Lewischemie

Lewischemie is a branch of chemistry that studies Lewis acids and Lewis bases, defined as species that accept or donate an electron pair, respectively, and the interactions that arise from these exchanges. The framework extends beyond proton transfer and Bronsted-Lowry concepts to describe many reactions in solution, catalysis, and materials science. The field traces its conceptual roots to Gilbert N. Lewis’s early 20th-century theory of acid-base interactions and has since broadened to encompass coordination chemistry, organometallics, polymerization, and activation of inert molecules.

Key concepts include the definitions of Lewis acids and bases, adduct formation, and the notion of Lewis acidity and basicity scales. Experimental measures such as the Gutmann-Beckett method, which uses NMR shifts of probe bases to quantify acidity, as well as computational descriptors like fluoride affinity and LUMO energy, are used to compare species. The idea of frustrated Lewis pairs (FLPs)—bulky combinations of Lewis acids and bases that do not form stable adducts—is an active area with applications in small-molecule activation.

Applications of Lewischemie include catalysis, where Lewis acids catalyze reactions such as Friedel–Crafts alkylation, polymerization, and the activation of small molecules like CO2 and N2; Lewis bases stabilize reactive intermediates and enhance catalytic cycles. In materials science, Lewis acid-base interactions influence bonding in polymers and metal-organic frameworks.

Lewischemie sits alongside Bronsted-Lowry acid-base theory and the hard-soft acid-base (HSAB) framework, offering a complementary electron-pair perspective. Ongoing research addresses quantifying acidity across solvents, developing new boron and silicon Lewis acids, and expanding applications in energy storage and catalysis.