Some Di- and tri-nuclear compounds of copper(II) with 4-amino-4-methylpentan-2-one oxime; structures and magnetism

Green [{Cu(amox)(amoxH)}2](NO3)2 (amoxH = 4-amino-4-methylpentan-2-one oxime) has 2-fold sym., oximato-bridged, dinuclear cations. Each Cu(II) ion is bonded to the N atoms of one bidentate amox- and one bidentate amoxH (marked * below) ligand {Cu-Namine 2.039(4), 2.006(4)* Å and Cu-Noxime 1.975(5), 2.192(5)* Å}. The dinuclear cations have bonds between each Cu(II) ion and the oximato O atom of the other (marked # below) unit {Cu-O# 2.062(4) Å, Cu-Cu# 3.801(5) Å}. The Cu(II) ion is in asym. trigonal-bipyramidal coordination, with Namine*-Cu-Noximate axial {176.5(2)°}, and Namine-Cu-O# {136.6(2)°}, Namine-Cu-Noxime* {126.2(2)°} and Namine-Cu-O# {96.9(2)°} equatorial [orthorhombic, space group Pbcn, a 12.218(1), b 23.361(3), c 12.275(1) Å, Z = 4, R1 = 0.057 for 2239 reflections]. The magnetic susceptibility values follow the Curie Weiss relation, with θ = -10(2) K. Dark green [{{Cu(amox)}3O}2H](ClO4)3·3H2O has 3-fold sym. trinuclear cations, with each Cu(II) ion chelated by the amine {Cu-N 1.977(3) Å} and oxime {Cu-N 1.994(2) Å} N atoms of one amox- ligand, and coordinated by the bridging oximato O atom of another amox- ligand {Cu-O# 1.938(2) Å}. A central O atom on the 3-fold axis completes square-planar tetracoordination about each Cu(II) ion {Cu-O 1.910(1) Å}. Cu-Cu# distances are 3.283(2) Å, with the central O atom 0.233(2) Å out of the Cu3 plane. Two of these trinuclear cations are linked confacially by a proton on the common 3-fold axis {O-O# 2.474(1) Å}, to form novel hexanuclear clusters, with dihedral angles about the central Cu-O-O#-Cu# axis of 37.4(1)°. Distances Cu-Cu# between the triangles are 3.180(5), 3.860(5) and 4.738(5) Å [trigonal, space group R3c, a 23.932(5), c 18.581(4) Å, Z = 12, R1 = 0.034 for 1660 reflections]. The magnetic susceptibility values indicate extensive antiferromagnetic spin-coupling within the triangles. A blue compd. Cu(amox)(H2O)(NO3) has susceptibility values supporting a dinuclear spin-coupled structure. [on SciFinder(R)]