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A coordination polymer of the general formula [Co(OOCCMe 3 ) 2 ] n (2) was prepared by mild thermolysis of the coordination polymer of variable composi tion [(HOOCCMe 3 ) x Co(OH) n (OOCCMe 3 ) 2-n ] m , the dinuclear cobalt com plex Co 2 (µ H 2 O)(OOCCMe 3 ) 4 (HOOCCMe 3 ) 4 , the tetranuclear cobalt cluster Co 4 (µ 3 OH) 2 (OOCCMe 3 ) 6 (HOEt) 6 , and the hexanuclear cluster [Co 6 (µ 4 O) 2 (µ n OOCCMe 3 ) 10 (C 4 H 8 O) 3 (H 2 O)]•1.5(C 4 H 8 O) (7) in organic solvents. In the crystal, the poly mer has a chain structure. Unlike thermolysis of cobalt pivalates, thermolysis of the dinuclear complex Ni 2 (µ H 2 O)(OOCCMe 3 ) 4 (HOOCCMe 3 ) 4 gave rise to the hexanuclear complex Ni 6 (µ 2 OOCCMe 3 ) 6 (µ 3 OOCCMe 3 ) 6 (3). The magnetic properties of compound 2 are sub stantially different from those of 3. Compound 2 undergoes the magnetic phase transition into the ordered state at T c = 3.4 K (H = 1 Oe), whereas compound 3 exhibits antiferromagnetic properties. Solid state decomposition of polymeric cobalt carboxylate 2 (below 350 °C) af forded the octanuclear cluster Co 8 (µ 4 O) 2 (µ 2 OOCCMe 3 ) 6 (µ 3 OOCCMe 3 ) 6 (9) as the major product, which sublimes without decomposition. Decomposition of 3 gave nickel oxide as the final product. Pivalates 2 and 3 reacted with 2,3 lutidine in acetonitrile at 80 °C to form the isostructural dinuclear complexes (2,3 Me 2 C 5 H 3 N) 2 M 2 (µ OOCCMe 3 ) 4 (M = Co or Ni). The structures of compounds 3 and 7 were established by X ray diffraction. The structure of polymer 2 was determined by powder X ray diffraction analysis.The development of efficient methods for the synthe sis of convenient starting "spin materials" is of importance for the chemical design of molecular magnets with de sired properties and the preparation of precursors for the production of various inorganic materials by thermo chemical methods. Polynuclear (or even polymeric) metal complexes of constant composition with particular struc tures, which are highly reactive toward various organic donors and are readily decomposed at moderate tempera tures (60-450 °C), hold promise as spin materials. It is desirable that the starting complexes be able to generate "magnetic molecules" (for example, in reactions with or ganic donors) or form materials (for example, oxides by mild thermolysis) with desired physical properties. Among such compounds are pivalate coordination poly mers of simple composition [M(OOCCMe 3 ) 2 ] n (M is a 3d element). Compounds with M = Fe (S = 2), 1,2 Co (S = 3/2), 3,4 or Ni (S = 1) 5,6 have already found use in the synthesis of carboxylate complexes. How ever, only the structure of [Fe(OOCCMe 3 ) 2 ] n (1) was established by X ray diffraction. 7 Most of analogous Co II and Ni II compounds, which were prepared from salts of these metals by the exchange reactions with KOOCCMe 3 in water or by melting aqua acetates (M = Co) with pivalic acid, 3,5 have variable composition [(HOOCCMe 3 ) x M(OH) n (OOCCMe 3 ) 2-n ] m (M = Co or Ni). The structures of these compounds are unknown, * Dedicated to...

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New binuclear cymantrenecarboxylate complexes of rare earth metals, [Ln 2 (μ O,η 2 O 2 CCym) 2 (μ 2 O,O' O 2 CCym) 2 (η 2 O 2 CCym) 2 (DMSO) 4 ] (Ln = Tb (I), Dy (II); Cym = (η 5 C 5 H 4 )Mn(CO) 3 ) and [Ln 2 (μ 2 O,O' O 2 CCym) 4 (η 2 -NO 3 ) 2 (DMSO) 4 ] (Ln = Tb (III), Dy (IV)), are synthe sized and characterized by X ray diffraction analysis. The carboxylate clusters containing the Mn 2+ ion, which is formed due to the destruction of the cymantrenenecarboxylate anion, [Tb 4 (μ 3 OH) 4 (μ 2 O,O' O 2 CCym) 6 (H 2 O) 3 (THF) 4 ][MnCl 4] ⋅ 4CH 2 Cl 2 ⋅ 6THF (V) with the cubane like structure, and [Er 2 Mn(μ 2 O 2 CCym) 6 (η 2 O 2 CCym) 2 ((MeO) 3 PO) 4 ] ⋅ 2MePh (VI) with linear structure, are also obtained. The magne tism of complexes I, II, V, and VI is studied in a direct magnetic field. The magnetic properties of complexes II and VI are studied in direct and alternating magnetic fields. Complex II exhibits the properties of a single molecule magnet. The thermal decomposition of complexes I-IV is studied by differential scanning calorim etry and thermogravimetric analysis. According to the X ray diffraction analysis data, the final thermolysis products of complexes III and IV in air are multiferroics LnMn 2 O 5 .

The thermolysis and reactions of the polymeric high spin Mn II and Fe II complexes [Mn(µ OOCBu t ) 2 (HOEt)] n (1) and [Fe(µ OOCBu t ) 2 ] n (3) with pivalic acid and o phenylenedi amines 1,2 (NH 2 ) 2 C 6 H 2 R 2 (R = H or Me) were studied. The synthesis of compound 1 per formed with a deficiency of pivalate anions affords the antiferromagnetic chloropivalate poly mer {(MeCN)(HOOCBu t )(H 2 O)Mn 5 Cl(OH)(OOCBu t ) 8 •MeCN} n . The reaction of 1 with an excess of pivalic acid produces the antiferromagnetic polymer [Mn 4 (OOCBu t ) 8 (HOOCBu t ) 2 ] n . The analogous reaction of pivalic acid with polymer 3 gives the mononuclear complex Fe(η 1 OOCBu t ) 2 (η 1 HOOCBu t ) 4 containing the high spin iron(II) atom as the major product. Study of the reactions of 3 with a deficiency (<1 : 1) and an excess (>1 : 1) of diamines demonstrated that the polymer {[(η 2 (NH 2 ) 2 C 6 H 4 ) 2 Fe(µ OOCBu t ) 2 ][Fe 2 (µ OOCBu t ) 4 ]• •2MeCN} n is generated as the major product in the former case, whereas the mononuclear complexes Fe(η 1

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