Catalysis and CO₂ Capture by Palladium‐Incorporated Covalent Organic Frameworks

Abstract

Triazine‐based imine and β‐ketoenamine linked covalent organic frameworks (COFs), TAT‐DHBD (1) and TAT‐TFP (2), have been synthesized from 1,3,5‐tris‐(4′‐aminophenyl)triazine (TAT) and 2,5‐dihydroxybenzene‐1,4‐dicarboxaldehyde (DHBD) or 1,3,5‐triformylphloroglucinol (TFP) under solvothermal conditions in dioxane/mesitylene mixture. These COFs exhibit significant surface areas owing to their meso‐ and micropores. The presence of basic nitrogen sites offers excellent affinity towards Pd nanoparticles and carbon dioxide. Post treatment of COFs 1 and 2 with palladium acetate gives PdII/TAT‐DHBD (3) and PdII/TAT‐TFP (4), which on reduction by NaBH4 yields Pd0/TAT‐DHBD (5) and Pd0/TAT‐TFP (6), respectively. The new COFs have been characterized by FTIR, solid‐state 13C NMR spectroscopy, X‐ray photoelectron spectroscopy (XPS), SEM, TEM, and Brunauer–Emmett–Teller (BET) surface area measurements. TEM studies corroborated the uniform distribution of PdII and Pd0 sites in the COFs. Compounds 3–6 are active towards the Suzuki–Miyaura cross‐coupling of arenes with meager catalyst leaching even after five cycles. In addition, 4 exhibits CO2 uptake of 11 wt % and 7.5 wt % at 273 and 298 K, respectively, at 1 bar.

Highly Stable COF‐Supported Co/Co(OH)2 Nanoparticles Heterogeneous Catalyst for Reduction of Nitrile/Nitro Compounds under Mild Conditions

“…In fact, this is an ubiquitous observation in supported catalyst systems. [4,5a,6b,8,45,46] Thus, providing a plausible explanation for this would be of immense value. We realize that in these porous supports, the clusters could be growing from within the pores and the growth can extend beyond the pore dimension ( Figure and Figure S51, Supporting Information).…”

Covalent Organic Frameworks in Catalytic Organic Synthesis

“…In the same year, Ramaswamy and co-workers also developed two COFs (TAT-DHBD, see COF-JLU6, Figure 5, Table 4, TAT-TFP, Figure 9, Table 8) to immobilize Pd/Pd 2 + and catalyzed the Suzuki reaction (Scheme 46, b). [94] Interestingly, Pd in these COF exhibited better selectivity and catalytic activities in substrates with electro-withdrawing groups. As for electro-donating groups, only medium conversions and selectivity were obtained, which was different from works introduced before.…”

“…This result was even better than classic Pd catalysts like Pd(PPh 3 ) 4 and Pd(PPh 3 ) 2 Cl 2 . In the same year, Ramaswamy and co‐workers also developed two COFs (TAT‐DHBD, see COF‐JLU6, Figure 5, Table 4, TAT‐TFP, Figure 9, Table 8) to immobilize Pd/Pd 2+ and catalyzed the Suzuki reaction (Scheme 46, b) [94] . Interestingly, Pd in these COF exhibited better selectivity and catalytic activities in substrates with electro‐withdrawing groups.…”

1,3,5-Triphenylbenzene: a versatile photoluminescent chemo-sensor platform and supramolecular building block

“…Several COFs with exciting gas storage and separation, catalysis, energy storage and proton conduction properties have been reported over the last decade. [45][46][47][48] Condensation between an amino group and a carbonyl group (of an aldehyde and a ketone) has been extensively exploited for preparing COFs with imine linkages. Fig.…”