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5. Using Redox-Active Ligands to Generate Actinide Ligand Radical Species

Author

Galley, Shane S., primary, Pattenaude, Scott A., additional, Ray, Debmalya, additional, Gaggioli, Carlo Alberto, additional, Whitefoot, Megan A., additional, Qiao, Yusen, additional, Higgins, Robert F., additional, Nelson, W. L., additional, Baumbach, Ryan, additional, Sperling, Joseph M., additional, Zeller, Matthias, additional, Collins, Tyler S., additional, Schelter, Eric J., additional, Gagliardi, Laura, additional, Albrecht-Schönzart, Thomas E., additional, and Bart, Suzanne C., additional

Published
2021
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6. A Tunable Multivariate Metal-Organic Framework as a Platform for Designing Photocatalysts

Author

Wang, Yang, Lv, Hao, Svensson Grape, Erik, Gaggioli, Carlo Alberto, Tayal, Akhil, Dharanipragada, Aditya, Willhammar, Tom, Inge, A. Ken, Zou, Xiaodong, Liu, Ben, Huang, Zhehao, Wang, Yang, Lv, Hao, Svensson Grape, Erik, Gaggioli, Carlo Alberto, Tayal, Akhil, Dharanipragada, Aditya, Willhammar, Tom, Inge, A. Ken, Zou, Xiaodong, Liu, Ben, and Huang, Zhehao

Abstract

Catalysts for photochemical reactions underlie many foundations in our lives, from natural light harvesting to modern energy storage and conversion, including processes such as water photolysis by TiO2. Recently, metal–organic frameworks (MOFs) have attracted large interest within the chemical research community, as their structural variety and tunability yield advantages in designing photocatalysts to address energy and environmental challenges. Here, we report a series of novel multivariate metal–organic frameworks (MTV-MOFs), denoted as MTV-MIL-100. They are constructed by linking aromatic carboxylates and AB2OX3 bimetallic clusters, which have ordered atomic arrangements. Synthesized through a solvent-assisted approach, these ordered and multivariate metal clusters offer an opportunity to enhance and fine-tune the electronic structures of the crystalline materials. Moreover, mass transport is improved by taking advantage of the high porosity of the MOF structure. Combining these key advantages, MTV-MIL-100(Ti,Co) exhibits a high photoactivity with a turnover frequency of 113.7 molH2 gcat.–1 min–1, a quantum efficiency of 4.25%, and a space time yield of 4.96 × 10–5 in the photocatalytic hydrolysis of ammonia borane. Bridging the fields of perovskites and MOFs, this work provides a novel platform for the design of highly active photocatalysts.

Published
2021
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11. Tuning Catalytic Sites on Zr6O8 Metal–Organic Framework Nodes via Ligand and Defect Chemistry Probed with tert-Butyl Alcohol Dehydration to Isobutylene

Author

Yang, Dong, Gaggioli, Carlo Alberto, Ray, Debmalya, Babucci, Melike, Gagliardi, Laura, Gates, Bruce C., Yang, Dong, Gaggioli, Carlo Alberto, Ray, Debmalya, Babucci, Melike, Gagliardi, Laura, and Gates, Bruce C.

