Quantum chemical calculations and interpretation of electronic transitions and spectroscopic characteristics belonging to 1-(3-Mesityl-3-methylcyclobutyl)-2-(naphthalene-1-yloxy)ethanone

Abstract

This comprehensive study reports the synthesis of the title compound, 1-(3-Mesityl-3-methylcyclobutyl)-2-(naphthalene-1-yloxy)ethanone (C26H28O2), and identification of the molecule by means of the standard experimental methods such as single-crystal X-ray diffraction, ultra violet-visible (UV-vis) spectra, Fourier transform infrared (FTIR) spectra, (13)C and (1)H NMR chemical shifts and quantum chemical calculations using density functional theory (B3LYP) method for the first time. The experimental results observed display that the synthesis of the C26H28O2 compound is perfectly conducted without any impurities. Additionally, the little deviations are noticed on the bond lengths and bond angles, confirming that the strong intra-molecular charge transfers appear in the due to the presence of the electron engagements and conjugative effects (bond weakening). Besides, the intermolecular C-H⋯O distance presents the interaction between the methylcyclobutyl C-H group and oxygen atom in the ethanone group. At the same time, the absorption wavelength (λmax) appears at 292 nm and interval 297-269 nm in the solvent of chloroform and THF as a consequence of the presence of effective π-π(∗) conjugated segments in the molecule studied. Besides, optical band gap energy of 3.22/3.25 eV (chloroform/THF), verifies the existence of the strong electronic donating groups in the structure. As for the quantum chemical computations, the determination of the optimized molecular structures, vibrational frequencies including infrared intensities, vibrational wavenumbers, thermodynamic properties, atomic charges, electronic transitions, dipole moment (charge distribution), optical band gap energy, (1)H and (13)C NMR chemical shifts are conducted using density functional theory/Becke-3-Lee-Yang-Parr (DFT/B3LYP) method with the standard 6-311++G(2d,2p) level of theory. The results obtained show that the strong intra-molecular charge transfer (ICT) appears between the donor and acceptor in the title compound due to the existence of the strong electronic donating groups and effective π-π(∗) conjugated segments with high electronic donor ability for the electrophilic attack (intermolecular interactions). Additionally, the presence of the non-uniform charge distributions (polar behavior) on the various atoms makes the title compound be useful to bond metallically.