Topological characterisation of intermolecular lithium bonding
TL;DR: In this article, Bader's atoms in molecules topological theory were employed to analyse the B3LYP/6-311++G(3d2f,3p2d) electron distributions of several adducts that contain LiF.
Abstract: Bader’s atoms in molecules topological theory was employed to analyse the B3LYP/6-311++G(3d2f,3p2d) electron distributions of several adducts that contain LiF. The results indicate significant differences between lithium bonding (LB) and hydrogen bonding (HB): (i) in spite of their larger stability, the charge density at the intermolecular critical points of LB complexes is about half of its value in the corresponding HB complexes, suggesting a dominant role of electrostatic interactions in the former; (ii) the Li atom in LB compounds is more shared between the base atom and the attached fluorine than hydrogen in HB complexes; and (iii) the Li atom gains electron charge from the hydrogens in all the complexes here studied, undergoing energetic stabilisation.
TL;DR: A hopeful perspective of the application of Li bond in Li batteries is presented, which renders a comprehensive understanding ofLi bond inLi batteries and also an outlook of its future development.
Abstract: Lithium bonds are analogous to hydrogen bonds and are therefore expected to exhibit similar characteristics and functions. Additionally, the metallic nature and large atomic radius of Li bestow the Li bond with special features. As one of the most important applications of the element, Li batteries afford emerging opportunities for the exploration of Li bond chemistry. Herein, the historical development and concept of the Li bond are reviewed, in addition to the application of Li bonds in Li batteries. In this way, a comprehensive understanding of the Li bond in Li batteries and an outlook on its future developments is presented.
TL;DR: The hydrogen bond interaction and σ-hole and π-hole bonds are steered by the same mechanisms and the increase of the polarization of bonds to this centre seems to be the common effect.
Abstract: The hydrogen bond interaction and σ-hole and π-hole bonds are steered by the same mechanisms. There is electron charge transfer from the Lewis base to the Lewis acid unit, and further, for various interactions the same mechanisms try to protect the former electronic structure of the Lewis acid centre. The increase of the polarization of bonds to this centre seems to be the common effect. In the case of the A-HB hydrogen bond it is the increase of the polarization of the A-H bond connected with the outflow of the electron charge from the H-atom to the A-centre. For other interactions the outflow of electron charge from the Lewis acid centre is also observed. These electron charge shifts try to protect the doublet/octet structure of the acidic centre. The extremely strong interaction is often equivalent to the formation of new covalent bonds or it may lead to chemical reactions. Numerous interactions may be treated as the preliminary stages of chemical reactions: hydrogen bond - proton transfer, dihydrogen bond - molecular hydrogen release, tetrel bond - SN2 reaction, etc.
TL;DR: The results show that the electrostatic interaction plays an important role in the enhancement of halogen bond.
Abstract: Quantum chemical calculations have been performed to study the complex of MCN-LiCN-XCCH (M = H, Li, and Na; X = Cl, Br, and I). The aim is to study the cooperative effect between halogen bond and lithium bond. The alkali metal has an enhancing effect on the lithium bond, making it increased by 77 and 94% for the Li and Na, respectively. There is the cooperativity between the lithium bond and halogen bond. The former has a larger enhancing effect on the latter, being in a range of 11.7–29.4%. The effect of cooperativity on the halogen bond is dependent on the type of metal and halogen atoms. The enhancing mechanism has been analyzed in views with the orbital interaction, charge transfer, dipole moment, polarizability, atom charges, and electrostatic potentials. The results show that the electrostatic interaction plays an important role in the enhancement of halogen bond. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
TL;DR: The complexes H(2)C-LiX have been studied with quantum chemical calculations at the MP2/6-311++G(d,p) level and a new type of lithium bond was proposed, in which the carbene acts as the electron donor.
Abstract: The complexes H 2 C-LiX (X = H, OH, F, Cl, Br, CN, NC, CH 3 , C 2 H 3 , C 2 H, NH 2 ) have been studied with quantum chemical calculations at the MP2/6-31 1++G(d,p) level. A new type of lithium bond was proposed, in which the carbene acts as the electron donor. This new type of lithium bond was characterized in view of the geometrical, spectral and energetic parameters. The Li—X bond elongates in all lithium bonded complexes. The Li—X stretch vibration has a red shift in the complexes H 2 C-LiX (X = H, OH, F); however, it exhibits a blue shift in the complexes H 2 C-LiX (X = Cl, Br, CN, NC, CH 3 , C 2 H 3 , C 2 H, NH 2 ). The binding energies are in a range of 16.88—21.13 kcal/mol, indicating that the carbene is a good electron donor in the interaction. The energy decomposition analyses show that the electrostatic contribution is largest, polarization counterpart is followed, and charge transfer is smallest. The effect of substitution and hybridization on this type of lithium bond has also been investigated.
