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Predicting the DNP-SENS efficiency in reactive heterogeneous catalysts from hydrophilicity

Identification of surfaces at the molecular level has benefited from progress in dynamic nuclear polarization surface enhanced NMR spectroscopy (DNP SENS). However, the technique is limited when using highly sensitive heterogeneous catalysts due to secondary reaction of surface organometallic fragme...

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Autores principales: Pump, Eva, Bendjeriou-Sedjerari, Anissa, Viger-Gravel, Jasmine, Gajan, David, Scotto, Baptiste, Samantaray, Manoja K., Abou-Hamad, Edy, Gurinov, Andrei, Almaksoud, Walid, Cao, Zhen, Lesage, Anne, Cavallo, Luigi, Emsley, Lyndon, Basset, Jean-Marie
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Royal Society of Chemistry 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5982197/
https://www.ncbi.nlm.nih.gov/pubmed/29910939
http://dx.doi.org/10.1039/c8sc00532j
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author Pump, Eva
Bendjeriou-Sedjerari, Anissa
Viger-Gravel, Jasmine
Gajan, David
Scotto, Baptiste
Samantaray, Manoja K.
Abou-Hamad, Edy
Gurinov, Andrei
Almaksoud, Walid
Cao, Zhen
Lesage, Anne
Cavallo, Luigi
Emsley, Lyndon
Basset, Jean-Marie
author_facet Pump, Eva
Bendjeriou-Sedjerari, Anissa
Viger-Gravel, Jasmine
Gajan, David
Scotto, Baptiste
Samantaray, Manoja K.
Abou-Hamad, Edy
Gurinov, Andrei
Almaksoud, Walid
Cao, Zhen
Lesage, Anne
Cavallo, Luigi
Emsley, Lyndon
Basset, Jean-Marie
author_sort Pump, Eva
collection PubMed
description Identification of surfaces at the molecular level has benefited from progress in dynamic nuclear polarization surface enhanced NMR spectroscopy (DNP SENS). However, the technique is limited when using highly sensitive heterogeneous catalysts due to secondary reaction of surface organometallic fragments (SOMFs) with stable radical polarization agents. Here, we observe that in non-porous silica nanoparticles (NPs) (d(particle) = 15 nm) some DNP enhanced NMR or SENS characterizations are possible, depending on the metal-loading of the SOMF and the type of SOMF substituents (methyl, isobutyl, neopentyl). This unexpected observation suggests that aggregation of the nanoparticles occurs in non-polar solvents (such as ortho-dichlorobenzene) leading to (partial) protection of the SOMF inside the interparticle space, thereby preventing reaction with bulky polarization agents. We discover that the DNP SENS efficiency is correlated with the hydrophilicity of the SOMF/support, which depends on the carbon and SOMF concentration. Nitrogen sorption measurements to determine the BET constant (C(BET)) were performed. This constant allows us to predict the aggregation of silica nanoparticles and consequently the efficiency of DNP SENS. Under optimal conditions, C(BET) > 60, we found signal enhancement factors of up to 30.
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spelling pubmed-59821972018-06-15 Predicting the DNP-SENS efficiency in reactive heterogeneous catalysts from hydrophilicity Pump, Eva Bendjeriou-Sedjerari, Anissa Viger-Gravel, Jasmine Gajan, David Scotto, Baptiste Samantaray, Manoja K. Abou-Hamad, Edy Gurinov, Andrei Almaksoud, Walid Cao, Zhen Lesage, Anne Cavallo, Luigi Emsley, Lyndon Basset, Jean-Marie Chem Sci Chemistry Identification of surfaces at the molecular level has benefited from progress in dynamic nuclear polarization surface enhanced NMR spectroscopy (DNP SENS). However, the technique is limited when using highly sensitive heterogeneous catalysts due to secondary reaction of surface organometallic fragments (SOMFs) with stable radical polarization agents. Here, we observe that in non-porous silica nanoparticles (NPs) (d(particle) = 15 nm) some DNP enhanced NMR or SENS characterizations are possible, depending on the metal-loading of the SOMF and the type of SOMF substituents (methyl, isobutyl, neopentyl). This unexpected observation suggests that aggregation of the nanoparticles occurs in non-polar solvents (such as ortho-dichlorobenzene) leading to (partial) protection of the SOMF inside the interparticle space, thereby preventing reaction with bulky polarization agents. We discover that the DNP SENS efficiency is correlated with the hydrophilicity of the SOMF/support, which depends on the carbon and SOMF concentration. Nitrogen sorption measurements to determine the BET constant (C(BET)) were performed. This constant allows us to predict the aggregation of silica nanoparticles and consequently the efficiency of DNP SENS. Under optimal conditions, C(BET) > 60, we found signal enhancement factors of up to 30. Royal Society of Chemistry 2018-04-30 /pmc/articles/PMC5982197/ /pubmed/29910939 http://dx.doi.org/10.1039/c8sc00532j Text en This journal is © The Royal Society of Chemistry 2018 https://creativecommons.org/licenses/by-nc/3.0/This article is freely available. This article is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported Licence (CC BY-NC 3.0)
spellingShingle Chemistry
Pump, Eva
Bendjeriou-Sedjerari, Anissa
Viger-Gravel, Jasmine
Gajan, David
Scotto, Baptiste
Samantaray, Manoja K.
Abou-Hamad, Edy
Gurinov, Andrei
Almaksoud, Walid
Cao, Zhen
Lesage, Anne
Cavallo, Luigi
Emsley, Lyndon
Basset, Jean-Marie
Predicting the DNP-SENS efficiency in reactive heterogeneous catalysts from hydrophilicity
title Predicting the DNP-SENS efficiency in reactive heterogeneous catalysts from hydrophilicity
title_full Predicting the DNP-SENS efficiency in reactive heterogeneous catalysts from hydrophilicity
title_fullStr Predicting the DNP-SENS efficiency in reactive heterogeneous catalysts from hydrophilicity
title_full_unstemmed Predicting the DNP-SENS efficiency in reactive heterogeneous catalysts from hydrophilicity
title_short Predicting the DNP-SENS efficiency in reactive heterogeneous catalysts from hydrophilicity
title_sort predicting the dnp-sens efficiency in reactive heterogeneous catalysts from hydrophilicity
topic Chemistry
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5982197/
https://www.ncbi.nlm.nih.gov/pubmed/29910939
http://dx.doi.org/10.1039/c8sc00532j
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