Multi-species Toxicity Testing of iPrNHC: A Candidate for Organic Coating Enhancements
Abstract
Corrosion is a natural process affecting the longevity and integrity of metals. N-Heterocyclic carbenes (NHCs) are robust organic compounds that can form strong σ-bonds with metal atoms, allowing for the formation of monolayers on the metal surface. This property makes NHCs promising for coating metals. However, their long-term effects on the aquatic environment are not well understood. The present study investigated the ecotoxicity of 1,3-diisopropyl-1H-benzoimidazolium bicarbonate (iPrNHC NCO3-), a candidate for organic coating enhancements, on various species of aquatic organisms. The results showed that high concentrations of iPrNHC significantly increased mortality rates in zebrafish embryos, planarians, Daphnia, and snail embryos, with notable impacts on heart rate and hatching. In contrast, low concentrations had minimal effects. A 96-hour study on planaria brown flatworms also found that higher temperatures (25°C) and neutral pH (7.5) increase the toxicity of iPrNHC, emphasizing the role of temperature and pH in its harmful effects.