Kunchala Dhanunjayarao

A highly selective ratiometric detection of F− based on excited-state intramolecular proton-transfer (imidazole) materials

Inspired by the importance of fluoride ions in the field of dental fluorosis and treatment of osteoporosis, we have synthesized a probe 2 (2-(2-tert-butyldiphenylsiloxy)phenyl-4,5-diphenyl-1-p-tolyl-1H-imidazole) for the detection of fluoride ions from simple starting materials. The probe was characterized using standard analytical and spectroscopic techniques including single crystal X-ray crystallography. The probe (2) exhibited a multi-channel rapid response and excellent selectivity and sensitivity towards fluoride ions through selective cleavage of Si–O bonds. Time-dependant density functional theory (TD-DFT) calculations were carried out to vindicate the optical properties of the probe (2) and its starting material (compound 1).

Tetraaryl pyrazole polymers: versatile synthesis, aggregation induced emission enhancement and detection of explosives

Here we report a new approach to obtain tetraaryl pyrazole polymers by free radical polymerization of styryl substituted pyrazole monomers. The resultant tetraaryl pyrazole polymers are stable at temperatures up to 300 °C and completely soluble in organic solvents. The study of the photophysical properties of the polymers in the aggregated and the non-aggregated form reveals that they exhibit the aggregation-induced emission enhancement (AIEE) phenomenon. Furthermore, we show that these new AIEE luminogens function as fluorescent chemosensors for the detection of explosives like picric acid.

Synthesis, characterization and aggregation induced enhanced emission properties of tetraaryl pyrazole decorated cyclophosphazenes

A series of cyclotriphosphazenes N3P3(O-C6H4-C3N2-(C6H5)3)6 (3), N3P3(O2C12H8)(O-C6H4-C3N2-(C6H5)3)4 (4), N3P3(O2C12H8)2(O-C6H4-C3N2-(C6H5)3)2 (5) and N3P3(OPh)5(O-C6H4-C3N2-(C6H5)3) (7) decorated with aggregation induced enhanced emission (AIEE) luminogen (tetraaryl pyrazole) are synthesized by the reaction of N3P3Cl6, N3P3(O2C12H8)Cl4, N3P3(O2C12H8)2Cl2 and N3P3Cl5(O-C6H4-C3N2-(C6H5)3) (6) with 4-(1,3,5-triphenyl-1H-pyrazol-4-yl)phenol (phenol in the case of 6). Intriguingly all the newly synthesized tetraaryl pyrazole decorated cyclotriphosphazenes exhibit the aggregation induced enhanced emission phenomenon. The luminogen decorated cyclophosphazenes have also been investigated as a probe for the detection of explosive picric acid.

CCDC 1446359: Experimental Crystal Structure Determination

Related Article: Ramesh Mamidala, Vanga Mukundam, Kunchala Dhanunjayarao, Krishnan Venkatasubbaiah|2017|Tetrahedron|73|2225|doi:10.1016/j.tet.2017.03.001