Abstract

Metal–organic frameworks (MOFs) have drawn wide attention as candidate catalysts, but some essential questions about their nature and performance have barely been addressed. (1) How do OH groups on MOF nodes act as catalytic sites? (2) What are the relationships among these groups, node defects, and MOF stability, and how do reaction conditions influence them? (3) What are the interplays between catalytic properties and transport limitations? To address these questions, we report an experimental and theoretical investigation of the catalytic dehydration of tert-butyl alcohol (TBA) used to probe the activities of OH groups of Zr6O8 nodes in the MOFs UiO-66 and MOF-808, which have different densities of vacancy sites and different pore sizes. The results show that (1) terminal node OH groups are formed as formate and/or acetate ligands present initially on the nodes react with TBA to form esters, (2) these OH groups act as catalytic sites for TBA dehydration to isobutylene, and (3) TBA also reacts to break node–linker bonds to form esters and thereby unzip the MOFs. The small pores of UiO-66 limit the access of TBA and the reaction with the formate/acetate ligands bound within the pores, whereas the larger pores of MOF-808 facilitate transport and favor reaction in the MOF interior. However, after removal of the formate and acetate ligands by reaction with methanol to form esters, interior active sites in UiO-66 become accessible for the reaction of TBA, with the activity depending on the density of defect sites with terminal OH groups. The number of vacancies on the nodes is important in determining a tradeoff between the catalytic activity of a MOF and its resistance to unzipping. Computations at the level of density functional theory show how the terminal OH groups on node vacancies act as Brønsted bases, facilitating TBA dehydration via a carbocation intermediate in an E1 mechanism; the calculations further illuminate the comparable chemistry of the unzipping.

Published
2020
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16. Synthesis and Characterization of Tris-chelate Complexes for Understanding f-Orbital Bonding in Later Actinides

Author

Galley, Shane S., primary, Pattenaude, Scott A., additional, Gaggioli, Carlo Alberto, additional, Qiao, Yusen, additional, Sperling, Joseph M., additional, Zeller, Matthias, additional, Pakhira, Srimanta, additional, Mendoza-Cortes, Jose L., additional, Schelter, Eric J., additional, Albrecht-Schmitt, Thomas E., additional, Gagliardi, Laura, additional, and Bart, Suzanne C., additional

Published
2019
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20. Dioxygen insertion into the gold(i)-hydride bond: spin orbit coupling effects in the spotlight for oxidative addition

Author

Gaggioli, Carlo Alberto, Belpassi, Leonardo, Tarantelli, Francesco, Zuccaccia, Daniele, Harvey, Jeremy N., and Belanzoni, Paola

Subjects
Spin transition, Spin-orbit coupling effects, spin forbidden reaction, 010402 general chemistry, Photochemistry, Hydrogen atom abstraction, 01 natural sciences, Metastable intermediate, chemistry.chemical_compound, Potential energy, Insertion reaction, Hydrides, Quantum chemistry, Solvents, Activation parameter, Catalytic applications, Experimental investigations, Rate determining step, Recombination process, Spin-orbit couplings, spin orbit coupling, gold spin-orbit coupling, 010405 organic chemistry, Hydride, fungi, Oxidative addition, food and beverages, General Chemistry, Rate-determining step, eye diseases, gold catalysis, spin forbidden reactions, 0104 chemical sciences, Chemistry, chemistry, Potential energy surface, MECP, Oxidative addition, spin forbidden reaction, spin orbit coupling, gold catalysis, MECP, sense organs, Solvent effects
Abstract

O2 insertion into a Au(i)–H bond occurs through an oxidative addition/recombination mechanism that can only be described accurately by inclusion of spin orbit coupling (SOC) effects., O2 insertion into a Au(i)–H bond occurs through an oxidative addition/recombination mechanism, showing peculiar differences with respect to Pd(ii)–H, for which O2 insertion takes place through a hydrogen abstraction mechanism in the triplet potential energy surface with a pure spin transition state. We demonstrate that the spin-forbidden Au(i)–hydride O2 insertion reaction can only be described accurately by inclusion of spin orbit coupling (SOC) effects. We further find that a new mechanism involving two O2 molecules is also feasible, and this result, together with the unexpectedly high experimental entropic activation parameter, suggests the possibility that a third species could be involved in the rate determining step of the reaction. Finally, we show that the O2 oxidative addition into a Au(i)–alkyl (CH3) bond also occurs but the following recombination process using O2 is unfeasible and the metastable intermediate Au(iii) species will revert to reactants, thus accounting for the experimental inertness of Au–alkyl complexes toward oxygen, as frequently observed in catalytic applications. We believe that this study can pave the way for further theoretical and experimental investigations in the field of Au(i)/Au(iii) oxidation reactions, including ligand, additive and solvent effects.

