Abstract
The present study investigates the structural and thermodynamic properties of 4,5-difluoro-2-nitroaniline using computational quantum chemical methods based on Hartree–Fock (HF) and Density Functional Theory (DFT). The molecular geometry, electronic structure, and thermodynamic functions of the compound were theoretically evaluated to understand its stability and physicochemical behaviour. Optimised structural parameters, including bond lengths, bond angles, and dihedral angles, were calculated and compared using the selected computational approaches. In addition, the electric dipole moment (?), mean polarizability (?), and first hyperpolarizability (?) were determined to assess the molecule's nonlinear optical (NLO) response. Thermodynamic parameters, including heat capacity, entropy, and enthalpy, were evaluated over a range of temperatures to examine the thermal behaviour of the molecule. The calculated results provide useful insights into the relationship between molecular structure, electronic properties, thermal characteristics, and optical response. The study demonstrates the applicability of HF and DFT calculations for predicting important molecular properties of 4,5-difluoro-2-nitroaniline and assessing its potential relevance in materials and molecular science.
Introduction
Aniline is six membered homoaromatic simplest amine containing – NH2 functional group. Aniline has significant industrially commodity chemical and also use for fine chemical synthesis. Due to having electron rich benzene ring aniline goes to electrophilic aromatic substitution. After formation of diazonium salt through diazotization reaction this diazonium salt goes to a huge number of nucleophile substitution and form a lot number of compounds used in daily life. They have been broadly used for pharmaceutical manufacturing, electro-optical, chemical dye industries and for other commercial and industrial use, and have been studied extensively [1-3]. Some para substituted compounds of aniline are frequently used local anaesthetics. Among these compounds the amino group plays crucial role in the interaction with the receptor. Therefore, studies of properties as well as the extensive experimental nature of reaction mechanics, [4] and theoretical investigations of substituted aniline have focused on determine the structure and vibrational assignments of aniline and its methyl derivatives [1-8]. Molecular geometry alters due to enhanced interaction between the aromatic ring and the amino group. Substituent group inclusion in aniline also explains the change of charge distribution with in the molecule [9-13]. “It’sgeometry has been reported using semi-empirical [14-15], ab-initio methods [14,16-17]. Extensive recent studies on vibrational spectra of substituted anilines assigned [1,5,8,18-20] complete vibrational mode and frequency analyses. G. Karimi et al. reported ? conjugation, band gape energy, Ionisation potential electron affinity and red shift in doped state of fluoro substituted aniline [21]. M. George et al. have been investigated ? conjugation in the carbon ring system [22].
Conclusion
In the present investigation of the molecule 4,5-difloro-2-nitroaniline a detailed geometrical, have been done with the help of both empirical quantum chemical method Hartree Fock and density functional theory. This is the first time that optimized structure, bond length, bond angle, thermodynamic parameters, mulliken charges is produced for the title compound 4,5-difloro-2-nitroanilineThe parameters, bond length, bond angle, obtained from molecular geometry are very well correlated to the data available in literature for aniline.
References
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