TL;DR: The natural bond orbital and atoms in molecules analyses indicate that the electrostatic force plays a main role in the lithium bonding and both the charge transfer and induction effect due to the electro static interaction are responsible for the cooperativity in the trimer.
Abstract: The lithium- and hydrogen-bonded complex of HLi-NCH-NCH is studied with ab initio calculations. The optimized structure, vibrational frequencies, and binding energy are calculated at the MP2 level with 6-311++G(2d,2p) basis set. The interplay between lithium bonding and hydrogen bonding in the complex is investigated with these properties. The effect of lithium bonding on the properties of hydrogen bonding is larger than that of hydrogen bonding on the properties of lithium bonding. In the trimer, the binding energies are increased by about 19% and 61% for the lithium and hydrogen bonds, respectively. A big cooperative energy (-5.50 kcal mol(-1)) is observed in the complex. Both the charge transfer and induction effect due to the electrostatic interaction are responsible for the cooperativity in the trimer. The effect of HCN chain length on the lithium bonding has been considered. The natural bond orbital and atoms in molecules analyses indicate that the electrostatic force plays a main role in the lithium bonding. A many-body interaction analysis has also been performed for HLi-(NCH)(N) (N=2-5) systems.
01 Jan 1950
13 Mar 1997
TL;DR: In this paper, the authors discuss the properties of strong and moderate hydrogen bonds in biological molecules and include inclusion of inclusion compounds in the graph set theory of graph set theories, which is used in this paper.
Abstract: 1. Brief History 2. Nature and Properties 3. Strong Hydrogen Bonds 4. Moderate Hydrogen Bonds 5. Weak Hydrogen Bonds 6. Cooperativity, Patterns, Graph Set Theory, Liquid Crystals 7. Disorder, Proton Transfer, Isotope Effect, Ferroelectrics, Transitions 8. Water, Water Dimers, Ices, Hydrates 9. Inclusion Compounds 10. Hydrogen Bonding in Biological Molecules 11. Methods
TL;DR: In this paper, a set of criteria are proposed based on the theory of "atoms in molecules" to establish hydrogen bonding, even for multiple interactions involving C-H-O hydrogen bonds.
Abstract: It is shown that the total charge density is a valid source to confirm hydrogen bonding without invoking a reference charge density. A set of criteria are proposed based on the theory of “atoms in molecules” to establish hydrogen bonding, even for multiple interactions involving C-H-O hydrogen bonds. These criteria are applied to several van der Waals complexes. Finally a bifurcated intramolecular C-H-O hydrogen bond is predicted in the anti-AIDS drug AZT, which may highlight a crucial feature of the biological activity of a whole class of anti-AIDS drugs. Almost all the methods of physical chemistry, spectroscopy, and diffraction can be used to recognize and study hydrogen bonding.] Each technique focuses on specific properties in order to detect and characterize this phenomenon in its own way. This work is concerned with the manifestation of hydrogen bonding in the charge density obtained from ab initio calculations. Whereas crystallographers have concluded upon hydrogen bonding via purely geometrical criteria, recent deformation density2 studies allow one to observe hydrogen bonding beyond mere ge~metry.~ However, it is not necessary to subtract an arbitrary (promolecular) charge density from the total density to reveal hydrogen bonding, not even in the interpretation of X-ray experiment^.^ Boyd and Choi have shown in two important contribution^^^^ that the theory of “atoms in molecules’’ (AIM)7,8 can be used to characterize hydrogen bonding solely from the (total) charge density for a large set of acceptor molecules, involving HF and HC1 as donors. In a next stage Carroll and Bader performed a more extended analysis on a large set of BASE-HF comple~es.~ This theory has not only provided new insights in conventional intermolecular hydrogenI0.’ ] bonding but has also been successful in intramolecularI33l4 and x-type hydrogen bonds.I5 Drawing from earlier ob~ervations~~~~ ~.’~~~~ and the present work, we formulate eight concerted effects occurring in the charge density which are indicative of hydrogen bonding. All of these effects can be viewed as necessary criteria to conclude that hydrogen bonding is present. By observation one of these conditions has proven to be sufficient as well. This case study on C-H-O interactions shows that this less common type of hydrogen bonding obeys all of the proposed criteria. Moreover, the multiple interactions appearing in the present five examples do not impair the consistency of the global phenomenon of hydrogen bonding as it expresses itself in the charge density. In spite of an early affirmative infrared review,I6 the old controversy on whether C-H-O hydrogen bonds really exist continued for another decade,” but now the dust has settled’* (for an entertaining account of this controversy, see ref 19). The importance of these bonds has been recognized in crystal engineering’9,20 since C-H-O contacts have a determining influence on packing motifs.21