Crystal Structures and Magnetic Properties of Binuclear Copper(II) Complexes with Alkoxo and Benzoato or Silanecarboxylato Bridges

The crystal structures of the binuclear copper(II) complexes [Cu2(L-ac)(PhCOO)] (1), [Cu2(L-ac)(2-Me–PhCOO)·1/2MeOH (2), [Cu2(L-ac)(2,6-Me2–PhCOO)] (3), [Cu2(L-ac)(2,6-Cl2-PhCOO)]·0.7DMF (4), and [Cu2(L-ac)(Ph2MeSiCOO)] (5) were determined by X-ray diffraction. The ligand H3(L-ac) is a 1 : 2 Schiff base derived from 1,3-diaminopropan-2-ol and acetylacetone. These complexes are antiferromagnetic and their −2J values are (1) 183, (2) 188, (3) 133, (4) 207, and (5) 95 cm−1, respectively. A rough positive correlation between the Cu···Cu distance and the −2J value was observed except for 5. The smaller −2J value of the triorganosilanecarboxylato complex, 5, than the benzoato complexes, 1–4, indicates a stronger orbital countercomplementary effect in 5. The geometrical parameters in the benzoato bridge have a minor effect on the magnitude of the antiferromagnetic interaction.

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