Sustained Acid Release from Stimuli Responsive Organic Crystals Facilitates Shape Modulation in Metal Nanoparticle Synthesis

Abstract

Stimuli-responsive fluorescent materials are gaining significant attention in the development of smart materials, particularly for applications in sensing, drug delivery, and environmental monitoring. In this study, we demonstrate how molecular engineering can transform simple naphthalidenimine-boron complexes - known for their remarkable photophysical properties - into functional materials with pH- and temperature-sensitive luminescence. Detailed crystallographic and spectroscopic analyses reveal the critical role of the donor moiety in modulating charge-transfer interactions, which not only enhance the photophysical characteristics but also introduce stimuli-responsive behaviour. Additionally, the gradual, sustained proton release from these molecules facilitates metal nanoparticle synthesis, which aids in surface passivation and controls nanoparticle growth kinetics, resulting in well-defined shapes. This research underscores the potential of molecular engineering to design advanced materials with tailored, responsive properties, opening new avenues for applications where environmental adaptability is key.