self-assembly processes of transition-metal complexes, supramolecular che- mistry and crystal engineering[1]. The ultimate goal is to gain control in order to direct their function[2]. Self-assembly through coordination and nonco- valent interactions such as hydrogen bonds, aromatic π···π stacking, steric repulsion and Van der Waals forces leads …  相似文献   

13.
A novel compound, (4,4'-Hbpy)3[NaMo8O26](4,4'-bpy)2(H2O)4 1 (bpy = bipydine),was synthesized by the hydrothermal method. Single-crystal X-ray diffraction shows that compound 1 belongs to the monoclinic system, space group C2/m with a = 19.1921(5), b = 18.6931(6), c = 9.3821 (3) (A), β = 104.8020(11)°, V = 3254.22(17) (A)3, C50H51Mo8N10NaO30, Mr = 2062.52, Z = 2,F(000) = 2016,μ = 1.591 mm- 1 and Dc = 2.105 g/cm3. The final R = 0.0283 and wR = 0.0912 for 3118 observed reflections (I > 2σ(Ⅰ)). Compound 1 contains the β-[Mo8O26]4- anion, sodium ion, 4,4'-bpy and lattice crystalline water molecules. The β-[Mo8O26] units link the sodium ion to form a chain structure. The infinitechains of [Na(Mo8O26)]3- blocks are surrounded by protonized 4,4'-bpy cations,4,4'-bpy and lattice crystalline water molecules. The 2D-IR correlation spectroscopy study indicates that the stretching vibrations of Mo=O occur more preferentially due to the thermal effect. The TGA analysis shows that compound 1 has high thermal stability.  相似文献   

14.
1 INTRODUCTION The transition metal complexes with 2,2-diamino-4,4-bi-1,3-thiazole (DABT) and their derivatives are excellent soft mag- netic materials[1]. Structural investigation of these complexes is helpful to under- standing the relationship betwee…  相似文献   

15.
A novel manganese(IV) monomer, [Mn(IV)(Me(3)TACN)(OMe)(3)](PF(6)), has been synthesized in methanol by the reaction of MnCl(2) with the ligand, N,N',N"-trimethyl-1,4,7-triazacyclononane (Me(3)TACN), in the presence of Na(2)O(2). The resulting product was isolated as the red/brown crystalline hexafluorophosphate salt. The compound crystallizes in the space group P2/c with the cell dimensions a = 15.652(2) ?, b = 8.740(1) ?, c = 15.208(2) ?, beta = 108.81(1) degrees, V = 1969.4(4) ?(3), and Z = 4. The structure was solved by the heavy-atom method and was refined by full-matrix least-squares techniques to a final value of R = 0.067 (R(w) = 0.097) based upon 3087 observations. The manganese atom in the molecule is six-coordinate in an N(3)O(3) ligand environment with the triazacyclononane facially coordinated. Pertinent average bond distances and angles are as follows: Mn-O, 1.797(5) ?; Mn-N, 2.116(5) ?; O-Mn-O, 97.8(2) degrees; N-Mn-N, 81.4(2) degrees; O-Mn-N, 167.8 degrees (2); O-Mn-N, 86.8(2) degrees; O-Mn-N, 92.8(2) degrees. The complex was further characterized by UV-vis and EPR spectroscopies, solution magnetic susceptibility measurements, FAB-MS, and electrochemistry. [Mn(IV)(Me(3)TACN)(OMe)(3)](PF(6)) was found to catalyze the oxidation of water-soluble olefins using hydrogen peroxide as the oxidant in an aqueous medium. The catalyzed rates of oxidation of these olefins indicate at least a 12-fold rate enhancement over oxidant alone. The unusual stability of the catalytic species was demonstrated by the repeated additions of substrate and oxidant while maintaining a constant catalytic rate of oxidation.  相似文献   

16.
1 INTRODUCTION Much research interest has been focused on metal- organic coordination polymers in past years because of the structural and topological novelty of these compounds and their potential applications as func- tional materials, such as catalyst, ion-exchange, gas sorption, optical material and molecule-based ma- gnet[1~6]. In this field, many organic bridging ligands such as bipyridine, polyaromatic carboxylate and re- lated species have been used to produce various types of met…  相似文献   

