Data for "Binding Affinity of Monoalkyl Phosphinic Acid Ligands toward Nanocrystal Surfaces".

Data of the figures in the publication "Binding Affinity of Monoalkyl Phosphinic Acid Ligands toward Nanocrystal Surfaces".

The .pxp documents contain the experimental data of the figures in the manuscript and they can be opened/edited with the software IGOR Pro 6.3 or higher.

Table of contents:

Figure 1. (A) General reaction scheme toward monoclinic HfO₂/oleate NCs. (B) TEM image and (C) DOSY NMR spectrum in C₆D₆ of HfO₂/oleate NCs. (D) General reaction scheme toward zinc blend CdSe/oleate NCs. (E) TEM image and (F) DOSY NMR spectrum in C₆D₆ of CdSe/oleate NCs.

Figure 2. (Left) Titration of HfO₂/oleate with 6-(hexyloxy)hexylphosphinic acid. (A) General reaction scheme. (B) ¹H NMR spectra of the titration. (C) ³¹P NMR after 0.95 and 1.15 equiv of phosphinic acid is added. (D) Quantification of the different compounds as a function of the added equivalents. (Right) Titration of CdSe/oleate with 6-(hexyloxy)hexylphosphinic acid. (E) General reaction scheme. (F) ¹H NMR spectra of the titration. (G) ³¹P NMR after 1.0 and 1.2 equiv of phosphinic acid is added. (H) Quantification of the different compounds as a function of the added equivalents.

Figure 3. (A) ¹H NMR spectrum of oleate-capped HfO₂ NCs in C₆D₆. (B) ¹H NMR spectrum of HfO₂ in C₆D₆ after ligand exchange for 6-(hexyloxy)hexylphosphinic acid and purification. The inset shows the ³¹P NMR spectrum.

Figure 4. (Left) Titration of HfO₂/[6-(hexyloxy)hexyl]phosphinate with oleylphosphonic acid. (A) General reaction scheme. (B) ¹H NMR spectra of the titration. (C) Quantification of the different compounds as a function of the added equivalents. Note that the small amount of residual oleic acid present at the start of the titration in (B) is due to a challenging purification (high solubility of the HfO₂/[6-(hexyloxy)hexyl]phosphinate NCs). This small signal was integrated and subtracted from the spectra for the quantification in (C). (Right) Titration of CdSe/[6-(hexyloxy)hexyl]phosphinate with oleylphosphonic acid. (D) General reaction scheme. (E) ¹H NMR spectra of the titration. (F) Quantification of the different compounds as a function of the added equivalents.

Figure 5. Mole fraction of bound oleylphosphonate in the ligand shell, χ_{phosphon (bound)}, as a function of the overall mole fraction of oleylphosphonic acid (=unbound phosphonic acid and bound phosphonate), χ_{phosphon (total)}, during the titrations of HfO₂ (blue), CdSe (red), and ZnS (green) NCs. The full lines represent different calculated equilibrium constants.

Figure 6. Mole fraction of a bound incoming ligand (= titrating ligand) in the ligand shell, χ_{incomingligand (bound)}, as a function of the overall mole fraction of the total incoming ligand (=unbound and  bound), χ_{incomingligand (total)}, during the titrations of ZnS NCs stabilized with a 50/50 mixture of n-hexyl/n-octadecylphosphinate with oleylphosphonic acid (gray), ZnS NCs stabilized with 6-(hexyloxy)hexylphosphinate  with oleylphosphonic acid (green) and ZnS NCs stabilized with oleate with a 50/50 mixture of n-hexyl/n-octadecylcarboxylic acids (orange). The full lines represent the different calculated equilibrium constants.

Figure S1. (A) HfO2/oleate NCs, (B) 1H NMR spectrum in C6D6, and (C) DOSY decay curve of the alkene region.

Figure S2. (A) CdSe/oleate NCs, (B) 1H NMR spectrum in C6D6, and (C) UV-vis absorption spectrum, (D) DOSY decay curve of the alkene region, and (E) DOSY decay curve of the methylene region.

