First-Principles Crystal Engineering Of Nonlinear Optical Materials. Ii. Effect Of Halogen Bonds On The Structure And Properties Of Triiodobenzenes

Abstract

Recently, we proposed a computational design strategy for organic nonlinear optical materials, based on the global minimization of lattice energy to predict the crystal packing from the first principles. Here, we validate this strategy on triiodobenzenes, which include CH···I hydrogen and I···I halogen bonding as the structure-determining components of their intermolecular interactions. To refine the van der Waals (vdW) parameters for an I atom, the ab initio potential surfaces for the model dimers were calculated at the CCSD(T)/cc-pVTZ + CP theory level. The hydrogen bond C-H···I was found to have an interaction energy of -0.5 kcal/mol. The I···I contact of type I (140°-140°) was found to be attractive with a well depth of -0.4 kcal/mol at a 4.6 Å distance, whereas type II contact (180°-90°) was found to be nearly twice more attractive. Its potential well depth reaches -0.7 kcal/mol at an I···I distance of 4.4 Å. These binding energies are therefore weaker than that of the typical hydrogen bonds. The AMOEBA force-field vdW parameters were fit to describe these interactions and used to predict the crystal structures. Our structure prediction, followed by density functional theory - many-body dispersion ranking established the noncentrosymmetric crystal packing to be the global minimum, in agreement with the experimental data. The coupled perturbed Kohn-Sham approach was used to estimate nonlinear susceptibility, and the predicted values were compared to that of the urea standard. The statistical analysis of the angular distribution for the I···I contacts in the predicted virtual polymorphs was compared to that found among the experimental crystal structures of iodoaromatic compounds. In both cases, symmetric (type I) contacts dominate for shorter and longer I···I distances, whereas L-shaped (type II) contacts are preferred for intermediate distances.

Publication Date

10-4-2018

Publication Title

Journal of Physical Chemistry C

Volume

122

Issue

39

Number of Pages

22622-22631

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1021/acs.jpcc.8b04932

Socpus ID

85054165105 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/85054165105

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