Spectroscopic, Structural, and Theoretical Studies of Halide Complexes with a Urea-Based Tripodal Receptor
摘要:
A urea-based tripodal receptor L substituted with p-cyanophenyl groups has been studied for halide anions using H-1 NMR spectroscopy, density functional theory (DFT) calculations, and X-ray crystallography. The H-1 NMR titration studies suggest that the receptor forms a 1:1 complex with an anion, showing a binding trend in the order of fluoride > chloride > bromide > iodide. The interaction of a fluoride anion with the receptor was further confirmed by 2D NOESY and F-19 NMR spectroscopy in DMSO-d(6). DFT calculations indicate that the internal halide anion is held by six NH center dot center dot center dot X interactions with L, showing the highest binding energy for the fluoride complex. Structural characterization of the chloride, bromide, and silicon hexafluoride complexes of [LH+] reveals that the anion is externally located via hydrogen bonding interactions. For the bromide or chloride complex, two anions are bridged with two receptors to form a centrosymmetric dimer, while for the silicon hexafluoride complex, the anion is located within a cage formed by six ligands and two water molecules.
Seven-coordinate anion complex with a tren-based urea: Binding discrepancy of hydrogen sulfate in solid and solution states
作者:Avijit Pramanik、Bethtrice Thompson、Trina Hayes、Kimberly Tucker、Douglas R. Powell、Peter V. Bonnesen、Erick D. Ellis、Ken S. Lee、Hongtao Yu、Md. Alamgir Hossain
DOI:10.1039/c1ob05052d
日期:——
Structural characterization of a hydrogen sulfate complex with a tren-based urea suggests that the anion is coordinated with six NH⋯O bonds (dN⋯O = 2.857 (3) to 3.092 (3) Å) and one OH⋯O bond (dO⋯O = 2.57 (2) Å) from three receptors; however, in solution the anion is bound within the pseudo-cavity of one receptor.
Spectroscopic, Structural, and Theoretical Studies of Halide Complexes with a Urea-Based Tripodal Receptor
作者:Avijit Pramanik、Douglas R. Powell、Bryan M. Wong、Md. Alamgir Hossain
DOI:10.1021/ic202747q
日期:2012.4.2
A urea-based tripodal receptor L substituted with p-cyanophenyl groups has been studied for halide anions using H-1 NMR spectroscopy, density functional theory (DFT) calculations, and X-ray crystallography. The H-1 NMR titration studies suggest that the receptor forms a 1:1 complex with an anion, showing a binding trend in the order of fluoride > chloride > bromide > iodide. The interaction of a fluoride anion with the receptor was further confirmed by 2D NOESY and F-19 NMR spectroscopy in DMSO-d(6). DFT calculations indicate that the internal halide anion is held by six NH center dot center dot center dot X interactions with L, showing the highest binding energy for the fluoride complex. Structural characterization of the chloride, bromide, and silicon hexafluoride complexes of [LH+] reveals that the anion is externally located via hydrogen bonding interactions. For the bromide or chloride complex, two anions are bridged with two receptors to form a centrosymmetric dimer, while for the silicon hexafluoride complex, the anion is located within a cage formed by six ligands and two water molecules.