The crystal structures of ethylene and tetrafluoroethylene complexes of rhodium(I)

Evans, John; Russell, David R.

doi:10.1039/c29710000197

Cited by 52 publications

(18 citation statements)

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“…The above discussion suggests that the effect of replacing hydrogen by fluorine is to strengthen the iron-to-olefin bonding and to increase the degree of o'-complexing. [Evans & Russell (1971) conclude from crystallographic studies that in rhodium complexes rc-complexing is increased.] The bonding between iron and olefin seems to be strengthened at the expense of a lengthening, and weakening, of the Fe-C(O) bonds.…”

Section: Discussionmentioning

confidence: 99%

The molecular structure of C₂F₄Fe(CO)₃, by gas-phase electron diffraction

Beagley¹,

Schmidling²,

Cruickshank³

1973

Acta Crystallogr Sect B

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Section: Discussionmentioning

confidence: 99%

The molecular structure of C₂F₄Fe(CO)₃, by gas-phase electron diffraction

Beagley¹,

Schmidling²,

Cruickshank³

1973

Acta Crystallogr Sect B

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“…The C=C bond length of the C EF 4 ligand is marginally longer than its value in other structures (Browning & Penfold, 1973;Evans & Russell, 1971;Green, Howard, Spencer & Stone, 1975a,b;Hitchcock, McPartlin & Mason, 1969;Guggenberger & Cramer, 1972) which ranges from 1.37 (3) to 1.44 (4) A. In view of the large e.s.d.…”

mentioning

confidence: 99%

Methyl[hydrotris(1-pyrazolyl)borato]tetrafluoroethyleneplatinum

Rice¹,

Oliver²

1978

Acta Crystallogr Sect B

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Abstract.(CH3)[HB (CsH3N2)3] (C 2Fa)Pt, CI2HI3-BF4N6Pt , M r -523.2, orthorhombic, P212121 (No. 19),a = 12.993 (2), b = 9.156 (1),c= 13.372 (2)A, V = 1590.8 A 3, Z = 4, g = 173.7 cm -~, D x = 2.18, D m = 2.14 (1) g cm -3. Full-matrix least-squares refinement of 1801 reflections yielded a final R of 0.037. The structure consists of a trigonal-bipyramidal arrangement of the three pyrazolyl N atoms, the methyl group and the C2F 4 ligand about the Pt atom. Short intramolecular contacts involving one methyl H atom and two of the F atoms of the C 2F4 ligand are observed.Introduction. Suitable crystals of the title compound, MTFPT, were obtained by slow evaporation of a hexane solution. All X-ray measurements were made using a Diano XRD-700 diffractometer equipped with a single-crystal orienter with Cu K¢~ radiation and at ambient room temperature (~22°C). Least-squares refinement of 37 independent reflections with K¢~ (1.54051 A) and Kct 2 (1.54433 A) well resolved yielded the unit-cell dimensions. The data crystal was bounded by {011}, 0.17 mm apart; {001}, 0.18 mm apart; {0i 1 }, 0.21 mm apart and was cut perpendicular to these faces to a height of 0.36 mm. The crystal was mounted with [100] parallel to the ¢p axis of the goniostat. Intensity-weighted plots of the reciprocal lattice were used to determine the space group. Measurements of 09 scans along the principal axes indicated suitable quality for data collection by the stationary-crystal/stationary-counter technique using a balanced Ni-Co filter pair. A total of 1826 unique reflections accessible within the range 3 ° < 20 < 145 ° were measured.Analysis of the intensities of the six check reflections indicated a 6% isotropic decay during the 5 d of data collection. The data were broken into five blocks of approximately equal size and the appropriate decay factors were applied. Additional corrections to the net intensities were applied to account for Lorentz and polarization effects, tt ~-~t2 splitting (Tulinsky, Worthington & Pignataro, 1959) and absorption as a function of crystal shape (J. M. Williams, Argonne National Laboratory program MET 176X). Standard deviations in the structure factor amplitudes, o(IFol),

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“…cis/trans optimized structures placed cis-stilbene close to the metal ion (3.8 and 4.3 between the olefinic carbons and the zinc [21] ), but placed trans-stilbene farther away (4.7 and 5.7 ). Hydrogenation would require that the p-electron cloud of the double bond face the metal center.…”

Section: Resultsmentioning

confidence: 96%

Stereoselective Hydrogenation of Olefins Using Rhodium‐Substituted Carbonic Anhydrase—A New Reductase

Jing

Okrasa

Kazlauskas

2009

Chemistry A European J

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One useful synthetic reaction missing from nature's toolbox is the direct hydrogenation of substrates using hydrogen. Instead nature uses cofactors like NADH to reduce organic substrates, which adds complexity and cost to these reductions. To create an enzyme that can directly reduce organic substrates with hydrogen, researchers have combined metal hydrogenation catalysts with proteins. One approach is an indirect link where a ligand is linked to a protein and the metal binds to the ligand. Another approach is direct linking of the metal to protein, but nonspecific binding of the metal limits this approach. Herein, we report a direct hydrogenation of olefins catalyzed by rhodium(I) bound to carbonic anhydrase (CA-[Rh]). We minimized nonspecific binding of rhodium by replacing histidine residues on the protein surface using site-directed mutagenesis or by chemically modifying the histidine residues. Hydrogenation catalyzed by CA-[Rh] is slightly slower than for uncomplexed rhodium(I), but the protein environment induces stereoselectivity favoring cis- over trans-stilbene by about 20:1. This enzyme is the first cofactor-independent reductase that reduces organic molecules using hydrogen. This catalyst is a good starting point to create variants with tailored reactivity and selectivity. This strategy to insert transition metals in the active site of metalloenzymes opens opportunities to a wider range of enzyme-catalyzed reactions.

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The crystal structures of ethylene and tetrafluoroethylene complexes of rhodium(I)

Cited by 52 publications

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The molecular structure of C₂F₄Fe(CO)₃, by gas-phase electron diffraction

The molecular structure of C₂F₄Fe(CO)₃, by gas-phase electron diffraction

Methyl[hydrotris(1-pyrazolyl)borato]tetrafluoroethyleneplatinum

Stereoselective Hydrogenation of Olefins Using Rhodium‐Substituted Carbonic Anhydrase—A New Reductase

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The crystal structures of ethylene and tetrafluoroethylene complexes of rhodium(I)

Cited by 52 publications

References 0 publications

The molecular structure of C2F4Fe(CO)3, by gas-phase electron diffraction

The molecular structure of C2F4Fe(CO)3, by gas-phase electron diffraction

Methyl[hydrotris(1-pyrazolyl)borato]tetrafluoroethyleneplatinum

Stereoselective Hydrogenation of Olefins Using Rhodium‐Substituted Carbonic Anhydrase—A New Reductase

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The molecular structure of C₂F₄Fe(CO)₃, by gas-phase electron diffraction

The molecular structure of C₂F₄Fe(CO)₃, by gas-phase electron diffraction