Electronic Excited-State Hydrogen Bonding Study Of The Organic Fluorescent Material

In the last decades, intermolecular hydrogen bonding, as a site-specific interaction between hydrogen donor and acceptor molecules, has gained wide attention because of its significance in physical, chemical and biological processes. Moreover, electronic excited state hydrogen bond could associate with many important photochemical and photophysical phenomena have been demonstrated recently.There are some interesting properties of photochemistry and optical physics. Because the fluorenone is an important chromophore molecule containing hydroxyl functional groups. If we change some of the features of fluorenone, for example, the following situations, forming fluorenone derivatives through adding substituents, replacing the oxygen atom into the other atoms in the oxygen family, similar to the other structures and changing the solvent, these changes arouse researchers interest. We use TDDFT method to research hydrogen-bonding dynamic of fluorenone and its derivatives, heteroatom effect, carboline and fluorenol.In the light of analysis on excitation energies and frontier molecular orbitals, we have theoretically demonstrated that the changes about the nature of the intermolecular hydrogen bonds. The hydrogen bonds of fluorenone and its derivatives have strenghened in the S1state. Heteroatoms have an effect on the strength of hydrogen bonds of fluorenone in the excited states. The hydrogen bonds of carboline are weakened in the S1state while strengthened in the S2state. The hydrogen bonds of fluorenol in the S2state are weakened in the alcoholic solvent while strengthened in the acetone solvent.