Dendrimers Functionalized with Palladium Complexes of N-, N,N-, and N,N,N-Ligands

Pyridine, pyridine imine, and bipyridine imine ligands functionalized by a phenol have been synthesized and characterized, in many cases by X-ray diffraction. Several of these N-, N,N-, and N,N,N,-ligands have been grafted onto the surface of phosphorhydrazone dendrimers, from generation 1 to generation 3. The complexation ability of these monomers and dendrimers towards palladium(II) has been assayed. The corresponding complexes have been either isolated or prepared in situ. In both cases, the monomeric and dendritic complexes have been tested as catalysts in Heck couplings and in Sonogashira couplings. In some cases, a positive dendritic effect has been observed, that is, an increase of the catalytic efficiency proportional to the dendrimer generation.     

Seven germacranolides,eupaglehnins A,B, C,D, E,and F,and 2alpha-acetoxyepitulipinolide from Eupatorium glehni

Four new germacrane-type sesquiterpenoids with unsaturated acids as esters at the 8-position, two chlorine atom-containing lactones, 2alpha-acetoxyepitulipinolide, and 12 previously known compounds have been isolated from the MeOH extract of Eupatorium glehni (Compositae) and their structures have been determined on the basis of spectral data analyses.     

Instrumental neutron activation determination of Pt,Ru, Ir,Sc, Cr,Fe, Co,La, Ce,Nd, Sm,Yb, Lu,Hf and Ta employing CIRUS reactor as a thermal neutron source

An accurate and simple method has been developed for the determination of Pt, Ru, Ir and other elements employing instrumental neutron activation analysis (INAA). Nondestructive analysis has been carried out for the determination of these elements in different rock samples such as Dolerite, Dyke Dolerite, Country Basalt, Hyaloclastite, Trachyte, Ijolite, Spillite, Diorite and Lamprophyre from various locations like Daman, Tapti, Murud, Talasari, Ranala and Bassein in Maharashtra state. High flux provided by the CIRUS reactor (1×10¹³ n cm^?2s^?1) has been used for thermal neutron bombardment followed by radioassaying of the (n,γ) products on a HPGe detector coupled to a PC-based MCA unit.     

New Materials Derived from Ybco: CrSr2RECu2O8 (RE = La, Pr, Nd, Eu, Gd, Tb, Dy, Y, Ho, Er, Lu)

Eleven new oxides, derived from yttrium barium copper oxide by replacing the square-planar copper [Cu-O4] of the basal plane of the triple perovskite-based structure with octahedral Cr(IV), have been prepared at high pressure and temperature. Their crystal structures have been determined, and their complex microstructure has been established by means of high-resolution electron microscopy and electron diffraction. The materials have a general formula of CrSr2RECu2O8 (RE = La, Pr, Nd, Eu, Gd, Tb, Dy, Y, Ho, Er, and Lu); they are tetragonal, show the symmetry of space group P4/mmm, and do not appear to be superconducting.     

Talaromycins C,D,E,and F

Four new spiroketal talaromycins have been isolated from T. stipitatus and, by equilibration with acid, have been structurally correlated with the previously identified talaromycins A and B.     

Instrumental neutron activation determination of Pt, Ru, Ir, Sc, Cr, Fe, Co, La, Ce, Nd, Sm, Yb, Lu, Hf and Ta employing CIRUS reactor as a thermal neutron source

An accurate and simple method has been developed for the determination of Pt, Ru, Ir and other elements employing instrumental neutron activation analysis (INAA). Nondestructive analysis has been carried out for the determination of these elements in different rock samples such as Dolerite, Dyke Dolerite, Country Basalt, Hyaloclastite, Trachyte, Ijolite, Spillite, Diorite and Lamprophyre from various locations like Daman, Tapti, Murud, Talasari, Ranala and Bassein in Maharashtra state. High flux provided by the CIRUS reactor (1×10¹³ n cm^–2s^–1) has been used for thermal neutron bombardment followed by radioassaying of the (n,) products on a HPGe detector coupled to a PC-based MCA unit.     

Synthesis, FTIR, FT-Raman, UV-visible, ab initio and DFT studies on benzohydrazide

A systematic vibrational spectroscopic assignment and analysis of benzohydrazide (BH) has been carried out by using FTIR and FT-Raman spectral data. The vibrational analysis were aided by electronic structure calculations--ab initio (RHF) and hybrid density functional methods (B3LYP and B3PW91) performed with 6-31G(d,p) and 6-311++G(d,p) basis sets. Molecular equilibrium geometries, electronic energies, IR intensities, harmonic vibrational frequencies, depolarization ratios and Raman activities have been computed. Potential energy distribution (PED) and normal mode analysis have also been performed. The assignments proposed based on the experimental IR and Raman spectra have been reviewed and complete assignment of the observed spectra have been proposed. UV-visible spectrum of the compound was also recorded and the electronic properties, such as HOMO and LUMO energies and λ(max) were determined by time-dependent DFT (TD-DFT) method. The geometrical, thermodynamical parameters and absorption wavelengths were compared with the experimental data. The interactions of carbonyl and hydrazide groups on the benzene ring skeletal modes were investigated.     

