Crystal structure of di-μ-acetato-diacetatobis(μ-6,6′-dimethoxy-2,2′-{[(propane-1,3-diylbis(azanylylidene)]bis(methanylylidene)}diphenolato)tetrazinc

The tetranuclear title complex, [Zn4(C19H20N2O4)2(CH3COO)4], is formed from two dinuclear motifs related by an inversion centre. The two crystallographically independent ZnII ions in the asymmetric unit are in different coordination environments. One is square-based pyramidal with one O atom of an acetate group occupying the axial position and two N and O atoms of one bmspd [H2bmspd = N,N′-bis(3-methoxysalicylidene)propylene-1,3-diamine] Schiff base ligand forming the basal plane. The other ZnII atom is six-coordinated by four O atoms of the bmspd ligand forming the equatoral plane and two O atoms of different acetate groups located in the axial positions. As a result, the two phenolic planes of the bicompartmental Schiff base ligand are distorted slightly. However, the planes of the two Schiff base ligands are parallel. In addition, the Zn—N and Zn—O bond lengths span the reasonable ranges 2.062 (2)–2.073 (2) and 1.9261 (15)–2.4356 (16) Å, respectively. The Zn...Zn distances separated by phenolic O atoms are 3.2466 (4) Å while the Zn...Zn distances bridged by acetate groups are 5.9835 (6) Å. The tetranuclear moieties are connected by van der Waals interactions, and form a chain along c axis.