Tetrakis(1,2-di­amino­benzene)-κ²N;κ⁴N,N′-nickel(II) dichloride

The title complex, [Ni(C₆H₈N₂)₄]Cl₂, consists of a centrosymmetric octahedral six-coordinate nickel(II) coordination complex cation and two chloride ions. The Ni atom sits on a crystallographic inversion center. Two of the 1,2-di­amino­benzene ligands are chelating and the other two are monodentate. The chelating ligands define an equatorial plane and the monodentate ligands are axially trans. In addition to one hydrogen bond between the non-coordinated N atom of the monodentate ligand and an adjacent metal complex, there is extensive hydrogen bonding to the chloride ions.

(μ-Diazenediyldiphen­yl-κ²C²,N²:κ²C^2′,N¹)bis­[(3,5-dimethyl­phen­yl)tellurium(II)]

The title compound, C₂₈H₂₆N₂Te₂, prepared by reduction of (3,5-dimethyl­phen­yl)(2-nitro­phen­yl)tellurium(II), is the first structurally characterized example of an azo group bridging two Te^II centers. The compound is centrosymmetric and the Te—N distance [2.6916 (19) Å] is longer than in non-bridging azo compounds.

2-{[N-(Pyridinium-2-ylmeth­yl)-N-(pyridin-2-ylmeth­yl)amino]meth­yl}-1-(pyridin-2-ylmeth­yl)pyridinium diperchlorate

The cation of the title salt, C₂₄H₂₅N₅²⁺·2ClO₄^-, contains a tris­(2-pyridylmeth­yl)amine core in which one of the pyridine N atoms is protonated and a second pyridine N atom forms an additional C-N bond to another 2-pyridylmeth­yl group, resulting in a second pyridinium center. The protonated pyridinium hydrogen bonds to a pyridine ring of a neighboring dication. The hydrogen-bonded H atom is disordered between the two N atoms.