Data for "Atomically precise surface chemistry of zirconium and hafnium metal oxo clusters beyond carboxylate ligands"

Data for Figures in the Publication: "Atomically Precise Surface Chemistry of Zirconium and Hafnium Metal Oxo Clusters Beyond Carboxylate Ligands"

The provided .pxp files contain the experimental data corresponding to the figures presented in the manuscript. These files can be opened and edited using IGOR Pro version 8.0 or higher. Additionally, the .psd files contain image data and can be accessed or modified using Adobe Photoshop.

Table of Contents:

Scheme 1: (A) Schematic representation of a colloidally stable zirconium/hafnium oxide nanocrystal depicting the inorganic core and organic ligand shell. (B) The structure of M6O8H4(OOCR)12, where the M6O8 core is capped with four protons and twelve carboxylate ligands, M=Zr/Hf. The ligands that have been reported to cap nanocrystals and clusters in nonpolar media are listed. Cyan atoms represent zirconium or hafnium, all other atoms follow conventional CPK coloring.

Figure 1: (A) Scheme representing the exchange of acetate ligands for phosphorus-based ligands on a fully bridged Zr6 cluster. (B) Enthalpy of ligand exchange reactions as a function of equivalents of exchanged ligands, ΔH. (C) The enthalpy change for every step, ΔΔH.

Figure 2: cis and trans Zr-Zr distances as a function of the equivalents of exchanged methylphosphinate ligands obtained from DFT calculations.

Figure 3: (A) Different binding modes of acetate ligands in the structure of Zr12O16H8(OOCMe)24 · 6MeCOOH - CCDC-604528. (B) Enthalpy of ligand exchange reactions at different binding sites.

Figure 4: 31P NMR spectra of the titrations of (A) Zr12-acetate and (B) Zr6- methylbutanoate with dioctylphosphinic acid (expressed as equivalents with respect to a
monomer unit). The cluster concentration is 20 mg/mL in CDCl3. The reference 31P NMR spectrum of dioctylphosphinic acid with one equivalent acetic acid is also provided.

Figure 5: 31P NMR spectra of the titrations of Zr12-acetate with (A) hexyl- and (B) phenylphosphinic acid. The cluster concentration is 20 mg/mL in CDCl3. 31P NMR spectra of the free phosphinic acids with an equivalent of acetic acid are provided as references.

Figure 6: (A) Crystal structure of Zr6-phenylphosphinate cluster - Zr6O8H4(O2PHPh)12. Cyan atoms represent zirconium and all other atoms follow conventional CPK coloring. The co-crystallized dichloromethane molecules and hydrogen atoms are omitted for clarity. (B) PDF fit for Zr6-phenylphosphinate cluster with its crystal structure. PDF fit of Zr6-hexylphosphinate cluster with distorted Zr6 phosphinate cluster is also shown. (C) FTIR spectra of Zr6 phosphinate clusters. IR spectra of free ligands are also provided for reference. (D) 31P NMR of purified Zr6 phosphinate clusters. 31P NMR of free acids are provided as reference.

Figure 7: Ligand exchange of Zr12-acetate with 2-hexyldecylphosphonic acid. (A) 31P spectra of the titration, with the reference spectrum of 2-hexyldecylphosphonic acid with one equivalent of acetic acid added. The concentration of the cluster was 20 mg/mL in CDCl3. (B) IR spectra of phosphonate exchanged zirconium clusters after isolation and purification. IR spectra of free acids are provided as a reference. (C) Structure model of Hf6 cut from the crystal structure of Hf12-acetate. (D) Structure of a 3 x 3 layer zirconium phenylphosphonate (JPCDS:44-2000). Cyan and blue atoms represent zirconium and hafnium, respectively; all other atoms follow conventional CPK coloring. Only the carbon bonded to phosphonate is shown, and the rest of the phenyl ring is omitted for clarity. (E) Dual-phase PDF fit for phosphonate exchanged Hf clusters with a 3 x 3 layer of Hf phenylphosphonate (contains 9 hafnium atoms in total) and Hf6 chelating bridging acetate.