Figure S3. Synthesis of zinc blende ZnS/oleate NCs. (A) General reaction scheme, (B) TEM image, and (C) 1H NMR spectrum in C6D6, (D) DOSY NMR spectrum in C6D6, (E) DOSY decay curve of the alkene region, and (F) UV-vis absorption spectrum.

Figure S4. 1H NMR of (top, black line) the supernatant of the HfO2/oleate NCs after titration until 1.0 equivalent 6-(hexyloxy)hexyl phosphinic acid is added, and (bottom grey line) reference spectrum of oleic acid in CDCl3.

Figure S5. 1H NMR of (top, black line) the supernatant of the CdSe/oleate NCs after titration until 1.0 equivalent 6-(hexyloxy)hexyl phosphinic acid is added, and (bottom grey line) reference spectrum of oleic acid in CDCl3

Figure S6. Titration of ZnS/oleate NCs with 6-(hexyloxy)hexylphosphinic acid. (A) General reaction scheme, (B) 1H NMR spectra of the titration, (C) 31P NMR after 1.0 and 1.6 equivalent phosphinic acid is added, and (D) quantification of the different compounds as a function of added equivalents.

Figure S7. 1H and 31P NMR spectra of (top gray line) n-tetradecylphosphinic acid dehydrated
with dicyclohexylcarbodiimide (DCC) to form n-tetradecylphosphinic anhydride, and (bottom
black line) n-tetradecylphosphinic acid reference, both in C6D6. 

Figure S8. (A) 1H and (B) 31P NMR of (top black line) the supernatant of the ZnS/oleate NCs after titration until 1.6 equivalent 6-(hexyloxy)hexylphosphinic acid is added, and reference spectra of (red line) oleic acid and (blue line) 6-(hexyloxy)hexylphosphinic acid in CDCl3.

Figure S9. Purified HfO2/[6-(hexyloxy)hexyl]phosphinate NCs. (A) HfO2/phosphinate NCs. (B) 1H NMR spectrum in C6D6 with zoom inset of the broadened P-H resonance, (C) 31P NMR spectrum in C6D6, (D) DOSY NMR spectrum in C6D6, (E) DOSY decay curve of the ether region.

Figure S10. Purified CdSe/[6-(hexyloxy)hexyl]phosphinate NCs. (A) CdSe/phosphinate NCs. (B) 1H NMR spectrum in C6D6, (C) 31P NMR spectrum in C6D6, (D) DOSY NMR spectrum in C6D6, (E) DOSY decay curve of the ether region, (F) DOSY decay curve of the methylene region, and (G) UV-vis absorption spectrum.

Figure S11. Purified ZnS/[6-(hexyloxy)hexyl]phosphinate NCs. (A) ZnS/phosphinate NCs. (B) 1H NMR spectrum in C6D6 with zoom inset of the broadened P-H resonance, (C) 31P NMR spectrum in C6D6, (D) DOSY NMR spectrum in C6D6, (E) DOSY decay curve of the ether region, and (F) UV-vis absorption spectrum.

Figure S12. (A) 1H and (B) 31P NMR of the supernatant (black line) of the HfO2/phosphinate NCs after titration until 2.0 equivalent oleylphosphonic acid is added, and reference spectra of (green line) oleylphosphonic acid and (blue line) 6-(hexyloxy)hexylphosphinic acid in C6D6

Figure S13. (A) 1H and (B) 31P NMR of the supernatant (black line) of the CdSe/phosphinate NCs after titration until 2.0 equivalent oleylphosphonic acid is added, and reference spectra of (green line) oleylphosphonic acid and (blue line) 6-(hexyloxy)hexylphosphinic acid in C6D6. 

Figure S14. Titration of ZnS/[(6-hexyloxy)hexyl]phosphinate with oleylphosphonic acid. (A) General reaction scheme, (B) 1H NMR spectra of the titration, and (C) quantification of the different compounds as a function of added equivalents.

Figure S15. (A) 1H and (B) 31P NMR of the supernatant (black line) of the ZnS/phosphinate NCs after titration until 2.0 equivalent oleylphosphonic acid is added, and reference spectra of (green line) oleylphosphonic acid and (blue line) 6-(hexyloxy)hexyl phosphinic acid in C6D6.

