Dictating Catalytic Preference and Activity of a Nanoparticle by Modulating Its Multivalent Engagement

Abstract

Incorporating adaptive and dynamic behavior in a catalytic system is the foremost prerequisite to gain nature-like complex functionality in a synthetic chemical network. Herein, we report a self-assembled modular catalytic system based on the multivalent interaction between a cationic gold nanoparticle surface and nucleotides. It is shown that the catalytic preference and activity of the nanoparticle can be directed in a controllable manner toward either hydrazone formation or a proton transfer reaction only by creating a differential local microenvironment around the nanoparticle surface, simply by changing or converting the multivalent scaffold around it. The temporal control of the system in governing the reaction preference and catalytic activity will enable designing a system of higher complexity with a preprogrammed reaction networking property.

Perpetuating enzymatically induced spatiotemporal pH and catalytic heterogeneity of a hydrogel by nanoparticles

“…[33][34][35] Recently, we have shown that the catalytic ability of a cetyltrimethylammonium bromide (CTAB)-functionalized cationic gold nanoparticle (GNP) can be up-and downregulated by exploiting multivalent interactions between GNPs and adenosine-based nucleotides. 35 The alteration of the local surface pH of the GNPs due to the assembly of these differently charged nucleotides was the key reason for this modulatory catalytic behavior. In the present work, we have also synthesized and characterized CTAB-capped GNPs with a diameter of 20 AE 3 nm and a positive surface zeta potential of 85 AE 5 mV (Fig.…”

“…Notably, physical properties, such as pH and polarity, in the microenvironment of the micellar interface are different than those in bulk solution; and this property is also preserved in surfactant-layer-anchored nanoparticle surfaces. 33–35 Recently, we have shown that the catalytic ability of a cetyltrimethylammonium bromide (CTAB)-functionalized cationic gold nanoparticle (GNP) can be up- and downregulated by exploiting multivalent interactions between GNPs and adenosine-based nucleotides. 35 The alteration of the local surface pH of the GNPs due to the assembly of these differently charged nucleotides was the key reason for this modulatory catalytic behavior.…”

“…The seed-growth method was used to synthesize the gold nanoparticles (GNP), as described in the literature. 35 Firstly, a seed solution was prepared by mixing 0.052 ml of HAuCl 4 ·3H 2 O (24 mM) and 3.75 ml of CTAB (100 mM) solution, followed by the reduction of gold using 1.2 ml of freshly prepared ice-cold NaBH 4 (25 mM), resulting in a brown-colored solution indicating the formation of gold seeds. Then, a growth solution was prepared by mixing 10 ml of CTAB (100 mM) solution with 6.25 ml of HAuCl 4 ·3H 2 O (4 mM) followed by the addition of 7.5 ml of l -ascorbic acid (100 mM) with gentle shaking, which resulted in a colorless solution.…”

“…BTB is known to strongly bind to the cationic GNP surface owing to presence of anionic sulphonate group with aromatic moiety and has been previously used to determine interfacial pH of cationic micelles and nanoparticles. 35,38 We started by calibrating the change in UV absorbance of the BTB at different pH using buffered solution (Figure S2, ESI †). We found the pH of GNP interface was 6.0 ± 0.1 suggesting interfacial pH of the GNP did not alter only in presence of water.…”

Engineering at Subatomic Scale: Achieving Selective Catalytic Pathways via Tuning of the Oxidation States in Functionalized Single‐Atom Quantum Catalysts

“…[11] However, it has been established that mixed-valence states in nanomaterials coordinating environment exhibit extraordinarily high catalytic efficiencies due to the synergism among oxidation states. [12,13] Overlooking the tunability of the oxidation states of single atoms in SACs can, therefore, preclude the catalytic potential of these materials. Although, a few studies have been conducted on the effects of oxidation states of metal centers in precursors, they were only limited to the geometric and structure-dependent properties of the catalysts instead of the quantum dynamics of their oxidation states.…”