Normal modes and group frequencies.  Conflict or compromise?  In-depth vibrational analysis of cyclohexanone

Fuhrer, H.; Kartha, V. B.; Krueger, P. J.; Mantsch, Henry H.; Jones, Richard N.

doi:10.1021/cr60279a001

Cited by 121 publications

(49 citation statements)

References 4 publications

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“…26,27 The present calculations show that the boat-type conformations are ca 20 kJ mol 1 above the chair minimum. In this way, chair-type monomers were used in the building of all the C-HÐ Ð ÐO-bonded dimers.…”

Section: Ab Initio Calculationsmentioning

confidence: 52%

“…26,27 However, the splitting of the C O band has not been detected, because of either the large bandwidths in the infrared spectrum or the low signal-to-noise ratio of the reported Raman spectrum.…”

Section: The Nc O Spectral Regionmentioning

confidence: 99%

“…It has been 27 that the observed spectrum is far more complex than the predicted spectrum (for both bare cyclohexanone and its deuteriotopomers), but the eight bands observed in this region have already been assigned to C-H fundamental modes. 26,27 However, concerning the highest wavenumber band, at ca 2962 cm 1 , its particular concentration-dependent intensity suggests an alternative assignment. As it can be seen from Fig.…”

Section: The Nc-h Spectral Regionmentioning

confidence: 99%

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C—H···O hydrogen bonds in liquid cyclohexanone revealed by the νCO splitting and the νC–H blue shift

Vaz¹,

Ribeiro‐Claro²

2003

J Raman Spectroscopy

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The presence of C -H· · ·O hydrogen bonds in liquid cyclohexanone is concluded from a combined theoretical and vibrational spectroscopic study. The two bands present in the nC O region, clearly observed in the Raman spectrum, are assigned to 'free' and 'bonded' carbonyl groups from their temperature-dependent and solvent-dependent relative intensities. In addition, a band exhibiting the same intensity dependence in the nC-H region is tentatively assigned to the blue-shifted nC-H· · ·(O) mode.

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Section: Ab Initio Calculationsmentioning

confidence: 52%

Section: The Nc O Spectral Regionmentioning

confidence: 99%

Section: The Nc-h Spectral Regionmentioning

confidence: 99%

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C—H···O hydrogen bonds in liquid cyclohexanone revealed by the νCO splitting and the νC–H blue shift

Vaz¹,

Ribeiro‐Claro²

2003

J Raman Spectroscopy

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“…Normal coordinate analysis (NCA) was based on a Urey-Bradley force field with the FG-matrix method of Wilson (31) and was performed on a triatomic CuOOOCu model (C2v symmetry) with a modified version of Schachtschneider's GMAT and FPERT programs (32,33). DFT calculations.…”

Section: Calculations Normal Coordinate Analysis (Nca)mentioning

confidence: 99%

A [Cu ₂ O] ²⁺ core in Cu-ZSM-5, the active site in the oxidation of methane to methanol

Woertink

Smeets

Groothaert

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

608

653

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Driven by the depletion of crude oil, the direct oxidation of methane to methanol has been of considerable interest. Promising low-temperature activity of an oxygen-activated zeolite, Cu-ZSM-5, has recently been reported in this selective oxidation and the active site in this reaction correlates with an absorption feature at 22,700 cm ؊1 . In the present study, this absorption band is used to selectively resonance enhance Raman vibrations of this active site. 18 O2 labeling experiments allow definitive assignment of the observed vibrations and exclude all previously characterized copper-oxygen species for the active site. In combination with DFT and normal coordinate analysis calculations, the oxygen activated Cu core is uniquely defined as a bent mono-( -oxo)dicupric site. Spectroscopically validated electronic structure calculations show polarization of the low-lying singly-occupied molecular orbital of the [Cu 2O] 2؉ core, which is directed into the zeolite channel, upon approach of CH 4. This induces significant oxyl character into the bridging O atom leading to a low transition state energy consistent with experiment and explains why the bent mono-( -oxo)dicupric core is highly activated for H atom abstraction from CH 4. The oxygen intermediate of Cu-ZSM-5 is now the most well defined species active in the methane monooxygenase reaction. density functional theory ͉ dicopper(II)-oxo ͉ oxygen activation ͉ resonance Raman spectroscopy ͉ zeolite

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“…A mixture of 3-oxolupane 20 (611 mg, 0.4 mmol) and K2C03 (6.25 mg) in D20 (0.94 mL) was refluxed for 52 h according to the , method of Fuhrer et al (31). The mixture was saturated with NaCl and then extracted with ether, and the ether extracts were dried over anhydrous MgS04, filtered, and the solvent removed under vacuum to give 2,2-dideutero-3-oxolupane 26 in 28.6% yield (175 mg).…”

Section: Deuterntion Of3-o~olupnne 20mentioning

confidence: 99%

The synthesis of nor- and bisnorlupanes

Wahhab¹,

Ottosen²,

Bachelor³

1991

Can. J. Chem.

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In the course of our studies on geochemical biomarkers we required a series of lupane standards. We report here an efficient synthesis of lupane (1) in three steps from betulin (3) in an overall yield of 47.2%. 17β(H)-28-Norlupane (2) was obtained in 90% purity employing Barton's method for the decarboxylation of 3-oxolupan-28-oic acid (10). 24,28-Bisnorlupane (4) and 24-norlupane (5) were obtained by a series of reactions involving formation of the oxime, the seconitrile, the epoxynitrile, ring closure, and finally a Wolff–Kishner reduction of the C3 carbonyl to the methylene. Also, to aid in the quantitative determination of these lupanes from oil shales and geological samples, 3-deuterolupane (6) and 2,3-dideuterolupane (7) were needed, and a method for their preparation is reported. Key words: lupane, 24-norlupane, 28-norlupane, 24,28-bisnorlupane, 3-deuterolupane, 2,3-dideuterolupane.

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Normal modes and group frequencies. Conflict or compromise? In-depth vibrational analysis of cyclohexanone

Cited by 121 publications

References 4 publications

C—H···O hydrogen bonds in liquid cyclohexanone revealed by the νCO splitting and the νC–H blue shift

C—H···O hydrogen bonds in liquid cyclohexanone revealed by the νCO splitting and the νC–H blue shift

A [Cu ₂ O] ²⁺ core in Cu-ZSM-5, the active site in the oxidation of methane to methanol

The synthesis of nor- and bisnorlupanes

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Normal modes and group frequencies. Conflict or compromise? In-depth vibrational analysis of cyclohexanone

Cited by 121 publications

References 4 publications

C—H···O hydrogen bonds in liquid cyclohexanone revealed by the νCO splitting and the νC–H blue shift

C—H···O hydrogen bonds in liquid cyclohexanone revealed by the νCO splitting and the νC–H blue shift

A [Cu 2 O] 2+ core in Cu-ZSM-5, the active site in the oxidation of methane to methanol

The synthesis of nor- and bisnorlupanes

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Product

Resources

About

A [Cu ₂ O] ²⁺ core in Cu-ZSM-5, the active site in the oxidation of methane to methanol