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6. An acidity scale of phosphonium tetraphenylborate salts and ruthenium dihydrogen complexes in dichloromethane

Author

Li, Tianshu, Lough, Alan J., Zuccaccia, Cristiano, Macchioni, Alceo, and Morris, Robert H.

Subjects
Nuclear magnetic resonance -- Analysis -- Chemical properties -- Thermal properties, Ruthenium -- Chemical properties -- Thermal properties -- Analysis, Transition metal compounds -- Chemical properties -- Analysis -- Thermal properties, Chemistry, Thermal properties, Analysis, Chemical properties
Abstract

Equilibrium constants ([K.sup.DM]) for reactions between acids and bases of the title compounds in C[D.sub.2][Cl.sub.2] (DM) have been determined by [sup.31]p and ¹H NMR spectroscopy at room temperature. [HP[Cy.sub.3]]B[Ph.sub.4] and [HP[Cy.sub.3]]B[F.sub.4], with p[K.sup.DM] assigned by literature convention to 9.7, have been used as the anchor compounds for the p[K.sup.DM] determinations. A continuous scale of p[K.sup.DM] values covering the range 9.7 to 5.7 is created with the acidic compounds [HP[R.sub.3]]B[Ph.sub.4]. Those acids with p[K.sup.DM] greater than 6 are stable, while those with more acidic cations HP[R.sub.3.sup.+] protonate B[Ph.sub.4.sup.-] to produce [R.sub.3]PB[Ph.sub.3] and benzene. The literature p[K.sup.THF] values reported for [HP[Bu.sub.2]Ph]B[Ph.sub.4], [HPMe[Ph.sub.2]]B[Ph.sub.4], and [HPEt[Ph.sub.2]]B[Ph.sub.4] are questionable because of this protonation reaction. NOE and PGSE ¹H NMR techniques are used to show that [HP[Cy.sub.2]Ph]B[Ph.sub.4] in DM exists as ion pairs and higher aggregates up to quadrupoles at the concentrations used in the acid-base studies. The new dihydrogen complexes [Ru([H.sub.2]) Cl[(P[Ph.sub.3]).sub.2](dach)]B[F.sub.4] (dach = (1R,2R)-(-)-diaminocyclohexane) and [Ru([H.sub.2])Cl{tme [P.sub.2][(NH).sub.2]}]B[F.sub.4] (tme[P.sub.2][(NH).sub.2] = [Ph.sub.2][C.sub.6][H.sub.4]C[H.sub.2]NHC[Me.sub.2]C[Me.sub.2] NHC[H.sub.2][C.sub.6][H.sub.4]P[Ph.sub.2]) were prepared by reaction of RuHCl[(P[Ph.sub.3]).sub.2](dach) and RuHCl{tme[P.sub.2][(NH).sub.2]} with HB[F.sub.4]. Their crystal structures are reported, and the p[K.sup.DM] values of their B[Ph.sub.4.sup.-] salts were determined to be 8.6 and 6.9, respectively. Key words: acidity, dihydrogen complex, hydride, phosphonium, dichloromethane. Operant a la temperature et dans le C[D.sub.2][Cl.sub.2] (DM) comme solvant et faisant appel a la spectroscopie RMN du ¹H et du ¹P, on a determine les constantes d'equilibre, [K.sup.DM], des reactions entres les acides et les bases des composes mentionnes dans le titre. La valeur de 9,7 attribuee par convention dans la litterature pour les composes [HP[Cy.sub.3]]B[Ph.sub.4] et [HP[Cy.sub.3]]B[F.sub.4] a ete utilise comme composes de reference pour les determinations des p[K.sup.DM]. On a cree une echelle continue de valeurs de p[K.sup.DM] s'etalant de 9,7, a 5,7 en faisant appel aux composes acides [HP[R.sub.3]]B[Ph.sub.4]. Ces acides dont les valeurs de p[K.sup.DM] sont superieures a 6 sont stables alors que ceux des cations plus acides HP[R.sub.3.sup.+] se protonent au B[Ph.sub.4.sup.-] pour conduire a la formation de [R.sub.3]PB[Ph.sub.3] et de benzene. Les valeurs de p[K.sup.THF] rapportees dans la litterature pour les [HP[Bu.sub.2]Ph]B[Ph.sub.4], [HPMe[Ph.sub.2]]B[Ph.sub.4] et [HPEt[Ph.sub.2]]B[Ph.sub.4] ne sont pas fiables en raison de cette reaction de protonation. On a utilise les techniques d'effet Overhauser nucleaire et d'echo de spin a champ pulse PGSE en RMN du ¹H pour montrer que dans le DM, aux concentrations utilisees pour les Etudes acide-base, le [HP[Cy.sub.2]Ph]B[Ph.sub.4] existe sous la forme de paire d'ions et d'agregats plus importants allant jusqu'a des quadrupoles. La reaction du RuHCl[(P[Ph.sub.3]).sub.2](dach) et RuHCl{tme[P.sub.2][(NH).sub.2]} avec du HB[F.sub.4] a permid de preparer les deux nouveaux complexes de dihydrogene suivants [Ru([H.sub.2])Cl[(P[Ph.sub.3]).sub.2] (dach)]B[F.sub.4] (dach = (1R,2R)-(-)-diaminocyclohexane) et [Ru([H.sub.2])Cl{tme[P.sub.2][(NH).sub.2]}]B[F.sub.4] (tme[P.sub.2][(NH).sub.2] = P[Ph.sub.2][C.sub.6][H.sub.4] C[H.sub.2]NHC[Me.sub.2] C[Me.sub.2]NHC[H.sub.2][C.sub.6] [H.sub.4]P[Ph.sub.2]) dont on a determine les structures cristallines et les valeurs de p[K.sup.DM] de leurs sels B[Ph.sub.4.sup.-] qui s'etablissent respectivement a 8,6 et 6,9. Mots cles : acidite, complexe de dihydrogene, hydrure, phosphonium, dichloromethane. [Traduit par la Redaction], Introduction The quantitative study of the acidity of transition metal hydride and dihydrogen complexes serves to better the understanding of the reactions of these species in catalytic reactions, including those [...]

