Pd immobilization biguanidine modified Zr-UiO-66 MOF as a reusable heterogeneous catalyst in Suzuki–Miyaura coupling

Abstract

In recent days, nanohybrid metal organic frameworks (MOF) have been considered as next generation catalysts due to their unique features like large surface to volume ratio, tailorable geometry, uniform pore sizes and homogeneous distribution of active sites. In this report, we address the biguanidine modified 3D Zr-centred MOF UiO-66-NH2 following a post synthetic modification approach. Utilizing the excellent chelating ability of biguanidine, Pd ions are immobilized over the host matrix MOF. The as-synthesized material was physicochemically characterized using a broad range of analytical techniques like FT-IR, electron microscopy, EDS, elemental mapping, XRD and ICP-OES. Subsequently the material has been catalytically employed in the classical Suzuki–Miyaura coupling towards the synthesis of diverse biphenyl derivatives at sustainable conditions. There are very few reports on the covalently modified MOFs towards the organic coupling reactions. The catalyst has been isolated by centrifugation and recycled in 9 consecutive runs with almost insignificant leaching and minute decrease in reactivity.

Stabilization of Palladium-Nanoparticle-Decorated Postsynthesis-Modified Zr-UiO-66 MOF as a Reusable Heterogeneous Catalyst in C–C Coupling Reaction

“…The growth of a C–C bond is a consequence of a cross-coupling reaction, defined as the substitution of a heteroatom nucleophile for an alkyl, aryl, or vinyl halide . Multiple aryl derivatives may be made in one go with high selectivity and without the need for an intermediate product isolation. − Also, cross-coupling reactions are considered as a protagonist, which is specifically utilized in the synthesis of diverse symmetric and asymmetric heteroaryl and biaryl patterns which are essential as vital building structures to provide natural products; pharmaceuticals including important hypertensive, fungicide, antimicrobial, antidiabetic, and analgesic pharmaceutical structures; the antibiotic vancomycin; and anticancer drugs. − …”

Palladium‐Based Metal Organic Frameworks as Heterogeneous Catalysts for C−C Couplings

“…The functionalization of UiO-66-NH 2 with biguanidine moieties allowed the grafting of K 2 PdCl 4 to the -NH 2 groups under aqueous room temperature conditions (Figure 5). [78] The XRD pattern was similar before and after the metalation, while the BET surface area decreased from 831 to 629 m 2 g À 1 . The catalytic activity of the Pd-MOF (0.1 mol% Pd) was 98 % yield in 10 min (TON: 980, TOF: 5880 h À 1 ) in the Suzuki-Miyaura coupling between iodobenzene and phenylboronic acid at 50 °C in a water-ethanol mixture using K 2 CO 3 as a base.…”

Synthesis of UiO-66-Sal-Cu(OH)2 by a Simple and Novel Method: MOF-Based Metal Thin Film as a Heterogeneous Catalyst for Olefin Oxidation

“…Although considerable progress has recently been attained in this very active scope, the metal species utilized for the fabrication of metal@MOFs are mainly valuable metals. , In contrast, the earth-abundant metal (base metal) elements are relatively rarely employed to design and synthesize metal@MOFs catalysts. For example, in the purveyance of catalysts for the oxidation of olefins, valuable metals such as palladium, titanium, and molybdenum are often used, which is considered one of the problems of this type of reaction. , On the other hand, novel species of base metal-loaded MOF heterogeneous catalytic systems are obligatory because of increasing earnest sustainable and environmental subjects .…”

“…The postsynthetic modification (PSM) of MOFs is an appropriate way of synthesizing functionalized MOFs and begetting numerous active positions. , Postimmobilized metal ions or metal nanoparticles thereon on a MOF scaffolding is a very powerful instrumentation for inorganic catalysts that merges the preponderances of simple separation and restoration of heterogeneous catalysts with the great catalytic activity of dissolved transition-metal complexes. However, organic applications of active metal-adorned postfunctionalized MOFs have not been much delved and there are abundant scopes to expand this area. − …”