Published
2016
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22. Globularity-Selected Large Molecules for a New Generation of Multication Perovskites

Author

Gholipour, Somayeh, primary, Ali, Abdollah Morteza, additional, Correa-Baena, Juan-Pablo, additional, Turren-Cruz, Silver-Hamill, additional, Tajabadi, Fariba, additional, Tress, Wolfgang, additional, Taghavinia, Nima, additional, Grätzel, Michael, additional, Abate, Antonio, additional, De Angelis, Filippo, additional, Gaggioli, Carlo Alberto, additional, Mosconi, Edoardo, additional, Hagfeldt, Anders, additional, and Saliba, Michael, additional

Published
2017
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24. Tuning Catalytic Sites on Zr6O8Metal–Organic Framework Nodes via Ligand and Defect Chemistry Probed with tert-Butyl Alcohol Dehydration to Isobutylene

Author

Yang, Dong, Gaggioli, Carlo Alberto, Ray, Debmalya, Babucci, Melike, Gagliardi, Laura, and Gates, Bruce C.

Abstract

Metal–organic frameworks (MOFs) have drawn wide attention as candidate catalysts, but some essential questions about their nature and performance have barely been addressed. (1) How do OH groups on MOF nodes act as catalytic sites? (2) What are the relationships among these groups, node defects, and MOF stability, and how do reaction conditions influence them? (3) What are the interplays between catalytic properties and transport limitations? To address these questions, we report an experimental and theoretical investigation of the catalytic dehydration of tert-butyl alcohol (TBA) used to probe the activities of OH groups of Zr6O8nodes in the MOFs UiO-66 and MOF-808, which have different densities of vacancy sites and different pore sizes. The results show that (1) terminal node OH groups are formed as formate and/or acetate ligands present initially on the nodes react with TBA to form esters, (2) these OH groups act as catalytic sites for TBA dehydration to isobutylene, and (3) TBA also reacts to break node–linker bonds to form esters and thereby unzip the MOFs. The small pores of UiO-66 limit the access of TBA and the reaction with the formate/acetate ligands bound within the pores, whereas the larger pores of MOF-808 facilitate transport and favor reaction in the MOF interior. However, after removal of the formate and acetate ligands by reaction with methanol to form esters, interior active sites in UiO-66 become accessible for the reaction of TBA, with the activity depending on the density of defect sites with terminal OH groups. The number of vacancies on the nodes is important in determining a tradeoff between the catalytic activity of a MOF and its resistance to unzipping. Computations at the level of density functional theory show how the terminal OH groups on node vacancies act as Brønsted bases, facilitating TBA dehydration via a carbocation intermediate in an E1 mechanism; the calculations further illuminate the comparable chemistry of the unzipping.

Published
2020
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30. Spin‐Forbidden Reactions: Adiabatic Transition States Using Spin–Orbit Coupled Density Functional Theory.

Author

Gaggioli, Carlo Alberto, Belpassi, Leonardo, Tarantelli, Francesco, Harvey, Jeremy N., and Belanzoni, Paola

Subjects
*ADIABATIC processes, *DENSITY functional theory, *CHEMICAL reactions, *POTENTIAL energy surfaces, *MOLECULAR theory
Abstract

Abstract: A spin‐forbidden chemical reaction involves a change in the total electronic spin state from reactants to products. The mechanistic study is challenging because such a reaction does not occur on a single diabatic potential energy surface (PES), but rather on two (or multiple) spin diabatic PESs. One possible approach is to calculate the so‐called “minimum energy crossing point” (MECP) between the diabatic PESs, which however is not a stationary point. Inclusion of spin–orbit coupling between spin states (SOC approach) allows the reaction to occur on a single adiabatic PES, in which a transition state (TS SOC) as well as activation free energy can be calculated. This Concept article summarizes a previously published application in which, for the first time, the SOC effects, using spin–orbit ZORA Hamiltonian within density functional theory (DFT) framework, are included and account for the mechanism of a spin‐forbidden reaction in gold chemistry. The merits of the MECP and TS SOC approaches and the accuracy of the results are compared, considering both our recent calculations on molecular oxygen addition to gold(I)‐hydride complexes and new calculations for the prototype spin‐forbidden N2O and N2Se dissociation reactions. [ABSTRACT FROM AUTHOR]

