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Imino Group (imino + group)

Distribution by Scientific Domains
Chemistry100%

Selected Abstracts

Role of Imino Group in Photochemical Reactions of Fischer Carbene Complexes.

CHEMINFORM, Issue 25 2006
Pedro J. Campos
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source]

Excited State Intramolecular Proton Transfer of New Diphenyl- ethylene Derivatives Bearing Imino Group: A Combination of Experimental and Theoretical Investigation

CHINESE JOURNAL OF CHEMISTRY, Issue 7 2010
Fang Gao
Abstract In this paper, we described the synthesis and characterization of new diphenylethylene bearing imino group. We concentrated particularly on the investigation of the possibility of the excited state intramolecular charge transfer (ESIPT) of the new dyes experimentally and theoretically. The absorption and fluorescence spectroscopy of the dyes were determined in various solvents. The results showed that the maximal absorption wavelength of 2-[(4,- N,N -dimethylamino-diphenylethylene-4-ylimino)methyl]phenol (C1) and 4-[(4,- N,N -dimethylamino-diphenylethylene-4-ylimino)methyl]phenol (C2) exhibited almost independence on the solvent polarity. While as contrast, the maximal fluorescence wavelength of the dyes showed somewhat dependence on the solvent polarity. In particular, C1 displayed well-separated dual fluorescence spectroscopy. The second fluorescence peak was characterized with an "abnormal" fluorescence emission wavelength in aprotic solvents with large Stokes shift (ca. 140 nm in THF), which was much more than normal Stokes shift (ca. 30 nm in THF). This emission spectroscopy could be assigned to ESIPT emission. On the other hand, the ESIPT fluorescence of C1 was much reduced or lost in the protic solvents. While, only normal fluorescence emission was detected in various solvents. Although the absorption maxima of C1 exhibited about 10 nm red-shift with respect to those of C2, the normal fluorescence maxima of C1 and C2 were almost identical in various solvents. These results suggested that C1 could undergo ESIPT, but C2 was not able to proceed ESIPT. The molecular geometry optimization of phototautomers in the ground electronic state (S0) was carried out with HF method (Hartree-Fock) and at DFT level (Density Functional Theory) using B3LYP both, while the CIS was employed to optimize the geometries of the first singlet excited state (S1) of the phototautomers of C1 and C2 respectively. The properties of the ground state and the excited state of the phototautomers of C1 and C2, including the geometrical parameter, the energy, the frontier orbits, the Mulliken charge and the dipole moment change were performed and compared completely. The data were analyzed further based on our experimental results. Furthermore, the absorption and fluorescence spectra were calculated in theory and compared with the measured ones. The rate constant of internal proton transfer (9.831×1011 s,1) of C1 was much lower than that of salicylidene methylamine (C3, 2.045×1015 s,1), which was a typical Schiff base compound and was well demonstrated to undergo ESIPT easily under photoexcitation. [source]

Polymerization of methyl methacrylate using bis(,-ketoamino)nickel(II),MAO catalytic systems

APPLIED ORGANOMETALLIC CHEMISTRY, Issue 4 2006
Xiaohui He
Abstract The polymerization of methyl methacrylate (MMA) was investigated using a series of bis(,-ketoamino)nickel(II) complexes in combination with methylaluminoxane in toluene solution. The binary catalyst is necessary for initiating MMA polymerization and producing PMMA with high molecular weights but broad molecular weight distributions. The effects of reaction temperature and Al:Ni molar ratios on the polymerization of MMA were examined in detail. Both steric bulk and electronic effects of the substituents around the imino group in the ligand on MMA polymerization activities could be observed. Relative to electronic effects, the steric hindrance of the ligands displayed a more significant effect on the catalytic activities, with the catalytic activity sequence observed in the order 4 > 1 > 2 > 3 > 5 > 6. Structural analyses of the polymers by 13C NMR spectra indicate that polymerization yields PMMA with a syndiotactic-rich atactic microstructure. Copyright © 2006 John Wiley & Sons, Ltd. [source]

N -Carboxy- l -phenyl­alanine anhydride

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2000
Hitoshi Kanazawa
The mol­ecules of the title compound, 4-benzyl-1,3-oxazolidene-2,5-dione, C10H9NO3, are linked by intermolecular hydrogen bonds between the imino group of the five-membered ring and an adjacent carbonyl O-atom, along the c axis. The benzyl groups are stacked in a layer and the five-membered rings are arranged in another layer sandwiched by the benzyl group layer. This sandwich structure should explain the high polymerizability of the title compound in the solid state. [source]

Excited State Intramolecular Proton Transfer of New Diphenyl- ethylene Derivatives Bearing Imino Group: A Combination of Experimental and Theoretical Investigation

CHINESE JOURNAL OF CHEMISTRY, Issue 7 2010
Fang Gao
Abstract In this paper, we described the synthesis and characterization of new diphenylethylene bearing imino group. We concentrated particularly on the investigation of the possibility of the excited state intramolecular charge transfer (ESIPT) of the new dyes experimentally and theoretically. The absorption and fluorescence spectroscopy of the dyes were determined in various solvents. The results showed that the maximal absorption wavelength of 2-[(4,- N,N -dimethylamino-diphenylethylene-4-ylimino)methyl]phenol (C1) and 4-[(4,- N,N -dimethylamino-diphenylethylene-4-ylimino)methyl]phenol (C2) exhibited almost independence on the solvent polarity. While as contrast, the maximal fluorescence wavelength of the dyes showed somewhat dependence on the solvent polarity. In particular, C1 displayed well-separated dual fluorescence spectroscopy. The second fluorescence peak was characterized with an "abnormal" fluorescence emission wavelength in aprotic solvents with large Stokes shift (ca. 140 nm in THF), which was much more than normal Stokes shift (ca. 30 nm in THF). This emission spectroscopy could be assigned to ESIPT emission. On the other hand, the ESIPT fluorescence of C1 was much reduced or lost in the protic solvents. While, only normal fluorescence emission was detected in various solvents. Although the absorption maxima of C1 exhibited about 10 nm red-shift with respect to those of C2, the normal fluorescence maxima of C1 and C2 were almost identical in various solvents. These results suggested that C1 could undergo ESIPT, but C2 was not able to proceed ESIPT. The molecular geometry optimization of phototautomers in the ground electronic state (S0) was carried out with HF method (Hartree-Fock) and at DFT level (Density Functional Theory) using B3LYP both, while the CIS was employed to optimize the geometries of the first singlet excited state (S1) of the phototautomers of C1 and C2 respectively. The properties of the ground state and the excited state of the phototautomers of C1 and C2, including the geometrical parameter, the energy, the frontier orbits, the Mulliken charge and the dipole moment change were performed and compared completely. The data were analyzed further based on our experimental results. Furthermore, the absorption and fluorescence spectra were calculated in theory and compared with the measured ones. The rate constant of internal proton transfer (9.831×1011 s,1) of C1 was much lower than that of salicylidene methylamine (C3, 2.045×1015 s,1), which was a typical Schiff base compound and was well demonstrated to undergo ESIPT easily under photoexcitation. [source]