17.
<正> t Reaction of Et^NI, NaSCH2COOEt with Mo(CO)6 in MeCN affords a new dinuclear molybdenum(O) complex, [Eti,N]2 [Mo2(CO) 8(SCH2COOEt)2] (I) . The crystal and molecular structure has been determined from three-dimensional X-ray data. 1_ crystallizes in the triclinic, space group PI with a=10.362(1), b= 10.391(1), c=10.815(2) X, a=91.64(2), 6=100.07(2), Y=H4.46(1)? Z=l, R= 0.048 for 2975 reflections with I?o(I). Noribonding of Mo...Mo distance (3.939(11)A) in _! supports the previous speculation for the two-electron redox properity,of complex anion, [Mo2(CO)g(SR)2J2~.  相似文献   

18.
Wei M  Willett RD 《Inorganic chemistry》1996,35(22):6381-6385
The compound (dabcoH(2))(2)Cl(3)[CuCl(3)(H(2)O)(2)].H(2)O, where dabco = 1,4-diazabicyclo[2.2.2]octane, has been synthesized, its structure has been determined by single-crystal structural analysis, and its properties have been investigated by powder and single-crystal EPR spectroscopy. The compound crystallizes in space group Pnma at room temperature with unit cell dimensions of a = 15.227(1) ?, b = 7.467(1) ?, and c = 20.166(2) ? with Z = 4. The structure was solved by the Patterson method and refined by full-matrix least-squares to R = 4.3% for 1681 observed reflections (I > 2sigma(I)). The [CuCl(3)(H(2)O)(2)](-) anion exists with a slightly distorted trigonal bipyramidal geometry in which the three Cl atoms lie in equatorial positions and the two water molecules are in axial positions. The distortion appears to be driven by the presence of N-H.Cl hydrogen bonds. The EPR spectra are also consistent with the presence of only a small distortion from trigonal bipyramidal geometry since g(1) approximately g(2) > g(3) approximately 2.0. Analysis of the geometry indicates the distortion consists primarily of a "negative" C(2)(v)() type. Analysis of the thermal parameters supports the supposition that the observed geometry corresponds to disorder over two "positive" C(2)(v)() distortions.  相似文献   

19.
The title complex [CaCo(C3H2O4)2(H2O)4]n with a formula of C6H12CaCoO12 and Mr = 375.17 has been synthesized and structurally characterized by X-ray diffraction. The crystal is of monoclinic, space group C2/c with a = 14.195(9), b = 7.708(5), c = 13.441(8) (A),β = 119.575(9)°,V = 1279.0(14)(A)3, Dc = 1.948 g/cm3, μ = 1.803 mm-1, F(000) = 764 and Z = 4. The final R =0.0245 and wR = 0.0652 for 1344 observed reflections with I > 2o(I). The structure of the title complex consists of CaO8 polyhedra and CoO6 octahedra linked together by malonate ligands. The Ca(Ⅱ) cation on a twofold axis is coordinated by two water molecules and six malonate O atoms.The Co(Ⅱ) cation which lies in a centre of symmetry in an octahedral arrangement is coordinated by four malonate O atoms and two water molecules. The structure comprises alternating layers along the [101] plane, with the shortest Co-Co distance of 6.961(5) (A). The whole 3D structure is maintained and stabilized by the presence of hydrogen bonds.  相似文献   

20.
Single crystals of JEM-phase NdSi(6-z)Al(1+z)O(z)N(10-z) were successfully prepared from starting powders of Si?N?, AlN and Nd?O? at 1700 °C for 3 h under nitrogen atmosphere. The z value of Nd-doped JEM-phase was determined to be 0.4 via determination of oxygen and nitrogen by elemental analysis. This result may be beneficial for overcoming the difficulty on preparation of single-phase JEM-phase Sialon materials and further characterization on their properties. The detailed crystal structure of Nd-Sialon was solved on the basis of single-crystal X-ray diffraction data for the first time. The space group is Pbcn (no. 60); a = 9.3060(6) ?, b = 9.7224(6) ?, c = 8.8777(5) ?; Z = 4; V = 803.22(8) ?3; D(c) = 3.971 g cm?3; R? = 0.0297 and wR? = 0.0739 for all reflections refined against F2, with GooF value of 1.031.  相似文献   

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