Yan-Hong Zhang

(7,12‐Diphenyl‐5,6:13,14‐dibenzo‐8,11‐diazo­nia‐1,4‐diaza­cyclo­penta­deca‐7,12‐diene‐2,3‐dione)nickel(II)

Among the transition metal complexes of macrocyclic ligands (Wang et al., 2004; Zhang et al., 2003), the oxamide bridge serves as a pathway through which electron spin interaction takes place. The title complex, (I), has such a bridge (Fig. 1). As part of our ongoing investigation of macrocyclic complexes, we recently prepared (I). The Ni centre has a slightly distorted square-planar coordination formed by the four N atoms. The deviations of the four donors from their mean plane are 0.1225 (N1), 0.1245 (N2), 0.1228 (N3) and 0.1207 Å (N4), respectively, and the central Ni is 0.0352 Å out of the plane. Selected bond lengths and bond angles are listed in Table 1. Bond dimensions involving the Ni atom are comparable to those found in related compounds (Zhang et al., 2006; Wang et al., 2004).

[2,3-Dioxo-5,6:14,15-dibenzo-1,4,8,12-tetra­azacyclo­penta­deca-7,13-dienato(2–)]nickel(II)

In the title compound, [Ni(C21H20N4O2)], the central NiII atom is coordinated by four N atoms, providing a slightly distorted square-planar environment with Ni—N distances ranging from 1.863 (3) to 1.912 (3) A.