Isolation and characterization of conformational isomers of N,N′‐bis(3,5‐dichlorosalicylidene)‐2,2′‐ethylenedianiline: crystal structure,photoluminescence, and density functional theory calculation |
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Authors: | Kil Sik Min Yoon Jae Kim Hyun Jin Ko Dae Hyun Kwak Tae Wook Kim Jong Won Shin Bong Gon Kim |
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Affiliation: | 1. Department of Chemistry Education and Green‐Nano Materials Research Center, Kyungpook National University, , Daegu, 702‐701 Korea;2. Daegu Science High School, , Daegu, 706‐852 Korea;3. Department of Chemistry, Graduate School and Green‐Nano Materials Research Center, Kyungpook National University, , Daegu, 702‐701 Korea;4. Department of Chemistry Education, Gyeongsang National University, , Jinju, 660‐701 Korea |
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Abstract: | We have isolated two isomeric solids 1 and 2 of N,N′‐bis(3,5‐dichlorosalicylidene)‐2,2′‐ethylenedianiline and characterized by IR, UV/Vis, X‐ray powder diffraction, thermogravimetric analysis/differential thermal analysis, and X‐ray crystallography. Although the solids are same formulas, each shows different colors and crystal structures. Orange solid ( 1 ) shows endo conformation while yellow solid ( 2 ) exhibits exo form depending on packing modes. UV/Vis spectra of 1 and 2 appear very similar patterns in the solid state; however, the bands of 1 are slightly red‐shifted compared with those of 2 . 1 displays a strong fluorescent emission band at ~582 nm while 2 shows an intense fluorescent signal at ~563 nm. The charge density populations of 1 and 2 have been studied by computational simulations using density functional theory at pbe1pbe/6‐311G** level. The calculated highest occupied molecular orbital and lowest unoccupied molecular orbital energies of 1 and 2 confirm that charge transfer occurs within the organic molecules. The energy difference of HOMO‐LUMO in 1 is smaller slightly than that of 2 about 0.05 eV (~17 nm). Copyright © 2014 John Wiley & Sons, Ltd. |
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Keywords: | density functional theory fluorescence isomer organic ligand structure π ‐π interaction |
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