Effects of substituent and solvent on the structure and spectral properties of maleimide derivatives |
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Authors: | Chin-Kuen Tai Yih-Jiun Lin Pao-Ling Yeh Yi-Ren Tzeng Yu-Ma Chou Bo-Cheng Wang |
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Institution: | aDepartment of Chemistry, Tamkang University, Tamsui 251, Taiwan;bInstitute of Nuclear Energy Research (INER), Taiwan;cDepartment of Physics, Chinese Culture University, Taipei 110, Taiwan |
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Abstract: | The maximum absorption wavelength , emission wavelength (λem) and the related oscillator strength (f) of the maleimides in the ground and first excited states were calculated by using the DFT, CIS and the time-dependent density functional theory (TD-DFT) methods, where the molecular structures were optimized by DFT/B3LYP/6-31G* calculation. Solvent effects on the maleimides were examined using the PCM simulation at DFT/B3LYP level with the 6-31G* basis set. For N-substituted maleimide, the substituent gives only a slight influence on the maleimide chromophore, while planar conformation of PhMLH leads to the improvement in π-delocalization from substituent to maleimide unit. For 3,4-substituted maleimide, the steric repulsion between substituent and maleimide chromophore influences the extent of π-delocalization and the molecular conformation. The calculated and λem of maleimides are in good agreement with the experimental data. In the gas phase, both absorption and emission peaks are red-shift as compared to the non-substituted maleimide. Under solvent environment, the more planar conformation of PhMLH shows a blue-shift in the calculated and λem as compared with other N-substituted maleimides. For 3,4-substituted maleimides, the effect of substitution produces the most significant spectral red-shift as compared to other maleimides. |
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Keywords: | PCM simulation Density functional theory BLA Maleimide derivatives Substituted effect |
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