Theoretical interpretations of electronic and fluorescence spectra of new 2(1H)-pyridone derivatives in solution and solid state

• Synthesis of new 2(1H)-pyridones.
• Electronic and fluorescence spectra of the new compounds both in solution and solid state.
• Quantum chemistry analysis (TDDFT, CASSCF, MS-CASPT2, ONIOM) for the UV–vis and fluorescence spectra.
• Fragment Molecular Orbital analysis (FMO-TDDFT) of the condensed phase effects on the UV–vis and fluorescence spectra.

A combined experimental and computational study was performed for the spectroscopic properties of novel 2(1H)-pyridones. The compounds were found to be virtually non-fluorescence in solution while modestly fluorescent in solid state. The solvent effects on the UV–vis and fluorescence maxima were estimated by means of a series of ab-initio quantum chemical calculations in conjunction with Polarizable Continuum Model (PCM) method. Influence of structural displacements and intermolecular interactions in crystalline state were examined in details on the spectra of two representative compounds by using Fragment Molecular Orbital (FMO) scheme. The FMO pair interaction analysis of the spectra indicate that (1) intermolecular hydrogen bonds provoke bathochromic shifts (2) electrostatic interactions induce hypsochromic shifts (3) crystal packing effects induce hypsochromic shifts in total from the maxima in vacuo.

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