Figure S1: Crystal structure of Zr6-acetate cluster (Zr6O4(OH)4(OOCCH3)12) - CCDC-1051013. All twelve carboxylate ligands are in bridging mode. Hydrogen atoms and core oxygen atoms are omitted for clarity.

Figure S2: Crystal structure of Zr6-methacrylate cluster (Zr6O4(OH)4(OOC(CH3)C=CH2)12) - CCDC-106826. Ligand shell contains 9 bridging carboxylates and 3 chelating carboxylates. Hydrogen atoms, aliphatic chain carbon atoms and core oxygen atoms are omitted for clarity.

Figure S3: (A) Scheme representing the exchange of acetate ligands for phosphorus-based ligands on a fully bridged Hf6 cluster. (B) Enthalpy of ligand exchange reactions as a function of equivalents of exchanged ligands, ΔH. (C) The enthalpy change for every step, ΔΔH.

Figure S4: DFT optimized structures of Zr/Hf acetate clusters partially or fully exchanged with diethylphosphinic acid. Cyan and blue atoms represent zirconium and hafnium, respectively; all other atoms follow conventional CPK coloring. Hydrogen atoms and core oxygen atoms are omitted for clarity.

Figure S5: DFT optimized structures of Zr/Hf acetate clusters partially or fully exchanged with dimethylphosphinic acid. Cyan and blue atoms represent zirconium and hafnium, respectively; all other atoms follow conventional CPK coloring. Hydrogen atoms and core oxygen atoms are omitted for clarity.

Figure S6: DFT optimized structures of Zr/Hf acetate clusters partially or fully exchanged with ethylphosphinic acid. Cyan and blue atoms represent zirconium and hafnium, respectively; all other atoms follow conventional CPK coloring. Hydrogen atoms (except P-H) and core oxygen atoms are omitted for clarity.

Figure S7: DFT optimized structures of Zr/Hf acetate clusters partially or fully exchanged with methylphosphinic acid. Cyan and blue atoms represent zirconium and hafnium, respectively; all other atoms follow conventional CPK coloring. Hydrogen atoms (except P-H) and core oxygen atoms are omitted for clarity.

Figure S8: DFT optimized structures of Zr/Hf acetate clusters partially or fully exchanged with ethylphosphonic acid. Cyan and blue atoms represent zirconium and hafnium, respectively; all other atoms follow conventional CPK coloring. The dotted lines indicate some hydrogen bonds formed due to the second acidic group. Hydrogen atoms (except P-OH) and core oxygen atoms are omitted for clarity.

Figure S9: DFT optimized structures of Zr/Hf acetate clusters partially or fully exchanged with methylphosphonic acid. Cyan and blue atoms represent zirconium and hafnium, respectively; all other atoms follow conventional CPK coloring. The dotted lines indicate some hydrogen bonds formed due to the second acidic group. Hydrogen atoms (except P-OH) and core oxygen atoms are omitted for clarity.

Figure S10: (A) Both cis and trans Zr-Zr distances as a function of the equivalents of exchanged methylphosphinate ligands obtained from DFT calculations. The averaged distances with standard deviation are shown in B.

Figure S11: (A) Both cis and trans Zr-Zr distances as a function of the equivalents of exchanged ethylphosphinate ligands obtained from DFT calculations. The averaged distances with standard deviation are shown in B.

Figure S12: (A) Both cis and trans Zr-Zr distances as a function of the equivalents of exchanged methylphosphonate ligands obtained from DFT calculations. The averaged distances with standard deviation are shown in B.

Figure S13: (A) Both cis and trans Zr-Zr distances as a function of the equivalents of exchanged ethylphosphonate ligands obtained from DFT calculations. The averaged distances with standard deviation are shown in B.

Figure S14: (A) Both cis and trans Zr-Zr distances as a function of the equivalents of exchanged dimethylphosphinate ligands obtained from DFT calculations. The averaged distances with standard deviation are shown in B.

