An Interacting Quantum Atoms (IQA) and Relative Energy Gradient (REG) Study of the Halogen Bond with Explicit Analysis of Electron Correlation

Author(s)

Alkorta, Ibon ^[1] ; Silva, Arnaldo F. ^{[2, 3]} ; Popelier, Paul L. A. ^{[2, 3]}

Affiliation

^[1] Inst Quim Med CSIC, Juan Cierva 3, Madrid 28006 - Spain

^[2] Univ Manchester, Dept Chem, Oxford Rd, Manchester M13 9PL, Lancs - England

^[3] Manchester Inst Biotechnol MIB, 131 Princess St, Manchester M1 7DN, Lancs - England

• Document type: Journal article
• Source: Molecules; v. 25, n. 11 JUN 2020.
• Web of Science Citations: 0

Abstract

Energy profiles of seven halogen-bonded complexes were analysed with the topological energy partitioning called Interacting Quantum Atoms (IQA) at MP4(SDQ)/6-31 + G(2d,2p) level of theory. Explicit interatomic electron correlation energies are included in the analysis. Four complexes combine X-2 (X = Cl or F) with HCN or NH3, while the remaining three combine ClF with HCN, NH3 or N-2. Each complex was systematically deformed by translating the constituent molecules along its central axis linking X and N, and reoptimising its remaining geometry. The Relative Energy Gradient (REG) method (Theor. Chem. Acc.2017, 136, 86) then computes which IQA energies most correlate with the total energy during the process of complex formation and further compression beyond the respective equilibrium geometries. It turns out that the covalent energy (i.e., exchange) of the halogen bond, X...N, itself drives the complex formation. When the complexes are compressed from their equilibrium to shorter X...N distance then the intra-atomic energy of N is in charge. When the REG analysis is restricted to electron correlation then the interatomic correlation energy between X and N again drives the complex formation, and the complex compression is best described by the destabilisation of the through-space correlation energy between N and the ``outer{''} halogen. (AU)

• FAPESP's process: 14/21241-9 - The inclusion of polarization effects in the description of amino acids and peptides through the use of atomic multipoles obtained from electron densities
• Grantee: Arnaldo Fernandes da Silva Filho
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 15/22247-3 - Using the Quantum Chemical Topology theory for modeling force fields for peptides using electron densities
• Grantee: Arnaldo Fernandes da Silva Filho
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor