1H, 13C, 17O NMR and IR (CO-region) spectroscopic and mass-spectrometric studies of MenCpM(CO)2 (M = Co, Rh) homologs

Lyatifov, I.R.; Jafarov, G.M.; Babin, V. N.; Petrovskii, P. V.; Zagorevskii, V.

doi:10.1016/0022-328x(89)85318-5

Cited by 8 publications

(3 citation statements)

References 24 publications

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“…The room temperature { 1 H-} 13 C CP NMR spectrum of NaY loaded with Co(C 5 H 5 )(CO) 2 (not shown) reveals one signal with a Gaussian line shape at δ iso = 86.5 ppm, which originates from the 13 C nuclei of the cyclopentadienyl ring. The chemical shift is in good agreement with the chemical shift observed in solution, 84.5 ppm in CDCl 3 . Because of the large distance between the 1 H nuclei of the cyclopentadienyl ring and the 13 C nuclei of the CO ligands, signal enhancement of the latter carbon atoms by cross-polarization is relatively weak and thus these signals are not observed.…”

Section: Resultssupporting

confidence: 83%

“…Similar results were obtained at full loading (two molecules per supercage). At 313 K the spectrum consists of a single narrow Gaussian line at 209 ppm, which is caused by the 13 C nuclei of the carbonyl ligands (δ = 205 ppm in CDCl 3 ,). When the temperature is decreased, the component at 209 ppm starts to broaden and at 235 K an asymmetric line shape becomes apparent which is followed by a shift of the highest intensity in the spectrum to lower frequencies at 195 K. Upon a further decrease of the temperature, a shoulder appears at the left-hand side in the spectrum which increases in intensity at lowering the temperature further to 115 K. These spectra are deconvoluted as shown in Figure .…”

Section: Resultsmentioning

confidence: 99%

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Ferrocene and Dicarbonylcyclopentadienylcobalt in Faujasite-Type Zeolites: A Study of Molecular Motion

et al. 1999

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The anisotropic molecular motion of Fe(C5H5)2 and Co(C5H5)(CO)2 molecules in the supercages of faujasite-type zeolites has been examined by NMR and by Mössbauer spectroscopy. Static 2H quad-echo and {H-}13C CP NMR techniques show that below 225 K the Fe(C5H5)2 molecules have no translational freedom, the only motion being rapid rotation of the cyclopentadienyl rings about their 5-fold axes. This is indicated by an axially symmetric powder pattern (δiso = 69.7 ppm, Ω = 75.0 ppm) in the {1H-}13C CP NMR spectrum and a broad Pake-type powder pattern (QCC = 97.3 kHz) in the 2H NMR spectrum. As the temperature is raised the molecules gain translational freedom, and at temperatures above 358 K isotropic molecular motion is identified as the only type of molecular motion. A model is proposed suggesting that the translational, isotropic motion is mainly caused by intracage, SII→SII jumps of the Fe(C5H5)2 molecules. Based on this model activation energies and diffusion coefficients were calculated from the NMR parameters. The molecular motion of intrazeolite Fe(C5H5)2 depends on the Si/Al ratio of the Na-faujasite host as well, being the highest for Na-faujasites with the lowest Si/Al ratio. The higher amount of sodium cations in the supercages probably causes a decrease in the energy barriers for site-to-site hopping. {1H-}13C CP NMR experiments show that Co(C5H5)(CO)2 molecules get firmly fixed in the zeolite at 183 K. This observation enabled the study of the OC−Co−CO bite angle, φ, by use of 13C Hahn-echo NMR experiments on enriched Co(C5H5)(13CO)2. The presence of an inverted axially symmetric powder pattern with span, Ω, of 127 ppm and a second powder pattern with Ω = 287 ppm indicate changes in the bite angle.

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Section: Resultssupporting

confidence: 83%

Section: Resultsmentioning

confidence: 99%

Ferrocene and Dicarbonylcyclopentadienylcobalt in Faujasite-Type Zeolites: A Study of Molecular Motion

et al. 1999

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“…This is consistent with the lack of coupling observed for the methyl resonances in Cp*Rh-(CO) 2 . 28 IR spectroscopy shows four bands in the carbonyl region, one extra from that predicted for C 2v symmetry (A 1 + B 1 + B 2 ). The extra band could be dues to minor differences in packing that cause the molecule to be less symmetric.…”

Section: Resultsmentioning

confidence: 78%

Group 9 bimetallic carbonyl permethylpentalene complexes

et al. 2015

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We describe the synthesis, structure and bonding of the first iridium and rhodium permethylpentalene complexes, syn-[M(CO)2]2(μ:η(5):η(5)-Pn*) (M = Rh, Ir). In fact, [Ir(CO)2]2(μ:η(5):η(5)-Pn*) is the first iridium pentalene complex. An interesting preference for the isolation of the sterically more demanding syn-isomer is observed and substantiated by DFT analysis. Upon photolysis, the rhodium analogue yields an unusual tetrameric species Rh4(CO)6(μ:η(3):η(5)-Pn*)2 with bridging carbonyls and Rh-Rh bonds, which has been characterised by single crystal X-ray diffraction and by solution NMR spectroscopy.

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