Prediction and characterization of the HMgH⋯LiX (X = H, OH, F, CCH, CN, and NC) complexes: a lithium–hydride lithium bond

Abstract

In the present paper, a new type of lithium bonding complex HMgHLiX (X = H, OH, F, CCH, CN, and NC) has been predicted and characterized. Their geometries (C(infinityv)) with all real harmonic vibrational frequencies were obtained using the second-order Møller-Plesset perturbation theory (MP2) with 6-311++G(d,p) basis set. For each HMgHLiX complex, a lithium bond is formed between the negatively charged H atom of an HMgH molecule and the positively charged Li atom of an LiX molecule. Due to the formation of the complexes, the Mg-H and Li-H bonds are elongated. Interestingly, the Li-X harmonic vibrational stretching frequency is blueshifted in the HMgHLiX (Y = CCH, CN, and NC) complexes and redshifted in the HMgHLiX (X = H, OH, and F) complexes. The binding energy of this type of lithium bond ranges from 12.18 to 15.96 kcal mol(-1), depending on the chemical environment of the lithium. The nature of lithium-hydride lithium bond has also been analyzed with natural bond orbital (NBO) and atoms in molecules (AIM).

Interplay between halogen bond and lithium bond in MCN‐LiCN‐XCCH (M = H, Li, and Na; X = Cl, Br, and I) complex: The enhancement of halogen bond by a lithium bond

“…The abnormal phenomenon was also observed in other lithium-bonded complexes. [32][33][34] McDowell and Marcellin [46] studied this anomalous correlation of bond extension with blue shift using a model derived from perturbation theory, and thought that the large dipole moment of F 3 CLi produces substantial bond extension, whereas the repulsion between the core electrons of the Li atom and the electrons of the bonding partner produces the blue shift of the stretching frequency. The distant C-Li bond in LiCN-XCCH dyad shows a small red shift, which is consistent with the bond elongation.…”

“…Lithium bonding (LB) is one of the strongest intermolecular interactions and it is much stronger than hydrogen bonding. [32][33][34] In this article, we thus constructed HCN-LiCN-XCCH (X ¼ Cl, Br, I) complex where lithium bonding and halogen bonding coexist. To further enhance the halogen bonding, we also designed MCN-LiCN-XCCH (M ¼ Li and Na) complex.…”

Theoretical Study of the Interplay between Lithium Bond and Hydrogen Bond in Complexes Involved with HLi and HCN

“…[22,23] The singleelectron lithium bonded complexes H 3 C···LiY(Y=H, F, OH, CN, NC, and CCH) were predicted and characterized with theoretical methods. [24] Very recently, we proposed a new kind of lithium bond, [25] in which HMgH acts as the electron donor like that in dihydrogen bond. These studies show that lithium bonds have similar characteristics with hydrogen bonds although the electrostatic force is bigger in the lithium bonds.…”

Effect of cooperativity in lithium bonding on the strength of halogen bonding and tetrel bonding: (LiCN)n···ClYF3 and (LiCN)n···YF3Cl (Y= C, Si and n = 1–5) complexes as a working model

“…Lithium bonding (LB) is one of the strongest intermolecular interactions and it is much stronger than hydrogen bonding [57,58]. Therefore, in the present work, we designed (LiCN) n ···ClYF 3 and (LiCN) n ···YF 3 Cl (n=1-5 and Y= C, Si) complexes where lithium bonding, halogen bonding, and tetrel bonding are present simultaneously.…”

“…To date, lithium bonds have been identified in a variety of systems and the concept of lithium bonding has become important in many fields. However, studies on LB interactions are relatively rare [20][21][22].…”