Quantitative Solid-State NMR Study on Ligand–Surface Interaction in Cysteine-Capped CdSe Magic-Sized Clusters
journal contributionposted on 23.05.2017, 00:00 by Takuya Kurihara, Yasuto Noda, K. Takegoshi
Ligand–surface interaction of semiconductor nanoparticles (NPs) controls their optoelectronic properties, and thus examination of the interaction is essential for the nanoelectronic applications of NPs. Herein, solid-state nuclear magnetic resonance (NMR) is performed to unravel the ligand–surface interaction in cysteine-capped CdSe magic-sized clusters. 15N–113Cd through-bond J-filtered NMR directly shows the presence of the nitrogen–cadmium chemical bond for the first time and indicates that ∼43% of the amines form the chemical bond. 15N–113Cd through-space dipolar-correlated NMR reveals that ∼54% of the amines locate nearby the surface cadmium with the average nitrogen–cadmium distance of 0.247 nm. The average distance is comparable with that estimated by J-filtered NMR. The difference of the two ratios (∼11%) proposes that some amines locate on the surface without forming the chemical bond, and these amines affect the relatively long observed distance in the dipolar-based experiment. Our study shows effectiveness of solid-state NMR for investigation of the ligand–surface interactions of NPs.