https://libjncir.jncasr.ac.in/xmlui/handle/10572/1515 2026-04-04T05:31:55Z https://libjncir.jncasr.ac.in/xmlui/handle/10572/2522 Porous polyimides from polycyclic aromatic linkers: Selective CO2 capture and hydrogen storage Rao, K. Venkata; Haldar, Ritesh; Maji, Tapas Kumar; George, Subi Jacob Porous polyimides are important class of macromolecules owing to their excellent redox behaviour, efficient capture of CO2 and H-2 gases, interesting photocatalytic properties and superior thermal and chemical stabilities. Here we describe in detail, the synthesis and gas storage properties of a series of porous polyimides (Tr-NPI, Tr-PPI, Tr-CPI, Td-PPI and Td-CPI) with various network topologies derived from polycyclic aromatic hydrocarbon linkers. These polyimides are synthesized in a single step by the condensation of corresponding polycyclic aromatic dianhydrides (NDA, PDA and CDA) with structure directing amine (TAPA and TAPM) monomers, having trigonal and tetrahedral geometry. The structure of all the polymers was fully characterized by various techniques. The present work also introduces for the first time porous polyimides containing rigid polycyclic aromatic compounds such as coronene. All the polyimides presented here exhibit high thermal stability and show selectivity towards CO2 uptake at room temperature (293 K), due to the presence of aromatic clouds and CO2 phillic oxygen and nitrogen functionalities on their pore surface. Moreover these polymers also showed significant uptake of H-2 gas (77 K). The present work has significant implications on the design of robust porous organic solids from small molecules for efficient capture of CO2 and H-2 gases. 2014 Elsevier Ltd. All rights reserved. Restricted Access 2014-01-01T00:00:00Z https://libjncir.jncasr.ac.in/xmlui/handle/10572/2515 Amine-Responsive Adaptable Nanospaces: Fluorescent Porous Coordination Polymer for Molecular Recognition Haldar, Ritesh; Matsuda, Ryotaro; Kitagawa, Susumu; George, Subi Jacob; Maji, Tapas Kumar Flexible and dynamic porous coordination polymers (PCPs) with well-defined nanospaces composed of chromophoric organic linkers provide a scaffold for encapsulation of versatile guest molecules through noncovalent interactions. PCPs thus provide a potential platform for molecular recognition. Herein, we report a flexible 3D supramolecular framework {[Zn(ndc)(o-phen)]center dot DMF}(n) (o-phen= 1,10-phenanthroline, ndc=2,6-napthalenedicarboxylate) with confined nanospaces that can accommodate different electron-donating aromatic amine guests with selective turn-on emission signaling. This system serves as a molecular recognition platform through an emission-readout process. Such unprecedented tunable emission with different amines is attributed to its emissive charge-transfer (CT) complexation with o-phen linkers. In certain cases this CT emission is further amplified by energy transfer from the chromophoric linker unit ndc, as evidenced by single-crystal X-ray structural characterization. Restricted Access 2014-01-01T00:00:00Z https://libjncir.jncasr.ac.in/xmlui/handle/10572/2518 Charge-Transfer Nanostructures through Noncovalent Amphiphilic Self-Assembly: Extended Cofacial Donor-Acceptor Arrays Rao, K. Venkata; Jalani, Krishnendu; Jayaramulu, K.; Mogera, Umesha; Maji, Tapas Kumar; George, Subi Jacob Restricted Access 2014-01-01T00:00:00Z https://libjncir.jncasr.ac.in/xmlui/handle/10572/2434 Porous coordination polymers based on functionalized Schiff base linkers: enhanced CO2 uptake by pore surface modification Bhattacharya, Biswajit; Haldar, Ritesh; Dey, Rajdip; Maji, Tapas Kumar; Ghoshal, Debajyoti We report the synthesis, structural characterization and adsorption properties of three new porous coordination polymers {[Cu(Meazpy)(0.5)(glut)](H2O)}(n) (2), {[Zn(azpy)(0.5)(terep)](H2O)}(n) (3), and {[Zn(Meazpy)(0.5)(terep)]}(n) (4) [glut = glutarate, terep = terephthalate, azpy = N,N'-bis-(pyridin-4-ylmethylene) hydrazine and Meazpy = N, N'-bis-(1-pyridin-4-ylethylidene) hydrazine] composed of mixed linkers systems. Structure determination reveals that all three compounds have three-dimensional (3D) coordination frameworks bridged by dicarboxylates and Schiff base linkers. In all cases 2D dicarboxylate layers are supported by paddle-wheel M-2(CO2)(4) SBUs extended in three dimensions by designed Schiff base linkers. Compound 1, which has been reported in a paper earlier by our group, is a robust porous three-dimensional (3D) framework whose pore surface was found to be decorated with the -CH=N- groups of a linear Schiff base (azpy) and it showed reversible single-crystal-to-single-crystal transformation and selective CO2 uptake. By using another linear Schiff base linker Meazpy, we have synthesized compound 2 which is isostructural with 1, having an additional methyl group pointing towards the pore. Like 1 it also shows a reversible single-crystal-to-single-crystal transformation upon dehydration and rehydration. The dehydrated framework of 2 exhibits 50% enhanced CO2 uptake compared to 1. This has been achieved by the pore surface modification effected upon changing the pillar backbone from a -CH=N- to -CMe=N- group. It also adsorbs water vapour at 298 K. In the case of the two isostructural 3D MOFs 3 and 4, the use of a rigid carboxylate (terephthalate) linker arrested porosity by three-fold interpenetration. We showed that the use of aliphatic dicarboxylate (glutarate) results in a non-interpenetrated framework rather than the common interpenetrated framework with aromatic dicarboxylates in mixed ligand systems. Restricted Access 2014-01-01T00:00:00Z