# Giant Dipole Moments: Remarkable Effects Mono‐, Di‐, and Tri‐ Hydrated 5,6‐Diaminobenzene‐1,2,3,4‐Tetracarbonnitrile

## TL;DR

This paper explores how solvent molecules affect the dipole moment of a compound called MOI, showing that solvent placement significantly influences its properties.

## Contribution

The study reveals how solvent positioning impacts ultrastrong dipole moments, offering insights for designing macromolecules with MOI-like subunits.

## Key findings

- Solvent placement significantly increases the dipole moment of MOI, with THF showing the largest effect.
- Monohydrated MOI achieves a dipole moment of 14.2 Debye, close to the solvated value in THF.
- Hydrogen bonding in THF systems leads to higher dissociation energies and dipole moments.

## Abstract

The molecule 5,6‐diaminobenzene‐1,2,3,4‐tetracarbonnitrile (MOI) was first synthesized by Müllen and coworkers in 2016 and boasts an ultrastrong dipole moment of 14.1±0.7 Debye in THF. Gas phase DFT computations do not fully reflect this ultrastrong dipole moment, demonstrating the role of solvent in increasing this dipole moment. Here, we investigate the effect of solvent molecule position on the dipole moment of this species, computationally examining systems with giant dipole moments. These systems are optimized in the gas phase with the B3LYP functional, employing the aug‐cc‐pVTZ and def2‐TZVP basis sets, as well as the B3LYP‐D3BJ/aug‐cc‐pVTZ functional in Orca. Single point DLPNO‐CCSD/aug‐cc‐pVDZ results were obtained from Orca and Psi4, as well as DLPNO‐CCSD(T)/CBS information from Psi4. Additionally, these are compared to the dipole moments of di‐ and tri‐hydrated systems, and the SMD models for THF and water at the B3LYP/aug‐cc‐pVTZ level of theory. The dissociation energies, HOMO‐LUMO energy gaps, and dipole moments are presented. These metrics show the nh1nh1′ THF system boasts the largest dissociation energy and dipole moment of the singly solvated systems, due to its strong hydrogen bonding. The importance of solvent placement is highlighted and may guide the synthesis of macromolecules or organic frameworks incorporating the MOI or MOI‐like subunits. Remarkably, a single solvent molecule provides a good model for the difference between the gas phase and solvated species. The predicted gas phase dipole moments computed with B3LYP/aug‐cc‐pVTZ for the MOI, its monohydrated complex, dihydrated complex, and its trihydrated complex are 9.6, 14.2, 16.0, and 16.8 Debye, respectively.

Solvent placement has a significant impact on the dipole moment of neutral species, which is especially important in the case of ultrastrong dipole moments. Using water and THF, the dissociation energies, relative energies, HOMO‐LUMO gaps, dihedral angles, and dipole moments of 5,6‐diaminobenzene‐1,2,3,4‐tetracarbonnitrile are accessed.