No abstract

Two new mono-and dinuclear Cu(II) complexes, namely [CuL 1 ]Á0.5H 2 O (1) and [(Cu 2 (L 2 ) 2 )(DMF)]Á 0.5DMF (2) (H 2 L 1 = 1,2-bis{[(Z)-(3-methyl-5-oxo-1-phenyl-1H-pyrazolidin-4(4H)-yl)(phenyl)]methylene-aminooxy} ethane; H 2 L 2 = 1,3-bis{[(Z)-(3-methyl-5-oxo-1-phenyl-1H-pyrazolidin-4(4H)-yl)(phenyl)] methyleneaminooxy}pro-pane), have been synthesized and characterized by X-ray crystallography. The unit cell of complex 1 contains two crystallographically independent but chemically identical [CuL 1 ] molecules and one crystalline water molecule, showing a slightly distorted square-planar coordination geometry and forming a wave-like pattern running along the a-axis via hydrogen bonding and pÁÁÁp stacking interactions. Complex 2 has a dinuclear structure, comprising two Cu(II) atoms, two completely deprotonated phenolate bisoxime (L 2 ) 2-moieties (in the form of enol), and both coordinated and hemi-crystalline DMF molecules. Complex 2 has square-planar and square-pyramidal geometries around the two copper centers, whose basic coordination planes are almost perpendicular and form an infinite threedimensional supramolecular network structure involving intermolecular C-HÁÁÁN, C-HÁÁÁO, and C-HÁÁÁp(Ph) hydrogen bonding and pÁÁÁp stacking interactions of neighboring pyrazole rings.

A straightforward method for preparing 3,6-disubstituted-1,2,4-triazines through a redox-efficient cyclodehydration of β-keto- N-acylsulfonamides with hydrazine salts is described. Two approaches for synthesizing the requisite β-keto- N-acylsulfonamides are presented, which allow for the late stage incorporation of either the C3 or C6 substituent in a flexible manner from acid chlorides or α-bromoketones, respectively. The scope of this methodology includes primary and secondary sp-linked substituents at both the C3 and C6 positions, and the mild reaction conditions tolerate a variety of sensitive functionalities.

In the title compound, C14H11BrN2O2, the mean planes of the two benzene rings are almost parallel to each other, making a dihedral angle of 4.09 (1)°. An intra­molecular O—H⋯N hydrogen bond occurs. In the crystal, inter­molecular O—H⋯N and C—H⋯O hydrogen bonds link the mol­ecules into a chain-like supra­molecular structure.

The title complex, [Cu(C26H22N2O4)], is isostructural with its Ni analogue. All intramolecular distances and angles are very similar for the two structures, whereas the packing of the molecules, including C—H⋯O and C—H⋯π interactions, are slightly different.