New URJC-1 Material with Remarkable Stability and Acid-Base Catalytic Properties

Abstract

Abstract:Emerging new metal-organic structures with tunable physicochemical properties is an exciting research field for diverse applications. In this work, a novel metal-organic framework Cu(HIT)(DMF) 0.5 , named URJC-1, with a three-dimensional non-interpenetrated utp topological network, has been synthesized. This material exhibits a microporous structure with unsaturated copper centers and imidazole-tetrazole linkages that provide accessible Lewis acid/base sites. These features make URJC-1 an exceptional candidate for catalytic application in acid and base reactions of interest in fine chemistry. The URJC-1 material also displays a noteworthy thermal and chemical stability in different organic solvents of different polarity and boiling water. Its catalytic activity was evaluated in acid-catalyzed Friedel-Crafts acylation of anisole with acetyl chloride and base-catalyzed Knoevenagel condensation of benzaldehyde with malononitrile. In both cases, URJC-1 material showed very good performance, better than other metal organic frameworks and conventional catalysts. In addition, a remarkable structural stability was proven after several consecutive reaction cycles.

Improved Detonation Performance Via Coordination Substitution: Synthesis and Characterization of Two New Green Energetic Coordination Polymers

“…For the H 3 BTI ligand, it undergoes large structural deformation under acidic conditions and displays the same bridging coordination geometry consistent with 1 . Here, imidazole and two tetrazoles are not coplanar; only one tetrazole is protonated, which is different from the reported Cu-based ECP incorporating H 3 BTI ligand . The combined geometry is vital to the construction of trimetal units [Cu1-(μ 2 ’-H 2 BTI)-Cu1] in which each H 2 BTI – molecule connects two adjacent Cu­(II) ions, forming 1D chains (Figure a).…”

“…Here, imidazole and two tetrazoles are not coplanar; only one tetrazole is protonated, which is different from the reported Cu-based ECP incorporating H 3 BTI ligand. 31 The combined geometry is vital to the construction of trimetal units [Cu1-(μ 2 '-H 2 BTI)-Cu1] in which each H 2 BTI − molecule connects two adjacent Cu(II) ions, forming 1D chains (Figure 1a). Further formation of a 2D supramolecular layer (Figure 1b) and the expanding layers are finally connected to a stable 3D supermolecule configuration by lots of hydrogen bonding interactions (Figure1c, Table S4).…”

URJC‐1‐MOF as New Heterogeneous Recyclable Catalyst for C‐Heteroatom Coupling Reactions

“…Typical catalytic tests to assess the activity of catalyst for N‐ or O‐Arylation reactions, characterization technique for quantification of product yields and method for catalyst recovery to evaluate the reusability in successive catalytic cycles are described in SI‐5. URJC‐1‐MOF and Cu–MOF‐74 were synthesized following the procedure previously reported, and HKUST‐1 was purchased to Sigma‐Aldrich (Spain).…”

“…In this work, the copper‐based URJC‐1‐MOF developed in our research group has been extensively tested as heterogeneous catalyst in Chan‐Lam‐Evans‐type coupling reaction, particularly, in C−N and C−O coupling reactions, for a wide variety of substrates. Different reaction conditions such as solvent, type of base, temperature, reaction time and substrates have been studied, observing the effect on the performance of URJC‐1‐MOF catalyst.…”

“…URJC‐1‐MOF catalyst used in this work has a crystalline structure formed by Cu(II) linked to 1H‐imidazol‐4,5‐tetrazole ligand, displaying a BET surface area of 408 m 2 /g and a pore volume of 0.24 cm 3 /g. This material provides open metal sites as active centers (see SI‐1) and a remarkable thermal and chemical stability for different organic solvents with different polarity, even in boiling water . This structural robustness contrasts with the limited stability of other MOF materials shown in the literature.…”