Published
2006

9. A community-built calibration system: The case study of quantification of metabolites in grape juice by qNMR spectroscopy

Author

Musio, B, Ragone, R, Todisco, S, Rizzuti, A, Latronico, M, Mastrorilli, P, Pontrelli, S, Intini, N, Scapicchio, P, Triggiani, M, Di Noia, T, Acquotti, D, Airoldi, C, Assfalg, M, Barge, A, Bateman, L, Benevelli, F, Bertelli, D, Bertocchi, F, Bieliauskas, A, Borioni, A, Caligiani, A, Callone, E, Čamra, A, Cesare Marincola, F, Chalasani, D, Consonni, R, Dambruoso, P, Davalli, S, David, T, Diehl, B, Donarski, J, Gil, A, Gobetto, R, Goldoni, L, Hamon, E, Harwood, J, Kobrlová, A, Longobardi, F, Luisi, R, Mallamace, D, Mammi, S, Martin-Biran, M, Mazzei, P, Mele, A, Milone, S, Molero Vilchez, D, Mulder, R, Napoli, C, Ragno, D, Randazzo, A, Rossi, M, Rotondo, A, Šačkus, A, Sáez Barajas, E, Schievano, E, Sitaram, B, Stevanato, L, Takis, P, Teipel, J, Thomas, F, Torregiani, E, Valensin, D, Veronesi, M, Warren, J, Wist, J, Zailer-Hafer, E, Zuccaccia, C, Gallo, V, Musio, Biagia, Ragone, Rosa, Todisco, Stefano, Rizzuti, Antonino, Latronico, Mario, Mastrorilli, Piero, Pontrelli, Stefania, Intini, Nicola, Scapicchio, Pasquale, Triggiani, Maurizio, Di Noia, Tommaso, Acquotti, Domenico, Airoldi, Cristina, Assfalg, Michael, Barge, Alessandro, Bateman, Lorraine, Benevelli, Francesca, Bertelli, Davide, Bertocchi, Fabio, Bieliauskas, Aurimas, Borioni, Anna, Caligiani, Augusta, Callone, Emanuela, Čamra, Ales, Cesare Marincola, Flaminia, Chalasani, Dinesh, Consonni, Roberto, Dambruoso, Paolo, Davalli, Silvia, David, Taylor, Diehl, Bernd, Donarski, James, Gil, Ana M., Gobetto, Roberto, Goldoni, Luca, Hamon, Erwann, Harwood, John S., Kobrlová, Andrea, Longobardi, Francesco, Luisi, Renzo, Mallamace, Domenico, Mammi, Stefano, Martin-Biran, Magali, Mazzei, Pierluigi, Mele, Andrea, Milone, Salvatore, Molero Vilchez, Dolores, Mulder, Roger J., Napoli, Claudia, Ragno, Daniele, Randazzo, Antonio, Rossi, Maria Cecilia, Rotondo, Archimede, Šačkus, Algirdas, Sáez Barajas, Elena, Schievano, Elisabetta, Sitaram, Bhavaraju, Stevanato, Livio, Takis, Panteleimon