Hydrogen Bond and Ligand Dissociation Dynamics in Fluoride Sensing of Re(I)鈥揚olypyridyl Complex

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• 作者：Sandeep Verma ; Sunil Aute ; Amitava Das ; Hirendra N. Ghosh
• 刊名：Journal of Physical Chemistry B
• 出版年：2015
• 出版时间：November 25, 2015
• 年：2015
• 卷：119
• 期：47
• 页码：14952-14958
• 全文大小：368K
• ISSN：1520-5207

文摘

Hydrogen bonding interaction plays an essential role in the early phases of molecular recognition and colorimetric sensing of various anions in aprotic media. In this work, the host鈥揼uest interaction between fac-[Re(CO)₃Cl(L)] with L = 4-([2,2鈥?bipyridin]-4-yl)phenol and fluoride ions is investigated for the hydrogen bond dynamics and the changing local coordination environment. The stoichiometric studies using ¹H NMR and ESI-MS spectroscopies have shown that proton transfer in the H-bonded phenol鈥揻luoride complex activates the dissociation of the CO ligand in the Re(I) center. The phenol-to-phenolate conversion during formation of HF₂^{鈥?/sup> ion induces nucleophilic lability of the CO ligand which is probed by intraligand charge transfer (ILCT) and ligand-to-metal charge transfer (LMCT) transitions in transient absorption spectroscopy. After photoexcitation, phenol鈥損henoxide conversion rapidly equilibrates in 280 fs time scale and the ensuing excited state [ReII(bpy鈥?sup>鈥?/sup>鈥攑henolate炉) (CO)₃Cl]* undergoes CO dissociation in the ultrafast time scale of 鈭? ps. A concerted mechanism of hydrogen cleavage and coordination change is established in anion sensing studies of the rhenium complex.}