Two novel donor–acceptor Stenhouse adducts (DASAs) featuring the catechol moiety were synthesized and characterized. Both compounds bind strongly to the surfaces of magnetite nanoparticles. An adrenaline-derived DASA renders the particles insoluble in all common solvents, likely because of poor solvation of the zwitterionic isomer generated on the nanoparticle surfaces. Well-soluble nanoparticles were successfully obtained using dopamine-derived DASA equipped with a long alkyl chain. Upon its attachment to nanoparticles, this DASA undergoes an irreversible decoloration reaction owing to the formation of the zwitterionic form. The reaction follows first-order kinetics and proceeds more rapidly on large nanoparticles. Interestingly, decoloration can be suppressed in the presence of free DASA molecules in solution or at high nanoparticle concentrations.
- donor–acceptor Stenhouse adducts
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry
- Analytical Chemistry