TY - JOUR
T1 - Insights into Catalytic Hydrolysis of Organophosphonates at M-OH Sites of Azolate-Based Metal Organic Frameworks
AU - Mian, Mohammad Rasel
AU - Chen, Haoyuan
AU - Cao, Ran
AU - Kirlikovali, Kent O.
AU - Snurr, Randall Q.
AU - Islamoglu, Timur
AU - Farha, Omar K.
N1 - Funding Information:
The authors acknowledge the support from the Defense Threat Reduction Agency under Award Number HDTRA1-18-1-0003. K.O.K. gratefully acknowledges support from the IIN Postdoctoral Fellowship and the Northwestern University International Institute for Nanotechnology. This work made use of the Integrated Molecular Structure Education and Research Center (IMSERC) NMR facility at Northwestern University, which has received support from NSF CHE-1048773, the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS2025633) and Northwestern University. We also thank the EPIC facility of Northwestern University’s NUANCE Center, which has received support from the SHyNE Resource (NSF ECCS-2025633), the IIN, and Northwestern’s MRSEC program (NSF DMR-1720139). The authors appreciate Northwestern University Quantitative Bioelement Imaging Center for ICP-OES measurements.
Publisher Copyright:
© 2021 American Chemical Society.
PY - 2021/7/7
Y1 - 2021/7/7
N2 - Organophosphorus nerve agents, a class of extremely toxic chemical warfare agents (CWAs), have remained a threat to humanity because of their continued use against civilian populations. To date, Zr(IV)-based metal organic framework (MOFs) are the most prevalent nerve agent hydrolysis catalysts, and relatively few reports disclose MOFs containing nodes with other Lewis acidic transition metals. In this work, we leveraged this synthetic tunability to explore how the identity of the transition metal node in the M-MFU-4l series of MOFs (M = Zn, Cu, Ni, Co) influences the catalytic performance toward the hydrolysis of the nerve agent simulant dimethyl (4-nitrophenyl)phosphate (DMNP). Experimental studies reveal that Cu-MFU-4l exhibits the best performance in this series with a half-life for hydrolysis of ∼2 min under these conditions. In contrast, both Ni- and Co-MFU-4l demonstrate significantly slower reactivity toward DMNP, as they both fail to surpass 30% conversion of DMNP after 1 h under analogous conditions. Further modification of the active site within Cu-MFU-4l is possible, and we found that although the identity of the anion coordinated to the Cu(II)-X (X = Cl-, HCOO-, ClO4-, NO3-) active site has little influence on the catalytic performance, reduction of the Cu(II) sites yields nodes that contain Cu(I) ions in a trigonal geometry with open metal sites, leading to remarkable catalytic activity with a half-life for hydrolysis less than 2 min. Computational studies indicate the Cu(I) sites exhibit stronger binding affinities than Cu(II) to both water and DMNP, which corroborates the experimental results.
AB - Organophosphorus nerve agents, a class of extremely toxic chemical warfare agents (CWAs), have remained a threat to humanity because of their continued use against civilian populations. To date, Zr(IV)-based metal organic framework (MOFs) are the most prevalent nerve agent hydrolysis catalysts, and relatively few reports disclose MOFs containing nodes with other Lewis acidic transition metals. In this work, we leveraged this synthetic tunability to explore how the identity of the transition metal node in the M-MFU-4l series of MOFs (M = Zn, Cu, Ni, Co) influences the catalytic performance toward the hydrolysis of the nerve agent simulant dimethyl (4-nitrophenyl)phosphate (DMNP). Experimental studies reveal that Cu-MFU-4l exhibits the best performance in this series with a half-life for hydrolysis of ∼2 min under these conditions. In contrast, both Ni- and Co-MFU-4l demonstrate significantly slower reactivity toward DMNP, as they both fail to surpass 30% conversion of DMNP after 1 h under analogous conditions. Further modification of the active site within Cu-MFU-4l is possible, and we found that although the identity of the anion coordinated to the Cu(II)-X (X = Cl-, HCOO-, ClO4-, NO3-) active site has little influence on the catalytic performance, reduction of the Cu(II) sites yields nodes that contain Cu(I) ions in a trigonal geometry with open metal sites, leading to remarkable catalytic activity with a half-life for hydrolysis less than 2 min. Computational studies indicate the Cu(I) sites exhibit stronger binding affinities than Cu(II) to both water and DMNP, which corroborates the experimental results.
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U2 - 10.1021/jacs.1c03901
DO - 10.1021/jacs.1c03901
M3 - Article
C2 - 34160219
AN - SCOPUS:85110089245
VL - 143
SP - 9893
EP - 9900
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 26
ER -