Copper (I)–Organic Frameworks for Catalysis: Networking Metal Clusters with Dynamic Covalent Chemistry

Abstract

Metal clusters exhibit diverse structures, emerging functions, and applications; thus, incorporating clusters into metal-organic frameworks (MOFs) brings tremendous merits. Although the construction of cluster-based MOFs is sophisticated, the reticular materials constructed from a combination of the chemistry of metal clusters and covalent organic frameworks (COFs) remain unexplored. Herein, we prepared two Cu(I) cluster-based MOFs with cyclic trinuclear units (CTUs), termed JNM-1 and JNM-2, either by a stepwise synthetic approach or by a one-pot reaction, for networking clusters with dynamic covalent chemistry, rarely utilized in MOF synthesis. The generated JNMs exhibited excellent stability and could be used as recyclable catalysts for palladium-free Sonogashira coupling reactions with high efficiency and tolerance (>90% yield for nine examples), without loss of performance for at least five cycle runs. In addition, conjugated single molecular wires with lengths ranging from 1.6 to 2.7 nm were synthesized feasibly using the JNM-1 catalyst.

An Imine‐Linked Metal–Organic Framework as a Reactive Oxygen Species Generator

“…[17] With three aldehyde groups in an C 3 arrangement, Cu 3 (PyCA) 3 could serve as ar igid building unit for the construction of reticular structures.B yo rganic Schiff base reaction, which has been frequently practiced in the COF synthesis, [18] Cu 3 (PyCA) 3 is expected to react with an organic unit with multiple amine functionalities to form ar eticular structure with new dynamic covalent linkages.T his strategy was very recently demonstrated by two MOFs made from C 3 + C 3 imine condensation. [19] Following previous reports on mechanochemical synthesis of COFs, [20] PA in C 2 symmetry is ground with amodulator p-toluenesulfonic acid monohydrate (PTSA) thoroughly,a nd then Cu 3 (PyCA) 3 •H 2 Oc rystals and trace amount of H 2 Oare added to the mixture stepwise under constant grinding (Figure 1). Thesolid paste is further heated at 170 8 8C, and crystalline powders named FDM-71 are obtained after thorough washing,s olvent exchange,a nd supercritical CO 2 drying (See the Supporting Information for more details).…”

An Imine‐Linked Metal–Organic Framework as a Reactive Oxygen Species Generator

“…By organic Schiff base reaction, which has been frequently practiced in the COF synthesis, [18] Cu 3 (PyCA) 3 is expected to react with an organic unit with multiple amine functionalities to form a reticular structure with new dynamic covalent linkages. This strategy was very recently demonstrated by two MOFs made from C 3 + C 3 imine condensation [19] . Following previous reports on mechanochemical synthesis of COFs, [20] PA in C 2 symmetry is ground with a modulator p ‐toluenesulfonic acid monohydrate (PTSA) thoroughly, and then Cu 3 (PyCA) 3 ⋅H 2 O crystals and trace amount of H 2 O are added to the mixture stepwise under constant grinding (Figure 1).…”

Acid-triggered interlayer sliding of two-dimensional copper(i)–organic frameworks: more metal sites for catalysis

“…S3 † ), confirm the formation of imine linkages. The solid-state 13 C CP/MAS NMR spectra of JNM-3 reveal the removal of the aldehyde carbon signals of CTU 1 located at 184 ppm 26 and the appearance of characteristic resonance peaks of imine carbons at 155 and 151 ppm, for JNM-3-AA and JNM-3-ABC , respectively, also evidencing the formation of imine bonds (Fig. S4 † ).…”

“…Recently, we prepared copper( i ) cyclic trinuclear unit (CTU)-based 2D covalent metal–organic frameworks (CMOFs) by combining the chemistry of MOFs and COFs. 26 The CTU-based 2D CMOFs have inherited advantages from both MOFs and COFs, including good crystallinity and stability, high porosity, and excellent catalytic activities resulting from inborn metal open sites. 26,27 In addition, d 10 metal CTUs can provide additional non-covalent interactions, such as metallophilic attraction, 28,29 compared to pure organic systems, and bring merits for fine-tuning the interlayer stacking.…”

“… 26 The CTU-based 2D CMOFs have inherited advantages from both MOFs and COFs, including good crystallinity and stability, high porosity, and excellent catalytic activities resulting from inborn metal open sites. 26,27 In addition, d 10 metal CTUs can provide additional non-covalent interactions, such as metallophilic attraction, 28,29 compared to pure organic systems, and bring merits for fine-tuning the interlayer stacking. Moreover, Cu( i ) CTUs, acting as secondary building units to construct frameworks, have unsaturated metals as potential catalytic centers.…”