The Infra-Red Absorptions of Organic Hydroxyl Compounds in the Solid State in the 3μ Region

Abstract

The absorptions in the range 2.6μ to 3.5μ, covering the OH and CH fundamentals, have been measured for a variety of solid organic hydroxyl compounds in the form of thin films. For simple alcoholic and carboxylic structures the results, as expected, show complete association in the condensed state. In a number of other cases a sharp band with a narrow doublet structure (δv∼40 cm^‐1) is found near 2.9μ, and this is ascribed to relatively ``free'' OH groups in the solid resulting either from steric protection, as in triphenylmethyl carbinol, or weak intramolecular binding as in ethyl mandelate. Two very general features are the shift of the absorptions to longer wave‐lengths in the condensed phases, and the doublet nature of the absorption of the ``free'' hydroxyl groups in the solid as well as in other phases. Both these factors are discussed in the light of the new and previous data.