A theoretical insight into several common anion recognitions based on double‐dentate hydrogen bond and anion‐π coexistence. (1st April 2019) - Liu, Yan‐Zhi
Abstract: Anion recognitions of a pincer‐like receptor ( N, N' ‐bis‐(2‐fluoro‐benzoyl‐oxyethyl)‐urea, AR) for several common inorganic anions (F −, Cl −, Br −, I −, CN −, and SO4 2− ) were theoretically explored and predicted at a molecular level in this paper. Geometric configurations of the complex (AR@X (X = F −, Cl −, Br −, and SO4 2− )) show that two N─H groups as a claw and two ─C6 H4 F rings on AR as a pair of tweezers simultaneously interact with the captured anions through cooperative double‐dentate hydrogen bond and double‐side anion‐π interactions. However, there is no anion‐π contact between AR and I − ion in AR@I − complex. In the system of AR@CN −, a stable single‐side CN − ‐π is possible. The structure of stable 2:1 complex formed with two AR receptors and one SO4 2− is also predicted. The binding energies and thermodynamic information indicate that the recognitions of the above six anions by AR in the vacuum are spontaneously enthalpy‐driven and entropy‐opposed. The binding energy Δ E cp between SO4 2− and AR is higher than 340 kJ mol −1, suggesting that AR is an ideal selective anion receptor for SO4 2− . Additionally, energy decomposition analysis based on localized molecular orbital energy decomposition analysis (LMO‐EDA) was performed. Electronic properties and behaviors of the present systems were further discussed according to calculations on frontier molecular orbital, UV‐ vis spectra, and visualized weak interaction regions. Abstract : The coexistence of double‐dentate hydrogen bond and anion‐π interactions between common anion (F −, Cl −, Br −, I −, CN −, and SO4 2− ) and N, N' ‐ bis ‐(2‐fluoro‐benzoyl‐oxyethyl)‐urea are investigated at a molecular level by using density functional theory (DFT) computation. This work would be helpful for understanding anion recognition mechanism and design of novel urea analogous derivative receptors of anion.