Figure S15: (A) Both cis and trans Zr-Zr distances as a function of the equivalents of exchanged diethylphosphinate ligands obtained from DFT calculations. The averaged distances with standard deviation are shown in B.

Figure S16: (A) Both cis and trans Hf-Hf distances as a function of the equivalents of exchanged methylphosphinate ligands obtained from DFT calculations. The averaged distances with standard deviation are shown in B.

Figure S17: (A) Both cis and trans Hf-Hf distances as a function of the equivalents of exchanged ethylphosphinate ligands obtained from DFT calculations. The averaged distances with standard deviation are shown in B.

Figure S18: (A) Both cis and trans Hf-Hf distances as a function of the equivalents of exchanged methylphosphonate ligands obtained from DFT calculations. The averaged distances with standard deviation are shown in B.

Figure S19: (A) Both cis and trans Hf-Hf distances as a function of the equivalents of exchanged ethylphosphonate ligands obtained from DFT calculations. The averaged distances with standard deviation are shown in B.

Figure S20: (A) Both cis and trans Hf-Hf distances as a function of the equivalents of exchanged dimethylphosphinate ligands obtained from DFT calculations. The averaged distances with standard deviation are shown in B.

Figure S21: (A) Both cis and trans Hf-Hf distances as a function of the equivalents of exchanged diethylphosphinate ligands obtained from DFT calculations. The averaged distances with standard deviation are shown in B.

Figure S22: (A) Scheme representing the exchange of one equivalent of phosphonic acid or mono or dialkyl phosphinic acid with acetate ligand on a Hf12 cluster. Exchanged acetate can be chelating, belt-bridging, innerface-bridging, or intercluster-bridging. Enthalpy of ligand exchange reactions on Hf12 (B) Enthalpy of ligand exchange reactions at different binding sites.

Figure S23: Enthalpy of dimerisation of fully bridged Zr6 carboxylate or phosphinate clusters to their corresponding Zr12. The ligand binding modes in the Zr12 is also indicated.

Figure S24: (A) Scheme for the titration of Zr12-acetate cluster with diethylphosphinic acid. (B) 31P and (C) 1H NMR of the titration of Zr12-acetate cluster with increasing equivalents of diethylphosphinic acid (expressed as equivalents with respect to a monomer unit). The cluster concentration is 20 mg/mL in CDCl3. 31P and 1H NMR of free phosphinic acid are also provided (with one equivalent acetic acid added for the 31P NMR reference).

Figure S25: 1H NMR spectra of the titrations of (A) Zr12-acetate and (B) Zr6-methylbutanoate with dioctylphosphinic acid (expressed as equivalents with respect to a monomer unit). The cluster concentration is 20 mg/mL in CDCl3. The reference 1H NMR spectrum of dioctylphosphinic acid and carboxylate clusters are also provided.

Figure S26: 31P NMR of (A) dioctylphosphinic acid and (B) diethylphosphinic acid with increasing equivalents of acetic acid in CDCl3. The more the acetic acid, the more deshielded the phosphorus signal.

Figure S27: 1H NMR spectra of the titrations of Zr12-acetate with phenyl and hexyl phosphinic acid (expressed as equivalents with respect to a monomer unit). The cluster concentration is 20 mg/mL in CDCl3. 1H NMR spectra of the free phosphinic acids and acetate cluster are provided as reference.

Figure S28: (A) Scheme for the titration of Zr12-acetate cluster with tetradecylphosphinic acid. 31P (B) and 1H (C) NMR of the titration of Zr12-acetate cluster with increasing equivalents of tetradecylphosphinic acid (expressed as equivalents with respect to a monomer unit). The cluster concentration is 20 mg/mL in CDCl3. 31P and 1H NMR of tetradecylphosphinic acid and carboxylate clusters are also provided (with one equivalent acetic acid added for the 31P NMR reference).

