The asymmetric unit of the title Schiff base compound, C(16)H(12)Cl(2)F(2)N(2), contains one half of the centrosymmetric mol-ecule. Mol-ecules related by translation along the a axis form stacks with short inter-molecular C⋯C distances of 3.429 (3) Å. The crystal packing also exhibits short inter-molecular Cl⋯F contacts of 3.087 (1) Å.

The mol-ecule of the title Schiff base compound, C(16)H(14)Br(2)N(2), lies across a crystallographic inversion centre. The C=N bond adopts a trans configuration. The imino group is coplanar with the benzene ring. Within the mol-ecule, the planar units are parallel, but extend in opposite directions from the dimethyl-ene bridge. The inter-esting feature of the structure is the weak Br⋯Br inter-a...

The mol-ecule of the title centrosymmetric Schiff base compound, C(16)H(12)Cl(2)F(2)N(2), adopts an E configuration with respect to the azomethine C=N bond. The imino groups are coplanar with the aromatic rings. Within the mol-ecule, the planar units are parallel, but extend in opposite directions from the dimethyl-ene bridge. An inter-esting feature of the crystal structure is the short inter-...

The mol-ecule of the title bidentate Schiff base ligand, C(18)H(20)N(2)O(2), has twofold crystallographic rotation symmetry, giving one half-mol-ecule per asymmetric unit. It adopts a twisted E configuration with respect to the azomethine C=N bond. The imino group is coplanar with the aromatic ring. The dihedral angle between the two benzene rings is 69.52 (5)°. The meth-oxy group is coplanar w...

The title salt, [Pd(C3H4N2)4]Cl2, was obtained unexpectedly by the reaction of palladium(II) dichloride with equimolar amounts of 1-chloro-1-nitro-2,2,2-tris-(pyrazol-yl)ethane in methanol solution. The Pd(2+) cation is located on an inversion centre and has a square-planar coordination sphere defined by four N atoms of four neutral pyrazole ligands. The average Pd-N distance is 2.000 (2) Å. Th...

we investigate the long-term behavior of solutions of the difference equation[ x_{n+1}=x_{n}x_{n-3}-1 ,, n=0 ,, 1 ,, ldots ,, ]noindent where the initial conditions $x_{-3} ,, x_{-2} ,, x_{-1} ,, x_{0}$ are real numbers.  in particular, we look at the periodicity and asymptotic periodicity of solutions, as well as the existence of unbounded solutions.