Synthesis, characterization, crystal structure and DFT studies on 1′,3′-dihydrospiro[fluorene-9,2′-perimidine]

The title compound, 1′,3′-dihydrospiro[fluorene-9,2′-perimidine] has been synthesized and characterized by NMR, ESI-MS, IR, elemental analysis, UV–vis and fluorescence spectroscopy. The crystal structures of the title compound and its co-crsytal with 9-fluorenone have also been determined by X-ray single crystal diffraction. Density functional theory (DFT) calculations and vibrational frequencies have been performed at B3LYP/6-31G* level. The comparisons between the experimental vibrational frequencies and the predicted data show that B3LYP/6-31G* method can simulate the IR of the title compound on the whole. The theoretical electronic absorption spectra have been calculated by using TD-DFT method and compared with the experimental result. The solid-fluorescence determination of the title compound reveals two emission bans at 430 and 590 nm while its co-crystal reveals only one emission band at 590 nm.

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► We synthesize a novel 9-aryl fluorene and its co-crystal with fluorenone.
► We determine their crystal structures by using X-ray single crystal diffraction.
► We use density functional theory to calculate the IR spectra and electronic absorption spectra.
► The calculated results agree well with the experimental results.