Application of the MTD‐PLS method to heterocyclic dye–cellulose interactions

The minimal topologic difference method in a projection in latent structures variant procedure was applied to a series of heterocyclic monoazo dyes of the type: RC 6 H 4 N = NY (R = benzothiazole, benzimidazole, N‐containing aromatic pentacycles; Y = γ acid, H acid, chromotropic acid, R acid). A statistically excellent model was obtained: R X 2 = 0.625, R Y 2 = 0.940, Q 2 = 0.822. The analysis of this model reveals the nature of dye–fiber interactions, which determine the dye affinity. Hydrophobic character in the R group and H‐bond donor groups in a specific Y substitution position augment the dye affinity for cellulose. An increase of the polar nature of atoms in R depletes the affinity. Also some lateral substituents belonging to the Y coupling components suffer steric hindrance, and their presence is detrimental for the affinity. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007