Correlation of Infrared Stretching Frequencies and Hydrogen Bond Distances in Crystals

Abstract

Empirical correlations between X–H≡Y distance R and frequency shift of the X–H stretching motion Δv are presented for O–H≡O, N–H≡O, and N–H≡N hydrogen bonds. A linear correlation is possible provided a distinct straight line is assumed for each hydrogen bond type. The equations of the best straight lines and standard deviations are: O−H···O Δν(cm−1)=4.43·103(2.84−R) σ(Δν)=199cm−1N−H···O Δν(cm−1)=0.548·103(3.21−R)σ(Δν)=24cm−1N−H···N Δν(cm−1)=1.05·103(3.38−R) ?