(STEM) studies further validated the observations made through SEM analysis, synchrotron Xray diffraction measurements, and/or PXRD analysis. STEM images clearly show the formation of spherical nanoparticles with a diameter below 40 nm, as well as nanorods exhibiting widths ranging from 35 to 65 nm and lengths between 1000 and 1500 nm (Figure , 2C, and S4), values that align well to those obtained with SEM. The insets of Figures and present high-resolution (HR) STEM images and FFTs, which reveal distinct lattice fringes with a dspacing of 12.93 Å for the nanoparticles and 12.82 Å for the nanorods. These lattice fringes clearly confirm the crystalline nature of the nanoparticles and nanorods, with the nanoparticles exhibiting a lattice fringe corresponding to the 200-crystal lattice plane. Moreover, the successful formation of the imine bond in both the nanoparticles and nanorods was confirmed using solid-state cross-polarization magic angle spinning nuclear magnetic resonance ( 13 C CP-MAS NMR) spectroscopy. The NMR spectra displayed clear signals indicating the presence of the imine bond. Specifically, in the case of the nanoparticles, a signal was observed at 158.7 ppm, while for the nanorods, the signal appeared at 159.0 ppm (Figure and Table ). Additionally, attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy was also employed to further confirm the presence of the imine bond in the nanoparticles and nanorods with the observation of the characteristic C=N stretching band located at 1616 cm -1 and 1621 cm -1 , respectively (Figure ).