DOI: 10.5281/zenodo.5905393
title: Mapping out the aqueous surface chemistry of metal oxide nanocrystals; carboxylate, phosphonate and catecholate ligands

description: Data underlying the figures in the publication “Mapping out the aqueous surface chemistry of metal oxide nanocrystals; carboxylate, phosphonate and catecholate ligands”, published in JACS Au. Table of contents: The <em>.pxp</em> documents contain the experimental data of the figures in the manuscript and it can be opened/edited with the software IGOR Pro 8.0 or higher. <strong>1. Figure 1.pxp</strong>: Experimental data for <em>Figure 1</em>. (A) Solvothermal synthesis of HfO<sub>2</sub> nanocrystals starting from 1 equivalent Hf(O-tBu)<sub>4</sub> and 80 equivalents benzyl alcohol. (B) <sup>1</sup>H NMR spectra (normal or diffusion filtered) of MEEAA functionalized HfO<sub>2</sub> NCs in different solvents. The α and β resonances belong to the residual hydroxyl and methyl groups of methanol, respectively. (C) Transmission Electron Microscopy (TEM) image of the synthesized HfO<sub>2</sub> NCs. The NC diameter of the quasi-spherical NCs was calculated after measuring the surface area of at least 150 NCs and calculated the diameter as if it was a circle. A size distribution histogram and a zoomed-in image of a singular NC can be seen respectively in the bottom left and the top right corner. <strong>2. Figure 2.pxp</strong>: Experimental data for <em>Figure 2</em>. (A) Ligand exchange performed between MEEAA functionalized NCs and PA-PEG. (B) <sup>1</sup>H NMR reference spectra in MeOD of the free ligands as reference and the stepwise titration of MEEAA functionalized NCs with PA-PEG, equivalents are with respect to the total amount of MEEAA present. (C) <sup>31</sup>P NMR spectra (4096 scans) in MeOD for the stepwise titration of MEEAA functionalized NCs with PA-PEG, broadened signals are indicative of NC binding. (D) Diffusion filtered <sup>1</sup>H NMR spectra of MEEAA functionalized NCs in MeOD after addition of 1.3 equivalents of PA-PEG. Signals arising from bound MEEAA are denoted in red, signals arising from PA-PEG are denoted in striped blue. CNC = 1210 µmol.L<sup>-1</sup>, corresponding to 34 mg NCs of this size in 0.5 ml MeOD. Resonances denoted as * are unidentified impurities. <strong>3. Figure 3.pxp</strong>: Experimental data for <em>Figure 3. </em>Diffusion filtered <sup>1</sup>H NMR spectrum of the NC suspension in MeOD at 1.3 equivalents PA-hex-PEG added. <strong>4. Figure 4.pxp</strong>: Experimental data for <em>Figure 4.</em> (A) and (B) <sup>31</sup>P NMR spectra of PA-PEG and PA-hex-PEG functionalized NCs at different D<sub>2</sub>O volume %. (C) Free ligand fraction for PA-PEG and PA-hex-PEG at different D<sub>2</sub>O volume %, determined by peak deconvolution. <strong>5. Figure 5.pxp</strong>: Experimental data for <em>Figure 5.</em> (A) Ligand exchange performed between MEEAA functionalized NCs and nitrodopamine-mPEG. (B) <sup>1</sup>H NMR spectra before and after the ligand exchange titration performed in D<sub>2</sub>O with nitrodopamine-mPEG. 1.5 equivalents of nitrodopamine-mPEG were added and the pH was kept above 5 at all times during addition, the purified nitrodopamine functionalized NC spectrum was measured at pH = 7.4. CNC = 128 µmol.L<sup>-1</sup>, corresponding to 14.4 mg NCs of this size in 2 ml D<sub>2</sub>O. <strong>6. Figure 6.pxp</strong>: Experimental data for <em>Figure 6. </em>Effect of pH on ligand binding and stability in water for purified NCs functionalized with PA-PEG, PA-hex-PEG and nitrodopamine-mPEG. (A) Bound and unbound ligand fraction in D<sub>2</sub>O based on NMR peak deconvolution at different pH values. (B) Z-average value of NCs in DLS at different pH values. (C) Zeta potential of the NCs at different pH values. All measurements were performed at constant ionic strength (0.01 mol.L<sup>-1</sup> NaCl) at 25°C <strong>7. Figure 7.pxp</strong>: Experimental data for <em>Figure 7.</em> Stability of functionalized NCs in different concentrations of phosphate buffered saline (PBS) at pH 7.4 and 25°C. (A) Colloidal stability of functionalized nanocrystals measured using DLS z-average values at different PBS concentrations. (B) Stability of functionalized NCs in 2X PBS over time at pH 7.4 and 25°C. <strong>8. Figure 9.pxp</strong>: Experimental data for <em>Figure 9.</em> UV-VIS spectra of purified nitrodopamine-mPEG functionalized NCs at different pH values in H2O.