Hydrothermal synthesis and X-ray single crystal structure of bimetallic cluster complex [{Co(phen)(2)}(2)V4O12]center dot H2O

A new bimetallic cluster complex with the formula [{Co(phen)(2)}(2)V4O12](H2O)-H-. was synthesized from the hydrothermal reaction of V2O5, H2C2O4, Co(NO3)(2), 1,10-phenanthroline (phen), (C4H9)(4)NOH and water. The compound crystallizes in an orthorhombic system with space group Pbcn and unit cell parameters a = 19.106(3) Angstrom, b = 15.250(3) Angstrom, c = 16.321(2) Angstrom, V = 4755.4(13) Angstrom(3), Z = 4 and R = 0.0318. The bimetallic cluster complex [{Co(phen)(2)}(2)V4O12](H2O)-H-. is composed of a discrete V4O124- cluster eovalently attached to two [Co(phen)(2)](2+) fragments and the discrete hexanuclear bimetallic clusters of [{Co(phen)(2)}(V4O12)-V-2](H2O)-H-. are further extended into interesting three-dimensional supermolecular arrays via pi-pi stacking interactions of phen groups. Other characterizations by elemental analysis, IR, and thermal analysis are also described.

Nanostructured hybrid organic-inorganic lanthanide complex films produced in situ via a sol-gel approach

Communication: Nanostructural hybrid organic-inorganic lanthanide complex films were prepared in situ by use of a novel sol-gel precursor containing pendant triethoxy-silyl and carboxyl groups (see Figure). The resulting transparent and crack-free films gave rise to strong red or green emission, even at low lanthanide ion concentration. Phase separation and lanthanide ion aggregation were controlled at the nanoscale.

Metal ion and anion coordination in the thiamine-[Pt-II(NO2)(4)](2-) system. Structures of a metal complex, Pt(thiamine)(NO2)(3), and two salts, (H-thiamine)[Pt(NO2)(4)]center dot 2H(2)O and (thiamine monophosphate)(2)[Pt(NO2)(4)]center dot 2H(2)O

Reaction of thiamine or thiamine monophosphate (TMP) with K2Pt(NO2)(4) afforded a metal complex, Pt(thiamine)(NO2)(3) (1), and two salt-type compounds, (H-thiamine)[Pt(NO2)(4)]. 2H(2)O (2) and (TMP)(2)[Pt(NO2)(4)]. 2H(2)O (3), which were structurally characterized by X-ray diffraction. In 1, the square-planar Pt2+ ion is coordinated to the pyrimidine N(1'), a usual metal-binding site, and three NO2- groups. The thiamine molecule exists as a monovalent cation in 1 and a divalent cation in 2 while the TMP molecule is a monovalent cation in 3. In each compound, thiamine or TMP adopts the usual F conformation and forms two types of host-guest-like interactions with anions, which are of the bridging forms, C(2)-H . . . anion . . . pyrimidine-ring and N(4'1)-H(...)anion(...)thiazolium-ring. In 3, there is an additional anion-bridging interaction between the pyrimidine and thiazolium rings of TMP, being of the form C(6')-H . . . anion . . . thiazolium-ring. The salts 2 and 3 show similar hydrogen-bonded cyclic dimers of thiamine or TMP between which the anions are held. Results are compared with those of the other thiamine-platinum complexes. (C) 2001 Elsevier Science B.V. All rights reserved.

Synthesis and structure of alpha-B-Keggin type heteropoly complex K5H[Co-4(VW9O33)(2)]center dot 5H(2)O

A new complex K5H[Co-4(VW9O33)(2)]. 5H(2)O was prepared and its structure was determined by X - ray diffraction analysis. The anion has alpha - beta - Keggin structure. Two (VW9O33)(7-) moieties (alpha - B isomers) are linked via four Co(11)O-6 groups. The single crystal of the title complex is monoclinic P2(1/n) with a = 1.2307(3) nm, b = 2.1250(4) nm, c = 1.5817(3) nm, beta = 91.86(3)degrees, V = 4.1343 (14) nm(3), R = 0.0895, R-w = 0.2180.