Theoretical Study on the Structure and Stability of Si5X （X = Li, Be, B, C, N, O, F, Na, Mg, Al, Si, P, S, Cl） Clusters

1 INTRODUCTION In the later 60s of last century, silicon substituted for germanium to present as mainstream in semicon- ductor. The semi-conductive devices made by silicon have many advantages, for example, refractory pro- perty, high radioresistance, simple and stable process- ing technic, high machinability and low cost. So it was widely used to manufacture large power appara- tuses, for instance, digit and linear integrated circuit, large scale integrated circuit (LSI), etc. Thus, th…     

Theoretical study of dihydrogen bonds between (XH)2, X = Li, Na, BeH, and MgH, and weak hydrogen bond donors (HCN, HNC, and HCCH)

The dihydrogen-bonded (DHB) complexes formed by (XH)2, with X = Li, Na, BeH, and MgH, with one, two, and four protonic molecules (HCN, HNC, and HCCH) have been studied. These complexes have been compared to those of the XH monomers with the same hydrogen bond donor molecules. The energetic results have been rationalized based on the electrostatic potential of the isolated hydridic systems. The electron density properties have been analyzed within the AIM methodology, both at the bond critical points and the integrated values at the atomic basins. Exponential relationships between several properties calculated at the bond critical points (rho,nabla2rho, lambdai, G, and V) and variation of integrated properties (energy, charge, and volume) vs the DHB distance have been obtained.     

Preparation and properties of the MIIIU2O7.5 polyuranates (MIII = Y,Tb, Dy,Ho, Er,Tm, Yb,or Lu)

The novel compounds of the M^IIIU₂O_7.5 type (with M^III being yttrium or lanthanides from terbium to lutetium) have been prepared via hydrothermal synthesis from hydrated uranium(VI) oxide and aqueous solutions of M(III) nitrates at 200°C. Composition and structure of the products have been studied by means of elemental analysis, high-temperature X-ray diffraction, and IR spectroscopy; the products thermal stability has been estimated.     

Tunable Photochromism in the Robust Dithienylethene‐Containing Phospholes: Design,Synthesis, Characterization,Electrochemistry, Photophysics,and Photochromic Studies

A series of dithienylethene‐containing phosphole derivatives has been designed, synthesized and characterized. One of the compounds has been characterized by X‐ray crystallography. Upon photoexcitation, the compounds exhibit drastic color changes, ascribed to the reversible photochromic behavior. Their photochromic, photophysical and electrochemical properties have been studied. They show photochromic reactivities with high photocyclization quantum yields. Their photophysical and photochromic properties are found to be facilely tuned in this system by substitution at the phosphole backbone, as well as variation on the extent of π‐conjugation of the phosphole backbone. Some selected compounds have been demonstrated to exhibit photochromic properties in polymethylmethacrylate (PMMA) films.     

Study of geometry and electronic structure of molecules, cation-radicals, and anion-radicals of nitromethane, dimethylnitramine, and ethyl nitrate

The geometry of cation-radicals and anion-radicals of nitromethane, dimethylnitramine, and ethyl nitrate have been computed by means of modern quantum-chemical methods. Their electron affinities and ionization potentials have been determined. The validity of the results has been confirmed by comparison with the experiment.     

Transition metal chelates: Synthesis,physicochemical, thermal,and biological studies

The transition metal complex of Mn(II), Co(II), Ni(II), Cu(II), Ti(III), Cr(III), Fe(III), Zr(IV), and UO₂(VI) ion with a Schiff’s base ligand derived from 2-hydroxy-[2-oxo-1,2-dihydro-3H-indol-3-ylidene]-benzohydrazide have been prepared. The complexes have been characterized by elemental analysis data, IR and electronic absorption spectra, magnetic moments, and thermogravimetric analysis data. The complexes of the 1: 1 metal-to-ligand stoichiometry have been formed. The physico-chemical data have suggested the octahedral geometry for all the complexes except for Cu(II); the Cu(II) complex has been square planar. Thermal analysis data of the ligand and its complexes have been analyzed, and the kinetic parameters have been determined using the Horowitz–Metzger method. According to the solid-state electrical conductivity measurements, the ligand and its complexes are semiconducting in nature. The antimicrobial activity of the ligand and the complexes towards E. coli, S. typhi, P. aeruginosa, and S. aureus has been tested by the disc diffusion method.     

In situ study of electrocopolymerization of acrylamide,formaldehyde, and N,N′-methylenebisacrylamide

An apparatus and procedure for real-time in situ investigations of monomer electropolymerization in solution using optical microscopy with differential interference and phase contrast have been designed. The kinetics of electropolymerization of an acrylamide-formaldehyde monomer mixture in aqueous solution has been studied. An induction period of electropolymerization was fixed and evaluated for the first time. Growth of the polymer film after disconnection has been visualized. The dynamics of this phenomenon is evaluated, and possible reasons are discussed. Anisotropic mechanical stresses, arising in the polymer film during electropolymerization, have been found and characterized. The mechanism that is responsible for the formation of a dense near-cathode layer has been revealed. The formation of a zinc sublayer during electropolymerization has been examined. Reasons for the roughness of the near-electrode surface of the polymer film and for high adhesion of the electrodeposited polymer film to the metal have been established.     

