Improved modification for the density-functional theory calculation of thermodynamic properties for C-H-O composite compounds

A three-parametric modification equation and the least-squares approach are adopted to calibrating hybrid density-functional theory energies of C(1)-C(10) straight-chain aldehydes, alcohols, and alkoxides to accurate enthalpies of formation DeltaH(f) and Gibbs free energies of formation DeltaG(f), respectively. All calculated energies of the C-H-O composite compounds were obtained based on B3LYP6-311++G(3df,2pd) single-point energies and the related thermal corrections of B3LYP6-31G(d,p) optimized geometries. This investigation revealed that all compounds had 0.05% average absolute relative error (ARE) for the atomization energies, with mean value of absolute error (MAE) of just 2.1 kJ/mol (0.5 kcal/mol) for the DeltaH(f) and 2.4 kJ/mol (0.6 kcal/mol) for the DeltaG(f) of formation.     

Effect of particle size in preparative reversed-phase high-performance liquid chromatography on the isolation of epigallocatechin gallate from Korean green tea

To isolate epigallocatechin gallate (EGCG) of catechin compounds from Korean green tea (Bosung, Chonnam), a C18 reversed-phase preparative column (250x22 mm) packed with packings of three different sizes (15, 40-63, and 150 microm) was used. The sample extracted with water was partitioned with chloroform and ethyl acetate to remove the impurities including caffeine. The mobile phases in this experiment were composed of 0.1% acetic acid in water, acetonitrile, methanol and ethyl acetate. The injection volume was fixed at 400 microl and the flow rate was increased as the particle size becomes larger. The isolation of EGCG with particle size was compared at a preparative scale and the feasibility of separation of EGCG at larger particle sizes was confirmed. The optimum mobile phase composition for separating EGCG was experimentally obtained at the particle sizes of 15 and 40-63 microm in the isocratic mode, but EGCG was not purely separated at the particle size of 150 microm.     

Facile hydrometalation of alkynes by nido-1,2-(CpRuH)(2)B(3)H(7) yielding novel Ru-B edge-bridging alkylidenes. Stepwise conversion of HCtbd1;CC(O)OMe into nido-1,2-(CpRuH)(2)-3-HOB-4-MeC-5-MeOC-BH(3), Cp = eta(5)-C(5)Me(5)

The reaction of the alkyne HCCC(O)OMe with 7 sep 1,2-(Cp*RuH)2B3H7 leads to hydroboration plus hydroruthenation to produce nido-1,3-mu-Me{C(O)OMe}C-1,2-(Cp*Ru)2B3H7, a compound with an exocluster ruthenium-boron mu-alkylidene that exists in two isomeric forms. Both isomers undergo rearrangement with intramolecular chelation of the carbonyl oxygen at a boron site, thereby opening the cluster and generating arachno-2,3,-mu(C)-5-eta1(O)-Me{C(O)OMe}C-1,2-(Cp*Ru)2B3H7. Further heating leads to deoxygenation of the carbonyl fragment by a boron center concurrent with insertion of the carbon atom into the metallaborane cage to give nido-1,2-(Cp*RuH)2-3-HOB-4-MeC-5-MeOC-BH3.     

5-芳酰氨基-2-苯基-2H-1, 2, 4-噻二唑-3-酮的合成

用1-芳酰基-5-苯基-2-硫代双脲与溴进行氧化成环反应制备了九个新的5-芳酰氨基-2-苯基-2H-1, 2, 4-噻二唑-3-酮, 相应的1-芳酰基-5-苯基-2-硫代双脲可以通过苯基脲与酰基异硫氰酸酯加成制得。     

DOPING LEVEL INCREASE OF POLY(3-METHYLTHIOPHENE)FILM DURING ELECTROCHEMICAL POLYMERIZATION PROCESS

The Raman spectra of poly(3-methylthiophene) (PMeT) films with different thicknesses, which have beenelectrochemically deposited on a flat stainless steel electrode surface by direct oxidation of 3-methylthiophene in borontrifluoride diethyl etherate (BFEE) at a constant applied potential of 1.38 V (versus SCE), have been investigated byexcitation with a 633-nm laser beam. The spectroscopic results demonstrated that the doping level of PMeT film wasincreasing during film growth. This finding was also confirmed by electrochemical examination. Moreover, the Raman bandsassigned to radical cations and dications in doped PMeT films were found approximately at 1420 and 1400 cm~(-1),respectively. Radical cations and dications coexist on the backbone of PMeT as conductive species and their concentrationsincrease with the increase of doping level. Successive cyclic voltammetry was proved to be an effective approach toimproving the doping level of as-grown thin compact PMeT film.     