Synthesis and structural characterization of a novel polymeric praseodymium(III) complex with a new flexible double betaine

A novel polymeric Pr(III) complex with a new double betaine, namely [{Pr(L-1)(1.5)(H2O)(2)}(n)] [ClOli4]3(n). nH(2)O (1) (L-1= 1,4-diazoniobicyclo[2,2,2]octane- 1,4-dipropionate), has been synthesized and characterized by X-ray analysis. In the title complex, the Pr(III) atom is nine-coordinated by seven oxygen atoms from five L-1 ligands and two aqua ligands. Each pair of adjacent praseodymium(III) atoms is linked by a pair of mu(3) chelating and bridging carboxylate groups, thus forming an infinite metal metal chain running parallel to the a direction, and such chains are cross-linked by flexible backbones of L-1 ligands into a three-dimensional network with the perchlorate anions and lattice water molecules accommodated in the interstitial space. The title complex crystallizes in the monoclinic space group P2(1)/n with a = 8.085(2), b = 14.316(3), c = 29.775(6) Angstrom, beta = 103.04(3)degrees and Z = 4.

Nonlinear optical properties of (B3O7)(5-) and (B3O6)(3-) groups

From the chemical bond viewpoint, LiB3O5 (LBO) crystal has been studied by using the bond valence theory of complex crystals. Chemical bond parameters and linear and nonlinear optical (NLO) properties of each type of constituent chemical bonds are quantitatively determined. Because of the different crystal structure characteristics of LBO from those of beta-BaB2O4 (BBO), the two anionic groups, (B3O7)(5-) in LBO and (B3O6)(3-) in BBO, play different roles in contributions to their own total NLO tensor coefficients of LBO and BBO, respectively. By comparison, we find that planar (B3O6)(3-) groups are the ideal structure model, leading to little cancellation of contributions of each kind of bond in these groups, and this gives us a useful guide to design new NLO materials in the future.

Crystal structure of a Pr-III complex with a novel macrocyclic ligand

The crystal structure of a novel macrocyclic ligand complex of Pr-III, C112H178O52N8S4Pr2, [Pr2L2(HL)(2)(H2O)(6)]. 22H(2)O is reported. The macrocyclic ligand has pendant acetic acid through which the ligand is coordinated to the Pr-III ion. For the dimeric unit, [Pr2L2(HL)(2)(H2O)(6)], two Pr-III ions are connected by two bridging-chelating carboxyl groups and two bridging carboxyl groups of the ligands, and each Pr-III ion is also bonded to a unidentate carboxyl group of the ligand and three water molecules. The dimeric units are bridged by four ligands through their carboxyl groups to form an infinite one-dimensional chain. The coordination number of the Pr-III ion is nine, with a distorted tricapped trigonal prismatic configuration. (C) 1997 Elsevier Science Ltd.

Nonlinearity of the complex crystals with O-H bond

A systematic and quantitative research on the structure-property correlation has been carried out in KH2PO4 (KDP), NH4H2PO4 (ADP) and HIO3, based on the dielectric theory of complex crystals and the Levine bond charge model. We, for the first time, successfully solve the problems in the calculation of the nonlinearities of the complex inorganic nonlinear optical (NLO) crystals, which have O-H bonds in their crystal structures. We do this by introducing the bond-valence equation we have set up, calculating the nonlinear optical tensor coefficients d(ijk) of these three compounds, quantitatively determining the contributions of each type of bond to the total second-order NLO tensor coefficient (d(ijk)) of the crystal, and presenting the bond parameters and the linear properties of each kind of bond. For the first time, the NLO coefficient d(36) for ADP was calculated. All calculated results are in good agreement with experimental data. We found that O-H bonds also play an important role in these crystals, except for in the important anionic groups (PO4 groups and IO3 groups). All the results thus calculated show that our method is useful in evaluating the NLO coefficients of the inorganic NLO crystals containing O-H bonds in their structures, and should be a useful tool toward the future research into new nonlinear optical materials of this kind.

