Reaction of nitric oxide and silica-attached rhodium carbonyl complexes

Cannon, Kevin C.; Jo, Seung-Hyeon; White, J. M.

doi:10.1021/ja00196a007

Cited by 14 publications

(12 citation statements)

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“…NO/CO ligand exchange reactions can also take place in supported rhodium complexes but appear to be strongly affected by the nature of the support. For example, it has been shown that SiO 2 -supported Rh(CO) 2 complexes prepared from Rh(C 3 H 5 ) 3 do not react with NO at room temperature and form Rh oxide type species at elevated temperatures (i.e., 100 °C) . In contrast, γ-Al 2 O 3 -supported Rh(CO) 2 Cl complexes react with NO at 25 °C to form Rh(NO) 2 Cl intermediates, which are further converted into RhCl(NO) − species .…”

Section: Resultssupporting

confidence: 83%

“…For example, it has been shown that SiO 2 -supported Rh(CO) 2 complexes prepared from Rh(C 3 H 5 ) 3 do not react with NO at room temperature and form Rh oxide type species at elevated temperatures (i.e., 100 °C). 61 In contrast, γ-Al 2 O 3 -supported Rh(CO) 2 Cl complexes react with NO at 25 °C to form Rh(NO) 2 Cl intermediates, which are further converted into RhCl(NO) − species. 36 Similarly, FTIR results for highly dealuminated HY zeolite-supported Rh(CO) 2 species prepared from [Rh(NH 3 ) 5 Cl](OH) 2 show that their exposure to NO at room temperature yields Rh(NO) 2 complexes.…”

Section: Resultsmentioning

confidence: 99%

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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: Resultssupporting

confidence: 83%

Section: Resultsmentioning

confidence: 99%

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

et al. 2017

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“…When the SAPO-37-supported Rh(CO) 2 was exposed to flowing ethylene at 298 K, the ν CO bands at 2115 and 2052 cm –1 , assigned to the ν s and ν as vibrations, disappeared (Figure S10 in the SI), and a new band appeared, at 2053 cm –1 (Figure S10 in the SI), assigned on the basis of observations for zeolite DAY-supported species to Rh(CO)(C 2 H 4 ) . A weak band appeared at 2030 cm –1 , assigned tentatively to the species bonded to small amorphous regions of the support on the basis of observations with Rh(CO)(C 2 H 4 ) on SiO 2 ; , alternatively, it could be assigned to linear Rh(CO) on amorphous SiO 2 …”

Section: Resultsmentioning

confidence: 63%

“…31 A weak band appeared at 2030 cm −1 , assigned tentatively to the species bonded to small amorphous regions of the support on the basis of observations with Rh(CO)(C 2 H 4 ) on SiO 2 ; 52,53 alternatively, it could be assigned to linear Rh(CO) on amorphous SiO 2 . 54 EXAFS data characterizing the SAPO-37-supported rhodium gem-dicarbonyls confirm the site-isolation of the rhodium and give evidence of the non-carbonyl ligands bonded to itthat is, the support itself. Structure parameters corresponding to the best-fit models (details in the SI) are given in Table 1, with data for rhodium carbonyls on other supports shown for comparison.…”

Section: Xanes Evidence Of Positively Charged Rhodium In Rhodium Diet...mentioning

confidence: 62%

Isostructural Atomically Dispersed Rhodium Catalysts Supported on SAPO-37 and on HY Zeolite

Perez-Aguilar

Chen

Hughes³

et al. 2020

J. Am. Chem. Soc.

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Zeolites are widely applied supports for metal catalysts, but molecular sieves with comparable structuressilicoaluminophosphates (SAPOs)have drawn much less attention and been overlooked as supports for atomically dispersed metals. Now, we report SAPO-37 as a support for atomically dispersed rhodium in rhodium diethylene complexes, made by the reaction of Rh(η2-C2H4)2(acetylacetonate) with the support and anchored by two Rh–O bonds at framework tetrahedral sites, as shown by infrared and extended X-ray absorption fine structure spectra. The ethylene ligands were readily replaced with CO, giving sharp νCO bands indicating highly uniform supported species. A comparison of the spectra with those of comparable rhodium complexes on zeolite HY shows that the SAPO- and zeolite-supported complexes are isostructural, providing an unmatched opportunity for determining support effects in catalysis. The two catalysts had similar initial room-temperature activities per Rh atom for ethylene conversion in the presence of H2, but the SAPO-supported catalyst was selective for ethylene hydrogenation and the zeolite-supported catalyst selective for ethylene dimerization; correspondingly, the catalyst on the SAPO was more stable than that on the zeolite during operation in a flow reactor.