Synthesis, Structure Characterization, and Cu^2＋ Recognition of 3-{ [3- （Phenylsulfonamido） benzoyl ] methylidene } -3,4- dihydroquinoxaline-2 （1H） -one

IntroductionSubstituted diketo acid derivatives possess a varie-ty of biological properties, such as analgesic[1—3], anti-bacterial[4]as well as anti-inflammatory[3]. Very re-cently, the results of random screening of millions ofcompounds have shown that…     

二（胍基）锆配合物的合成和表征

Addition of one equivalent of LiN（i-Pr）2 or LiN（CH2）5 to carbodiimides, RN=C=NR [R=cyclohexyl （Cy）, isopropyl （i-Pr）], generated the corresponding lithium of tetrasubstituted guanidinates {Li[RNC（N R^′2）NR]（THF）}2 [R=i-Pr, N R^′2=N（i-Pr）2 （1）, N（CH2）5 （2）; R=Cy, N R^′2=N（i-Pr）2 （3）, N（CH2）5 （4）]. Treatment of ZrCl4 with freshly prepared solutions of their lithium guanidinates provided a series of bis（guanidinate） complexes of Zr with the general formula Zr[RNC（N R^′2）NR]2Cl2 [R=i-Pr, N R^′2=N（i-Pr）2 （5）, N（CH2）5 （6）; R=Cy, N R^′2=N（i-Pr）2 （7）, N（CH2）5 （8）]. Complexes 1, 2, 5-8 were characterized by elemental analysis, IR and ^1H NMR spectra. The molecular structures of complexes 1, 7 and 8 were further determined by X-ray diffraction studies.     

Integration of gene amplification and capillary gel electrophoresis on a polydimethylsiloxane-glass hybrid microchip

We report on the development of a hybrid polydimethylsiloxane (PDMS)-glass microchip for genetic analysis by functional integration of polymerase chain reaction (PCR) and capillary gel electrophoresis (CGE), and on related temperature control systems for PCR on a PDMS-glass hybrid microchip. The microchip was produced by molding PDMS against a microfabricated master with comparatively simple and inexpensive methods. PCR was successfully carried out on the PDMS-glass hybrid microchip with 500 bp target of lambdaDNA and the amplified gene was subsequently analyzed by CGE on the same PDMS-glass microchip. The chip could be considered as an inexpensive single-use apparatus compared to glass or silicon-made microchips for the same purpose.     

Chains, ladders and sheets of d metal–organic polymers generated from the flexible bipyridyl ligands

By use of the three-layer diffusion method, reactions of flexible bipyridyl ligands (4,4′-bpp or 3,3′-bpp) with M(II) salts (M = Zn, Cd) and multi-carboxylate ligands resulted in the formation of four interesting d¹⁰ metal–organic coordination polymers: [Zn(μ-4,4′-bpp)Br₂]_n (1), [Zn(μ-4,4′-bpp)(1,2-bdc)]_n · nH₂O (2), [Zn(μ-3,3′-bpp)(1,3-bdc)]_n · nCH₃OH · 2nH₂O (3) and [Cd(μ-3,3′-bpp)(C₄H₂O₄)]_n · 3nH₂O (4) (4,4′-bpp = 2,2′-bis(4-pyridylmethyleneoxy)-1,1′-biphenylene; 3,3′-bpp = 2,2 ′-bis(3-pyridylmethyleneoxy)-1,1′-biphenylene; bdc=benzenedicarboxylate, C₄H₄O₄ = fumaric acid). Complex 1 has a 2D sheet structure consisting of two unusual zigzag Zn(II) chains which are nearly perpendicular to each other. Complex 2 is comprised of two-leg ladders, in which [Zn(4,4′-bpp)] chains serve as the side rails and 1,2-bdc ligands serve as the cross rungs. In complex 3, every two 1,3-bdc ligands connect the neighbouring Zn(II)-3,3′-bpp dimetallic rings in η¹ coordination modes into an interesting chain structure. Complex 4 consists of an anionic macrocycle-containing cadmium dicarboxylate sheets that are separated by 3,3′-bpp. These d¹⁰ metal complexes exhibit high thermal stabilities and strong luminescence efficiencies.     

Converged quantum calculations of HO2 bound states and resonances for J=6 and 10

Bound and resonance states of HO(2) are calculated quantum mechanically using both the Lanczos homogeneous filter diagonalization method and the real Chebyshev filter diagonalization method for nonzero total angular momentum J=6 and 10, using a parallel computing strategy. For bound states, agreement between the two methods is quite satisfactory; for resonances, while the energies are in good agreement, the widths are in general agreement. The quantum nonzero-J specific unimolecular dissociation rates for HO(2) are also calculated.