Aromatic out-of-plane bending region

Table II. Band Assignments for the Aliphatic Stretching and Aromatic Out-of-plane Bending Regions...

Before the FTIR data were analyzed together with coalification parameters in a components analysis, it was first necessary to select which variables to use. In general, the number of variables should not exceed one-third of the number of samples (in this study the maximum number is 8). Components analyses were performed on data for the aliphatic stretching and aromatic out-of-plane bending regions of the infrared spectrum in order to eliminate those variables that did not provide new information. 

Table VI. Rotated Matrix of Factor Loadings for Components Analysis of FTIR Absorption Bands in the Aromatic Out-of-Plane Bending Region...

FIGURE 2.35. Pyridine. Aromatic C—H stretch, 3090-3000 cm-1. C—C, C—N ring stretching (skeletal bands), 1600-1430 cm-1. C—H out-of-plane bending, 753,707 cm 1. See Appendix E, Table E-l for patterns in region C for substituted pyridines. 

Strong absorptions in the region 690-900 cm-1, due to C-H out-of-plane bending, can be used to determine the substitution pattern of an aromatic ring. 

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