A New Complex [Ni(L)_2]·2H_2O Containing an Interesting Six-membered Water Ring (HL=2-Iminomethyl-6-methoxy-phenol)

A new complex, [Ni（L）2]·2（H2O） I （HL = 2-iminomethyl-6-methoxyphenol）, has been synthesized and structurally determined. The crystal belongs to the trigonal system, space group R3- with a = 1.9341 （3）, b = 1.9341 （3）, C = 1.2048（2） nm, V = 3.9029（11） nm^3, Mr = 395.05, Z = 9, Dc = 1.513 g·cm^-3, F（000） = 1854,μ= 1.153 mm^-1 and S = 1.014. Each Ni^Ⅱ atom is four-coordinated by two N and two O atoms from two different L anions to give a slightly distorted square-plane geometry. The complex forms a 3-D network structure through N-H...O and O-H...O hydrogen bonds containing an interesting six-membered water ring.

Extremal Graphs with Respect to Matching Energy for Random Six-membered Ring Spiro Chains

Gutman and Wagner(in the matching energy of a graph, Disc. Appl. Math., 2012) defined the matching energy of a graph and pointed out that its chemical applications go back to the 1970 s. Now the research on matching energy mainly focuses on graphs with pendent vertices and only a few papers reported the progress on matching energy of graphs without pendent vertices. For a random six-membered ring spiro chain, the number of k-matchings and the matching energy are random variables. In this paper, we determine the extremal graphs with respect to the matching energy for random six-membered ring spiro chains which have no pendent vertices.

A comparative study of the aromaticity in some typical conjugated six-membered rings by the method of localized molecular orbital

The localized molecular orbitals and energy levels for four typical conjugated six-membered ring systems C_6H_6, C_3N_3H_3, B_3N_3H_6, and (B_3O_6)^(3-) as well as a non-aromatic reference molecule N_3Cl_6 have been calculated by using Edmiston-Ruedenberg energy localization technique under the CNDO/2 approximation in order to investigate the nature of aromaticity or quasi-aromaticity of the six-membered ring systems studied. The contour maps for π-type localized MO's (LMO) have been plotted to illustrate the bonding characteristics of the five ring systems studied. These LMO calculations show that for all the conjugated six-membered ring systems considered there exists local delocalization of π-bonds or three-centered and occasionally four-centered two-electron π-bonds in our terminology, and the cooperative effect among these π-bonds leading to the formation of a closed continuous x-conjugation system around the ring, which is necessary for the creation of aromaticity in the systems studied. We have been able to discuss the properties of these three-centered π-bonds in terms of the constituent atoms and electrons and the relevant orbitals involved.

Localized molecular orbital studies of certain compounds with [A_3X_3] six-membered rings

The localized molecular orbitals (LMOs) of certain quasi-aromatic organic and inor- ganic molecules with six-membered rings have been calculated by virtue of the ab initio method using STO-3G and 4-31G basis sets as well as the CNDO/2 method. It is shown that there exists extensively-delocalized p-pπ bonding in these quasi-aromatic systems. The localized pictures of the π-type LMOs for the heterocyclic and homocyclic systems from the σ-π localization scheme are discussed. The Generator Orbital approach is utilized to account for the bonding patterns.

A Pd(Ⅱ)-Catalyzed Oxidative Cyclization for the Preparation of AryI-Fused Six-Membered Nitrogen Heterocycles with 2-Acetoxy Functionality

A Pd（II）-catalyzed oxidative cyclization of olefinic tosylamides was developed for the preparation of aryl-fused and N-containing six-membered heterocycles. Under optimized conditions the reaction proceeded with high activity and selectivity, with yields of up to 83% being obtained. This procedure provides a facile and efficient route to the aforementioned heterocycles with 2-acetoxy functionality.

The Reaction of Molybdenum with 2,3-Dihydroxynaphthalene

[H2N（CH2）3NH312[MoO2（C10H6O2）2] （1） was synthesized by the 2,3-dihydroxynaphthalene in the mixed solvent of CH3OH, CH3CN reaction of （n-Bu4N）4[Mo8O26] with and 1,3-propanediarnine. （C5HllN2）2- [HeN（CH2）3NH2][MoO2（CloH6O2）2] （2） was obtained by the reaction of Na2MoO4.2H20 with 2,3-dihydroxynaphthalene in the same solvent above. Both of the complexes possess complex anion [Mo（VI）O2（OC10H6O）2]^2- which shows pseudo-octahedrally coordinated fashion, while the counterions are two protonated 1,3-propanediamine in complex 1 and （CsH11N2）^＋ in complex 2. （C5H11N2）＋ is the byproduct of reaction 2, which results from combination of acetonitrile with 1,3-propanediamine. Packing diagrams of the two complexes are also different. There is anti-parallel-aligned-double-meso-bilayer unit in complex 1. However there are four chiral anions arranged in anticlockwise orientation in complex 2.

Discovery of the low temperature phase barium metaborate (BBO) and its significance in the search for new type nonlinear optical materials

1 History of discovery of the low temperature phase barium metaborate （BBO）——an excel-lent new-type ultraviolet radiation frequency-doubling crystalline materialTHE first laser excitation in 1960 with ruby （α-Al2O3: Cr） as a laser crystal and the first dou-bling of frequency （347. 15 nm） in 1961 by irradiating quartz crystal （α-SiO2） with a 694. 3nm laser beam have laid the basis for the study of laser and nonlinear optical （NLO） crystals,