Research of immobilization features of hetarylformazanes onto cellulose containing matrix
Keywords:
formazane, hard-phase supporter, modified sorbents, formazan adsorption, scanning electronic microscopy.Abstract
Benzazolyl- and diphenyl pyrimidinyl formazans before and after immobilization them onto ricehusk
cellulose matrices have been studied by IR-, electronic spectroscopies and the DFT method B3LYP/6-
31G** using the Spartan’14 and Gaussian 08.
«Hardness» and «softness» of the compounds were determined on the basis of calculated values for
the highest occupied molecular orbital energy (EHOMO) and lowest unoccupied molecular orbital energy
(ELUMO). It was established that adsorption capacity of 1-phenyl formazans is increasing in the series: diphenyl-
pyrimidinyl-<benzyl-benzimidazolyl-<benzthiazolylformazans; adsorption capacity of 1-paracarboxyphenyl
formazans is increasing in the series: diphenyl-pyrimidinyl-< benzthiazolyl formazans; and
adsorption capacity of 1-ortho-tolyl derivatives is increasing in the series: diphenyl-pyrimidinyl-
<benzthiazolyl-<benzyl-benzimidazolyl formazans. Under the same conditions of adsorption, 1-(4-
carboxyphenyl)-3-methyl-5-(4,6-diphenylpyridine-2-yl)formazan having a greater dipole moment is kept
stronger on the rice-husk cellulose matrix than the others, despite similar values of the physical and chemical
parameters of the compounds.
Using the diffuse reflectance spectroscopy in the infrared spectrum, it was shown that sterically
more accessible hydroxyl groups of the C-3 atom in the cellulose molecule are involved into the «soft» immobilization
of benzazolyl- and diphenilpyrimidinyl formazans onto the cellulose matrix.
High flexibility of the formazan molecule and unlimited possibility to have fine structure variations
due to the influence on the nature of the donor atoms and the substituents in the formazan molecule, allow to
synthesize cellulose-based sorbents with formazans "fixed" in various tautomeric forms; that directly affects
their characteristics, including analytical ones, and consequently, that allows to synthesize sorbents with predetermined
operational characteristics.









