Tuning the Competition between Hydrogen and Tetrel Bonds by a Magnesium Bond |
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Authors: | Dr Mingchang Hou Yifan Zhu Qingzhong Li Prof Steve Scheiner |
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Institution: | 1. Laboratory of Theoretical and Computational Chemistry and School of Chemistry and Chemical Engineering, Yantai University, Yantai, 264005 China;2. Department of Chemistry and Biochemistry, Utah State University, Logan, UT 84322-0300 USA |
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Abstract: | A computational study of the complexes formed by TF3OH (T=C, Si, Ge) with three nitrogen-containing bases NCH, NH3, and imidazole (IM) is carried out at the MP2/aug-cc-pVTZ level. TF3OH can participate in two different types of noncovalent interactions: a hydrogen bond (HB) involving the hydroxyl proton and a tetrel bond (TB) with the tetel atom T. The strength of the HB is largely unaffected by the identity of T while the TB is enhanced as T grows larger. The HB is preferred over the TB for most systems, with the exception of GeF3OH with either NH3 or IM. MgCl2 engages in a Mg⋅⋅⋅O Magnesium bond (Mg-bond) with the TF3OH O atom, which cooperatively enhances both the HB and TB. The HB strengthening is particularly large for the NH3 or IM bases, and especially for CF3OH, but is slowly reduced as the T atom grows larger. The TB enhancement, on the other hand, behaves in the opposite fashion, accelerating for the larger T atoms. As a bottom line, the Mg-bond generally reinforces and accentuates the preference for the HB or TB that is already present in the dimer. The Mg-bond is also responsible for a proton transfer in the HB configurations with NH3 and IM. |
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Keywords: | cooperativity deformation energy molecular electrostatic potential noncovalent interactions proton transfer |
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