Spectroscopy, NMR and DFT studies on molecular recognition of crown ether bridged chiral heterotrinuclear salen Zn(II) complex
| Autor: | Wen-Juan Ruan, Jia-Mei Chen, Ying-Hui Zhang, Zhi-Ang Zhu, Feng Gao |
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| Rok vydání: | 2005 |
| Předmět: |
Circular dichroism
Magnetic Resonance Spectroscopy Denticity Molecular Conformation DABCO Analytical Chemistry Supramolecular assembly chemistry.chemical_compound Molecular recognition Computational chemistry Crown Ethers Imidazole Instrumentation Spectroscopy Crown ether chemistry.chemical_classification Circular Dichroism Titrimetry Stereoisomerism Ethylenediamines Atomic and Molecular Physics and Optics Zinc Crystallography Models Chemical chemistry Barium Proton NMR Spectrophotometry Ultraviolet |
| Zdroj: | Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy. 62:886-895 |
| ISSN: | 1386-1425 |
| DOI: | 10.1016/j.saa.2005.03.021 |
| Popis: | A barium-containing crown ether bridged chiral heterotrinuclear salen Zn(II) complex BaZn2L(ClO4)2, where L is a folded dinuclear chiral (R,R)-salen ligand, has been synthesized and characterized by elemental analysis, 1H NMR, UV–vis, IR, circular dichroism (CD) spectra, and mass spectra. As a folded dinuclear chiral host, its recognition with achiral guests (imidazole derivatives), rigid bidentate guest (1,4-diazobicyclo[2,2,2]octane, DABCO) and chiral guests (amino acid methyl esters) was investigated by means of UV–vis spectrophotometric titration, CD spectra. The association constants of d -amino acid methyl esters are found to be higher than those of their l -enantiomer. The sandwich-type binding of BaZn2L(ClO4)2–DABCO supramolecular assembly was specially studied via 1H NMR titration and 1H ROESY. To understand the recognition on molecular level, density functional theory (DFT) calculations on B3LYP/LanL2DZ were performed on the minimal energy conformations of host, guests, and host–guest complexes. The minimal energy conformations were obtained by molecular mechanics (MM) optimization and molecular dynamics (MD) simulation. The results of single point energy, HOMO energy, and charges transfer were analyzed. The results of theoretical calculations are in good agreement with the experimental data. |
| Databáze: | OpenAIRE |
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