Currently, catalytic process account for a quarter of the global energy usage, however, traditional heterogeneous catalysts lack efficiency due to poorly defined active sites. Single Atom Catalysts (SACs) have recently emerged as potential candidates to bridge the gap to a more efficient and sustainable future. SACs are a class of heterogenous catalysts, important for stability and recyclability, however in contrast to other systems, they feature well-defined active “edge” sites in direct contact with the “support” material. Well-defined active sites improve catalytic efficiency and increase metal atom utilization, an important trait especially when using expensive noble metals (Pd, Pt, Ru, etc.). Despite these advantages, the rational synthesis of SACs remains a challenge, primarily due to the difficulty in studying the complex interactions that occur between the edge and the support during catalysis. Our group has recently developed an atomically precise nanopropeller cluster framework in which three surface edge metals are in direct contact the cluster support. Herein, we report the synthesis of a new heteroleptic cluster metalloligand, Co6Se8(PEt3)4L2 (L = Ph2PNHR; R = iPr or 4-tolyl), which features a single “edge” site at the surface of the redox active Co6Se8 “support”. Metallation of the cluster ligand with a variety of divalent metal halides has produced a series of surface-functionalized clusters, MCo6Se8(PEt3)4L2 (M = Fe, Co, Cu, Zn), in which the metal-support interaction was interrogated directly via single-crystal X-ray data, NMR studies, electrochemical analysis, and DFT calculations. Additionally, the cooperativity between the edge metal and the cluster support in FeCo6Se8(PEt3)4L2 is demonstrated in the catalytic coupling of tosyl azide (TsN3) and tert-butyl isocyanide (CNtBu) to form the asymmetric carbodiimide, TsN=C=NtBu.

Atomically defined nanoclusters as functional models for the electronic metal-support interaction and high catalytic activity for carbodiimide formation

ACS Spring Meeting 2021

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