Two-photon, carbon-13 and two-dimensional proton NMR spectroscopic studies of retinyl Schiff bases, protonated Schiff bases and Schiff base salts: evidence for a protonation induced .pi..pi.* excited state level ordering reversal

1987 ◽  
Vol 109 (7) ◽  
pp. 2090-2101 ◽  
Author(s):  
Robert R. Birge ◽  
Lionel P. Murray ◽  
Raphael Zidovetzki ◽  
Henry M. Knapp
Keyword(s):  
Schiff Base ◽  
Excited State ◽  
Schiff Bases ◽  
Proton Nmr ◽  
State Level ◽  
Spectroscopic Studies ◽  
Two Dimensional ◽  
Two Photon

Femtosecond Spectroscopic Studies of the One- and Two-Photon Excited-State Dynamics of 2,2,17,17-Tetramethyloctadeca-5,9,13-trien-3,7,11,15-tetrayne:  A Trimeric Oligodiacetylene

2006 ◽  
Vol 110 (40) ◽  
pp. 11435-11439 ◽  
Author(s):  
Grzegorz M. Balkowski ◽  
Michiel Groeneveld ◽  
Hong Zhang ◽  
Cindy C. J. Hendrikx ◽  
Michael Polhuis ◽  
...  
Keyword(s):  
Excited State ◽  
Spectroscopic Studies ◽  
Excited State Dynamics ◽  
Two Photon ◽  
The One

scholarly journals Mössbauer Spectroscopic Studies of Molecule-Based Magnets: Two-Dimensional Complexes Derived from Metal Schiff-Bases and Hexacyanoferrate(III)

2002 ◽  
Vol 57 (6-7) ◽  
pp. 603-606 ◽  
Author(s):  
S. Iijima ◽  
F. Mizutani ◽  
H. Miyasaka ◽  
N. Matsumoto ◽  
H. Ōkawa
Keyword(s):  
Long Range ◽  
Schiff Bases ◽  
Applied Field ◽  
Variable Temperature ◽  
Magnetic Ordering ◽  
Spectroscopic Studies ◽  
Paramagnetic State ◽  
Two Dimensional ◽  
Mössbauer Measurements

Variable-temperature 57Fe Mössbauer measurements on cyanide-bridged 2-D bimetallic assemblies NEt4[Mn(salen)]2[Fe(CN)6] (1), K[Mn(3-MeOsalen)]2[Fe(CN)6] (2) and K[Mn(3- MeOsalen)]2[Fe(CN)6]2 DMF (3), where salen2- = N,N'-ethylenebis(salicylidene iminato) dianion, revealed that these compounds exhibit a long range magnetic ordering below ca. 10 K under zero applied field. The quadrupole splittings of 1 - 3 showed intermediate values between those of typical cyano-bridged 1-D and 3-D complexes. The paramagnetic state of K[Mn(5-Clsalen)]2- [Fe(CN)6] 4 H2O (4) turned to a bulk magnetic one with desolvation

STUDY OF THE S1 AND S2 EXCITED STATES OF GAS-PHASE PROTONATED SCHIFF BASE RETINAL CHROMOPHORES IN ONE AND TWO PHOTON ABSORPTION

2011 ◽  
Vol 10 (02) ◽  
pp. 121-132 ◽  
Author(s):  
YUANZUO LI ◽  
PENG SONG ◽  
YING SHI ◽  
YONG DING ◽  
FENGJIE ZHOU ◽  
...  
Keyword(s):  
Schiff Base ◽  
Excited State ◽  
Charge Transfer ◽  
Gas Phase ◽  
Excited States ◽  
Density Functional ◽  
Three Dimensional ◽  
Photon Absorption ◽  
Two Photon ◽  
The One

The S1 and S2 excited states of gas-phase protonated Schiff base retinal chromophores in the one- and two-photon absorptions (TPAs) are investigated with time-dependent density functional theory. In one-photon absorption, the two-dimensional (2D) site and three-dimensional (3D) cube representations reveal that S1 and S2 excited states of gas-phase protonated Schiff base retinal chromophores are all charge transfer excited states. To better study the weak S2 excited states of gas-phase protonated Schiff base retinal chromophores, we investigated theoretically excited state properties of them in TPA. For 11-cis dimethyl retinal, it is found that the cross section of S2 excited state is 51.04 GM in PTA, which is only slightly smaller than that of S1 (77.04 GM) in TPA. Therefore, the S2 excited state of 11-cis dimethyl retinal can be clearly observed in TPA experiment. The 2D site and 3D cube representations reveal that electronic transition from S1 to S2 excited state of gas-phase protonated Schiff base retinal chromophores in TPA are also of charge transfer character.

Magnetic and spectroscopic studies on nickel(II) and copper(II) complexes of some neutral tridentate ONS ligands

1980 ◽  
Vol 58 (7) ◽  
pp. 727-732 ◽  
Author(s):  
M. Akbar Ali
Keyword(s):  
Schiff Base ◽  
Schiff Bases ◽  
Elemental Analysis ◽  
Room Temperature ◽  
Chelating Agents ◽  
Spectroscopic Studies ◽  
Chloro Complex ◽  
Octahedral Structure ◽  
Schiff Base Ligands ◽  
Hydrolysis Of

New Schiff base ligands formed from 2-methoxybenzaldehyde and 2,4-dimethoxybenzaldehyde with N-methyl-S-alkyldithiocarbazates and their nickel(II) and copper(II) complexes have been prepared and characterised by elemental analysis and magnetic and spectroscopic measurements. The Schiff bases behave as neutral tridentate chelating agents forming stable nickel(II) complexes of stoichiometry NiLX2•xC2H5OH (L = 2-methoxy- or 2,4-dimethoxybenzaldehyde Schiff bases of N-methyl-S-methyldithiocarbazate; X = I−, SCN−; x = 0, 1). Conductivity, magnetic, and spectral data support an octahedral structure for the nickel(II) complexes. The CuLCl2 complexes were also isolated. Magnetic and spectral evidence are in accord with a chloro-bridged dimeric structure. The chloro-complex of copper(II) with the 2-methoxybenzaldehyde Schiff base displays a room-temperature magnetic moment of 1.81 BM, which remains virtually constant over the temperature range 343–123 K.Hydrated copper(II) chloride promotes complete hydrolysis of the 2,4-dimethoxybenzaldehyde and 2-methoxybenzaldehyde Schiff bases of N-methyl-S-benzyldithiocarbazate with the concomitant formation of copper(II) complexes of the parent N-methyl-S-benzyldithiocarbazate of general formula, Cu(N—SR)Cl2 (R = C6H5CH2—).

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