548 ISSN 0036-0236, Russian Journal of Inorganic Chemistry, 2009, Vol. 54, No. 4, pp. 548–557. © Pleiades Publishing, Inc., 2009. Original Russian Text © M.A. Bykov, A.L. Emelina, E.V. Orlova, M.A. Kiskin, G.G. Aleksandrov, A.S. Bogomyakov, Zh.V. Dobrokhotova, V.M. Novotortsev, I.L. Eremenko, 2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 4, pp. 601–611. Oxide materials are the most important class of solid materials. The oxide functional materials are domi- nated by perovskite compounds. Perovskite oxide phases of the general formula ÄÇé 3 are known to have unique physicochemical properties [1–3]. The follow- ing technologies are usually used to prepare materials on the basis of these oxides: (1) conventional ceramic synthesis; (2) MOCVD (Metal-Organic Chemical Vapor Deposition); and (3) MOD (Metal-Organic Dep- osition), which involves decomposition of compounds from solution and is a particular case of the sol–gel pro- cess. In these technologies, complex oxides are usually prepared from mixtures of proper molecular precur- sors. In this case, however, the possibility of reactions between the components of the batch to be thermolyzed cannot be ruled out, as well as the attendant change the cationic composition of products. Heterometallic com- pounds of d and f elements with pivalic acid anions are advisable precursors for complex oxide compounds because of the high solubility of polynuclear pivalates in organic solvents, including high-boiling liquids, which is important for wet synthesis. Here, we synthesize heterometallic pivalate Co 2 SmPiv 7 Lut 2 , a potential molecular precursor for samarium cobaltate, and study its structure, magnetic and thermophysical properties, and solid-phase ther- molysis in various atmospheres. EXPERIMENTAL The complex was synthesized in freshly distilled acetonitrile. The Co 2 (Piv) 4 (2,4-Lut) 2 (2) and Sm 2 (Piv) 6 (HPiv) 6 · Hpiv (3) used in the synthesis were prepared by familiar procedures. Compound 2 was pre- pared as Co 2 (Piv) 4 (2-NH 2 -5-Me-py) 2 [4]. Compound 3 was prepared as described earlier [5]. Synthesis of Co 2 Sm(Piv) 7 (2,4-Lut) 2 (1). To a solu- tion of Co 2 (Piv) 4 (2,4-Lut) 2 (1.0 g, 13.6 mmol) in MeCN (30 mL), Sm 2 (Piv) 6 (HPiv) 6 · Hpiv (1.1 g, 6.8 mmol) was added and stirred for 30 min at 80°ë. The resulting dark blue solution was filtered and concentrated to 15 mL. Dark blue crystals of complex 1 suitable for an X-ray diffraction experiment appeared after 3 h; they were separated from solution by filtering, washed with cold MeCN (0°C), and dried in air. Yield of complex 1 1.6 g (95%). Elemental analysis was performed on a Carlo Erba analyzer at the Shared Facilities Center of the Kurna- kov Institute of General and Inorganic Chemistry. For C 49 H 81 Co 2 N 2 O 14 Sm anal. calcd., %: C, 49.44; H, 6.86; N, 2.35. Found, %: C, 49.55; H, 6.84; N, 2.25. IR, ν (cm –1 ): 2960 s, 2928 m, 2868 m, 1696 w, 1684 w, 1646 m, 1624 m, 1600 s, 1536 s, 1484 s, 1456 w, 1416 s, 1372 m, 1360 m, 1304 w, 1228 m, 1148 w, 1028 w, 856 w, 808 w, 788 w, 616 w, 572 w, 548 w, 444 m, 436 w. Magnetochemical measurements were performed at the International Tomography Center on an MPMS-5S SQUID magnetometer (Quantum Design) within 2– 300 K in magnetic field H = 5 kOe. Magnetic suscepti- bility χ was calculated with account for atomic diamag- netism using the Pascal additive scheme. In the para- Synthesis, Structure, Physicochemical Properties, and Solid-Phase Thermolysis of Co 2 Sm(Piv) 7 (2,4-Lut) 2 M. A. Bykov a , A. L. Emelina a , E. V. Orlova b , M. A. Kiskin b , G. G. Aleksandrov b , A. S. Bogomyakov c , Zh. V. Dobrokhotova b , V. M. Novotortsev b , and I. L. Eremenko b a Moscow State University, Moscow, 119991 Russia b Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninskii pr. 31, Moscow, 119991 Russia c International Tomography Center, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090 Russia Received May 14, 2008 Abstract—Heterometallic pivalate Co 2 Sm(Piv) 7 (2,4-Lut) 2 (1) was prepared for the first time and structurally characterized at 293 and 160 K. Antiferromagnetic exchange interactions are dominant in complex 1. This com- pound experiences a first-order phase transition within 210–260 K. A set of thermodynamic functions was obtained for this complex (C p , – , and ), and parameters were determined for solid-phase thermol- ysis where samarium cobaltate SmCoO 3 is the only product. DOI: 10.1134/S003602360904010X H T 0 H 180 0 S T 0 COORDINATION COMPOUNDS 1 The C, H, and N determination error was 0.5 wt %.