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CTURE OF ORGANIC COMPOUNDS Dedicated to the memory of N.V. Belov

Synthesis and Crystal Structure of the Coordination Compound of Pyridoxine with Manganese Sulfate N. G. Furmanovaa, I. A. Verina, N. Shyityevab, K. S. Sulaimankulovb, Zh. Berdalievab, V. F. Resnyanskiib†, and A. T. Duishenbaevac a

Shubnikov Institute of Crystallography, Russian Academy of Sciences, Leninskii pr. 59, Moscow, 119333 Russia email: [email protected] b Institute of Chemistry and Chemical Technology, National Academy of Sciences of Kyrgyzstan, pr. Chui 267, Bishkek, 720071 Kyrgyzstan c Kyrgyz National University, ul. Frunze 547, Bishkek, 720033 Kyrgyzstan Received May 11, 2011

Abstract—The reaction of pyridoxine with manganese sulfate in an aqueous solution gave the coordination compound MnSO4 · 2C8H11O3N · 2H2O (I). The structure of I was determined from singlecrystal Xray dif fraction data. In the centrosymmetric complex (sp. gr. P 1 , Z = 1), the Mn atom is coordinated by two pyri doxine molecules and two water molecules, thus adopting an octahedral coordination. The sulfate anion is also at a center of symmetry and, consequently, is disordered. The pyridoxine molecules are coordinated to the metal atom through the oxygen atoms of the deprotonated hydroxyl group and the CH2OH group that retains the hydrogen atom. The nitrogen atom is protonated in such a way that the heterocycle assumes a pyri dinium character. The crystal structure also contains six water molecules of crystallization. A thermogravi metric study showed that the decomposition of I occurs in several successive steps, such as dehydration, the combustion of organic ligands, and the formation of an inorganic residue. DOI: 10.1134/S1063774511060095

INTRODUCTION Pyridoxine, 2methyl3hydroxy4,5bis(hydroxym ethyl)pyridine, belongs to the hydroxymethylpyridine containing vitamins of the В6 group. In the form of pyridoxal phosphate, pyridoxine is a cofactor for many enzymes that catalyze transamination, racemization, and decarboxylation. Almost all enzymatic reactions (in which pyridoxine acts as a cofactor or a substrate) require the presence of divalent metal ions responsible for an increase in the rate of enzymatic reactions [1]. It is known [2] that ions having the lipotropic (Zn) action are characterized by the presence of 3d elec trons. Aqua complexes possess the lowest lipotropic activity, acido amine complexes are more active, and the chelate compounds exert the highest activity. The activity of the latter compounds depends on the nature of the chelate environment of the metal atom. Metal complexes are more strongly activated by chelate units containing the O,O set of atoms (pyridoxine) than by chelate rings containing the N,N set of atoms (ethyl enediamine) [2]. Complexes of pyridoxine with tran

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Deceased.

sition metals show promise as drugs. For instance, complexes of pyridoxine with manganese nitrate [3] and zinc nitrate [4] exhibiting antiatherosclerotic activity were documented. A complex with chromium chloride possessing hypoglycemic activity