Supramolecular structure formation of molecular copper(II)methylsalicylate complexes with nicotinamide or methylnicotinamide – Crystal structure and spectral properties.

As the systematic investigation of salicylatocopper complexes with nicotinamide derivatives the preparation, characterization and X-ray structure determination of four new molecular copper(II) complexes with x -methylsalicylate anion ( x -Mesal − ) and nicotinamide (nia) or N -methylnicotinamide (mna) are reported. The molecular complexes [Cu(5-Mesal) 2 (nia) 2 ] ( 1 ), [Cu(3-Mesal) 2 (nia) 2 ] ( 2 ) build up 2-D supramolecular structures of different character. The ladder-type supramolecular structure of ( 1 ) is formed by the head-to-head H-bonds of neighbouring carboxamide groups, while the supramolecular structure of ( 2 ) is formed by N H⋯O H-bonds of carboxamide groups into 1-D chain that are by the additional H H⋯O H-bonds of N H carboxamide and the carboxylate group oxygen atoms linked to 2-D layers. The centrosymmetrical crystal molecular structure of [Cu(4-Mesal) 2 (mna) 2 (H 2 O) 2 ]⋅2EtOH ( 3 ) or [Cu(5-Mesal) 2 (mna) 2 (H 2 O) 2 ]⋅2MeOH ( 4 ) are forming 1-D supramolecular chains that involve the methylcarboxamide N H group, the crystalosolvate alcohol O H group, the coordinated water molecule O H bond and oxygen atom of neighbouring complex molecule. The coordination polyhedron symmetry corresponds with the isotropic character of EPR spectra of ( 1 ) and ( 2 ) while the EPR spectrum of ( 4 ) is of axial symmetry. [ABSTRACT FROM AUTHOR]