Metal-Micelle Interaction Leading to Spontaneous Formation of Ligand-Free Palladium(0) Nanoparticles: Highly Efficient Catalysis Enabling Biaryl Ketone Formation from Carboxylic Acid Derivatives

Gaganpreet Kaur; Jacek B Jasinski; Fabrice Gallou; Sachin Handa

doi:10.1021/acsami.2c15099

Metal-Micelle Interaction Leading to Spontaneous Formation of Ligand-Free Palladium(0) Nanoparticles: Highly Efficient Catalysis Enabling Biaryl Ketone Formation from Carboxylic Acid Derivatives

ACS Appl Mater Interfaces. 2022 Nov 16;14(45):50947-50955. doi: 10.1021/acsami.2c15099. Epub 2022 Nov 7.

Authors

Gaganpreet Kaur¹, Jacek B Jasinski², Fabrice Gallou³, Sachin Handa¹

Affiliations

¹ Department of Chemistry, University of Louisville, Louisville, Kentucky 40292, United States.
² Materials Characterization, Conn Center for Renewable Energy Research, University of Louisville, Louisville, Kentucky 40292, United States.
³ Chemical & Analytical Development, Novartis, Basel 4056, Switzerland.

PMID: 36341774
DOI: 10.1021/acsami.2c15099

Abstract

A novel strategy has been developed to spontaneously form ligand-free Pd(0) nanoparticles (NPs) from water- and air-sensitive Pd₂dba₃ in water. These NPs are thoroughly characterized by IR, NMR, and mass spectrometry, revealing that the metal-micelle binding plays a critical role in their stability and activity. High-resolution transmission electron microscopy supported the ultrasmall nature of NPs, whereas X-ray photoelectron spectroscopy analysis confirmed the zero-oxidation state of Pd. The shielding effect of micelles and enhanced stability of NPs enabled fast cross-couplings of water-sensitive triazine adducts of carboxylic acid to form nonsymmetrical biaryl ketones. These naturally formed NPs are more efficient than new synthetic NPs formed under a hydrogen atmosphere and traditional NPs formed using the air-sensitive Grignard reagent as a reductant. The activity of naturally formed NPs is compared with that of synthetic NPs over 34 substrates, revealing that naturally formed NPs are much more efficient than synthetic NPs.

Keywords: amphiphile; chemistry in water; cross-couplings; micellar catalysis; palladium nanoparticles.