Mechanochemistry is a growing field for chemical reactions that proceed in the solid state in the absence, or with miniscule amounts, of solvent added. For decades, solvents have been considered conventional for the progression of modern chemistry, nonetheless, researchers are increasingly demonstrating that mechanochemistry can synthesize complex molecules more effectively. With more progress, mechanochemistry could alleviate solvent-related environmental and financial burdens in chemical industries.
Using mechanochemistry, researchers from Nagoya University including Koya M. Hori, Yoshifumi Toyama, and Hideto Ito successfully developed a two-step synthetic method for dihydrodinapthopentalenes (DHDPs), conductive organic molecules that are considerably challenging to synthesize. These findings were recently published in the journal RSC Mechanochemistry on February 5, 2026, and is available as Open Access. The results are expected to advance the synthesis of compounds with applications in organic materials.
Conductive organic molecules are used in growingly essential technologies such as OLEDs in smartphone screens, solar cells for renewable energy, anti-static polymer coatings, and more. Perhaps due to their complex and expensive synthesis, however, DHDPs have not been integrated into any commercialized products. Previous reports for synthesizing DHDPs required multiple reaction steps, long reactions times (12-48 hours), structural constraints in starting materials, and were air sensitive. With the new mechanochemical method, several DHDP derivatives could be synthesized in 15 minutes while open to air and with ~99% less solvent waste compared to previous methods.
The mechanochemical experimental procedure is simple. Solid reagents, such as lithium wire and 2-arylethynylnapthalene (organic starting material), and a very small amount of THF (6.5 equivalents, <1 mL) as an additive are placed in a small stainless-steel container with stainless-steel balls. The container is placed in a ball mill that mixes and agitates the reagents with high-speed vibrations. After 15 minutes of vibration, the container is opened, and an aqueous ammonium chloride solution is added to neutralize the reaction and procure the new DHDP. Using this facile method, both simple and complex structural derivatives could be isolated using inexpensive starting materials.
RSC Mechanochemistry
Experimental study
Lithium-mediated mechanochemical annulative dimerization of diarylacetylenes for synthesis of 1,4-dihydrodinaphthopentalenes
5-Feb-2026