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 twofold symmetrical, oximato-bridged, dinuclear cations. Eac h copper( II) ion is bonded to the nitrogen atoms of one bidentate amox and one bidentate amoxH (marked *) ligand {Cu N-amine 2.039(4), 2.006(4)* Angs trom and Cu- N-oxime 1.975(5), 2.192(5)* Angstrom}. The dinuclear cations h ave bonds between each copper(II) ion and the oximato oxygen atom of the ot her (marked #) unit {Cu O# 2.062(4) Angstrom, Cu Cu# 3.801(5) Angstrom}. Th e copper(II) ion is in asymmetrical trigonal-bipyramidal coordination, with N-amine* Cu N-oximate axial {176.5(2)degrees}, and N-amine Cu O# {136.6(2) degrees}, N-amine Cu N-oxime* {126.2(2)degrees} and N-amine Cu O# {96.9(2)d egrees} equatorial [orthorhombic, Pbcn, a 12.218(1), b 23.361(3), c 12.275( 1) Angstrom, Z4, R-1 0.057 for 2239 reflections]. The magnetic susceptibili ty values follow the Curie Weiss relation, with theta = -10(2) K. Dark-gree n [{{Cu( amox)}(3)O}(2)H](ClO4)(3)3H(2)O has threefold symmetrical trinucle ar cations, with each copper(II) ion chelated by the amine {Cu N 1.977(3) A ngstrom} and oxime {Cu N 1.994(2) Angstrom} nitrogen atoms of one amox - li gand, and coordinated by the bridging oximato oxygen atom of another amox l igand {Cu O# 1.938(2) Angstrom}. A central oxygen atom on the threefold axi s completes square-planar tetracoordination about each copper(II) ion {Cu O 1.910(1) Angstrom}. Cu Cu# distances are 3.283(2) Angstrom, with the centr al oxygen atom 0.233(2) Angstrom out of the Cu-3 plane. Two of these trinuc lear cations are linked confacially by a proton on the common threefold axi s {O O# 2.474(1) Angstrom}, to form novel hexanuclear clusters, with dihedr al angles about the central Cu O O# Cu# axis of 37.4(1)degrees. Distances C u Cu# between the triangles are 3.180(5), 3.860(5) and 4.738(5) Angstrom [t rigonal, R3c, a 23.932(5), c 18.581(4) Angstrom, Z12, R-1 0.034 for 1660 re flections]. The magnetic susceptibility values indicate extensive antiferro magnetic spin-coupling within the triangles. A blue compound of stoichiomet ry Cu(amox)(H2O)(NO3) has susceptibility values supporting a dinuclear spin -coupled structure.