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Sub-normal magnetic moments in copper (II) complexes: Five-coordinate copper in an oxygen-bridged dimer

1970; Elsevier BV; Volume: 4; Linguagem: Inglês

10.1016/s0020-1693(00)93281-x

1873-3255

J. A. Bertrand, James A. Kelley, J. L. Breece,

Metal-Catalyzed Oxygenation Mechanisms

The preparation, structure, and properties of a dimeric copper(II) compound, chloro-N-(2-hydroxypropyl)salicylaldimino copper(II), are reported. The compound, which has a magnetic moment of 1.1 B.M., crystallizes as brown, monoclinic crystals (a = 8.56(1) Å; b = 12.35(2) Å; c = 10.31(2) Å; and β = 98.43(3)°) of space group P21/c with two dimers per unit cell; the calculated density of 1.71 g/cm3 agrees well with the observed density of 1.69 g/cm3. A total of 644 unique, non-zero reflections were collected (four-circle diffractometer); least-squares refinement with anisotrophic temperature parameters for copper and chlorine resulted in a conventional R value of 0.089. Each copper is five-coordinate (distorted trigonal bipyramid) and the phenolic oxygens are the bridging groups. The four-membered copper-oxygen ring is planar with a CuCu distance of 3.294(7) Å; coordination of the bridging oxygen is also planar. The low magnetic moment is attributed to a π-interation delocalized over the four membered ring. For the atoms bonded to copper the bond distances and bond angles are: CuN (axial), 2.18(2) Å; CuO (axial), 2.22(1) Å; CuO (equatorial), 1.78(1) and 2.24(2) Å; CuCl (equatorial), 2.12(1) Å; NCuO (axial), 168.9(6)°; OCuO (equatorial), 123.4(7)°; ClCuO (equatorial), 126.2(5)° and 110.1(4)°.