Cytosine in Context:  A Theoretical Study of Substituent Effects on the Excitation Energies of 2-Pyrimidinone Derivatives

2007 ◽  
Vol 111 (35) ◽  
pp. 8708-8716 ◽  
Author(s):  
Kurt A. Kistler ◽  
Spiridoula Matsika
Keyword(s):  
Theoretical Study ◽  
Substituent Effects ◽  
Excitation Energies

A theoretical study on solvatofluorochromic asymmetric thiazolothiazole (TTz) dyes using dielectric-dependent density functional theory

2021 ◽  
Vol 23 (37) ◽  
pp. 21078-21086
Author(s):  
Tomomi Shimazaki ◽  
Masanori Tachikawa
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Theoretical Study ◽  
Dye Molecules ◽  
Excitation Energies ◽  
Functional Theory ◽  
Dependent Density

In this work, the excitation energies of asymmetric thiazolothizaole (TTz) dye molecules have been theoretically studied using dielectric-dependent density functional theory (DFT).

Theoretical study of substituent effects. Analysis of steric repulsion by means of paired interacting orbitals

1989 ◽  
Vol 54 (11) ◽  
pp. 2568-2573 ◽  
Author(s):  
Hiroshi Fujimoto ◽  
Yoshitaka Mizutani ◽  
Jun Endo ◽  
Yasuhisa Jinbu
Keyword(s):  
Theoretical Study ◽  
Substituent Effects ◽  
Steric Repulsion

Experimental and Theoretical Study of Substituent Effects of Iodonitrobenzenes

2007 ◽  
Vol 111 (40) ◽  
pp. 10105-10110 ◽  
Author(s):  
Li Yao ◽  
Lin Du ◽  
Maofa Ge ◽  
Chunping Ma ◽  
Dianxun Wang
Keyword(s):  
Theoretical Study ◽  
Substituent Effects

Theoretical Analysis of the Unusual Vicinal Effects on Electronic Circular Dichroism Spectra of Cobalt(III) Complexes with ED3A-Type and Related Ligands

2014 ◽  
Vol 69 (7) ◽  
pp. 371-384
Author(s):  
Yuekui Wang ◽  
Chunxia Zhang
Keyword(s):  
Circular Dichroism ◽  
Optical Activity ◽  
Density Functional ◽  
Substituent Effects ◽  
Basis Set ◽  
Excitation Energies ◽  
Electronic Circular Dichroism ◽  
Special Cases ◽  
Circular Dichroïsm ◽  
Optimized Geometries

To investigate the origin of unusual N-vicinal effects, the geometries of the two series of cobalt(III) complexes, [Co(ED3A-type)(X)]-(X = CN-, NO2-) and [Co(EDDS-type)]-, with the pentadentate ethylenediamine-N;N;N0-triacetate (ED3A), hexadentate (S,S)-ethylenediamine-N;N0-dissuccinate (EDDS), and their N-alkyl-substituted ligands in aqueous solution have been optimized at the DFT/B3P86/6-311++G(2d,p) level of theory. Based on the optimized geometries, the excitation energies and rotational strengths have been calculated using the time dependent density functional theory (TDDFT) method with the same functional and basis set. The optimized geometries and calculated electronic circular dichroism (ECD) curves are in good agreement with the observed ones. Based on this agreement, the characteristics of usual and unusual N-vicinal effects as well as the related chiral stereochemistry phenomena have been discussed. To reveal the origin of the unusual N-vicinal effects, a novel calculation scheme has been proposed, which permits efficiently assessing the contribution of the octahedral core to the optical activities of the chelates. The results show that the substituent effects and conformational relaxation effects make opposite contributions to the overall N-vicinal effects with the former being dominant. The unusual N-vicinal effects originate from the negligible chirality of the octahedral core in the unsubstituted [Co(ED3A)(X)]-chelates. For this reason, their optical activity is dominated by the asymmetric nitrogens and behaves different from the normal cases. The unusual vicinal effects observed in the N-alkyl-substituted ED3A-type chelates reflect an increase in the contribution of the octahedral core to their optical activity, which recovers the ECD spectra from the special cases to the normal ones. These findings provide some insight into the unusual N-vicinal effects as well as the chiroptical properties of the chelates.

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