Insight into the nature of the interactions of furan and thiophene with hydrogen halides and lithium halides: ab initio and QTAIM studies

Abstract

The nature of the interactions of furan and thiophene with hydrogen halides and lithium halides has been investigated using ab initio calculations and QTAIM analysis. The concept of molecule formation density difference (MFDD) is introduced to study weak hydrogen bond (HB) and lithium bond (LB) interactions. The results have shown the molecular electrostatic potentials of furan and thiophene, as well as of the hydrogen halides and lithium halides, determine the geometries of the complexes. Both the studied HB and LB interactions can be classified as "closed-shell" weak interactions. The topological properties and energy properties at the bond critical points of HB and LB have been shown to be exponentially dependent on intermolecular distances d(H-bond) and d(Li-bond), which enables interpretation of the strength of the HB and LB interactions in terms of these ρ(r) properties. Electron transfer plays a more important role in the formation of HB than in that of LB, while electrostatic interaction in LB is more dominant than that in HB.

Characterizing Traditional and Chlorine-Shared Halogen Bonds in Complexes of Phosphine Derivatives with ClF and Cl2

“…The electron densities at the BCPs (ρ BCP ) in the chlorine-shared complexes are large, with values between 0.081 and 0.147 au. An excellent exponential relationship with a correlation coefficient of 0.999 is found between ρ BCP and the P–Cl distance, in agreement with previous reports that show similar relationships for other intermolecular interactions. − All H 2 XP:ClF complexes and the two chlorine-shared complexes H 2 (OH)P:Cl 2 and H 2 FP:Cl 2 with the shortest intermolecular distances have negative values of the total energy density H BCP and the Laplacian. The negative values of these two parameters are indicative of the partial covalent character of the P···Cl interaction.…”

Dual-Regulation Strategy to Improve Anchoring and Conversion of Polysulfides in Lithium–Sulfur Batteries

“…However, the peak at approximately 684.8 eV corresponding to LiF products of the decomposition of LiTFSI was not observed for the cathodes containing OFN (CNTs–S/Gh/OFN, CNTs–S/Gh/FePc+OFN) and was only detected in the CNTs–S/Gh and CNTs–S/Gh/FePc spectra, suggesting that OFN might regulate the interface reaction . Additionally, the peaks in the Li 1s spectra of the CNTs–S/Gh/OFN and CNTs–S/Gh/FePc+OFN cathodes were significantly shifted to a lower field compared with those of the CNTs–S/Gh/FePc and CNTs–S/Gh cathodes, as observed in Figure b, which is attributed to the electron transfer from the F atom of OFN to Li + (or LiPSs) that results in Li-bond formation, namely, the formation of the Li···F bond, according to previous reports. − Since the electronegativity of F (3.98) is higher than Li (0.98), a Li-bond (Li···F) can be formed according to Lewis acid–base theory. , The F atom in OFN with extra electron pairs, as an electron-rich donor, naturally serves as a Lewis base site and interacts with a strong Lewis acid of terminal Li in LiPSs. The Li–F bond in typical LiF compounds is an ionic bond, which is formed by electrostatic attraction between cations and anions.…”

“…42−44 Since the electronegativity of F (3.98) is higher than Li (0.98), a Li-bond (Li•••F) can be formed according to Lewis acid−base theory. 43,44 The F atom in OFN with extra electron pairs, as an electron-rich donor, naturally serves as a Lewis base site and interacts with a strong Lewis acid of terminal Li in LiPSs. The Li−F bond in typical LiF compounds is an ionic bond, which is formed by electrostatic attraction between cations and anions.…”

Interfacial Molecule Mediators in Cathodes for Advanced Li–S Batteries

“…In addition, the peak at 686.4 eV associated with LiF in the CNTs/S/TFPP spectrum is almost nonexistent, meaning that the F–Li bonds in this system were different from those in typical LiF compounds. The Li spectrum (Figure B) contains a peak attributed to TFPP that has a distinct low-field shift, suggesting the existence of lithium bonds. − This result together with the EIS analyses above (Figure ) confirms that the F in the TFPP undergoes strong chemical anchoring to LiPSs species to accelerate Li + transport between low-chain and high-chain sulfides at the interface, which in turn retards the degradation of the interface during cycling. ,, In the high-resolution S 2p spectra (Figure C), the S–P interaction peak appears at 163.9 eV in the case of those cathodes having small molecules, and the peak produced by CNTs/S/TFPP is stronger than those generated by the other two cathodes with meditators (CNTs/S/TPP and CNTs/S/TPPO). These data suggest the presence of powerful S–P interactions in CNTs/S/TFPP, which may accelerate the catalytic conversion of polysulfides.…”