Crystal and Molecular Structure and Magnetic Exchange Properties of Bis(di- -ethoxo-bis(3,5-di-tert-butylsemiquinonato)dicopper(II)) Complex. A Synergy between DFT and Experimental Magnetochemistry

The compound bis(di-í-ethoxo-bis(3,5-di-tert-butylsemiquinonato)dicopper(II)) has been synthesized and its structure was determined by single-crystal X-ray diffraction. The compound crystallizes in the monoclinic system, space group C2/c, with a ) 37.736(8) Å, b ) 9.173(2) Å, c ) 23.270(5) Å, â ) 122.24(3)°. The structure can be described as a Lewis adduct between two dinuclear [Cu(DBSQ)(C2H5O)]2 units (DBSQ ) 3,5-di-tert-butylsemiquinonato). The temperature dependence of the magnetic susceptibility was efficiently analyzed by a combined DFT/experimental approach, showing that a rather strong ferromagnetic interaction exists between the DBSQ- and the copper(II) ions modulated by an antiferromagnetic interaction between the two copper(II) ions of the dinuclear units. Weak antiferromagnetism between the two units in the unit cell was measured.