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DFT Study for a Series of Less‐Symmetrical Crown Ethers and Their Complexes with Alkali Metal Cations
Author(s) -
Miao Yuan,
Wang Xueye,
Jin Xin,
Yi Ling,
Ren Cuihuan
Publication year - 2010
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.201090307
Subject(s) - chemistry , crown ether , alkali metal , density functional theory , methylene , homo/lumo , computational chemistry , ring (chemistry) , crown (dentistry) , crystallography , molecular geometry , molecule , medicinal chemistry , organic chemistry , ion , medicine , dentistry
A series of ring‐contracted (14‐crown‐5, 17‐crown‐6) and ring‐enlarged (16‐crown‐5, 17‐crown‐5, 19‐crown‐6, 20‐crown‐6) crown ethers and their complexes with alkali‐metal cations Na + and K + had been explored using density functional theory (DFT) at B3LYP/6‐31G* level in order to reveal the effects of the methylene‐chain length in a crown ether. The nucleophilicity of all crown ethers had been investigated by the Fukui functions. The quantum chemistry parameters, such as the energy gap (Δ E ), the highest occupied molecular orbital energy ( E HOMO ) and the lowest unoccupied molecular orbital energy ( E LUMO ) for less‐symmetrical crown ethers and symmetrical frameworks (15‐crown‐5, 18‐crown‐6) had been calculated. In addition, the thermodynamic energies of complexation reactions had also been studied. The results of the DFT calculations show that the methylene‐chain length plays an important role in determining the structure characters of the crown ethers and also strongly influences the properties of the ethers. Some of the calculated results are in a good agreement with the experimental values.