Question

can someone please tell me all the peaks bends etc in the first IR as well as the functional groups. also interpret the nmr please

07- 04- Absorbanco (au) 0.1- 0+ 3000 3000 15 1000 500 2000 Frequency (wavenumbers) Figure 3. IR spectrum of the second intermediate, bis(2,4,5-trifluorophenyl)methanone (6).

Answer 1

The assigned IR and NMR spectra of bis(2,4,5-trifluorophenyl)methanone is shown below

benzene C=C stretching F F C-F stretching F F F F Absorbance (au) C=0 stretching aromatic sp2 C-H stretching N 0.1- 0+ 3000 3000 15 1000 500 2000 Frequency (wavenumbers) Figure 3. IR spectrum of the second intermediate, bis(2,4,5-trifluorophenyl)methanone (6).

The peak observed in between 3000 -3100 cm^-1 is due to the aromatic sp² C-H stretching absorption band. The peak observed in between 1650 and 1700 cm^-1 is due to the carbonyl group (C=O) stretching band. The benzene ring C=C stretching bands appear around 1500 cm^-1 and 1600 cm^-1. The C-F stretching band appears in between 1300 and 1400 cm^-1.

o a a F F www. F ד BE 753 725 701 b F Fb b protons a protons 10.5 10.0 9.5 9.0 8.5 8.0 7520 6.5 6.0 5.5 4.5 4.0 3.5 Com 50 3.0 2.5 2.0 1.5 1.0 0.5

The compound contains two types of protons (a and b protons). So two NMR signals are expected as shown in the assigned spectrum. Since these are aromatic protons, their chemical shift observed around 7-8 ppm. "a protons" are slightly more deshielded than b protons and appears around 7.5 ppm as multiplet. b protons are slightly less deshielded than a protons and appear around 7.0 ppm as multiplet. Due to the presence of several fluorine substituent in the aromatic ring and carbonyl group attached to aromatic ring, there are complicated interactions work between protons and substituents. As a result, multiplet signals observed for both types of protons