ISSN 0036-0244, Russian Journal of Physical Chemistry A, 2009, Vol. 83, No. 9, pp. 1520–1525. © Pleiades Publishing, Ltd., 2009. 1520 INTRODUCTION Dextran is a polysaccharide consisting of α-D-glu- copyranose units coupled into long branched chains, mainly through the α-(1 6) and partly through the α-(1 3)-glycosidic linkages (Fig. 1). This unique linkage pattern gives dextran with distinctive physical properties. Due to these properties, dextran has been extensively used as a drug carrier system, including for antidiabetics, antibiotics, anticancer drugs, peptides and enzymes [1, 2]. Dextran is derivatized easily to control its solubility or provide reactive groups. Con- sequently, dextran and its derivatives have numerous potential food, pharmaceutical, and industrial appli- cations [3, 4]. The aim of this work is to use attenuated total reflectance—Fourier transform infrared (ATR– FTIR) spectroscopy, and FTIR imaging microscopy as the main tools to verify the conformation and structure of this type of ligand around the copper(II) ions. Many types of polysaccharides such as chitin [5], chitosan [6], heparin [7], alginate [8], inulin [9], dex- tran [10], and pullulan [11, 12] have been derivatized for biomedical applications. The numerous investiga- tions have indicated that the polysaccharide dextran and its derivatives have the extraordinary power to forming the water–soluble complexes with various biometals [13, 14]. It has been established that the degree of Cu(II) ion binding within the complex depends primarily on the pH of the solution, as well as on the participation both of the OH groups and the H 2 O molecules in the first coordination sphere of Cu(II) ion. Reduced low–molar dextran (RLMD), was chosen as a material for complexing, and the sub- sequent interactions with Cu(II) ions were investi- gated in this study. Copper(II) complexes were pre- pared from sodium salts, and investigated in the solid state. ATR–FTIR microspectroscopic data of synthe- sized complexes are rare in literature. The emergence of modern structural chemical methods such as ATR– FTIR spectroscopy and FTIR microscopy made it possible to assign the binding OH or other groups, and also to characterize the metal ion coordination of polysaccharides, monitoring the ligand conformation or/and configuration changes forced by the complex- ation processes [15–18]. The major goal of this work is to use of ATR–FTIR microspectroscopy and FTIR imaging as the main tools to verify the conformation and structure of this type of ligand around the cop- per(II) ions. Attenuated Total Reflectance–Fourier Transform Infrared Microspectroscopy of Copper(II) Complexes with Reduced Dextran Derivatives* G. S. Nikoli a , M. Caki a , . Miti b , B. Ili c , and P. Premovi c a Faculty of Technology, Leskovac, Serbia, b Faculty of Medicine, Department of Pharmacy, Niš, Serbia c Laboratory for Geochemistry, Cosmochemistry and Astrochemistry, University of Niš, Niš, Serbia e-mail: goranchem_yu@yahoo.com, zak_chem2001@yahoo.com Abstract—Dextran is a water-soluble, extracellular neutral polysaccharide with a linear flexible chain of α-(1 6)–linked α-D-glucopyranose units, in a single compounds. In alkali solutions Cu(II) ion forms complexes with reduced low-molar dextran (RLMD). The metal content and the solution composition depended on pH. The complexing process begins in weak alkali solution (pH > 7), and involves OH groups in C2 and C3 dextran monomer units. Synthesized copper(II) complexes with RLMD, of average molar mass M w = 5000 g/mol were investigated by attenuated total reflectance–Fourier transform infrared (ATR–FTIR) spectroscopy and FTIR imaging microscopy. ATR–FTIR microspectroscopic data of synthesized complexes are rare in literature. The changes in intensity and width of the IR bands in region 1500–1000 cm –1 were related to changes in conformation and short-range interactions of the ligand dextran. FTIR microscopy images shows more and less ordered structures of the Cu(II)–RLMD complexes. ATR–FTIR microspectro- scopic data shows homogeneity of the Cu(II)–RLMD samples and green color of the samples confirm exist- ence of Cu(II) ions. DOI: 10.1134/S0036024409090180 c  c  Z ˆ c  c  c  STRUCTURE OF MATTER AND QUANTUM CHEMISTRY *The article is published in the original.