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991.
992.
Barbara A. Leasher 《代数通讯》2013,41(14):5355-5368
993.
994.
Vita Surzhko Thierry Roisnel Barbara Le Grel Philippe Le Grel Claudia Lalli Gilles Argouarch 《Tetrahedron letters》2017,58(13):1343-1347
A set of picolinohydrazides was prepared by reaction between hydrazines and either 2-picolinic acid or ethyl pyridine-2-carboxylate, and characterized. These molecules were evaluated as ligands in the zinc-catalyzed hydrosilylation of ketones. Thus, several aromatic and aliphatic ketones were successfully reduced by diethoxymethylsilane as the hydride source in the presence of a catalytic system made of diethylzinc combined in situ to the picolinohydrazides described herein. 相似文献
995.
Bankiewicz Barbara Wojtulewski Sławomir Markiewicz Karolina H. Wilczewska Agnieszka Z. 《Structural chemistry》2017,28(3):801-812
Structural Chemistry - The structural studies of carbamohydrazonothioate derivative and its hydrochloride solvate are the aim of hereunder presented research. The combination of the... 相似文献
996.
997.
Brena B Puglia C de Simone M Coreno M Tarafder K Feyer V Banerjee R Göthelid E Sanyal B Oppeneer PM Eriksson O 《The Journal of chemical physics》2011,134(7):074312
The electronic structure of iron phthalocyanine (FePc) in the valence region was examined within a joint theoretical-experimental collaboration. Particular emphasis was placed on the determination of the energy position of the Fe 3d levels in proximity of the highest occupied molecular orbital (HOMO). Photoelectron spectroscopy (PES) measurements were performed on FePc in gas phase at several photon energies in the interval between 21 and 150 eV. Significant variations of the relative intensities were observed, indicating a different elemental and atomic orbital composition of the highest lying spectral features. The electronic structure of a single FePc molecule was first computed by quantum chemical calculations by means of density functional theory (DFT). The hybrid Becke 3-parameter, Lee, Yang and Parr (B3LYP) functional and the semilocal 1996 functional of Perdew, Burke and Ernzerhof (PBE) of the generalized gradient approximation (GGA-)type, exchange-correlation functionals were used. The DFT/B3LYP calculations find that the HOMO is a doubly occupied π-type orbital formed by the carbon 2p electrons, and the HOMO-1 is a mixing of carbon 2p and iron 3d electrons. In contrast, the DFT/PBE calculations find an iron 3d contribution in the HOMO. The experimental photoelectron spectra of the valence band taken at different energies were simulated by means of the Gelius model, taking into account the atomic subshell photoionization cross sections. Moreover, calculations of the electronic structure of FePc using the GGA+U method were performed, where the strong correlations of the Fe 3d electronic states were incorporated through the Hubbard model. Through a comparison with our quantum chemical calculations we find that the best agreement with the experimental results is obtained for a U(eff) value of 5 eV. 相似文献
998.
Roberto Centore Antonio Roviello Angela Tuzi Barbara Panunzi 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(1):m26-m28
The title compounds, {5‐(dimethylamino)‐2‐[N‐(4‐methoxyphenyl)iminomethyl]phenyl}[N‐(4‐methoxyphenyl)‐4‐nitrosalicylaldiminato]palladium(II), [Pd(C14H11N2O4)(C16H17N2O)], (I), and [4‐(diethylamino)‐N‐(4‐methoxyphenyl)salicylaldiminato]{2‐[N‐(4‐methoxyphenyl)iminomethyl]‐5‐nitrophenyl}palladium(II) dichloromethane hemisolvate, [Pd(C14H11N2O3)(C18H21N2O2)]·0.5CH2Cl2, (II), both contain push–pull chromophores coordinated to Pd in a square‐planar arrangement. In both compounds, the five‐membered orthopalladated ring is essentially planar, while the coordinated six‐membered ring is not. Deviations from a coplanar arrangement of the phenylene rings of the coordinated Schiff bases are observed in both (I) and (II) as a result of intramolecular steric interactions. 相似文献
999.
Eva Jedlovsk Lubor Fiera Albert Lvai Gbor Tth Barbara Balzs 《Journal of heterocyclic chemistry》1999,36(4):1087-1090
The regio- and stereoselective synthesis of spiropyrazolines 7 and 8 via 1,3-dipolar cycloaddition of C-2-(5-nitrofuryl)-N-methylnitrilimine, C-2-(5-nitrofuryl)-N-phenylnitrilimine and C-4-nitrophenyl-N-methyl-nitrilimine to (E)-3-benzylidenechromanone (1), -1-thiochromanone 2, -1-tetralone 3 and (E)-3-benzylidene-flavanone (4) is reported. The relative configuration and conformations of the spiropyrazolines were elucidated by various nmr methods. 相似文献
1000.
Quici S Cavazzini M Marzanni G Accorsi G Armaroli N Ventura B Barigelletti F 《Inorganic chemistry》2005,44(3):529-537
The synthesis of a new ligand (1) containing a single phenanthroline (phen) chromophore and a flexibly connected diethylenetriamine tetracarboxylic acid unit (DTTA) as a lanthanide (Ln) coordination site is reported [1 is 4-[(9-methyl-1,10-phenantrol-2-yl)methyl]-1,4,7-triazaheptane-1,1,7,7-tetraacetic acid]. From 1, an extended series of water-soluble Ln.1 complexes was obtained, where Ln is Eu(III), Tb(III), Gd(III), Sm(III), Dy(III), Pr(III), Ho(III), Yb(III), Nd(III), and Er(III). The stoichiometry for the association was found 1:1, with an association constant K(A) > or = 10(7) s(-1) as determined by employing luminescence spectroscopy. The luminescence and photophysical properties of the series of lanthanide complexes were investigated in both H2O and D2O solutions. High efficiencies for the sensitized emission, phi(se), in air-equilibrated water were observed for the Ln.1 complexes of Eu(III) and Tb(III) in the visible region (phi(se) = 0.24 and 0.15, respectively) and of Sm(III), Dy(III), Pr(III), Ho(III), Yb(III), Nd(III), and Er(III) in the vis and/or near-infrared region [phi(se) = 2.5 x 10(-3), 5 x 10(-4), 3 x 10(-5), 2 x 10(-5), 2 x 10(-4), 4 x 10(-5), and (in D2O) 4 x 10(-5), respectively]. For Eu.1 and Tb.1, luminescence data for water and deuterated water allowed us to estimate that no solvent molecules (q) are bound to the ion centers (q = 0). Luminescence quenching by oxygen was investigated in selected cases. 相似文献