RESUMO
The photochemistry of nitrous acid (HONO), encompassing dissociation into OH and NO as well as the reverse association reaction, plays a pivotal role in atmospheric chemistry. Here, we report the direct observation of nitrosyl-O-hydroxide (HOON) in the photochemistry of HONO, employing matrix-isolation IR and UV-vis spectroscopy. Despite a barrier of approximately 30 kJ/mol, HOON undergoes spontaneous rearrangement to the more stable HONO isomer through quantum mechanical tunneling, with a half-life of 28 min at 4 K. Kinetic isotope effects and instanton theory calculations reveal that the tunneling process involves the concerted motion of the NO moiety (65.2%) and the hydrogen atom (32.3%). Our findings underscore the significance of HOON as a key intermediate in the photolytic dissociation-association cycle of HONO at low temperatures.
RESUMO
OBJECTIVE: To evaluate the molluscicidal activities of methanol extract of Jatropha curcas leaves against Ampullaria gigas. METHODS: Young snails, adult snails and eggs of Ampullaria gigas were treated with the methanol extract of J. curcas leaves at different doses for different time lengths and the molluscicidal effects of the extract were evaluated. RESULTS: The methanol extract showed a significant molluscicidal effect on the young snails at a low concentration, and treatment with 75 mg/L extract for more than 3 days resulted in a 100% mortality rate of the young snails. The Jatropha leaf methanol extract also showed toxicity to adult snails and eggs. CONCLUSION: Jatropha leaves have a great potential for developing green pesticides to control Ampullaria gigas, but its biochemical mechanism needs further research.
