Isostructural Zeolite-Supported Rhodium and Iridium Complexes: Tuning Catalytic Activity and Selectivity by Ligand Modification

Martínez-Macias, Claudia; Serna, Pedro; Gates, Bruce C.

doi:10.1021/acscatal.5b00995

Cited by 62 publications

(121 citation statements)

References 36 publications

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“…18 This result can be attributed to the stronger trans-influence of NO ligands as compared to CO. 64 Finally, DFT calculations reported elsewhere 34 obtained for them were found to be in the 0.6-1.3 and 2.74-3.39 Å ranges, respectively. 12,34,65 Consistent with these literature reports, RhAl and RhSi contributions with average coordination numbers of 0.8 and 0.4 at average bond distances of 3.12 and 3.61 Å, respectively, were identified in the EXAFS spectra of the Rh(NO)2/HY30 sample (Table 2). Including these two contributions in the analysis was necessary, since the overall fit of the raw data was not satisfactory in their absence.…”

Section: High Resolution Scanning Transmission Electronsupporting

confidence: 88%

Synthesis, Modeling, and Catalytic Properties of HY Zeolite-Supported Rhodium Dinitrosyl Complexes

et al. 2017

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HY zeolite-supported Rh(CO)2 complexes were used as precursors for the surface mediated synthesis of Rh(NO)2 species. The results of FTIR, EXAFS, and Mass Spectrometry measurements, as well as DFT calculations show that the replacement of the CO ligands in the Rh(CO)2 complexes by NO is a facile substitution process which is not affected by the Si/Al ratio of the zeolite support used. The Rh(NO)2 complexes thus formed are site-isolated 14electron species with a Rh-N bond distance of 1.77 Å, a N-Rh-N angle of ~104°, and NO ligands significantly deviating from a linear configuration (Rh-NO angle ~148°). These species exhibit a characteristic set of well-defined νNO bands at 1855 and 1779 cm-1 in their FTIR spectra and have an additional empty d-orbital at the rhodium center allowing for coordination of a third electron-donating ligand. Therefore, the Rh(NO)2 species react with C2H4 to form 16-electron Rh(NO)2(C2H4) species which are stable in the presence of gas phase C2H4 and can be further converted into Rh(NO)2(C2H5) complexes by addition of H2. The Rh(NO)2/HY30 material catalyzed both C2H4 hydrogenation and dimerization reactions at room temperature with TOFs of 0.01 and 6.7•10-3 s-1 at steady state, respectively. During these processes, the Rh sites remain mono-dispersed. An inverse kinetic isotope effect was observed for both reactions, thus underlining the similarities of the catalytic properties of the supported Rh(NO)2 species examined and molecular organometallic Rh complexes in solution. This is the first example demonstrating that Rh dinitrosyl complexes anchored on a solid support can catalyze hydrocarbon reactions.

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Section: High Resolution Scanning Transmission Electronsupporting

confidence: 88%

Synthesis, Modeling, and Catalytic Properties of HY Zeolite-Supported Rhodium Dinitrosyl Complexes

et al. 2017

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“…There are many examples of zeolite‐supported catalysts, M(C 2 H 4 ) 2 /Y, in which M=Rh, Ir, and [M(C 2 H 4 ) 2 (acac)] complexes (acac=acetylacetonate) are used as precursors. IR and extended X‐ray absorption fine structure (EXAFS) spectroscopy show that the coordination of the metal complex on the zeolite surface occurs through the formation of two M−O bonds .…”

Section: Single‐site Catalystsmentioning

confidence: 99%

Single‐Site Heterogeneous Catalysts: From Synthesis to NMR Signal Enhancement

Burueva

Kovtunova

Bukhtiyarov

et al. 2018

Chemistry A European J

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Catalysts with well-defined, single, active centers are of great importance and their utilization allows the gap between homo- and heterogeneous catalysis to be bridged and, importantly, the main selectivity problem of heterogeneous catalysis and the main separation challenge of homogeneous catalysis to be overcome. Moreover, the use of single-site catalysts allows the NMR signal to be significantly enhanced through the pairwise addition of two hydrogen atoms from a parahydrogen molecule to an unsaturated substrate. This review covers the fundamentals of the synthesis of single-site catalysts and shows the new aspects of their applications in both modern catalysis and the field of parahydrogen-based hyperpolarization. The different novel aspects of the formation and utilization of single-site catalysts, along with the possibility of NMR signal enhancement observations are described.

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“…Attempts to prepare immobilized transition metal catalysts follow three major methods: (1) covalent bond formation or ion pairing between support and complex, (2) non‐bonding interactions including hydrogen bridging, halogen bridges, π‐stacking, sigma C–H– π‐stacking or London forces (van der Waals interactions) with the support and (3) encapsulation. Various supports including polymers, Fe 3 O 4 nanoparticles, silicates, zeolites and carbon materials such as graphene oxide (GO) and reduced graphene oxide (rGO) have been used in the immobilization of metal complexes. Pd(II) complexes of N‐heterocyclic carbenes (NHCs) have been reported as immobilized homogeneous catalysts for C&bond;C coupling reactions on various suitable supports .…”

Section: Introductionmentioning

confidence: 99%

Catalytic activity and facile recovery of a cyclometalated N‐heterocyclic carbene palladium(II) complex immobilized by non‐covalent interactions on reduced graphene oxide

Karami

Ramezanpour

Zakariazadeh

et al. 2019

Applied Organom Chemis

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The growing concern about the potentially adverse effects of the production of chemical compounds on the sustainable development of the environment has led to a great deal of efforts to search for low-cost and environmentally friendly catalytic systems. A pyrene-tagged N-heterocyclic carbene palladacycle complex ([Pd{(C,N)C 6 H 4 CH 2 NH(Et)}(Imd-P)Br]) was prepared by reacting imidazolium salt with dimer ([Pd 2 {(C,N)C 6 H 4 CH 2 NH(Et)} 2 (μ-OAc) 2 ]). Then, it was immobilized onto the surface of reduced graphene oxide (rGO) via π-π stacking forces. The hybrid compound ((NHC)Pd-rGO) was made in a one-step process. Various techniques were employed to characterize the compound. In addition, computational studies were used to verify the interaction between the Pd complex and rGO. The catalytic activity of the molecular complex and hybrid material was evaluated in both Suzuki-Miyaura cross-coupling reactions and reduction of p-nitrophenol to p-aminophenol. The catalytic activity of the hybrid material was enhanced in comparison with the corresponding homogeneous analogue. Thus, rGO seems to play a significant role in catalytic activity. Hot filtration experiments show the heterogeneous nature of the catalyst resulting from the strong interaction between pyrene and graphene. The hybrid (NHC)Pd-rGO material could be recycled up to six times with no decrease in catalytic activity.

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Isostructural Zeolite-Supported Rhodium and Iridium Complexes: Tuning Catalytic Activity and Selectivity by Ligand Modification

Cited by 62 publications

References 36 publications

Synthesis, Modeling, and Catalytic Properties of HY Zeolite-Supported Rhodium Dinitrosyl Complexes

Synthesis, Modeling, and Catalytic Properties of HY Zeolite-Supported Rhodium Dinitrosyl Complexes

Single‐Site Heterogeneous Catalysts: From Synthesis to NMR Signal Enhancement

Catalytic activity and facile recovery of a cyclometalated N‐heterocyclic carbene palladium(II) complex immobilized by non‐covalent interactions on reduced graphene oxide

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