Surface-Functionalized Mesoporous Nanoparticles as Heterogeneous Supports To Transfer Bifunctional Catalysts into Organic Solvents for Tandem Catalysis

Abstract

The combination of chemo-and biocatalysts offers a powerful platform to address synthetic challenges in chemistry, particularly in synthetic cascades. However, transferring both of them into organic solvents remains technically difficult due to the enzyme inactivation and catalyst precipitation. Herein, we designed a facile approach using functionalized mesoporous silica nanoparticles (MSN) to transfer chemo-and biocatalysts into a variety of organic solvents. As a proof-of-concept, two distinct catalysts, palladium nanoparticles (Pd NPs) and Candida antarctica lipase B (CalB), were stepwise loaded into separate locations of the mesoporous structure, which not only provided catalysts with heterogeneous supports for the recycling but also avoided their mutual inactivation. Moreover, mesoporous particles were hydrophobized by surface alkylation, resulting in a tailor-made particle hydrophobicity, which allowed bifunctional catalysts to be dispersed in eight organic solvents. Eventually, these attractive material properties provided the MSN-based bifunctional catalysts with remarkable catalytic performance for cascade reaction synthesizing benzyl hexanoate in toluene. On a broader perspective, the success of this study opens new avenues in the field of multifunctional catalysts where a plethora of other chemo-and biocatalysts can be incorporated into surface-functionalized materials ranging from soft matters to porous networks for synthetic purpose in organic solvents.

Continuous artificial synthesis of glucose precursor using enzyme-immobilized microfluidic reactors

“…Moreover, the immobilization amount of RuBisCO is still small due to the limited space of the microreactor. Some new material such as MOFs 59 , COFs 60 , mesoporous nanoparticles 61 , and carbon nitride 62 could be applied to the microreactor to provide larger surface areas in the future. The reactor can also be easily scaled up 63–66 to increase the output and more functionalities can be integrated, such as deoxygenation, temperature control of individual reaction, etc.…”

Palladium and Copper: Advantageous Nanocatalysts for Multi-Step Transformations

“…Marks and co-workers were interested in the ether C-O bond hydrogenolysis via a dual catalytic system where lanthanide triflate-catalyzed C-O bond scission, followed by Pd-catalyzed hydrogenation [100]. PdNPs were prepared by reduction of palladium hexafluoroacetylacetonate (Pd(hfac)2) with formaldehyde, giving small nanoparticles (1.1-2.9 nm) that were deposited on alumina via atomic layer deposition [101] Recently, Wu et al prepared a bifunctional catalyst consisting of mesoporous silica nanoparticles (MSN) loaded with both PdNPs and Candida antartica lipase B (CalB) [99]. This material was also tuned by surface alkylation resulting in a tailor-made particle hydrophobicity, which permitted to disperse the catalyst in organic solvents.…”

“…Recently, Wu et al prepared a bifunctional catalyst consisting of mesoporous silica nanoparticles (MSN) loaded with both PdNPs and Candida antartica lipase B (CalB) [ 99 ]. This material was also tuned by surface alkylation resulting in a tailor-made particle hydrophobicity, which permitted to disperse the catalyst in organic solvents.…”

Enzyme–Metal Hybrid Catalysts for Chemoenzymatic Reactions

“…With this strategy, enzymes and Pd NPs (≈2 nm) were highly dispersed on the AmP‐MCF and loaded in one compartment which might enhance the efficiency of intermediate diffusion. More recently, Zhang et al reported a stepwise approach to load Pd NPs and CALB into separate locations of the functionalized mesoporous silica nanoparticles (MSN), which avoided the mutual inactivation between enzymes and metal nanoparticles (Figure b). To improve the solubility of hybrid catalyst in organic solvents, the mesoporous silica particles were modified with alkyl chains, resulting in a tailor‐made hydrophobicity of the particle.…”

“…b) The construction process of CALB@Pd@ mMSN. Reproduced with permission . Copyright 2018, American Chemical Society.…”