Solvent-Assisted Control of Metal-Organic Nanotube Size and Morphology

While intensive studies have focused on the synthesis and characterization of new metal-organic nanotube (MONT) structures, the lack of size and morphology control remains an obstacle in broadening applications for this class of materials. Herein, we demonstrate control of MONT crystallite size and morphology by tuning polarity and the protic/aprotic nature of solvents, including dimethylformamide, N-methyl-2-pyrrolidone, ethanol, and 2-methyltetrahydrofuran, for the isostructural syntheses of two MONTs. Through a combination of transmission electron microscopy, powder X-ray diffraction, and selected area electron diffraction, we find that MONT crystallite sizes can be tuned while maintaining control over the relative dispersity without significantly altering the underlying crystal structure.