Letter | Published:

Infra-red Spectrum and Molecular Structure of Diketopiperazine and Tetramethyldiketopiperazine

Abstract

SANBORN1 has concluded from her work on the chemical properties of glycine anhydride (diketopiperazine), that the molecule exists only in the enolform (I). In view of the importance of the diketo-piperazine configuration for the knowledge of the structure of the proteins, it seemed not without interest to look for further means of investigating the molecular structure of this substance. A very suitable method is the analysis of the infra-red spectrum. The absorption bands of diketopiperazine and its tetramethyl derivative were therefore observed with a quartz spectrometer in the region 2·8–3·6 µ. The effective slit-width was 0·02 µ Each substance was deposited from a suspension in alcohol or ether, respectively, as a crystalline layer on the quartz window of an absorption cell. Following a suggestion of Dr. W. T. Astbury, the cell was then dried in vacuo over phosphorus pentoxide for 38 hours, so as to eliminate all traces of water which might have been adsorbed on the surface of the crystals. The cell was kept dry with phosphorus pentoxide throughout the course of the experiments.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

References

  1. 1

    Sanborn, J. phys. Chem., 36, 1799 (1932).

Download references

Author information

Rights and permissions

Reprints and Permissions

About this article

Further reading

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.