G., Teipel, Jan, Thomas, Freddy, Torregiani, Elisabetta, Valensin, Daniela, Veronesi, Marina, Warren, John, Wist, Julien, Zailer-Hafer, Elina, Zuccaccia, Cristiano, Gallo, Vito, Musio, B, Ragone, R, Todisco, S, Rizzuti, A, Latronico, M, Mastrorilli, P, Pontrelli, S, Intini, N, Scapicchio, P, Triggiani, M, Di Noia, T, Acquotti, D, Airoldi, C, Assfalg, M, Barge, A, Bateman, L, Benevelli, F, Bertelli, D, Bertocchi, F, Bieliauskas, A, Borioni, A, Caligiani, A, Callone, E, Čamra, A, Cesare Marincola, F, Chalasani, D, Consonni, R, Dambruoso, P, Davalli, S, David, T, Diehl, B, Donarski, J, Gil, A, Gobetto, R, Goldoni, L, Hamon, E, Harwood, J, Kobrlová, A, Longobardi, F, Luisi, R, Mallamace, D, Mammi, S, Martin-Biran, M, Mazzei, P, Mele, A, Milone, S, Molero Vilchez, D, Mulder, R, Napoli, C, Ragno, D, Randazzo, A, Rossi, M, Rotondo, A, Šačkus, A, Sáez Barajas, E, Schievano, E, Sitaram, B, Stevanato, L, Takis, P, Teipel, J, Thomas, F, Torregiani, E, Valensin, D, Veronesi, M, Warren, J, Wist, J, Zailer-Hafer, E, Zuccaccia, C, Gallo, V, Musio, Biagia, Ragone, Rosa, Todisco, Stefano, Rizzuti, Antonino, Latronico, Mario, Mastrorilli, Piero, Pontrelli, Stefania, Intini, Nicola, Scapicchio, Pasquale, Triggiani, Maurizio, Di Noia, Tommaso, Acquotti, Domenico, Airoldi, Cristina, Assfalg, Michael, Barge, Alessandro, Bateman, Lorraine, Benevelli, Francesca, Bertelli, Davide, Bertocchi, Fabio, Bieliauskas, Aurimas, Borioni, Anna, Caligiani, Augusta, Callone, Emanuela, Čamra, Ales, Cesare Marincola, Flaminia, Chalasani, Dinesh, Consonni, Roberto, Dambruoso, Paolo, Davalli, Silvia, David, Taylor, Diehl, Bernd, Donarski, James, Gil, Ana M., Gobetto, Roberto, Goldoni, Luca, Hamon, Erwann, Harwood, John S., Kobrlová, Andrea, Longobardi, Francesco, Luisi, Renzo, Mallamace, Domenico, Mammi, Stefano, Martin-Biran, Magali, Mazzei, Pierluigi, Mele, Andrea, Milone, Salvatore, Molero Vilchez, Dolores, Mulder, Roger J., Napoli, Claudia, Ragno, Daniele, Randazzo, Antonio, Rossi, Maria Cecilia, Rotondo, Archimede, Šačkus, Algirdas, Sáez Barajas, Elena, Schievano, Elisabetta, Sitaram, Bhavaraju, Stevanato, Livio, Takis, Panteleimon G., Teipel, Jan, Thomas, Freddy, Torregiani, Elisabetta, Valensin, Daniela, Veronesi, Marina, Warren, John, Wist, Julien, Zailer-Hafer, Elina, Zuccaccia, Cristiano, and Gallo, Vito