Effect of structures of modifiers on electrochemistry of di-mu-oxo dimanganese 2,2'-bipyridine complex

The gold electrodes modified with 2-picolinic acid , nicotinic acid, iso-nicotinic or thiophene were prepared using membrane transfer method, The electrochemistry of di-mu-oxodimanganese 2,2'-bipyridine complex was studied in the acetic acid buffer solution at different modified gold electrodes, It was found that the modifiers which can promote the electrochemical reaction of the complex should be of at least two functional groups, One group can be bound to the electrode surface and the other can form electron transfer pathway between the modifier and the complex through sal; bridge or hydrogen bond, In addition, the mechanism of the electrochemical reaction was discussed.

STRUCTURE OF AN ERBIUM COMPLEX WITH L-PROLINE

In the structure of catena-poly[{triaqua(L-pro-line-O)erbium(III)}-bis-mu-(L-proline-O:O')-{triaqua-(L-proline-O)erbium(III)}-bis-mu-(L-proline-O:O') hexaperchlorate], each Er3+ ion is coordinated by five carboxyl O atoms from the L-proline molecules and three water molecules. Four of the SiX L-proline molecules act as bidentate bridging ligands to link the Er3+ ions through the carboxyl groups, thus producing a one-dimensional chain structure. The other two ligands coordinate unidentately to the rare-earth ions. Hydrogen bonds formed between the coordinated water molecules and between the water and unidentate proline ligand stabilize the polymeric chain.

SYNTHESIS AND X-RAY CRYSTAL-STRUCTURE OF AN ORGANOLANTHANIDE COMPLEX [(BU(T)CP)3NDBRLI(THF)3]

(ButCp)2NdCl.2THF reacts with one equivalent of phenyllithum in THF yielding tris(tert-butylcyclopentadienyl)neodymium lithium bromide tetrahydrofuran, [(ButCP)3 NdBrLi(THF)3], as a by-product, whose structure has been determined by X-ray crystallography. The 10-coordinated neodymium atom is bonded to three tert-butyl-cyclopentadienyl groups and one bromine atom, forming a distorted pseudo-tetrahedron.

SYNTHESIS AND X-RAY CRYSTAL-STRUCTURE OF [EU(ETA-6-C6ME6)(ALCL4)2]4 - THE 1ST CYCLOTETRAMERIC LANTHANIDE(II) COMPLEX WITH A NEUTRAL PI-LIGAND

The reaction of EuCl3, AlCl3 and C6Me6 in toluene gives the Eu(II) complex [Eu(eta-6-C6Me6)(AlCl4)2]4; X-ray crystal determination shows the molecule to be a cyclotetramer, in which the four Eu(C6Me6)AlCl4 units are connected via four groups of eta-2-AlCl4.