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“…Species such as Rh(CO) 2 , Rh(NO + ), Rh(NCO), Rh(CO)(NO), Rh(NO) 2 , and two forms of Rh(NO -) have all been identified. [9][10][11][12][13][14][15][16][17][18][19][20][21][22] However, an assessment of the structural and kinetic characters of the various of processes possible in these systems is generally absent.…”

Section: Introductionmentioning

confidence: 99%

Energy Dispersive Extended X-ray Absorption Fine Structure, Mass Spectrometric, and Diffuse Reflectance Infrared Studies of the Interaction of Al₂O₃-Supported Rh^I(CO)₂Cl Species with NO and Re-formation under CO

et al. 2002

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The interaction between supported Rh I (CO) 2 Cl species, prepared by metallo-organic chemical vapor deposition (MOCVD) of [Rh(CO) 2 Cl] 2 to hydroxylated γ-Al 2 O 3 , and NO has been investigated using time-resolved, energy dispersive extended X-ray absorption fine structure (EDE)/mass spectrometry (MS) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). MOCVD of [Rh I (CO) 2 Cl] 2 leads to the formation of a Rh I (CO) 2 Cl{O-Al} adlayer which, when fresh, reacts with NO to form a majority {Al-O} 2 RhCl(NO -) species at room temperature via a two-step mechanism involving an {Al-O}Rh(NO) 2 Cl species. The application of DRIFTS allows a direct association of the bent RhNO bonding in the {Al-O} 2 RhCl(NO)with "highwavenumber" Rh(NO -) species displaying ν(NO) at ca. 1750 cm -1 often observed in supported Rh systems. DRIFTS investigations on analogous Rh I (CO) 2 Cl/TiO 2 systems show the same reactivity toward NO, with a bent nitrosyl being formed rather than the more commonly dominant linear Rh(NO + ) species. DRIFTS also indicates that a second reaction is possible. This becomes increasingly significant for Rh(CO) 2 Cl{O-Al} samples exposed to air for ca. 2-3 days and results in the {Al-O}Rh I (CO) 2 Cl species reacting with NO to form a new species displaying adsorptions at 2150-2110 and 1750-1700 cm -1 . Once formed, this latter species reacts no further at room temperature under NO. The DRIFTS spectrum of this species is interpreted as being due to {Al-O}Rh(CO)(NO)Cl species existing in cis and trans configurations: the isomer with the carbonyl group trans to the Cl ligand being the preferred form at room temperature. The reconversion of the Rh(NO -) species under CO shows complex temperature dependence. The consumption of the Rh(NO -) shows only a weak temperature dependence in terms of EDE, but the observed evolution of NO g shows a strong temperature dependence. The combination of EDE and MS indicates rapid formation of an intermediate species, most likely {Al-O}Rh(CO)(NO)Cl, which at room temperature converts to the geminal dicarbonyl species slowly. The possible origins of this behavior, and the parameters determining the formation of "linear" and/ or "bent" rhodium nitrosyls in support Rh systems are discussed.

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Reaction of nitric oxide and silica-attached rhodium carbonyl complexes

Cited by 14 publications

References 0 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

Isostructural Atomically Dispersed Rhodium Catalysts Supported on SAPO-37 and on HY Zeolite

Energy Dispersive Extended X-ray Absorption Fine Structure, Mass Spectrometric, and Diffuse Reflectance Infrared Studies of the Interaction of Al₂O₃-Supported Rh^I(CO)₂Cl Species with NO and Re-formation under CO

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Reaction of nitric oxide and silica-attached rhodium carbonyl complexes

Cited by 14 publications

References 0 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

Isostructural Atomically Dispersed Rhodium Catalysts Supported on SAPO-37 and on HY Zeolite

Energy Dispersive Extended X-ray Absorption Fine Structure, Mass Spectrometric, and Diffuse Reflectance Infrared Studies of the Interaction of Al2O3-Supported RhI(CO)2Cl Species with NO and Re-formation under CO

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Energy Dispersive Extended X-ray Absorption Fine Structure, Mass Spectrometric, and Diffuse Reflectance Infrared Studies of the Interaction of Al₂O₃-Supported Rh^I(CO)₂Cl Species with NO and Re-formation under CO