Abstract

Nuclear Magnetic Resonance (NMR) is an analytical technique extensively used in almost every chemical laboratory for structural identification. This technique provides statistically equivalent signals in spite of using spectrometer with different hardware features and is successfully used for the traceability and quantification of analytes in food samples. Nevertheless, to date only a few internationally agreed guidelines have been reported on the use of NMR for quantitative analysis. The main goal of the present study is to provide a methodological pipeline to assess the reproducibility of NMR data produced for a given matrix by spectrometers from different manufacturers, with different magnetic field strengths, age and hardware configurations. The results have been analyzed through a sequence of chemometric tests to generate a community-built calibration system which was used to verify the performance of the spectrometers and the reproducibility of the predicted sample concentrations.

Published
2020

14. Heterogenized water oxidation catalysts prepared by immobilizing Klaui-type organometallic precursors

Author

Universitat Politècnica de Catalunya. Departament d'Enginyeria Química, Universitat Politècnica de Catalunya. NEMEN - Nanoenginyeria de materials aplicats a l'energia, Pastori, Gabriele, Wahab, Khaja, Bucci, Alberto, Bellachioma, Gianfranco, Zuccaccia, Cristiano, Llorca Piqué, Jordi, Idriss, Hicham, Macchioni, Alceo, Universitat Politècnica de Catalunya. Departament d'Enginyeria Química, Universitat Politècnica de Catalunya. NEMEN - Nanoenginyeria de materials aplicats a l'energia, Pastori, Gabriele, Wahab, Khaja, Bucci, Alberto, Bellachioma, Gianfranco, Zuccaccia, Cristiano, Llorca Piqué, Jordi, Idriss, Hicham, and Macchioni, Alceo

Abstract

An efficient heterogenized water oxidation catalyst (2_TiO2) has been synthesized by immobilizing the Kläui-type organometallic precursor [Cp*Ir{P(O)(OH)2}3]Na (2, Cp*=1,2,3,4,5-pentamethylcyclopentadienyl ligand) onto rutile TiO2. Iridium is homogeneously distributed at the molecular and atomic/small cluster level in 2_TiO2 and 2'_TiO2 (solid catalyst recovered after the first catalytic run), respectively, as indicated by STEM-HAADF (scanning transmission electron microscopy - high angle annular dark field) studies. 2'_TiO2 exhibits TOF values up to 23.7 min-1 in the oxidation of water to O2 driven by NaIO4 at nearly neutral pH, and a TON only limited by the amount of NaIO4 used, as indicated by multiple run experiments. Furthermore, while roughly 40¿% leaching is observed during the first catalytic run, 2'_TiO2 does not undergo any further leaching even when in contact with strongly basic solutions and completely maintains its activity for thousands of cycles. NMR studies, in combination with ICP-OES (inductively coupled plasma optical emission spectrometry), indicate that the activation of 2_TiO2 occurs through the initial oxidative dissociation of PO43-, ultimately leading to active centers in which a 1:1 P/Ir ratio is present (derived from the removal of two PO43- units) likely missing the Cp* ligand., Peer Reviewed, Postprint (author's final draft)

Published
2016

18. An acidity scale of phosphonium tetraphenylborate salts and ruthenium dihydrogen complexes in dichloromethane.

Author

Tianshu Li, Lough, Alan J., Zuccaccia, Cristiano, Macchioni, Alceo, and Morris, Robert H.

