Kinetic analysis of tautomer forms of aromatic-urea compounds with acetate ions: solvent effect of excited state intermolecular proton transfer.

In this paper, we report the solvent effect of excited state intermolecular proton transfer (ESIPT) reactions of urea compounds in the presence of tetrabutylammonium acetate (TBAAc). We prepared anthracene-urea compounds (9An and 2An), a pyrene-urea compound (Py) and an anthracene-diurea compound (9,10An), which have alkylsulfonyl groups to improve their solubility in various organic solvents. We investigated the solvent effects of the ESIPT reaction using absorption, fluorescence, and 1H NMR spectroscopy along with fluorescence decay measurements in dimethyl sulfoxide (DMSO), acetonitrile (MeCN), tetrahydrofuran (THF) and toluene.

Excited-state intermolecular proton transfer dependent on the substitution pattern of anthracene-diurea compounds involved in fluorescent ON-OFF-ON response by the addition of acetate ions.

We report anthracene-diurea compounds which behave as anion sensors based on the fluorescence emission regulated by the substitution position on the anthracene ring. Anthracene-diurea compounds exhibit different excited-state intermolecular proton transfer (ESIPT) reactions depending on the pattern of the substituents. Three new anthracene-diurea compounds that have two phenylurea groups substituted at different positions on anthracene were synthesized.

Fluorescence Sensor with A New ON -OFF-ON Switching Mechanism Using the Excited State Intermolecular Proton Transfer Reaction of An Anthracene-diurea Compound.

A new photoreaction mechanism of "Three-state molecular switch" fluorescence sensor based on ON -OFF-ON sequence was achieved by anthracene-diurea compound, which was designed using two phenylurea groups and one anthracene, 9,10BtDSPUA. Photochemical properties of 9,10BtDSPUA and interaction between 9,10BtDSPUA and anion were investigated in detail by absorption, H NMR, fluorescence, and fluorescence decay measurements. While the fluorescence of 9,10BtDSPUA in DMSO (ON ) was quenched in the presence of low concentration of acetate anion (OFF), fluorescence enhancement occurred by the addition of high concentration of acetate anion (ON ).

Control of the intermolecular photodimerization of anthracene derivatives by hydrogen bonding of urea groups in dilute solution.

The photodimerization reaction of anthracene derivatives was performed by capitalizing on intermolecular hydrogen bonds. Anthracene derivatives that can control the dimerization reaction depending on the substitution site were designed by using two anthryl moieties and one urea group, referred to as N,N'-dianthracen-n-ylurea, nDAU (n = 1, 2 and 9), which are symmetrically substituted by 1-anthryl, 2-anthryl and 9-anthryl groups, respectively. We investigated the excimer emission and photodimerization reaction of these anthracene-urea derivatives using absorption, emission, and (1)H NMR spectroscopy along with fluorescence decay measurements.