Bis(2-{1-[(2,4,6-trimethylphenyl)imino]ethyl}pyrrol-1-ido-κ(2)N,N')nickel(II): a supramolecular structure formed by C-H...π(arene) hydrogen bonds

Acta Crystallogr C Struct Chem. 2015 Dec 1;71(Pt 12):1053-6. doi: 10.1107/S2053229615020781. Epub 2015 Nov 7.

Abstract

Nitrogen-based polydentate ligands are of interest owing to their flexible complexation to transition metal atoms. For the title compound, [Ni(C15H17N2)2], a transition metal complex formed by the coordination of two identical N,N'-bidentate mono(imino)pyrrolyl ligands to an Ni(II) centre, an X-ray crystal diffraction study indicates that the two ligands show an inverted arrangement with respect to one another around the Ni(II) centre, which is located on a crystallographic inversion centre. The planes of the aromatic substituents at the imine N atoms of the ligands show dihedral angles of 85.91 (5)° with respect to the NiN4 plane. The Ni-N bond lengths are in the range 1.9072 (15)-1.9330 (15) Å and the Nimino-Ni-Npyrrole bite angles are 83.18 (6)°. The Ni-Npyrrole bond is substantially shorter than the Ni-Nimino bond. Molecules are linked into an extensive network by means of intermolecular C-H...π(arene) hydrogen bonds in which every molecule acts both as hydrogen-bond donor and acceptor. The supramolecular assembly takes the form of an infinite two-dimensional sheet.

Keywords: crystal structure; hydrogen bonding; imine; nickel(II) complex; pyrrolide ligand; supramolecular chemistry.