Subjects
TETRAPHENYLBORATES, RUTHENIUM, DICHLOROMETHANE, ACIDITY function, NUCLEAR magnetic resonance spectroscopy
Abstract

Copyright of Canadian Journal of Chemistry is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2006
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19. Efficient Hydrogenation of N-Heterocycles Catalyzed by NNP-Manganese(I) Pincer Complexes at Ambient Temperature

Author

Veronica Papa, Johannes Fessler, Francesco Zaccaria, Julien Hervochon, Phong Dam, Christoph Kubis, Anke Spannenberg, Zhihong Wei, Haijun Jiao, Cristiano Zuccaccia, Alceo Macchioni, Kathrin Junge, Matthias Beller, Papa, Veronica, Fessler, Johanne, Zaccaria, Francesco, Hervochon, Julien, Dam, Phong, Kubis, Christoph, Spannenberg, Anke, Wei, Zhihong, Jiao, Haijun, Zuccaccia, Cristiano, Macchioni, Alceo, Junge, Kathrin, and Beller, Matthias

Subjects
reaction mechanisms, pincer ligand, Organic Chemistry, manganese, pincer ligands, nitrogen heterocycle, General Chemistry, nitrogen heterocycles, hydrogenation, Catalysis
Abstract

Manganese-catalyzed hydrogenation reactions have aroused widespread interest in recent years. Among the catalytic systems described, especially PNP- and NNP-Mn pincer catalysts have been reported for the hydrogenation of aldehydes, ketones, nitriles, aldimines and esters. Furthermore, NNP-Mn pincer compounds are efficient catalysts for the hydrogenolysis of less reactive amides, ureas, carbonates, and carbamates. Herein, the synthesis and application of specific imidazolylaminophosphine ligands and the corresponding Mn pincer complexes are described. These new catalysts have been characterized and studied by a combination of experimental and theoretical investigations, and their catalytic activities have been tested in several hydrogenation reactions with good to excellent performance. Especially, the reduction of N-heterocycles can be performed under very mild conditions.

Published
2023

20. Methylaluminoxane’s Molecular Cousin: A Well-defined and 'Complete' Al-Activator for Molecular Olefin Polymerization Catalysts

Author

Christian Ehm, Peter H. M. Budzelaar, Vincenzo Busico, Francesco Zaccaria, Cristiano Zuccaccia, Antonio Vittoria, Alceo Macchioni, Roberta Cipullo, Zaccaria, Francesco, Zuccaccia, Cristiano, Cipullo, Roberta, Budzelaar, Peter H. M., Vittoria, Antonio, Macchioni, Alceo, Busico, Vincenzo, Ehm, Christian, EuCheMS International Organometallic Conference XXIV, Zaccaria, F., Zuccaccia, C., Cipullo, R., Budzelaar, P. H. M., Vittoria, A., Macchioni, A., Busico, V., and Ehm, C.

Subjects
molecular catalysts, 010405 organic chemistry, Chemistry, Activator (genetics), borate activator, Methylaluminoxane, impurity scavenging, olefin polymerization catalysis, General Chemistry, 010402 general chemistry, 01 natural sciences, Catalysis, Scavenger (chemistry), 0104 chemical sciences, "latent" Lewis acidity, chemistry.chemical_compound, Polymer chemistry, Olefin polymerization, alkyl aluminum, catalyst activation
Abstract

Catalytic activity in olefin polymerization depends not only on the catalyst but also, crucially, on activator/alkylator/scavenger “packages.” Along with binary mixtures containing Lewis or Bronste...

Published
2021

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