文摘
Structural, bonding and electronic characteristics of complexes of anthraquinone and 1-arylazo-2-naphtol dyes and cellulose I β are studied using B3LYP density functional method with 6-31G** basis set based on the partially and fully optimized structures. Results reveal that for both partially and fully optimized complexes, there is a stabilizing attraction between dyes and cellulose surface. The hydrazone (Hy) tautomer in anionic state (Hy–SO3 ?/sup>) shows the strongest interaction with the cellulose surface. Natural bond orbital (NBO) and atoms-in-molecules (AIM) analyses have been carried out to study the nature of azo dyes-cellulose bonds in detail. According to NBO analysis, a remarkable charge transfer occurs between the –SO3 ?/sup> and –SO3H functional groups of the dye and the cellulose surface which can be regarded as the main source of the large dye–cellulose interaction energy. AIM analysis confirms the existence of hydrogen and van der Waals bonds between the azo dyes and cellulose. Furthermore, a very good agreement is observed between the number of hydrogen bonding sites and dye–cellulose interaction energies.