Published
2018
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31. Tuning the Properties of Zr6O8Nodes in the Metal Organic Framework UiO-66 by Selection of Node-Bound Ligands and Linkers

Author

Wei, Ruiping, Gaggioli, Carlo Alberto, Li, Guozhu, Islamoglu, Timur, Zhang, Zhuxiu, Yu, Ping, Farha, Omar K., Cramer, Christopher J., Gagliardi, Laura, Yang, Dong, and Gates, Bruce C.

Abstract

The metal organic framework (MOF) UiO-66, which incorporates Zr6O8nodes, exhibits high stability under a wide range of conditions that commends it for potential applications. The MOF properties can be tuned by the choice of the groups bonded to the node defect sites and to the linkers. We report data for UiO-66 incorporating formate, acetate, benzoate, and trifluoroacetate on the nodes and −NH2, −OH, −NO2, and phenyl substituents on the benzene rings of the benzene-1,4-dicarboxylic acid-derived linkers. The MOFs were characterized by IR and 1H NMR spectroscopies, thermal gravimetric analysis, N2adsorption, X-ray diffraction crystallography, scanning and transmission electron microscopy, and electronic structure calculations. The ligands on the nodes were identified and quantified by 1H NMR spectra of the MOFs digested in NaOH/D2O solutions. The effects of the node and linker groups on the electronic properties of the nodes have been quantified with IR spectra of the node μ3-OH groups and by density functional theory calculations, which are in good agreement with one another.

Published
2019
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33. Tuning Catalytic Sites on Zr 6 O 8 Metal-Organic Framework Nodes via Ligand and Defect Chemistry Probed with tert -Butyl Alcohol Dehydration to Isobutylene.

Author

Yang D, Gaggioli CA, Ray D, Babucci M, Gagliardi L, and Gates BC

Abstract

Metal-organic frameworks (MOFs) have drawn wide attention as candidate catalysts, but some essential questions about their nature and performance have barely been addressed. (1) How do OH groups on MOF nodes act as catalytic sites? (2) What are the relationships among these groups, node defects, and MOF stability, and how do reaction conditions influence them? (3) What are the interplays between catalytic properties and transport limitations? To address these questions, we report an experimental and theoretical investigation of the catalytic dehydration of tert -butyl alcohol (TBA) used to probe the activities of OH groups of Zr 6 O 8 nodes in the MOFs UiO-66 and MOF-808, which have different densities of vacancy sites and different pore sizes. The results show that (1) terminal node OH groups are formed as formate and/or acetate ligands present initially on the nodes react with TBA to form esters, (2) these OH groups act as catalytic sites for TBA dehydration to isobutylene, and (3) TBA also reacts to break node-linker bonds to form esters and thereby unzip the MOFs. The small pores of UiO-66 limit the access of TBA and the reaction with the formate/acetate ligands bound within the pores, whereas the larger pores of MOF-808 facilitate transport and favor reaction in the MOF interior. However, after removal of the formate and acetate ligands by reaction with methanol to form esters, interior active sites in UiO-66 become accessible for the reaction of TBA, with the activity depending on the density of defect sites with terminal OH groups. The number of vacancies on the nodes is important in determining a tradeoff between the catalytic activity of a MOF and its resistance to unzipping. Computations at the level of density functional theory show how the terminal OH groups on node vacancies act as Brønsted bases, facilitating TBA dehydration via a carbocation intermediate in an E1 mechanism; the calculations further illuminate the comparable chemistry of the unzipping.

Published
2020
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