Three Resorcin[4]arene-Based Two-Dimensional Zn(II) Supramolecular Isomers Synthesized via a Structure-Directing Strategy for Knoevenagel Condensation

Abstract

Herein, in the presence of three structure-directing agents (SDAs), a family of imidazole-functionalized resorcin[4]arenebased coordination polymers (CPs), [Zn(TIC4R)(HCOO)]•HCOO• 0.5DMF•1.5H 2 O (1), [Zn(TIC4R)(CN)]•HCOO•DMF•2.5H 2 O (2), and [Zn(TIC4R)(H 2 O)]•2HCOO•2H 2 O (3), were assembled under solvothermal conditions [TIC4R = tetra(imidazole) resorcin[4]arene].1 exhibits a double-layer structure with rectangle windows, and 2 and 3 display monolayer structures. The layers of CPs 2 and 3 are slides with different offsets along the a-axis. In addition, three CPs were used as catalysts to catalyze Knoevenagel condensations. Strikingly, all CPs exhibit remarkable catalytic performance for several substrates. To the best of our knowledge, this is the first time that a small organic acid as SDA was used in the syntheses of resorcin[4]arene-based supramolecular isomers.

Highly Active Cyclic Zinc(II) Thione Catalyst for C−C and C−N Bond Formation Reactions

“…Based on the previous literature, [2–4,11–18] a plausible catalytic mechanism for the Knoevenagel condensation reaction is illustrated in scheme 7. We presume that zinc(II) in 1 can act as a Lewis acidic site to lead to catalytic activities.…”

“…The high yield synthesis of 2-phenyl-2,3-dihydro1-H perimidine derivatives catalyzed by 1 was accomplished using lower catalyst loading within 5 minutes under mild reaction conditions compared to known catalytic strategies, Cu(NO 3 ) 2 (5 mol%/RT/EtOH/10 min; Yield: 83%), [26] Nano-γ-Al 2 O 3 /SbCl 5 (solvent-free, RT, 95%), [24] Fe 3 O 4 /SO 3 H@zeolite-Y (EtOH, RT, 98%). [25] Based on the previous literature, [2][3][4][11][12][13][14][15][16][17][18] a plausible catalytic mechanism for the Knoevenagel condensation reaction is illustrated in scheme 7. We presume that zinc(II) in 1 can act as a Lewis acidic site to lead to catalytic activities.…”

“…Notably, the majority of these catalysts have been developed for the Knoevenagel condensation reactions. Zinc(II) clusters and metal‐organic frameworks have been used as the active catalysts for the Knoevenagel condensation reactions [11–17] . We presume that the unsaturated open metal sited of zinc(II) can act as Lewis acid sites while ligand can act as Lewis base sites to promote the catalytic application in Knoevenagel condensation reactions.…”

“…Zinc(II) clusters and metal-organic frameworks have been used as the active catalysts for the Knoevenagel condensation reactions. [11][12][13][14][15][16][17] We presume that the unsaturated open metal sited of zinc(II) can act as Lewis acid sites while ligand can act as Lewis base sites to promote the catalytic application in Knoevenagel condensation reactions. On account of earlier literature, the four coordinated zinc(II) complexes have been considered to be the coordinatively unsaturated open catalytically active metal sites.…”

Structural transformation of copper coordination complexes accompanied with chiral transformation

“…The precise design and preparation of coordination polymers (CPs) with operable network structure has been the focus of crystal engineering research in recent years, [1][2][3][4][5] and it has gradually shown great potential application in gas storage, 6 catalysis, 7,8 ion exchange, 9 photoluminescence, 10,11 magnetism, [12][13][14] and other aspects. CPs are an assembly of metal ions (or metal clusters) and organic ligands connected by coordination bonds.…”