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Hai-Bei Li

Bio: Hai-Bei Li is an academic researcher from Shandong University. The author has contributed to research in topics: Hydrogen bond & Lewis acids and bases. The author has an hindex of 7, co-authored 13 publications receiving 350 citations.

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TL;DR: The energy decomposition analysis highlights the importance of the electrostatic interaction in the formation of the tetrel Bond, although the dispersion part is also non-negligible for the weak tetrel bond.
Abstract: A single-electron tetrel bond was predicted and characterized in FXH3⋯CH3 (X = C, Si, Ge, and Sn) complexes by performing quantum chemical calculations, where the methyl radical acts as the Lewis base and the σ-hole on the X atom in FXH3 as the Lewis acid. The interaction between the methyl radical and FXH3 is characterized by a red shift of F–X stretching frequency. The strength of the tetrel bond becomes stronger by not only increasing the atomic number of the central atom X (X = C, Si, Ge, and Sn) but also by enhancing the electron-withdrawing ability of substituents in the Lewis acid. The energy decomposition analysis highlights the importance of the electrostatic interaction in the formation of the tetrel bond, although the dispersion part is also non-negligible for the weak tetrel bond. There is a competition between the formation of single-electron tetrel bonds and hydrogen bonds for the complexes composed of the methyl radical and CNCH3 or NCCH3. Furthermore, the single-electron tetrel bond exhibits the cooperative effect not only with the hydrogen bond in the complex of NCH⋯NCCH3⋯CH3, but also with the conventional tetrel bond in NCCH3⋯NCCH3⋯CH3.

115 citations

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TL;DR: A tetrel-hydride interaction was predicted and characterized in the complexes of XH3F···HM at the MP2/aug-cc-pVTZ level and NBO analyses demonstrate that both BD(H-M) → BD*(X-F) and BD-M → BD-H) orbital interactions play the stabilizing role in the formation of the complex.
Abstract: A tetrel–hydride interaction was predicted and characterized in the complexes of XH3F···HM (X = C, Si, Ge, Sn; M = Li, Na, BeH, MgH) at the MP2/aug-cc-pVTZ level, where XH3F and HM are treated as the Lewis acid and base, respectively. This new interaction was analyzed in terms of geometrical parameters, interaction energies, and spectroscopic characteristics of the complexes. The strength of the interaction is essentially related to the nature of X and M groups, with both the larger atomic number of X and the increased reactivity of M giving rise to a stronger tetrel–hydride interaction. The tetrel–hydride interaction exhibits similar substituent effects to that of dihydrogen bonds, where the electron-donating CH3 and Li groups in the metal hydride strengthen the binding interactions. NBO analyses demonstrate that both BDH–M → BD*X–F and BDH–M → BD*X–H orbital interactions play the stabilizing role in the formation of the complex XH3F···HM (X = C, Si, Ge, and Sn; M = Li, Na, BeH, and MgH). The major contr...

80 citations

Journal ArticleDOI
TL;DR: The complexes of XH3F⋯N3-/OCN-/SCN- (X = C, Si, Ge, and Sn) have been investigated at the MP2/aug-cc-pVTZ(PP) level and the tetrel bond in the complexes exhibits a significant degree of covalency with Xh3F distorted significantly in these complexes.
Abstract: The complexes of XH3F⋯N3−/OCN−/SCN− (X = C, Si, Ge, and Sn) have been investigated at the MP2/aug-cc-pVTZ(PP) level. The σ-hole of X atom in XH3F acts as a Lewis acid forming a tetrel bond with pseudohalide anions. Interaction energies of these complexes vary from −8 to −50 kcal/mol, mainly depending on the nature of X and pseudohalide anions. Charge transfer from N/O/S lone pair to X–F and X–H σ* orbitals results in the stabilization of these complexes, and the former orbital interaction is responsible for the large elongation of X–F bond length and the remarkable red shift of its stretch vibration. The tetrel bond in the complexes of XH3F (X = Si, Ge, and Sn) exhibits a significant degree of covalency with XH3F distorted significantly in these complexes. A breakdown of the individual forces involved attributes the stability of the interaction to mainly electrostatic energy, with a relatively large contribution from polarization. The transition state structures that connect the two minima for CH3Br⋯N3− c...

