Meta-Hybrid Density Functional Theory Prediction of the Reactivity, Stability, and IGM of Azepane, Oxepane, Thiepane, and Halogenated Cycloheptane

Abstract

The application of plain cycloalkanes and heterocyclic derivatives in the synthesis of valuable natural products and pharmacologically active intermediates has increased tremendously in recent times with much attention being paid to the lower cycloalkane members. The structural and molecular properties of higher seven-membered and nonaromatic heterocyclic derivatives are less known despite their stable nature and vast application; thus, an insight into their structural and electronic properties is still needed. Appropriate quantum chemical calculations utilizing the ab initio (MP2) method, meta-hybrid (M06-2X) functional, and long-range-separated functionals (ωB97XD) have been utilized in this work to investigate the structural reactivity, stability, and behavior of substituents on cycloheptane (CHP) and its derivatives: azepane, oxepane, thiepane, fluorocycloheptane (FCHP), bromocycloheptane (BrCHP), and chlorocycloheptane (ClCHP). Molecular global reactivity descriptors such as Fukui function, frontier molecular orbitals (FMOs), and molecular electrostatic potential were computed and compared with lower members. The results of two population methods CHELPG and Atomic Dipole Corrected Hirshfeld Charges (ADCH) were equally compared to scrutinize the charge distribution in the molecules. The susceptibility of intramolecular interactions between the substituents and cycloalkane ring is revealed by natural bond orbital analysis and intramolecular weak interactions by the independent gradient model (IGM). Other properties such as atomic density of states, intrinsic bond strength index (IBSI), and dipole moments are considered. It is acclaimed that the strain effect is a major determinant effect in the energy balance of cyclic molecules; thus, the ring strain energies and validation of spectroscopic specificities with reference to the X-ray crystallographic data are also considered.

Antispasmodic activity of novel 2,4-dichloroanilinium perchlorate hybrid material (I): X-ray crystallography, DFT studies, and molecular docking approach

“…Table 5 list the various descriptors as computed with the M06-2X/6-311 + + G(2df,2pd and aug-cc-pVTZ basis set. in line with the notion of Koopmans' ionization potential and electron a nity are absolute values of the negative of HOMO and LUMO respectively [46] thus, the ease of electron acceptance or donation is very much dependent on these two parameters and higher or lower tendencies of charge transfer is also appraised by increased or decreased values of IP and EA respectively [31]. The inference from the results in table is that the compound possesses high probability for electron acceptance and a considerable aptitude for electron donation, this assertion is a rmed by the high IP value and low EA value which are computed to be 9.3515 eV and 1.5532 eV respectively.…”

“…and provided a platform for further clinical investigations. Similarly the application of Density functional theory (DFT) in unrevealing the reactivity, stability, and molecular interactions in both simple and complex systems, has been fully exploited by numerous scientist and has accelerated the discovery of important chemical agent for medicinal purpose [29][30][31].…”

Electrocatalytic activity of metal encapsulated, doped, and engineered fullerene-based nanostructured materials towards hydrogen evolution reaction

“…It can also be concluded from the NBO analysis that the Carbon(C), and Nickel (NI) atom of the studied molecules in S 1 –S 4 , H a –H d are stronger donors compared to the other atoms in the molecules. Also, the significance of the chemical interactions which was assessed using the total sum of the delocalization energies (ΣE) could be interpreted according to literature 31 and explicit studies that larger ΣE connotes those interactions resulting from electron delocalization from donor to acceptor between S 1 –S 4 , H a –H d and the adsorbing H-molecule is very essential.…”

“…Charge transfer interaction can densely occur when we have an electron donor and an electron acceptor site in a molecule that determines donor –acceptor complexes. As such, natural bond order (NBO) instituted an enhanced technique for investigating the bonding interactions within atomic orbitals and between atomic orbitals, providing an insight for studying the intermolecular charge transfer in molecule 31 . Thus, the charge transfers for the studied bare systems and the hydrogenated engineered systems were calculated using the equation 32 , 33 .…”

Theoretical investigation of the structural, optoelectronic, and the application of waste graphene oxide/polymer nanocomposite as a photosensitizer

“…The concept of density of state is critical because it provides significant information about specific molecular orbitals of specific atoms or groups to molecular stability [32,33]. Figures 4(a highest density contribution to the frontier molecular orbitals in all cases.…”