Solvent influence on the optical absorption, frontier molecular orbitals, and electronic structure of 1-bromo...

The study of the influence of solvent on 1-bromo adamantane (BAD) exposes prominent solvatochromatic shifts in the optical absorbance and substantial solvent effects on the electronic structure. This facilitates the molecular probe abilities for the BAD with respect to the surrounding environments such as dielectric constant and polarity. BAD exhibits positive solvatochromism for nonpolar solvents and negative solvatochromatic shifts for polar and aromatic solvents. In accordance with this, significant energy changes are obtained on the orbital occupancies of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO), resulting in a large difference in energy among the various solvation environments. According to this, the HOMO-LUMO gap decreases in nonpolar solvents, and it increases with respect to polarity in the case of polar and aromatic solvents. Computed thermodynamic parameters and noncovalent interaction analysis also demonstrate the noticeable changes for different solvent dielectric continuums with more changes for solvent continuums with large dielectric constants.

Experimentally recorded UV-Vis absorption spectra of the solvents exhibit positive and negative solvatochromism for the n to σ* electronic transition. Computational investigations carried out with equation-of-motion coupled-cluster with single and double excitations and configuration interaction singles calculations by means of the solvent model density implicit solvation model clearly demonstrate the strong influence of solvents on the electronic structure of the BAD molecule.