Figure S29: (A) Scheme for the titration of Zr6-methylbutanoate cluster with hexylphosphinic acid. 31P (B) and 1H (C) NMR of the titration of Zr6-methylbutanoate cluster with increasing equivalents of hexylphosphinic acid. The cluster concentration is 20 mg/mL in CDCl3. The appearance of free 2-methylbutanoic acid confirms the ligand exchange. 31P and 1H NMR of hexylphosphinic acid and carboxylate clusters are also provided (with one equivalent acetic acid added for the 31P NMR reference).

Figure S30: 31P NMR of (A) hexylphosphinic acid and (B) tetradecylphosphinic acid with increasing equivalents of acetic acid in CDCl3. The more the acetic acid, the more deshielded the phosphorus signal.

Figure S31: 31P NMR of phenylphosphinic acid with increasing equivalents of acetic acid in CDCl3. The more the acetic acid, the more deshielded the phosphorus signal.

Figure S32: (A) Crystal structure of Hf6-phenylphosphinate cluster - Hf6O4(OH)4(OOPHPh)12. Blue atoms represent hafnium and all other atoms follow conventional CPK coloring. The co-crystallized dichloromethane molecules and hydrogen atoms are omitted for clarity. (B) PDF fit for Hf6-phenylphosphinate cluster with its
crystal structure. PDF fit of Hf6-hexylphosphinate cluster with distorted Hf6-phosphinate cluster is also shown. (C) FTIR spectra of Hf6-phosphinate clusters. IR spectra of free ligands are also provided for reference. (D) 31P NMR of purified Hf6-phosphinate clusters. 31P NMR of free acids are provided as reference.

Figure S33: (A) Both cis and trans Zr-Zr distances of different zirconium crystal structures - Zr12-acetate (CCDC-604528), Zr6-acetate (CCDC-1051013),S1 Zr6-benzoate (CCDC-117768), Zr6-dimethylphosphate (CCDC-1863035), and Zr6-phenylphosphinate (this work). The averaged distances with standard deviation are shown in B.

Figure S34: Structure of distorted Zr6 phosphinate predicted from PDF refinement. Cyan atoms represent zirconium and all other atoms follow conventional CPK coloring.

Figure S35: (A) Both cis and trans Zr-Zr distances of Zr6-phenylphosphinate and distorted Zr6-phosphinate structure. The averaged distances with standard deviation are shown in B.

Figure S36: PDF fit for synthesized Zr6-hexylphosphinate cluster with the crystal structure of Zr6-phenylphosphinate and distorted phosphinate clusters.

Figure S37: PDF fit for synthesized Zr6-tetradecylphosphinate cluster with the crystal structure of Zr6 phenylphosphinate and distorted phosphinate clusters.

Figure S38: PDF fit for synthesized Hf6-hexylphosphinate cluster with the crystal structure of Hf6-phenylphosphinate and distorted phosphinate clusters.

Figure S39: PDF fit for synthesized Hf6-tetradecylphosphinate cluster with the crystal structure of Hf6-phenylphosphinate and distorted phosphinate clusters.

Figure S40: (A) DLS particle size distribution and (B) correlogram for measurements of 40 mg/mL solution of Zr6-hexylphosphinate in dichloromethane after manual fitting. Average solvodynamic radius = 0.64 ± 0.04 nm, polydispersity index = 0.03 ± 0.02. The different colors represent individual measurements taken in triplicate.

Figure S41: (A) DLS particle size distribution and (B) correlogram for measurements of 40 mg/mL solution of Zr12-hexanoate in dichloromethane after manual fitting. Average solvodynamic radius = 0.91 ± 0.05 nm, polydispersity index = 0.05 ± 0.02. The different colors represent individual measurements taken in triplicate.

Figure S42: 1H (A) and 31P (B) NMR of purified Zr6-phenylphosphinate cluster in CDCl3. 1H and 31P NMR of free acids are provided as reference. The broadening of NMR signals confirms the cluster binding of new phenylphosphinate ligands.

Figure S43: 1H (A) and 31P (B) NMR of purified Hf6-phenylphosphinate cluster in CDCl3. 1H and 31P NMR of free acids are provided as reference. The broadening of NMR signals confirms the cluster binding of new phenylphosphinate ligands.

