Pradeepkumar Jagadesan
The University of Texas at San Antonio, USA
Title: Synthesis of imine-linked two dimensional porous organic polymers exhibiting excited-state intramolecular proton transfer properties
Biography
Biography: Pradeepkumar Jagadesan
Abstract
The synthesis and photophysical properties of three tris(N-salicylideneaniline) (TSA) compounds containing 1,3,5-triarylbenzene (TAB), -tristyrylbenzene (TSB), and -tris(arylethynyl)benzene (TEB) core units were studied. The TSA compounds underwent efficient excited-state intramolecular proton transfer (ESIPT) in solution and in solid state due to the preformed C=N···H_O hydrogen-bonded motifs of the structures. Steady-state fluorescence emission spectra of the TSA molecules revealed dual bands only in DMSO, and large Stokes shifts in other polar aprotic and protic solvents. Femtosecond transient absorption spectroscopic measurements in THF revealed lifetime values in the range of 14-16 ps for the excited-state keto-tautomer. The TSA compounds are also responsive to metal ions (Cu2+ and Zn2+) in DMSO and exhibit enhanced aggregate-induced emission (AIE) properties in DMSO/water mixture. Three tris(N-salicylideneaniline)-based imine-linked 2D-porous organic polymers (POPs) using the same C3-symmetric TAB, TSB and TAE amines were synthesized that exhibit reversible type IV isotherms, which is indicative of their mesoporosity. These TSA-POPs also exhibited ESIPT emission and responsive to Cu2+ and Pd2+ making them potentially useful as fluorescent-based chemosensors