Small molecular organic nanocrystals resemble carbon nanodots in terms of their properties† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c7sc02528a

• Published in: Chemical science (Cambridge) 2017-10, Vol.9 (1), p.175-180
• Main Authors: Khan, Syamantak, Sharma, Akshita, Ghoshal, Sourav, Jain, Sanjhal, Hazra, Montu K., Nandi, Chayan K.
• Format: Article
• Language: English
• Subjects: Chemistry
• ISSN: 2041-6520; 2041-6539
• DOI: 10.1039/c7sc02528a

We show that hydrothermal treatment of citric acid produces methylenesuccinic acid, which gives rise to hydrogen-bonded nano-assemblies with CND-like properties. The most commonly observed phenomena in carbon nanodots (CNDs) are the strong excitation wavelength dependent multicolor fluorescence emission and the particle size distribution between 3–5 nm observed using a transmission electron microscope (TEM). However, it is not evident yet whether the emission originates from the particles observed using a TEM. In this article, we show that hydrothermal treatment of citric acid produces methylenesuccinic acid, which gives rise to hydrogen-bonded nano-assemblies with CND-like properties. While single crystal X-ray crystallography confirms the structure of methylenesuccinic acid, fluorescence correlation spectroscopy (FCS) confirms the presence of a molecular fluorophore with an average hydrodynamic diameter of ∼0.9 nm. This size is much smaller than the size of the particles observed using a TEM. We conclude that the particles observed using a TEM are the drying mediated nanocrystals of methylenesuccinic acid.