Keith R. Morgan

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. Each copper(II) ion is bonded to the nitrogen atoms of one bidentate amox – and one bidentate amoxH (marked *) ligand {Cu–Namine 2.039(4), 2.006(4)* A and Cu–Noxime 1.975(5), 2.192(5)* A}. The dinuclear cations have bonds between each copper(II) ion and the oximato oxygen atom of the other (marked #) unit {Cu–O# 2.062(4) A, Cu–Cu# 3.801(5) A}. The copper(II) ion is in asymmetrical 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, Pbcn, a 12.218(1), b 23.361(3), c 12.275(1) A, Z 4, R1 0.057 for 2239 reflections]. The magnetic susceptibility values follow the Curie Weiss relation, with q = –10(2) K. Dark-green [{{Cu(amox)}3O}2H] (ClO4)3·3H2O has threefold symmetrical trinuclear cations, with each copper(II) ion chelated by the amine {Cu–N 1.977(3) A} and oxime {Cu–N 1.994(2) A} nitrogen atoms of one amox – ligand, and coordinated by the bridging oximato oxygen atom of another amox – ligand {Cu–O# 1.938(2) A}. A central oxygen atom on the threefold axis completes square-planar tetracoordination about each copper(II) ion {Cu–O 1.910(1) A}. Cu–Cu# distances are 3.283(2) A, with the central oxygen atom 0.233(2) A out of the Cu3 plane. Two of these tri-nuclear cations are linked confacially by a proton on the common threefold axis {O–O# 2.474(1) A}, 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) A [trigonal, R3 – c, a 23.932(5), c 18.581(4) A, Z 12, R1 0.034 for 1660 reflections]. The magnetic susceptibility values indicate extensive antiferromagnetic spin-coupling within the triangles. A blue compound of stoichiometry Cu(amox)(H2O)(NO3) has susceptibility values supporting a di-nuclear spin-coupled structure.

Preparation, structure, and properties of mercury layer and chain compounds

In this paper is reviewed the preparation, structure, and electrical properties of salts of the polyatomic mercury cations Hg32+ and Hg42+, the infinite chain compounds Hg3−δMF6 (M=As, Sb, Nb, and Ta), and the layer compounds Hg3NbF6 and Hg3TaF6.

Hexaco-ordination of a diamino-substituted tetra-azameacrocycle to cobalt(III) and nickel(II): compressed Co–N bonds?

The substituted cyclam macrocycle 6,13-diamino-6,13-dimethyl-1,4,8,11-tetra-azacyclotetradecane (L2) can co-ordiante to metal ions as a hexadentate ligand; whereas M–N distances for the NiII complex are ‘normal,’ those for the CoIII complex are unusually short, and this is reflected in a very negative CoIII/II redox couple and a significant shift of the electronic spectrum mmaxima to higher energy.

The preparation and structure of chain and sheet mercury compounds

This paper is a review of the preparation and structures of the polymercury cations Hg32+ and Hg32+, the mercury chain compounds, Hg3-δAsF6, Hg3-δSbF6, Hg3-δ NbF6 and Hg3_δTaF6, and the mercury layer compounds Hg3NbF6 and Hg3TaF6. The chain compounds Hg3-δMF6 are hard, golden yellow insoluble crystals with a shiny metallic appearance that have linear chains of mercury atoms parallel to the a and b axes of a tetragonal cell. They are non-stoichiometric because the Hg-Hg distance is not com mensurate with the tetragonal lattice of AsF6− octahedra. The layer compounds have a silver colour with a distinct metallic lustre, but they are quite soft. They have sheets of hexagonally close-packed mercury atoms separated by a layer of NbF6− or TaF6− octahedra. In contrast to the chain compounds the layer compounds are stoichiometric. The interconversion of the chain and layer compounds is described and discussed.

Di-μ-olato dinuclear copper(II) compounds. The structure of bis-μ-O-[(4,6,6-trimethyl-9-(pyridin-2-yl)-3,7-diazanon-3-en-1-olato)copper(II)] perchlorate

Preparations are reported for blue-green[{Cu(pyen)(eto)}2](ClO4)2[pyen is 2-(2-aminoethyl)pyridine, eto– isdeprotonated 2-aminoethanol] and of green[{Cu(pyaceto)}2](ClO4)2,formed by reaction of this compound with acetone[pyaceto– is deprotonated4,6,6-trimethyl-9-(pyridin-2-yl)-3,7-diazanon-3-en-1-ol]. The structureof[{Cu(pyaceto)}2](ClO4)2shows a unit cell containing two independent, but closely similar,centrosymmetrical dinuclear diolato-bridged cations. The copper(II) ions arein square pyramidal coordination, with the two bridging oxygen atoms, and theimine and secondary amine nitrogen atoms in the basal plane, with the pyridinenitrogen atom more weakly coordinated axially. Mean dimensions for the twocations are Cu–Cu# 2.99, Cu–Nbasal 2.01,Cu–O 1.96, Cu–Naxial 2.24 A,O–Cu–O# 99, Cu–O–Cu# 81, C–O–Cu110, C–O–Cu# 130˚[C30H46Cl2Cu2N6O10,monoclinic, space group P21/n, a 13.487(1),b 13.356(1), c 20.921(2) A,β 103.235(3)˚, R1 = 0.0516 for 4694reflections]. Magnetic susceptibilities (100–300 K) showantiferromagnetic spin coupling for[{Cu(pyaceto)}2](ClO4)2and[{Cu(pyen)(eto)}2](ClO4)2with singlet–triplet level separation J of–110(10) and –65(10) cm–1,respectively, indicating that[{Cu(pyen)(eto)}2](ClO4)2also has a dinuclear structure.

A Centrosymmetrical Di-thiolato-bridged Dinuclear Nickel(II) Compound; Bis-"-S-(7-amino-2,4-dimethyl- 5-azahept-4-ene-2-thiolato)dinickel(II) Perchlorate

The title compound, formed by reaction of 4-mercapto-4-methylpentan-2-one with bis(ethane-1,2-diamine)nickel(II) perchlorate, has a centrosymmetrical dinuclear cation. Each singlet ground-state nickel(II) ion is in tetrahedrally twisted square-planar coordination by the primary amine and imine nitrogen atoms and the thiolato sulfur atom of one molecule of 7-amino-2,4-dimethyl-5-azahept-4-ene-2-thiolate (adet¯), and the sulfur atom of another molecule, with the sulfur atoms of two ligands forming a planar Ni2S2 bridging group {[Ni2-µ-(adet)2] (ClO4)2, C16H34C12N4Ni2O8S2, Mr 662·9, monoclinic, P21/c, a 8·267(1), b 9·952(1), c 16·234(2) A, β 103·010(2)°, R1 0·033 for 2531 reflections}.