STRUCTURAL VARIATIONS IN MACROCYCLIC COPPER(II) COMPLEXES - CRYSTAL AND MOLECULAR-STRUCTURES OF [CU(CYCLOPS)H2O](CLO4) AND [CU(PREH)H2O](CLO4).H2O

The crystal and molecular structures of [Cu(cyclops)H20](C104) (1, cyclops = difluoro-3, 3-(trimethylenedinitrilo)bis-(2-butanone oximato)borate) and of [Cu(PreH)H20](C104)-H20 (2, PreH = 3, 3-(trimethylenedinitrilo)bis(2-butanone oximate)) have been determined from three-dimensional single-crystal X-ray diffraction data, collected by counter techniques. Violet crystals of 1 were monoclinic, space group P2/n, with four formula units in the unit cell (a = 9.427 (5) A, b = 15.921 (9) A, c = 12.808 (8) A, 0 = 96.69 (2)). The structure of 1 was refined to R = 0.070 (R= 0.072) for 1333 independent reflections with f2 ia(Ft). Red-violet crystals of 2 were orthorhombic, space group P2 l li, with four formula units in the unit cell (a = 6.860 (2) A, b = 12.436 (5) A, c = 21.595 (7) A). The structure of 2 was refined to R = 0.049 = 0.064) for 1538 independent reflections with F2 > 3a(F). In both cases, the monomeric complex ions exhibited square-pyramidal coordination geometries about the copper(II) ion. In the structure of 2, the copper(II) ion was only 0.10 A above the plane of the four coordinating nitrogen atoms of the highly planar nonmacrocyclic ligand, and the Cu-0(H20) bond length of 2.355 (7) A observed was elongated by an amount normal for apically bound water in square-pyramidal copper(II) complexes. Closure of the dioximate ligand of 2 to form the macrocyclic complex 1 resulted in an increase in the apical displacement of the copper(II) ion to the relatively large distance of 0.32 A above the plane of the coordinating nitrogen atoms. In 1 themacrocyclic ligand was found to be nonplanar, and the bond to the apical water molecule (Cu-0(H20) =2.253 (9) A) was shortened considerably relative to that in 2. © 1979, American Chemical Society. All rights reserved.