Spatially isolated palladium in porous organic polymers by direct knitting for versatile organic transformations

Abstract

et al. (2017) Spatially isolated palladium in porous organic polymers by direct knitting for versatile organic transformations.

The Multifaceted Reactivity of Single‐Atom Heterogeneous Catalysts

“…[10] Aided by synthetic and analytical advancements,ahuge range of potential host materials has now been reported (Figure 2), which encompasses metal oxides, [11][12][13][14] metal hydroxides, [15,16] metals (also termed single-atom alloys (SAAs)), [17,18] micro/ mesoporous materials such as zeolites, [19,20] metal-organic frameworks (MOFs), [21,22] silicas, [23,24] carbon-based materials, [25][26][27][28] organopolymers, [29,30] nitrides, [31][32][33] and carbides. [10] Aided by synthetic and analytical advancements,ahuge range of potential host materials has now been reported (Figure 2), which encompasses metal oxides, [11][12][13][14] metal hydroxides, [15,16] metals (also termed single-atom alloys (SAAs)), [17,18] micro/ mesoporous materials such as zeolites, [19,20] metal-organic frameworks (MOFs), [21,22] silicas, [23,24] carbon-based materials, [25][26][27]…”

“…[38] Most reported systems comprise substitutional alloys, which reflects the similarity in the atomic radii. [26][27][28][29][30][31][32] Theh igh level of control over the heteroatom content (for example,nitrogen can be varied from 0-60 wt %) provides immense scope for tuning the density and structure of the coordination sites within functionalized carbons. [39] Furthermore,itisknown that the active metal can go into sites beneath the top-most layer (subsurface) [40] and become inaccessible in amanner similar to bulk atoms in NPs.…”

“…One of the first challenges in the development of SACs was how to stabilize metal atoms against sintering or leaching in sufficient amounts to give appreciable activity.M etalcontaining zeolites and zeotypes,inwhich metal centers were mainly isolated in crystallographic positions,were among the most notable early examples of successful SACs. [10] Aided by synthetic and analytical advancements,ahuge range of potential host materials has now been reported ( Figure 2), which encompasses metal oxides, [11][12][13][14] metal hydroxides, [15,16] metals (also termed single-atom alloys (SAAs)), [17,18] micro/ mesoporous materials such as zeolites, [19,20] metal-organic frameworks (MOFs), [21,22] silicas, [23,24] carbon-based materials, [25][26][27][28] organopolymers, [29,30] nitrides, [31][32][33] and carbides. [34] Further extending the diversity of this framework with host functionalization strategies (such as,t hrough partial surface hydration, [35] introduction of alkali metals, [36] or decoration with ethylene glycolate species [37] )h as also been demonstrated to successfully enhance the anchoring of metal atoms.…”

“…In carbon-based hosts and related materials the most favorable coordination sites are usually heteroatoms (N,O , S, or P). [26][27][28][29][30][31][32] Theh igh level of control over the heteroatom content (for example,nitrogen can be varied from 0-60 wt %) provides immense scope for tuning the density and structure of the coordination sites within functionalized carbons. [41] There is some indication that metals can become encapsulated in the bulk of carbon-based supports,w hich may also lead to reduced specific activity.…”

Palladium Nanoparticles Supported on Triphenylphosphine-Functionalized Porous Polymer as an Active and Recyclable Catalyst for the Carbonylation of Chloroacetates

“…In recent years, a series of POPs containing a PPh 3 ligand and its derivatives, have been successfully prepared and applied as catalysis supports for immobilizing transition metals [30][31][32][33][34]. Due to the strong interaction between transition metals and phosphine ligands, these catalysts usually exhibit high catalytic activities, long-term reusability, and excellent leaching resistant ability [30][31][32][33][34][35][36][37]. Some of them have even outperformed the activities of their homogeneous analogues [30,[35][36][37].…”