An antiferromagnetic 2D-polymer [Mn(- N,N’,O-3,5-Me2C3HN2C2(O)N4)2]n (2) (as a solvate with EtOH) was obtained by reaction of pivalate polymer [Mn(OOCCMe3)2(EtOH)] n (1) with 3-hydroxy-6-(3,5-dimethylpyrazol- 1-yl)-1,2,4,5-tetrazine. According to the X-ray analysis data the mononuclear manganese(II) Mn(3,5-Me2C3HN2C2(O) N4)2 units form a 2D-infinite network in the lattice of compound. The metal centers are surrounded with two N atoms of two pyrazolylterazine fragments (Mn-Ntet 2.333(4) Å; Mn-Npyr 2.273(4) Å) and two oxygen atoms of deprotonated hydroxyl groups of ligand (Mn-O 2.098(3) Å) belonging to two neighboring complex fragments. The reaction of 1 with bis[3,5- (dimethylpyrazolyl)]-1,2,4,5-tetrazine in MeCN solution in air results in an hexanuclear pivalate cluster Mn6(μ4-О)2(μ-

ООССМе3)10(L1)4 (3) where L1 is a dimethylpyrazole molecule – product of
hydrolytic splitting of initial bispyrazolyltetrazine. The X-ray study shows
compound 3 to contain the metal carboxylate Mn6(О)2(ООССМе3)10 core (Mn-
μ4-O 1.879(4) – 2.219(5) Å, Mn-O(OOCR) 1.950(4) – 2.346(5) Å).
Newly complexes synthesized were characterized by thermographic study
in diapason 20-600oC.
Acknowledgements. We are thankful to the Russian Foundation for Basic
Research (Project Nos. 04-03-32880, 04-03-32883, 05-03-32767, 05-03-
32794), the INTAS (Project No 03-51-4532), the Russian academy of sciences
(Project “Development of methods for the direct design of new molecules and
ligands in the inner sphere of mono- and polynuclear transition metal complexes”
and Target Program of Basic Research “Chemistry and Physical Chemistry of
Supramolecular Systems and Atomic Clusters”).