title: Crystal structures of a copper(II) and the isotypic nickel(II) and palladium(II) complexes of the ligand (E)-1-[(2,4,6-tri-bromo-phen-yl)diazen-yl]naphthalen-2-ol.
abstract: In the copper(II) complex, bis-{(E)-1-[(2,4,6-tri-bromo-phen-yl)diazen-yl]naph-thalen-2-olato}copper(II), [Cu(C16H8Br3N2O)2], (I), the metal cation is coord-inated by two N atoms and two O atoms from two bidentate (E)-1-[(2,4,6-tri-bromo-phen-yl)diazen-yl]naphthalen-2-olate ligands, forming a slightly distorted square-planar environment. In one of the ligands, the tri-bromo-benzene ring is inclined to the naphthalene ring system by 37.4 (5)°, creating a weak intra-molecular Cu⋯Br inter-action [3.134 (2) Å], while in the other ligand, the tri-bromo-benzene ring is inclined to the naphthalene ring system by 72.1 (6)°. In the isotypic nickel(II) and palladium(II) complexes, namely bis-{(E)-1-[(2,4,6-tri-bromo-phen-yl)diazen-yl]naphthalen-2-olato}nickel(II), [Ni(C16H8Br3N2O)2], (II), and bis-{(E)-1-[(2,4,6-tri-bromo-phen-yl)diazen-yl]naphthalen-2-olato}palladium(II), [Pd(C16H8Br3N2O)2], (III), respectively, the metal atoms are located on centres of inversion, hence the metal coordination spheres have perfect square-planar geometries. The tri-bromo-benzene rings are inclined to the naphthalene ring systems by 80.79 (18)° in (II) and by 80.8 (3)° in (III). In the crystal of (I), mol-ecules are linked by C-H⋯Br hydrogen bonds, forming chains along [010]. The chains are linked by C-H⋯π inter-actions, forming sheets parallel to (011). In the crystals of (II) and (III), mol-ecules are linked by C-H⋯π inter-actions, forming slabs parallel to (10-1). For the copper(II) complex (I), a region of disordered electron density was corrected for using the SQUEEZE routine in PLATON [Spek (2015 ▸). Acta Cryst. C71, 9-18]. The formula mass and unit-cell characteristics of the disordered solvent mol-ecules were not taken into account during refinement.
authors.affiliation: Unité de Recherche de Chimie de l'Environnement et Moléculaire Structurale (CHEMS), Faculté des Sciences Exactes, Département de Chimie, Université des Frères Mentouri Constantine, Constantine 25000, Algeria.
authors.forename: Souheyla
authors.initials: S
authors.lastname: Chetioui
authors.affiliation: Unité de Recherche de Chimie de l'Environnement et Moléculaire Structurale (CHEMS), Faculté des Sciences Exactes, Département de Chimie, Université des Frères Mentouri Constantine, Constantine 25000, Algeria.
authors.forename: Djamil-Azzeddine
authors.initials: DA
authors.lastname: Rouag
authors.affiliation: Laboratoire de Chimie et Systémique Organométallique (LCSOM), Institut de Chimie, Université de Strasbourg, UMR 7177., 4 rue Blaise Pascal, F-67070 Strasbourg Cedex, France.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Djukic
authors.affiliation: Chemistry Department, University of Fribourg, Chemin du Musee 9, CH-1700 Fribourg, Switzerland.
authors.forename: Christian G
authors.initials: CG
authors.lastname: Bochet
authors.affiliation: Laboratoire de Chimie Appliquée et Environnement, LCAE-URAC18, COSTE, Faculté des Sciences, Université Mohamed Premier, BP524, 60000 Oujda, Morocco; Faculté Pluridisciplinaire Nador BP 300, Selouane 62702, Nador, Morocco.
authors.forename: Rachid
authors.initials: R
authors.lastname: Touzani
authors.affiliation: Service de Radiocristallographie, Institut de Chimie, Université de Strasbourg, UMR 7177, 67008 Strasbourg Cedex, France.
authors.forename: Corinne
authors.initials: C
authors.lastname: Bailly
authors.affiliation: Fribourg Center for Nanomaterials, FriMat, University of Fribourg, Chemin du Musee 9, CH-1700 Fribourg, Switzerland.
authors.forename: Aurélien
authors.initials: A
authors.lastname: Crochet
authors.affiliation: Chemistry Department, University of Fribourg, Chemin du Musee 9, CH-1700 Fribourg, Switzerland.
authors.forename: Katharina M
authors.initials: KM
authors.lastname: Fromm
keywords: Cu⋯Br short contact; C—H⋯Br hydrogen bonds; C—H⋯π inter­actions; copper(II); crystal structures; isotypic complexes; nickel(II); palladium(II)