2, 3, 5, 6-Tetrachlorpyridine-4-sulfenyl chloride

2,3,5,6-Tetrachloropyridine-4-sulfenyl chloride has been prepared, and its reactions with nucleophilic reagents have been examined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp 1232–1235, September, 1970.     

SYNTHESIS AND CRYSTAL STRUCTURE OF 5, 10, 15, 20, 22, 24-HEXAHYDRO-5, 5, 10, 10, 15, 15, 20, 20-OCTAMETHYL-PORPHINE

<正> The title com pound (HHOMP) has been synthesized with the pho-toinduced condensation of acetone and pyrrole in the presence of iodoaromatic hydrocarbons, and its molecular and crystal structures have been determined by X-ray analysis. C28H36N4, Mr = 428. 63, triclinic; space group P1; a =10. 165(3), b = 10. 185(2), c=13. 012(3)(?); α=85. 41(2), β=67. 84(2), γ= 89. 75(2)°; V = 1243 (?)3; Z = 2; D = 1. 145g. cm-3; μ= 0. 635cm-1; F (000) = 464. Although the HHOMP molecule twists, it is found that the four nitrogen atoms are still in a plane.     

Lacticin 3147--biosynthesis, molecular analysis, immunity, bioengineering and applications

The continuing problem of the emergence of multidrug resistance in pathogens has resulted in renewed efforts to identify novel antimicrobials that could be used in clinical settings. Lantibiotics are bacterially produced gene encoded antimicrobial peptides which have been the focus of extensive investigation in recent years because of their broad spectrum of activity. Lantibiotics (lanthionine-containing antibiotics), which have traditionally been regarded as antimicrobials for use in food or veterinary medicine, may provide at least part of the solution to these problems. Lacticin 3147 is a two peptide lantibiotic (consisting of the peptides Ltnα and Ltnβ) which is active at low concentrations against many pathogens. It has been the subject of extensive research, which has generated significant insights into the mechanisms of lacticin 3147 biosynthesis, immunity, structure function relationships and the consequences of molecular bioengineering. The merits of employing lacticin 3147 to control spoilage microbes as well as its potential in the elimination of food, human and veterinary pathogens have also been highlighted. Here we review the knowledge which has been gained with respect to lacticin 3147 since its discovery in 1995.     

1, 3, 4-Thiadiazole-2, 5-dithiol as a Complexing Agent II. Complexes of NiII,RhI, PdII,PtII, AuIII,and CuII

1, 3, 4-Thiadiazol-2, 5-Dithiol als Komplexierungsreagenz. II. Komplexe des Ni^II, Rh^I, Pd^II, Pt^II, Au^III und Cu^II Complexes of Ni^II, Rh^I, Pd^II, Pt^II, Au^III, and Cu^II with 1, 3, 4-thiadiazole-2, 5- dithiol have been prepared. Probable structures have been proposed for the complexes on the basis of chemical analysis, magnetic susceptibility and spectral data. Crystal field parameters have been calculated which are in keeping with the structures proposed.     

DFT Investigations(Geometry Optimization,UV/Vis,FT-IR,NMR, HOMO-LUMO,FMO, MEP,NBO, Excited States) and the Syntheses of New Pyrimidine Dyes

In the present work, the molecular structures of two new synthesized dyes:(4,6-dimethylpyrimidin-2-ylamino)(5-p-tolylisoxazol-3-yl)methanol(PS-1) and N-(4,6-dimethylpyrimidin-2-yl)-5-phenylisoxazole-3-carboxamide(PS-2), have been investigated using density functional theory(DFT) in dimethylformamide(DMF) for the first time. The electronic spectra of new dyes in a DMF solvent were carried out by time dependent density functional theory(TD-DFT) method. After quantum-chemical calculations two new dyes for the optoelectronic applications were synthesized. FT-IR spectra of the title compounds are recorded and discussed. NucleusIndependent Chemical Shifts(NICS) calculations have also been carried out for the title compounds. The computed absorption spectral data of the title compounds are in good agreement with the experimental data, thus allowing an assignment of the UV spectra. The HOMO and LUMO molecular orbitals, excitation energies and oscillator strengths for the dyes have also been calculated and presented.     

Preparation,purification, and analysis of alkylated cyclodextrins

Methods of alkylation of α-, β- and γ-cyclodextrins have been optimized with regard to the parameters of reaction, degree of alkylation and yields. The analysis of the reaction mixtures and of the isolated single species has been performed by high temperature GC and HPLC. The phase systems of the preferably applied HPLC have been carefully adjusted by variation of both the stationary and mobile phases to the very different hydrophobicities of the various alkylated CD species which have been synthesized. Several partially or fully alkylated CD species were isolated from preparative scale HPLC separations in high purity.