picric acid sensing and co 2 capture by a sterically encumbered azo-linked fluorescent triphenylbenzene based covalent organic polymer

Abstract: a sterically encumbered isopropyl group substituted fluorescent triphenylbenzene based azo-linked covalent organic polymer, iprtapb-azo-cop, has been synthesized by cu(i) catalysed homo coupling (amine-amine) reaction of 1,3,5-tris(4 ′-amino-3 ′, 5 ′-isopropylphenyl)benzene (iprtapb) under aerobic conditions. the brunauer-emmett-teller (bet) and langmuir surface areas of iprtapb-azo-cop have been estimated to be 395 and 697 m 2 g- 1 with a pore diameter of 11.6 å. due to the presence of fluorescent triphenylbenzene platform iprtapb-azo-cop exhibits broad emission band centred at 428 nm, when excited at 300 nm, as a result of extended conjugation. the inherent fluorescent nature of iprtapb-azo-cop has been utilized for sensing electron-deficient polynitroaromatic compounds (pnacs) such as a picric acid (pa), dinitrotoluene (dnt), p-dinitrobenzene (p-dnb) and m-dinitrobenzene (m-dnb). further, iprtapb-azo-cop has also been utilized for capture of carbon dioxide as the azo-cop is enriched with co 2-philic nitrogen atoms apart from its microporosity. since the azo (–n=n-) linkages are masked by the bulky isopropyl groups, iprtapb-azo-cop exhibits a co 2 uptake of 6.5 and 19.4 wt% at 1 bar and 30 bar, respectively, at 273 k. graphical abstract : synopsis sterically encumbered azo-linked covalent organic polymer (iprtapb-azo-cop) has been synthesized from a fluorescent hexaisopropyl substituted triphenylbenzene platform. the resulting fluorescent porous cop has been utilized for picric acid sensing and co 2 capture.[figure not available: see fulltext.]. © 2018, indian academy of sciences.