Methane formation in the reaction of carbon monoxide and hydrogen in the presence of iridium and osmium clusters

Schunn, R. A.; Demitras, G. C.; Choi, Henry W.; Muetterties, E. L.

doi:10.1021/ic50225a092

Cited by 18 publications

(4 citation statements)

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“…The details of the reaction have not been clarified although transfer of Me from P(OMe)3 to the metal is a probable step. 58 Either the ionic or the radical mechanism can be imagined as responsible for alkyl migration to the metal in the reaction of (Cp)2Mo2(CO)4(Ph2CS) complexes with alkyl phosphites.59…”

Section: Dlfflcult-to-classlfy Examplesmentioning

confidence: 99%

Arbuzov-like dealkylation reactions of transition-metal-phosphite complexes

Brill¹,

Landon²

1984

Chem. Rev.

122

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Section: Dlfflcult-to-classlfy Examplesmentioning

confidence: 99%

Arbuzov-like dealkylation reactions of transition-metal-phosphite complexes

Brill¹,

Landon²

1984

Chem. Rev.

122

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“…The tetra-iridium cluster framework is one of the simplest structures presenting neighboring metal centers, and numerous tetra-iridium clusters are known. The chemistry of tetra-iridium carbonyl clusters is especially extensive, as the metal frame is relatively stable, so that many compounds in this class have been investigated, including those that are catalysts both in solution and on supports [29][30][31][32]. The parent tetra-iridium cluster Ir 4 (CO) 12 has two structures which are minima on the potential energy surface, one T d structure with all 12 carbonyls being terminal, and one C 3v structure with nine terminal carbonyls and three bridging carbonyls on the basal plane (Fig.…”

Section: Introductionmentioning

confidence: 99%

Structures, relative energies, and ligand dissociation energies of iridium carbonyl phosphine clusters

Zhang

Katz

Gates

et al. 2015

Computational and Theoretical Chemistry

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a b s t r a c tThere is significant interest in the catalytic properties of substituted iridium carbonyl clusters but little thermodynamic information available characterizing them. The low-energy isomers of Ir x (PH 3 ) y (CO) z (x = 1, 2, 4) were investigated with density functional theory and correlated molecular orbital theory at the coupled cluster CCSD(T) level. The relative energies and ligand dissociation energies were calculated. Differences in relative energies are consequences of both electronic and steric effects of the phosphines and carbonyls. The calculations predict three fundamental structural types for Ir 2 (PH 3 ) y (CO) z : C 2v , C 2 , and D 3d . Ten exchange-correlation functionals were used for the ligand dissociation energy calculations in addition to CCSD(T) for the smaller clusters. The xB97X-D functional gave the most consistent ligand dissociation energies as compared with the CCSD(T) benchmark calculations, and, so it was used to predict the dissociation energies for larger clusters when CCSD(T) calculations were infeasible. The dissociation energies characteristic of Ir 4 (PH 3 ) y (CO) z were in the range of $30 to $60 kcal/mol. Dissociation of a bridging ligand often involved a hydrogen atom transfer from a phosphine to a coordinatively unsaturated iridium atom and a phosphine converting from a bridging site to an equatorial site. The products of such reactions are predicted to have lower relative energies than other isomers.Phosphines act as r-electron donors, and there is a trend of an increase in carbonyl ligand dissociation energies as more phosphines are substituted in the small clusters.

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“…In the absence of additional hyperfine interactions the EPR spectra of coordinated semiquinones are identical with uncomplexed semiquinones.19 Sawyer has reported that the dianion can be regenerated from the monoanion by electrolysis. If the monoanion was subject to ligand dissociation, it would likely occur under conditions of the elec- 0.4192 (8) 0.0251 (5) 0.0008 (4) 6.4 (3) -0.4 (5) 0.0 (5) -0.3 (5) 0(4) 0.0428 (7) -0.0293 (5) -0.0090 (3)…”

Section: Description Of the Mo205(35-dbcat)22~a Nionmentioning

confidence: 99%