Thermally Induced Single-Crystal-to-Single-Crystal Transformation and Heterogeneous Catalysts for Epoxidation Reaction of Co(II) Based Metal–Organic Frameworks Containing 1,4-Phenylenediacetic Acid

Abstract

Four new metal−organic frameworks (MOFs) based on 1,4-phenylenediacetic acid (1,4-H 2 phda), [Co(1,4-phda)(4,4′-bpa)] (1), [Co(1,4-phda)(4,4′-bpp)] (2), [Co(1,4-phda)(4,4′-bpa)(H 2 O) 2 ] (3), and [Co(1,4-phda)-(4,4′-bpa)] (3a) (4,4′-bpa = 1,2-bis(4-pyridyl)ethane and 4,4′-bpp = 1,3-bis(4-pyridyl)propane) were successfully synthesized. The various synthetic methods play an important role in the formation of diverse structural frameworks.Compound 1 shows a 3D framework, while 2, 3, and 3a exhibit 2D layered MOFs with different architectures. The irreversible thermally induced single-crystal-to-single-crystal transformation with chromotropism from 3 to 3a was observed, which was established by the breakage and reformation of coordination bonds around Co(II) centers. The orientation of coordinated 4,4′-bpa ligand and conformation of 1,4-phda ligand play a key role on pore opening in 3 and pore closing in 3a. Furthermore, the functional properties as heterogeneous catalysts of these MOFs including epoxidation of alkenes and photocatalytic performance for MB degradation have been investigated. The heterogeneous catalytic properties of 1, 2, and 3a exhibit high catalytic activity with good catalyst stability.

Enhanced Catalytic Activity of a Copper(II) Metal–Organic Framework Constructed via Semireversible Single-Crystal-to-Single-Crystal Dehydration

“…This is consistent with previous literature reports on styrene oxidation using MeCN as a solvent, ,,− which reported 80 °C as the optimum temperature. Entries 12 and 13 (Table S10) demonstrate the catalytic behavior of [Cu 2 (bipy) 2 (btec)] MOF 32 in various solvents and oxidants, with 100% (H 2 O 2 ) and 26% ( t -BuOOH) benzaldehyde selectivity.…”

Bifunctional Dinuclear Complexes Based on Iminodiacetate and 1,2-Di(4-pyridyl)ethylene: Crystal Structures, Vapochromism, and Iodine Adsorption

“…(ii) The strong chelating fashion of IDA 2– leads to good thermal stability of the complex. (iii) The flexibility of rotatable C–N and C–C bonds of IDA 2– can generate the different torsion angles causing the different coordination modes and conformations. − N , N′ -linkers are also important in the dimensional extension and the stability of the complexes and their supramolecular structures …”

Design of five two-dimensional Co-metal-organic frameworks for oxygen evolution reaction and dye degradation properties

“…The UV-Vis DRS and optical band gaps were determined to gain an insight into the semiconductor behaviors of 1–5. As shown in Supplementary Figures S19–S23 , strong and broad-range ultraviolet light absorption in the 220–340 nm range was observed for 1–5, attributed to π→π* transitions in the ligands or ligand-to-metal charge transfer (LMCT) ( Othong et al, 2017 ). In addition, a relatively weak absorption band was observed at 440–620 nm for 1–5; the d→d spin-allowed transition of Co 2+ (d 7 ) ions ( Liu et al, 2014 ).…”