supplementary materials

Nickel complexes with Schiff bases have received much attention in recent years due to their pharmacological and catalytic properties (Borisova et al., 2007; Bruckner et al., 2000). 2-(Tri-2-pyridylmethyliminomethyl)phenol is a potential N₄O pentadentate Schiff base ligand and its complexes with copper(II) and nickel(II) have been reported (Arnold et al., 2003; Li & Gao, 2007; Tian et al., 2007). As a continuation of the work, the synthesis and structure of the title compound, (I), now are discussed.

In this mononuclear nickel complex, the environment around the central nickel atom is a distorted octahedron (Table 1) with the three axial bond angles being 173.34 (6), 168.45 (6) and 168.03 (6)°. The two Schiff base ligands are both tridentate and coordinated in a meridional fashion. Each ligand coordinates to the metal by an NN'O donor set via an imine N, one pyridine N and a phenolate O. The other two N atoms of the pyridine rings in each Schiff base ligand are distant from the metal. The meridional coordination of each ligand leads to cis orientations of the two coordinated pyridine rings and two phenolate rings, and the trans orientation of two imine N atoms. The Ni1—N2 and Ni1—N4 (pyridine) distances are appreciably longer than those for Ni1—N1 and Ni1—N3 (imine), which is agreement with those of azido{2-[(tri-2-pyridylmethylimino)methyl]phenolato}nickel(II) (Tian et al., 2007). The Ni1—O1 and Ni1—O2 distances are almost the same as those found in the six-coordinated NiN₄O₂ complexes such as [N,N'-bis(2-Salicylideneaminoethyl)ethylenediamine]nickel(II) (Cumming et al., 1977), {N,N'-bis[2-Hydroxy-3-(1-morpholinioylmethyl)-5-\ methylbenzylidene] triethylenetetraamine}nickel(II) (Manonmani et al., 2001), and bis{2,4-dibutyl-6-[2-(dimethylamino)ethyliminomethyl]phenolato}nickel(II) (Parker et al., 2007).