67 citations

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TL;DR: The cyano groups adjoined to the fulvene ring not only cause a change in the interaction type, from vdW interactions in the unsubstituted system of –OCF3 to carbon bonding, but also greatly strengthen tetrel bonding.
Abstract: Carbon bonding is a weak interaction, particularly when a neutral molecule acts as an electron donor. Thus, there is an interesting question of how to enhance carbon bonding. In this paper, we found that the –OCH3 group at the exocyclic carbon of fulvene can form a moderate carbon bond with NH3 with an interaction energy of about −10 kJ/mol. The –OSiH3 group engages in a stronger tetrel bond than does the –OGeH3 group, while a reverse result is found for both –OSiF3 and –OGeF3 groups. The abnormal order in the former is mainly due to the stronger orbital interaction in the –OSiH3 complex, which has a larger deformation energy. The cyano groups adjoined to the fulvene ring not only cause a change in the interaction type, from vdW interactions in the unsubstituted system of –OCF3 to carbon bonding, but also greatly strengthen tetrel bonding. The formation of tetrel bonding has an enhancing effect on the aromaticity of the fulvene ring.

39 citations

Journal ArticleDOI
Meng Gao1, Qingzhong Li1, Hai-Bei Li2, Wenzuo Li1, Jianbo Cheng1 
TL;DR: In this article, an anisotropic distribution of molecular electrostatic potentials on the Au and X atoms was analyzed and two types of structures, represented as GB and XB, respectively, were obtained.
Abstract: An Au⋯X interaction has been predicted in the complexes between the organic gold compound RAu (R = CH3, C2H3, and C2H) and the organic halogen compound R′X (R′ = CH3, C2H, C2H3, and CF3; X = Cl, Br, and I) using quantum chemical calculations. Upon the basis of the anisotropic distribution of molecular electrostatic potentials on the Au and X atoms, two types of structures, represented as GB and XB, respectively, were obtained. In the GB structure, the Au atom acts as a Lewis acid and X is a Lewis base, but reversed roles are found for Au and X in XB. Interestingly, the former structure is far more stable than the latter one. Their difference in stability can be regulated by the substitution and hybridization effects, similarly to those in hydrogen bonds. The partially covalent-interaction nature of GBs was characterized with the large charge transfer and the negative energy density as well as the high interaction energy. GB interaction is dominated by electrostatic and polarization energies, whereas electrostatic and dispersion energies are responsible for the stability of most XB complexes. This is an interesting finding that both patterns of interactions are different in nature even though the two monomers are only different in the spatial orientation for both interactions.

20 citations


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TL;DR: The physical nature of σ- and π-hole interactions is described, a selection of inquiries that utilise ρ- andπ-holes are presented, and an overview of analyses of structural databases (CSD/PDB) that demonstrate how prevalent these interactions already are in solid-state structures are given.
Abstract: Non-covalent interactions play a crucial role in (supramolecular) chemistry and much of biology. Supramolecular forces can indeed determine the structure and function of a host–guest system. Many sensors, for example, rely on reversible bonding with the analyte. Natural machineries also often have a significant non-covalent component (e.g. protein folding, recognition) and rational interference in such ‘living’ devices can have pharmacological implications. For the rational design/tweaking of supramolecular systems it is helpful to know what supramolecular synthons are available and to understand the forces that make these synthons stick to one another. In this review we focus on σ-hole and π-hole interactions. A σ- or π-hole can be seen as positive electrostatic potential on unpopulated σ* or π(*) orbitals, which are thus capable of interacting with some electron dense region. A σ-hole is typically located along the vector of a covalent bond such as XH or XHlg (X=any atom, Hlg=halogen), which are respectively known as hydrogen and halogen bond donors. Only recently it has become clear that σ-holes can also be found along a covalent bond with chalcogen (XCh), pnictogen (XPn) and tetrel (XTr) atoms. Interactions with these synthons are named chalcogen, pnigtogen and tetrel interactions. A π-hole is typically located perpendicular to the molecular framework of diatomic π-systems such as carbonyls, or conjugated π-systems such as hexafluorobenzene. Anion–π and lone-pair–π interactions are examples of named π-hole interactions between conjugated π-systems and anions or lone-pair electrons respectively. While the above nomenclature indicates the distinct chemical identity of the supramolecular synthon acting as Lewis acid, it is worth stressing that the underlying physics is very similar. This implies that interactions that are now not so well-established might turn out to be equally useful as conventional hydrogen and halogen bonds. In summary, we describe the physical nature of σ- and π-hole interactions, present a selection of inquiries that utilise σ- and π-holes, and give an overview of analyses of structural databases (CSD/PDB) that demonstrate how prevalent these interactions already are in solid-state structures.

