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Reactions involving Y(thd) 3 and Cu(thd) 2 with barium tert-butoxide or 2-dimethylamino-2-propoxide were investigated. The mixed-metal complexes [YBa 3 (OBu t ) 6 (thd) 3 ] ( 1 ) and [BaCu(OBu t ) 2 (thd) 2 ] m ( 3 ) (thdH = 2,2,6,6-tetramethylheptane-3,5-dione) were isolated in hexane. Dissolution of 3 in Et 2 O or THF afforded [Cu 3 (OBu t ) 6 (thd) 3 ] ( 4 ) and [Cu(thd) 2 (OBu t ) 2 (THF) 2 ] ( 5 ), respectively, while [Ba(thd) 2 (TMEDA) 2 ] ( 2 ) was obtained in the presence of N ′, N ′-tetramethylenediamine. Dissolution of 1 in THF afforded a THF adduct ( 1a ) giving 1 by sublimation at 190°C/10 −3 Torr. By contrast, the reaction between the barium aminoalkoxide and Y(thd) 3 in hexane proceeded directly to the formation of homometallic compounds, whereas with Cu(thd) 2 the mixed-metal compound {Ba 2 Cu [OCHMeCH 2 NMe 2 ] 2 (thd) 4 (Pr i OH) 2 } ( 6 ) was obtained by crystallization from Pr i OH. All compounds were characterized by elemental analysis, IR, 1 H NMR, ESR and TGA for the copper species. Compounds 2, 4 and 6 were characterized by single-crystal X-ray diffraction. The [Ba(thd) 2 (TMEDA) 2 ] adduct is monomeric. The structures of 4 and 6 consist of triangular aggregates with Cu 3 ( μ 3 -OBu t ) 2 ( μ -OBu t )thd) 3 and Ba 2 Cu( μ 3 , η 2 -OCHMeCH 2 NMe 2 ) 2 ( μ , η 2 -thd) 2 ( η 2 -thd) 2 (Pr i OH) 2 cores, respectively. Compound 4 exhibits one square planar and two square pyramidal copper centres. The CuO bond lengths range from 1.90(2) to 2.27(2) A, the order of variation being CuO(thd) μ -OR μ 3 -OR. For compound 6 , the thd, OR and Pr i OH ligands are bonded asymmetrically to the three metallic centres. Each barium atom bears a chelating thd ligand, two other thd are bridging-chelating, linking the two barium atoms, and one barium, Ba(2), to the copper atom, respectively. The nitrogen-donor sites of the two μ 3 -aminoalkoxide ligands interact with the copper and Ba(2) centres. The two isopropanol molecules are bonded to the other barium, Ba(1); the solvate is stabilized by intramolecular hydrogen bonds. This allows the barium atoms to reach high coordination numbers, seven and eight, and the copper atom to be pentacoordinated. The BaO bond lengths range from 2.59(1) to 2.87(1) A. The BaN bond distance is 2.85(1) A. Compounds 4 and 5 are volatile; 5 loses its THF upon sublimation to yield 4 . |
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