On interacting pyridine-containing formazans with cobalt(II) and copper(II) chlorides the richlorometallates of the corresponding cations are isolated, the structures of which were established by X-ray structural analysis. Using data of cyclic voltamperometry a scheme is proposed for the oxidationreduction process of converting formazans into tetrazolium cations.One of the most vigorously growing directions of supramolecular chemistry is the chemistry of coordination polymers, which are promising materials possessing semiconductor, optical, and magnetic properties [1,2]. The process of forming coordination polymers 2 may consist of the preliminary preparation of a complex ligand 1 (with metal M 1 ) with another metal M 2 . The complex ligands 1 (metalloligands or metalorganic building blocks/tectones) must possess as a minimum, two exodentate groups capable of forming additional coordination bonds [3][4][5][6]. L L L M 1 M 1 M 2 M 2 L L M 1 n 1 2 n N N H N N R 2 R 1 R 3 A R 3 N N N N R 1 R 2 H B Formazans are convenient substrates for building such metalloligands thanks to the presence of potentially chelate chromophoric groupings and the possibility of varying the substituents in positions 1, 3, and 5. It is known that formazans may exist in two forms, chelate A (E,Z) and linear B (E,E) (the Z-form of the azo group is usually not considered) [7]. _______ * Dedicated to deeply respected Academician M. G. Voronkov in connection with his birthday and as a mark of gratitude for his contribution to heterocyclic chemistry __________________________________________________________________________________________ Moscow M. V

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Three procedures were used for the synthesis of α , β , and γ pyridyl substituted (5Z ) 3 phenyl 5 (pyridylmethylene) 2 thiohydantoins: the reaction of 2 thiohydantoin with the corresponding aldehyde in AcOH in the presence of AcONa, the two step one pot synthe sis with the use of the same starting compounds, and three component condensation of aryl isothiocyanate, glycine, and aldehyde in AcOH. Alkylation of the resulting thiohydantoins with iodomethane in the presence of a base afforded the corresponding S methylated deriva tives, viz., 2 methylthio 3 phenyl 5 (pyridylmethylene) 3,5 dihydro 4H imidazol 4 ones. The structures of (5Z ) 3 phenyl 5 (pyridin 2 ylmethylene) 2 thioxoimidazolin 4 one and (5Z ) 2 methylthio 3 phenyl 5 (pyridin 2 ylmethylene) 3,5 dihydro 4H imidazol 4 one were established by X ray diffraction analysis.

Five diamagnetic nickel(II) complexes with pyridine containing formazans of composition 2L•M were synthesized by slow diffusion. X ray diffraction study of three of these complexes demonstrated that the nickel atoms are coordinated by four nitrogen atoms of two ligands and are in a square planar environment. The nickel atoms lie on inversion centers. The chelate six membered rings Ni-N-N-C-N-N are nonplanar due to noncovalent repulsions between the closely arranged aryl groups. Data from NMR spectroscopy, electronic absorption spec troscopy, and electrochemistry (cyclic voltammetry and rotating disk electrode) show that all complexes have similar structures in solution.In the last third of the 20th century, supramolecular chemistry, which has been earlier the subject of a few studies on selective complexing agents and molecular rec ognition, became a rapidly developing field of chemistry. 1 Extensive studies have been carried out on the chemistry of supramolecular polymers, i.e., high molecular weight compounds composed of repeated low molecular weight fragments linked to each other by noncovalent interac tions. 2 Coordination polymers consisting of an organic molecule and a metal atom/ion as two components, which are linked to each other by a coordination bond, are con sidered by many researchers as promising materials pos sessing the semiconducting, optical, and magnetic prop erties. 3,4 These properties are largely determined by a vir tually infinite series of combinations of inorganic and organic components of structural polymers. However, an empirical search for such combinations becomes increas ingly less advantageous and attractive.Instead of methods based on the use of simple organic ligands, procedures with the use of "complex" ligands in cluding one or several metal atoms have gained increasing acceptance. Complex ligands provide an approach to nu merous structures containing at least two exodentate groups, which can form additional coordination bonds. We will refer to such compounds as metalloligands.The formation of a coordination polymer with the use of metalloligands as building blocks can be represented by Scheme 1, which involves the synthesis of the metallo ligand by the reaction of an organic component L with metal M 1 followed by the reaction of this metalloligand with metal M 2 . Compounds, which can form chelates with the central metal ion with retention of the donor centers directed outward, are commonly used as the or ganic component L. 5-7 Scheme 1Formazans and their complexes are convenient sub strates for the construction of metalloligands due to the presence of a potentially chelating chromophoric group and the possibility of introducing electron donating sub stituents at positions 1, 3, and 5. The deprotonated form of formazan, in which the negative charge is delocalized throughout the conjugated chain, is generally involved in complexation with metal salts to form six membered metal chelates A in which the hydrogen atom is replaced by metal. 8 Complexes with Co II , Ni II , Cu II , Cd...

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