Giant Dipole Moments: Remarkable Effect of Single Solvent Molecules on 5, 6- Diaminobenzene-1,2,3,4-Tetracarbonnitrile

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 $14.1\pm 0.7$ debye in THF. Gas phase DFT computations do not fully reflect this ultrastrong dipole moment, demonstrating the role of solvent in increasing this dipole. 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 gas the 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 \textsc{Psi4}. These are additionally compared to the dipole moments predicted with SMD models at the B3LYP/aug-cc-pVTZ level of theory. The dissociation energy, HOMO-LUMO energy gaps, and dipole moments are presented. These metrics show the nh1nh1\emprime THF system (Figure \ref{THF Structures}.b) 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.