501 citations

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TL;DR: High-level ab initio calculations show that the interaction of the π-electrons with the CH3X molecules leads to the formation of X-C···π carbon bonds.
Abstract: High-level ab initio calculations have been used to study the interactions between the CH3 group of CH3X (X = F, Cl, Br, CN) molecules and π-electrons. These interactions are important because of the abundance of both the CH3 groups and π-electrons in biological systems. Complexes between C2H4/C2H2 and CH3X molecules have been used as model systems. Various theoretical methods such as atoms in molecules theory, reduced density gradient analysis, and natural bond orbital analysis have been used to discern these interactions. These analyses show that the interaction of the π-electrons with the CH3X molecules leads to the formation of X–C···π carbon bonds. Similar complexes with other tetrel molecules, SiH3X and GeH3X, have also been considered.

109 citations

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TL;DR: A theoretical study of the cooperativity in linear chains of ( H3SiCN)n and (H3SiNC)n complexes connected by tetrel bonds has been carried out by means of MP2 and CCSD(T) computational methods, and positive cooperativity is obtained.
Abstract: A theoretical study of the cooperativity in linear chains of (H3SiCN)n and (H3SiNC)n complexes connected by tetrel bonds has been carried out by means of MP2 and CCSD(T) computational methods. In all cases, a favorable cooperativity is observed, especially in some of the largest linear chains of (H3SiNC)n, where the effect is so large that the SiH3 group is almost equidistant to the two surrounding CN groups and it becomes planar. In addition, the combination of tetrel bonds with other weak interactions (halogen, chalcogen, pnicogen, triel, beryllium, lithium, and hydrogen bond) has been explored using ternary complexes, (H3SiCN)2:XY and (H3SiNC)2:XY. In all cases, positive cooperativity is obtained, especially in the (H3SiNC)2:ClF and (H3SiNC)2:SHF ternary complexes, where, respectively, halogen and chalcogen shared complexes are formed.

100 citations

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TL;DR: The tetrel bond is strengthened as the T atom moves further down the periodic table column, and the strongest bond amounts to 25.5 kcal/mol for SnF4··NH3.
Abstract: Quantum calculations are used to examine the properties of heterodimers formed by a series of tetrel-containing molecules with NH3 as universal Lewis base. TH4 was taken as a starting point, with T = C, Si, Ge, and Sn. The H atoms were replaced by various numbers of F atoms—TH3F, TF3H, and TF4—so as to monitor the effects of adding electron-withdrawing substituents. Unsubstituted TH4 molecules form the weakest tetrel bonds, only up to about 2 kcal/mol. The bond is strengthened when the H opposite NH3 is replaced by F, rising up to the 6–9 kcal/mol range. Another means of strengthening arises when the three peripheral H atoms of TH4 are replaced by F. The effect of the latter is heavily dependent on the nature of the T atom and is particularly noticeable for larger tetrels. The two sorts of fluorination patterns are cooperative, in that their combination in TF4 yields by far the most powerful tetrel bonding agent. The tetrel bond is strengthened as the T atom moves further down the periodic table column. T...

98 citations

Journal ArticleDOI
TL;DR: There is competition between the hydrogen and hydrogen bonds in the protonated complexes, in which the hydrogen bond is favored in the complexes of H+-p-PyCF3 but the tetrel bond is preferred in thecomplexs of H-o/m-PySiF3 and H--o-Py SiF3.
Abstract: Ab initio calculations have been performed for the complexes H+–PyTX3⋯NH3 and H+–furanTF3⋯NH3 (T = C, Si, and Ge; X = F and Cl) with focus on geometries, energies, orbital interactions, and electron densities to study the influence of protonation on the strength of tetrel bonding. The primary interaction mode between α/β-furanCF3/p-PyCF3 and NH3 changes from an F⋯H hydrogen bond to a C⋯N tetrel bond as a result of protonation. Importantly, the protonation has a prominent enhancing effect on the strength of tetrel bonding with an increase in binding energy from 14 to 30 kcal mol−1. The tetrel bonding becomes stronger in the order H+–p-PySiF3⋯NH3 < H+–m-PySiF3⋯NH3 < H+–o-PySiF3⋯NH3, showing a reverse trend from that of the neutral analogues. In addition, there is competition between the tetrel and hydrogen bonds in the protonated complexes, in which the hydrogen bond is favored in the complexes of H+–p-PyCF3 but the tetrel bond is preferred in the complexes of H+–p-PyTX3 (T = Si, Ge; X = F, Cl) and H+–o/m-PySiF3.

93 citations