In this mini-review, we summarize the solution syntheses of N,N-dimethylformamide (DMF)-protected metal nanoparticles (NPs) and nanoclusters (NCs) and their use in catalytic reactions. Representative examples are given of external-stabilizer/protectant-free metal NP and NC syntheses by reduction with DMF. In this method, DMF has three roles, i.e., a solvent, reductant, and protectant. Recent applications of DMF-stabilized metal NPs are summarized. These applications have enabled a versatile organic transformation such as cross-coupling reactions, hydrosilylation, and methylation to be achieved. These reactions proceed under low catalyst loadings and ligandless conditions.

Herein, the synthesis of new N,N-dimethylformamide (DMF)-protected palladium nanoparticles (Pd NPs-OAc) employing Pd (OAc)2 ( Pd­(OCOCH3)2) as the NP precursor is reported. Pd NPs-OAc were comprehensively characterized by transmission electron microscopy, FT-IR, NMR, and X-ray photoelectron spectroscopy to determine the Pd NP size distribution and the coordination state of DMF. Pd NPs-OAc were compared with Pd NPs-Cl, using PdCl2 as the NP precursor. The Suzuki–Miyaura cross-coupling reaction proceeded efficiently in the presence of Pd NPs-OAc and a high catalytic activity was observed with a turnover number of up to 1.5 × 105. Furthermore, the Pd NP-OAc catalysts could be recycled at least five times.

Nitrogen-containing six-membered heterocycles such as pyridines, pyrimidines, and triazines are widely used in the synthesis of natural products and pharmaceuticals. Recently, a promising approach to these structures via [2 + 2 + 2] cycloadditions of alkynes and nitriles has been developed. Transition-metal complex catalysts play key roles in the regio-, chemo-, or stereo-selectivity of transformations. Here, we summarize recent advances in metal-mediated/catalyzed [2 + 2 + 2] cycloadditions for synthesizing pyridines and pyrimidines. We also describe progress in triazine synthesis via metal-mediated/catalyzed nitrile cyclotrimerization.

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A highly efficient and reusable Pd NCs catalyst system for silylation of aryl halides was developed.