Progress in the Design of Cooperative Heterogeneous Catalytic Materials for C–C Bond Formation

Abstract

The application of cooperative heterogeneous catalysts for the promotion of C-C bond formation is of great potential for making such chemical processes more sustainable. In the design of such materials, the main challenges are to form specific catalytic sites and to control the cooperative interactions. Because of the high complexity inherent to cooperative active site interactions, much of the research is focused on so called "enzyme inspired-materials." The current Progress Report identifies three material subgroups that are characterized by a rigid-ordered backbone (layered material), a flexible backbone (polymer based), or a constrained-flexibleordered backbone (metal organic frameworks). In each of these material types, examples that illustrate how key structural and chemical characteristics functions are associated with the efficient promotion of the cooperative mechanism are highlighted. The limitations and strengths of each of the systems are considered with the aim of providing an outlook with regard to the minimum requirements needed to construct an efficient cooperative catalytic material. Given the current accumulated common knowledge in this area, it is suggested that getting inspiration from the synthetic existing systems is perhaps more beneficial than from enzymes.

Polystyrene-Supported Cu/2,2,6,6-Tetramethyl-1-piperidine-N-oxyl Catalytic Systems Constructed by Nanoprecipitation and Their Cooperative Catalysis for Benzyl Alcohol Oxidation

“…Based on polymer supports, several promising strategies were devised to construct cooperative multifunctional catalysts. − For instance, the molecular imprinting strategy was widely used to synthesize highly cross-linked polymer catalysts using the lock-and-key principle, − exhibiting excellent activity, efficiency, and proficiency. Such a strategy requires carefully designed transition state analogues as templates, causes high structural rigidity, lacks versatility, and limits the catalytic scope.…”

Elucidating Cooperative Interactions between Grafted Amines and Tin or Titanium Sites on Silica

“…As such, this class of heterogeneous catalysts can make the overall chemical process significantly more environmentally friendly. However, inducing and even more so controlling the cooperative catalytic interactions on a solid material is a challenging task. ,− To synthesize an efficient cooperative catalytic material, three architectural levels in material design need to be engineered: (1) the 3D structure of the support, (2) the immediate chemical environment surrounding the catalytic site, and (3) the precise positioning and orientation of the catalytic sites …”

Cooperatively Catalyzed Henry Reaction through Directed Metal‐Chitosan Interactions

“…[1] To efficiently achieve such interactions, common in natural enzymes, the properties of the active sites and its surrounding chemical environment needs to be precisely controlled. [2] A reaction catalyzed by a cooperative catalyst will typically have a lower activation energy compared to a reaction catalyzed by a single site catalyst, [3] and ultimately lead to a more energy friendly chemical process with less process waste. [2] Heterogeneous cooperative materials based on amines and acidic groups grafted on a mesoporous rigid silica support, were studied extensively.…”

“…[2] A reaction catalyzed by a cooperative catalyst will typically have a lower activation energy compared to a reaction catalyzed by a single site catalyst, [3] and ultimately lead to a more energy friendly chemical process with less process waste. [2] Heterogeneous cooperative materials based on amines and acidic groups grafted on a mesoporous rigid silica support, were studied extensively. [4][5][6][7] Using the silica based materials it was possible to isolate structural and chemical factors that govern the cooperative interactions.…”

“…For synthetic solid material it is a major challenge to induce cooperative catalytic interactions, in which two active sites work in concert to promote a single chemical transformation . To efficiently achieve such interactions, common in natural enzymes, the properties of the active sites and its surrounding chemical environment needs to be precisely controlled . A reaction catalyzed by a cooperative catalyst will typically have a lower activation energy compared to a reaction catalyzed by a single site catalyst, and ultimately lead to a more energy friendly chemical process with less process waste …”