Figure S16. Titration of HfO2 NCs stabilized with a mixed ligand shell consistent of 6-(hexyloxy)hexylphosphinate and oleylphosphonate. (A) General reaction scheme, (B) 1H NMR spectrum of the purified NCs prior to titration (at 0.0 added equivalents of 6-(hexyloxy)hexylphosphinic acid), (C) 1H NMR spectra of the titration, and (D) quantification of the different compounds as a function of added equivalents 6-(hexyloxy)hexylphosphinic acid.

Figure S17. Titration of CdSe NCs stabilized with a mixed ligand shell consistent of 6-(hexyloxy)hexylphosphinate and oleylphosphonate. (A) General reaction scheme, (B) 1H NMR spectrum of the purified NCs prior to titration (at 0.0 added equivalents of 6-(hexyloxy)hexylphosphinic acid), (C) 1H NMR spectra of the titration, and (D) quantification of the different compounds as a function of added equivalents 6-(hexyloxy)hexylphosphinic acid.

Figure S18. Titration of ZnS NCs stabilized with a mixed ligand shell consistent of 6-(hexyloxy)hexylphosphinate acid and oleylphosphonate. (A) General reaction scheme, (B) 1H NMR spectrum of the purified NCs prior to titration (at 0.0 added equivalents of 6-(hexyloxy)hexylphosphinic acid) (C) 1H NMR spectra of the titration, and (D) quantification of the different compounds as a function of added equivalents 6-(hexyloxy)hexylphosphinic acid.

Figure S19. The mole fraction of bound oleylphosphonate in the ligand shell, 𝜒𝑝ℎ𝑜𝑠𝑝ℎ𝐨𝑛 (𝑏𝑜𝑢𝑛𝑑), as a function of the overall mole fraction of oleylphosphonic acid (= unbound phosphonic acid and bound phosphonate), 𝜒𝑝ℎ𝑜𝑠𝑝ℎ𝐨𝑛 (𝑡𝑜𝑡𝑎𝑙) , during the titrations of (A) HfO2 (blue), (B) CdSe (red), and (C) ZnS (green) NCs. The full lines represent different calculated equilibrium constants.

Figure S20. Changes in chemical shift during the ligand exchange of phosphinate for phosphonate for HfO2, CdSe, and ZnS NCs

Figure S21. Purified ZnS/n-alkylphosphinate NCs with a 50/50 mixture of n-hexyl/noctadecylphosphinate. (A) ZnS/phosphinate NCs. (B) 1H NMR spectrum in C6D6 with zoom inset of the broadened P-H resonance, (C) 31P NMR spectrum in C6D6, (D) DOSY NMR spectrum in C6D6, (E) DOSY decay curve of the alkane region, and (F) UV-vis absorption spectrum.

Figure S22. Titration of ZnS/n-alkylphosphinate with a 50/50 mixture of n-hexyl/noctadecylphosphinate with oleylphosphonic acid. (A) General reaction scheme, (B) 1H NMR spectra of the titration (zoom of the alkene resonance and the adjacent methylene groups), and (C) quantification of the different compounds as a function of added equivalents.

Figure S23. Comparative ligand exchange experiments where oleate capped ZnS NCs are titrated with a 50/50 mixture of n-hexyl/n-octadecylcarboxylic, -phosphinic, or -phosphonic acids. (A) General reaction scheme for the 3 separate titrations with carboxylic, phosphinic, or phosphonic acids. (B) Bound fraction of oleate on ZnS NCs as a function of the added equivalents of the titrating acid mixture, including the theoretical expected quantitative and random exchange development.

Figure S24. Titration of ZnS/oleate NCs with a 50/50 mixture of n-hexyl, and n-octadecyl carboxylic, phosphinic, and phosphonic acids in C6D6. (A) General reaction scheme. (B) 1H NMR spectra of the titration with carboxylic acids. (C) 1H NMR spectra of the titration with phosphinic acids. (D) 1H NMR spectra of the titration with phosphonic acids (added from a concentrated solution in THF-d8).