Figure S44: 1H (A) and 31P (B) NMR of purified Zr6-hexylphosphinate cluster in CDCl3. 1H and 31P NMR of free acids are provided as reference. The broadening of NMR signals confirms the cluster binding of new hexylphosphinate ligands.

Figure S45: 1H (A) and 31P (B) NMR of purified Hf6-hexylphosphinate cluster in CDCl3. 1H and 31P NMR of free acids are provided as reference. The broadening of NMR signals confirms the cluster binding of new hexylphosphinate ligands.

Figure S46: 1H (a) and 31P (b) NMR of purified Zr6-tetradecylphosphinate cluster in CDCl3. 1H and 31P NMR of free acids are provided as reference. The broadening of NMR signals confirms the cluster binding of new phenylphosphinate ligands.

Figure S47: 1H (a) and 31P (b) NMR of purified Hf6-tetradecylphosphinate cluster in CDCl3. 1H and 31P NMR of free acids are provided as reference. The broadening of NMR signals confirms the cluster binding of new phenylphosphinate ligands.

Figure S48: ESI-HRMS analysis of Zr6-phenylphosphinate cluster - Zr6O4(OH)4(C6H5PHOO)12. Both the experimental and simulated spectra are shown.

Figure S49: ESI-HRMS analysis of Hf6-phenylphosphinate cluster - Hf6O4(OH)4(C6H5PHOO)12. Both the experimental and simulated spectra are shown.

Figure S50: Powder X-ray diffraction data of Zr6- and Hf6-phenylphosphinate clusters. The simulated powder patterns (λ = 0.1821 ˚A, same as experimental wavelength) are provided as reference.

Figure S51: 1H NMR of Zr6-hexylphosphinate cluster after ligand stripping experiments with trifluoroacetic acid. 1H NMR of hexylphosphinic acid and acetic acid in trifluoroacetic acid are provided as references. The integral values corresponding to the methyl group of both ligands are also mentioned.

Figure S52: 1H NMR of Zr6-tetradecylphosphinate cluster after ligand stripping experiments with trifluoroacetic acid. 1H NMR of tetradecylphosphinic acid and acetic acid in trifluoroacetic acid are provided as references. The integral values corresponding to the methyl group of both ligands are also mentioned.

Figure S53: Gelation of Zr12-acetate cluster solution in CDCl3 with 12 equivalents (per cluster monomer) of hexylphosphonic acid (A), dodecylphosphonic acid (B), oleylphosphonic acid (C) and 2-ethylhexylphosphonic acid (D). No gelation was observed for 2-hexyldecylphosphonic acid (E). The cluster concentration is 40 mg/mL.

Figure S54: Gelation of Zr6-methylbutanoate cluster solution in CDCl3 with 12 equivalents (per cluster monomer) of hexylphosphonic acid (A), dodecylphosphonic acid (B), oleylphosphonic acid (C) and 2-ethylhexylphosphonic acid (D). No gelation was observed for 2-hexyldecylphosphonic acid (E). The cluster concentration is 40 mg/mL.

Figure S55: (A) Scheme for the titration of Zr12-acetate cluster with 2-ethylhexylphosphonic acid. 31P (B) and 1H (C) NMR of the titration of Zr12-acetate cluster with increasing equivalents of 2-ethylhexylphosphonic acid (expressed as equivalents with respect to a monomer unit). The cluster concentration is 20 mg/mL in CDCl3. 31P and 1H NMR of 2-ethylhexylphosphonic acid and carboxylate clusters are also provided (with
one equivalent acetic acid added for the 31P NMR reference).

Figure S56: (A) Scheme for the titration of Zr12-acetate cluster with oleylphosphonic acid. 31P (B) and 1H (C) NMR of the titration of Zr12-acetate cluster with oleylphosphonic acid. Gelation prevented the data acquisition at high equivalents. 31P and 1H NMR of oleylphosphonic acid and carboxylate clusters are also provided (with one equivalent acetic acid added for the 31P NMR reference).

