Accurate and precise control of the transition-metal ions in the docking sites of porous functional materials especially covalent organic frameworks (COFs) is a challenging task in the synthesis of hybrid materials for calibrating properties and widening applications. COFs represent a new class of porous materials built by strong covalent bonds in a periodic arrangement of precursor units under the principle of reticular chemistry, have attracted enormous attention due to low-density, structural versatility, permanently high porosity, chemical and thermal stability. These fascinating properties not only make 2D and 3D COFs as a new area of materials research in recent years but, also an outstanding candidates for a plethora of applications such as gas adsorption/separations , catalysis, optoelectronic, environmental remediation, sensors, enzyme/drug uptake, photoconductivity, proton conduction, energy storage, and so on. The strong coordination between the organic linkers and transition metal ions is one of the potent ways to introduce active sites in the porous frameworks. Group-5 elements especially vanadium is well-known to form a range of complexes with bidentate O,O-donor and N,O-donor ligands of different symmetricity and point groups. We judiciously choose TAPT-2,3-DHTA and PyTTA-2,3-DHTA COFs bearing O,O functionalities synthesized by the Schiff base condensation of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (TAPT) / 4,4',4'',4'''-(pyrene-1,3,6,8-tetrayl) tetraaniline (PyTTA) and 2,3-dihydroxy-terephthaldehyde (2,3-DHTA) to immobilize vanadium functionalities to multiplicate the efficiency of modified framework in pivotal organic reactions namely Mannich-type reactions underlining the fact that organic linkers are evenly distributed in porous material. The obtained results revealed that the as-prepared vanadium-decorated COFs showed astounding catalytic activity with excellent recyclability, reusability for at least three times without any hinderance in stability and crystallinity. Significantly, this work opens the opportunity for docking other metals and exploring practically and industrially important reactions.

Post synthetically modified covalent organic frameworks as an effective heterogenous catalyst for modified Mannich type reactions.

2019 Spring National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.