Experimental and theoretical studies on the vibrational spectra and active sites of novel multisubstituted spirocycle isoindolinone-chromene hybrid derivatives

This study investigates the novel compound (Z)-2′-amino-3-(3,5-dichloro-4-hydroxybenzylidene)-6-(diethylamino)-3H-spiro[cyclopenta[ b ]chromene-9,1′-isoindolin]-3′-one( SPI ), a spiroindolenone-chromene, through experimental and theoretical methods. Vibrational modes of SPI were identified using DFT and PED analyses, with calculated spectra matching experimental data. Frontier molecular orbital analysis revealed a HOMO-LUMO gap of 2.934 eV and ESP maps identified electrophilic regions. UV–Vis absorption spectra in various solvents were obtained and validated through TD-DFT simulations, elucidating electron transitions. Molecular docking with MDM2 protein showed strong binding (−10.72 kcal/mol) via hydrogen bonding and π-π stacking. Thermodynamic analyses indicated a transition in dynamics above 700 K, suggesting SPI's potential for drug delivery. This approach lays the groundwork for designing spiro protodrugs with tailored properties, combining spectroscopy, electronic structure theory, and biomolecular modeling. • A combined experimental(FT-IR, FT-Raman, UV–Vis) and theoretical (DFT, TD-DFT) approach enables precise assignment of all 183 vibrational modes of the novel spiroisoindolinone-chromene hybrid ( SPI ), with calculated spectra showing excellent agreement with experimental data. • Frontier molecular orbital analysis reveals a HOMO-LUMO energy gap of 2.934 eV, while molecular electrostatic potential(ESP) mapping identifies electrophilic hotspots in the dichloro-substituted region, clarifying reactive sites. • Solvent-modulated π-π* electron transitions in SPI's polycyclic conjugated system are validated by UV–Vis spectroscopy (in Methanol,DMSO,n-Hexane,Water) and TD-DFT simulations, supporting its potential as a photosensitive scaffold. • Molecular docking with MDM2 protein (PDB ID: 5LAZ ) shows a high binding energy of −10.72 kcal/mol, driven by hydrogen bonding and π-π stacking, highlighting SPI's potential as an anticancer MDM2 inhibitor. • Thermodynamic analysis(100−1000 K ) identifies a critical transition above 700 K from enthalpy to entropy-dominated dynamics, underscoring SPI 's thermal responsiveness for light-triggered applications.