IR spectra and point group symmetry

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SUMMARY

The discussion centers on the impact of point group symmetry on the IR spectra of the Cr(CO)4(anisole) complex formed from the reaction of anisole with hexacarbonylchromium. The participant reports distinct IR peaks at 1830 cm-1 and 1930 cm-1, attributing the latter to backbonding effects. The inquiry seeks clarification on how point group symmetry influences these spectral features, particularly in comparison to pure Cr(CO)6.

PREREQUISITES
  • Understanding of IR spectroscopy principles
  • Knowledge of coordination chemistry, specifically Cr(CO) complexes
  • Familiarity with point group symmetry in molecular structures
  • Experience with NMR spectroscopy techniques
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  • Research the effects of point group symmetry on vibrational spectra
  • Study the backbonding mechanism in metal-carbonyl complexes
  • Compare IR spectra of Cr(CO)4(anisole) with Cr(CO)6
  • Explore the synthesis and characterization of transition metal complexes
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Chemistry students, researchers in coordination chemistry, and professionals studying vibrational spectroscopy and metal-ligand interactions.

Bladibla
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Hello

I'm currently studying the reaction of anisole with hexacarbonylchromium, and experiment shows the displacement of 2 of the carbonyl ligands with the anisole group, forming a 2-η ligand with the chromium ion.

After refluxing to obtain the crystals, IR and nmr spectra of the sample were obtained; Apprarently, the point group symmetry of the complex affects the IR spectra of the Cr(CO)4(anisole) compound, but I cannot see how it would affect the IR. Currently, In my IR spectra, I have a distinct peak at 1830 cm-1 corresponding the the CO stretch, and a lesser but nevetheless signficant peak at 1930 cm-1, which I can currently hypothesise is due to the backbonding of electrons to the carbonyl ligands.

Can anyone help with this?

Thanks.
 
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I doubt anyone can say offhand. But yeah, probably the C-Cr stretch. Have you compard to the spectrum of pure Cr(CO)6?