Hydrogen bonding network dynamics of crocin–water binary solutions by Raman spectroscopy

Crocin is a natural pigment with diverse physiological activities and finds extensive applications in the pharmaceutical, food, and cosmetics industries. Understanding the behavior and properties of crocin in solution can provide a scientific basis for its applications, thus further expanding its potential uses. In this study, we employed Raman spectroscopy to investigate the hydrogen bond (HB) network in a crocin–water binary solution. Our results revealed anomalous changes in the HBs at a concentration of 5 × 10−4 M. In particular, we observed an enhancement of the HBs in water accompanying the increasing concentration of crocin. Notably, at a concentration of 9 × 10−4 M, the free H–O groups of crocin formed strengthened hydrogen bonds with the HBs of water, ultimately leading to the disappearance of the free H–O groups. These findings provide valuable insights into the HB network in the crocin–water binary solution, shedding light on the intermolecular interactions in water solutions involving crocin. The use of Raman spectroscopy in our investigation presents a novel and effective approach for studying HB networks in similar systems.