Quantum Chemical Investigation of Novel Noncovalent interactions Utilizing Vibrational Spectroscopy

Theoretical/computational methods have been utilized to investigate a diverse array of questions currently at the forefront of modern chemistry research. The focus of this work is Local Vibrational Mode (LVM) Theory, originally formulated by Konkoli and Cremer, and under continuous development by the CaTcO research group. Derived from LVM theory, local stretching force constants (ka) represent physically meaningful measurements of chem- ical bond strength. Decomposition of normal vibrational modes into LVM contributions, also called characterization of normal modes (CNM), is another powerful manifestation of LVM theory; most notably when applied to the analysis of theoretical/experimental IR/Ra- man spectra. Recent developments in LVM theory aim to reveal new insights on the nature of noncovalent interactions (NCIs) and weak chemical bonds, including but not limited to: hypervalent iodine, halogen–metal bonds, halogen bonds in periodic systems, influence of intramolecular hydrogen bonds (IMHBs) on structure–stability relationships, ⇡–hole interac- tions involving aromatic centers, and breaking/forming bonds at transition states. The finer points of this work include important new chemical insights, such as: a better understand- ing of substituent and solvent effects, locating weak/strong points in molecular complexes to identify so–called ’trigger’ bonds in energetic materials, and assessing the performance of various HB donor/acceptor pairs. Much of this information can be further applied to the design of materials with specific properties, lowering/raising of reaction barriers, and catalytic control of chemical reactions