Multi-stimuli responsive materials based on cellulose nanocrystals (CNCs), especially using non-conventional stimuli including light, still need more explorations, to fulfill the requirements of complicated application environments. The structure determination of functional groups on the CNC surface constitutes a significant challenge, partially due to their low amounts. In this study, rhodamine spiroamide groups are immobilized onto the surface of CNCs leading to a hybrid compound being responsive to pH-values, heat and UV light. After the treatment with external stimuli, the fluorescent and correlated optical color change can be induced, which refers to a ring opening and closing process. Amine and amide groups in rhodamine spiroamide play the critical role in this switching process. Solid-state NMR spectroscopy coupled with sensitivity-enhanced dynamic nuclear polarization (DNP) was used to measure ¹³C and ¹⁵N in natural abundance, allowing the determination of structural changes during the switching process. It is shown that a temporary bond through an electrostatic interaction could be formed within the confined environment on the CNC surface during the heat treatment. The carboxyl groups on the CNC surface play a pivotal role in stabilizing the open status of rhodamine spiroamide groups.

The synthesis of ruthenium nanoparticles (RuNPs) using secondary phosphine oxides (SPOs) as ligands is reported. These easily accessible ligands allow the formation of small nanoparticles in the size range of 1–2 nm which display a high efficiency for hydrogenation of aromatics with TOFs up to 2700 mol h⁻¹.