Figure S57: 1H NMR of the titration of a solution of Zr12-acetate cluster with increasing 2-exyldecylphosphonic acid (expressed as equivalents with respect to a monomer unit). The cluster concentration is 20 mg/mL in CDCl3. 1H NMR of 2-hexyldecylphosphonic acid and acetate clusters are also provided.

Figure S58: (A) Scheme for the titration of Zr6-methylbutanoate cluster with hexylphosphonic acid. 31P (B) and 1H (C) NMR of the titration of Zr6-methylbutanoate cluster with increasing equivalents of hexylphosphonic acid. The cluster concentration is 20 mg/mL in CDCl3. Gelation prevented the data acquisition at high equivalents. 31P and 1H NMR of hexylphosphonic acid and methylbutanoate cluster are also provided (with one equivalent acetic acid added for the 31P NMR reference).

Figure S59: 31P NMR of (A) hexylphosphonic acid and (B) oleylphosphonic acid with increasing equivalents of acetic acid. The more the acetic acid, the more deshielded the phosphorus signal.

Figure S60: 31P NMR of (A) 2-hexyldecylphosphonic acid and (B) 2-ethylhexylphosphonic acid with increasing equivalents of acetic acid. The more the acetic acid, the more deshielded the phosphorus signal.

Figure S61: 1H (A) and 31P (B) NMR of purified ligand exchanged Zr12-acetate cluster with 2-hexyldecylphosphonic acid in CDCl3. 1H and 31P NMR of free acids are provided as reference. The broadening of NMR signals confirms the cluster binding of new 2-hexyldecylphosphonate ligands.

Figure S62: 1H (A) and 31P (B) NMR of purified ligand exchanged Hf12-acetate cluster with 2-hexyldecylphosphonic acid in CDCl3. 1H and 31P NMR of free acids are provided as reference. The broadening of NMR signals confirms the cluster binding of new 2-hexyldecylphosphonate ligands.

Figure S63: Crystal structure of layered zirconium phenylphosphonate (JPCDS:44-2000). Cyan atoms represent zirconium; all other atoms follow conventional CPK coloring. Hydrogen atoms are omitted for clarity. M, O, and P represent metal (zirconium), oxygen and phosphorus, respectively.

Figure S64: Single-phase PDF fit for hexyldecylphosphonate exchanged Zr clusters with various cluster structures reported in the literature. For each of the structural models, we removed the excess carbon atoms to arrive at a model with acetate ligands.

Figure S65: Single-phase PDF fit for hexyldecylphosphonate exchanged Zr clusters with a 3 x 3 layer of Zr phenylphosphonate (contains 9 zirconium atoms in total). The phenyl ring is removed from the structure model.

Figure S66: Structure model of Zr6-chelating bridging acetate cut from the crystal structure of Zr12-acetate.S3 Carbon atoms are removed from structure model. Cyan atoms represent zirconium; all other atoms follow conventional CPK coloring.

Figure S67: Dual phase PDF fit for phosphonate-exchanged Zr clusters with a 3 x 3 layer of Zr phenylphosphonate (which contains 9 zirconium atoms in total) and Zr6-chelating bridging acetate. Refined parameters are tabulated in Table S7.

Figure S68: (A) DLS particle size distribution (by volume) and (B) correlogram for measurements of 10 mg/mL solution of zirconium hexyldecylphosphonate in chloroform. Z-average = 22.74 ± 2.13 nm, polydispersity index = 0.2251 ± 0.0403. The different colors represent individual measurements taken in triplicate.

Figure S69: (A) DLS particle size distribution (by volume) and (B) correlogram for measurements of 10 mg/mL solution of hafnium hexyldecylphosphonate in chloroform. Z-average = 20.19 ± 0.05 nm, polydispersity index = 0.433 ± 0.0022. The different colors represent individual measurements taken in triplicate.

Figure S70: IR spectra of phosphonate exchanged hafnium clusters after isolation and purification. IR spectra of free acids are provided as reference.