地震波场模拟及叠前深度偏移的李群方法

The processes of seismic wave propagation in phase space and one way wave extrapolation in frequency-space domain, if without dissipation, are essentially transformation under the action of one parameter Lie groups. Consequently, the numerical calculation methods of the propagation ought to be Lie group transformation too, which is known as Lie group method. After a fruitful study on the fast methods in matrix inversion, some of the Lie group methods in seismic numerical modeling and depth migration are presented here. Firstly the Lie group description and method of seismic wave propagation in phase space is proposed, which is, in other words, symplectic group description and method for seismic wave propagation, since symplectic group is a Lie subgroup and symplectic method is a special Lie group method. Under the frame of Hamiltonian, the propagation of seismic wave is a symplectic group transformation with one parameter and consequently, the numerical calculation methods of the propagation ought to be symplectic method. After discrete the wave field in time and phase space, many explicit, implicit and leap-frog symplectic schemes are deduced for numerical modeling. Compared to symplectic schemes, Finite difference (FD) method is an approximate of symplectic method. Consequently, explicit, implicit and leap-frog symplectic schemes and FD method are applied in the same conditions to get a wave field in constant velocity model, a synthetic model and Marmousi model. The result illustrates the potential power of the symplectic methods. As an application, symplectic method is employed to give synthetic seismic record of Qinghai foothills model. Another application is the development of Ray+symplectic reverse-time migration method. To make a reasonable balance between the computational efficiency and accuracy, we combine the multi-valued wave field & Green function algorithm with symplectic reverse time migration and thus develop a new ray+wave equation prestack depth migration method. Marmousi model data and Qinghai foothills model data are processed here. The result shows that our method is a better alternative to ray migration for complex structure imaging. Similarly, the extrapolation of one way wave in frequency-space domain is a Lie group transformation with one parameter Z and consequently, the numerical calculation methods of the extrapolation ought to be Lie group methods. After discrete the wave field in depth and space, the Lie group transformation has the form of matrix exponential and each approximation of it gives a Lie group algorithm. Though Pade symmetrical series approximation of matrix exponential gives a extrapolation method which is traditionally regarded as implicit FD migration, it benefits the theoretic and applying study of seismic imaging for it represent the depth extrapolation and migration method in a entirely different way. While, the technique of coordinates of second kind for the approximation of the matrix exponential begins a new way to develop migration operator. The inversion of matrix plays a vital role in the numerical migration method given by Pade symmetrical series approximation. The matrix has a Toepelitz structure with a helical boundary condition and is easy to inverse with LU decomposition. A efficient LU decomposition method is spectral factorization. That is, after the minimum phase correlative function of each array of matrix had be given by a spectral factorization method, all of the functions are arranged in a position according to its former location to get a lower triangular matrix. The major merit of LU decomposition with spectral factorization (SF Decomposition) is its efficiency in dealing with a large number of matrixes. After the setup of a table of the spectral factorization results of each array of matrix, the SF decomposition can give the lower triangular matrix by reading the table. However, the relationship among arrays is ignored in this method, which brings errors in decomposition method. Especially for numerical calculation in complex model, the errors is fatal. Direct elimination method can give the exact LU decomposition But even it is simplified in our case, the large number of decomposition cost unendurable computer time. A hybrid method is proposed here, which combines spectral factorization with direct elimination. Its decomposition errors is 10 times little than that of spectral factorization, and its decomposition speed is quite faster than that of direct elimination, especially in dealing with a large number of matrix. With the hybrid method, the 3D implicit migration can be expected to apply on real seismic data. Finally, the impulse response of 3D implicit migration operator is presented.

Structure, function, and phylogeny of the mating locus in the Rhizopus oryzae complex.

The Rhizopus oryzae species complex is a group of zygomycete fungi that are common, cosmopolitan saprotrophs. Some strains are used beneficially for production of Asian fermented foods but they can also act as opportunistic human pathogens. Although R. oryzae reportedly has a heterothallic (+/-) mating system, most strains have not been observed to undergo sexual reproduction and the genetic structure of its mating locus has not been characterized. Here we report on the mating behavior and genetic structure of the mating locus for 54 isolates of the R. oryzae complex. All 54 strains have a mating locus similar in overall organization to Phycomyces blakesleeanus and Mucor circinelloides (Mucoromycotina, Zygomycota). In all of these fungi, the minus (-) allele features the SexM high mobility group (HMG) gene flanked by an RNA helicase gene and a TP transporter gene (TPT). Within the R. oryzae complex, the plus (+) mating allele includes an inserted region that codes for a BTB/POZ domain gene and the SexP HMG gene. Phylogenetic analyses of multiple genes, including the mating loci (HMG, TPT, RNA helicase), ITS1-5.8S-ITS2 rDNA, RPB2, and LDH genes, identified two distinct groups of strains. These correspond to previously described sibling species R. oryzae sensu stricto and R. delemar. Within each species, discordant gene phylogenies among multiple loci suggest an outcrossing population structure. The hypothesis of random-mating is also supported by a 50:50 ratio of plus and minus mating types in both cryptic species. When crossed with tester strains of the opposite mating type, most isolates of R. delemar failed to produce zygospores, while isolates of R. oryzae produced sterile zygospores. In spite of the reluctance of most strains to mate in vitro, the conserved sex locus structure and evidence for outcrossing suggest that a normal sexual cycle occurs in both species.

A finite volume approach to geometrically non-linear stress analysis

In this past decade finite volume (FV) methods have increasingly been used for the solution of solid mechanics problems. This contribution describes a cell vertex finite volume discretisation approach to the solution of geometrically nonlinear (GNL) problems. These problems, which may well have linear material properties, are subject to large deformation. This requires a distinct formulation, which is described in this paper together with the solution strategy for GNL problem. The competitive performance for this procedure against the conventional finite element (FE) formulation is illustrated for a three dimensional axially loaded column.