A tetranuclear nickel(ii) complex assembled from an asymmetric compartmental ligand and bearing an intramolecular [H3O2]– bridge

The asymmetric di-aminic compartmental ligand HL5 forms a tetranuclear nickel(II) complex in which the core is assembled from two confacial bioctahedra [Ni...Ni, approximately 2.90 A]; the open faces of the bioctahedra are joined at the O atoms of two mu-cresolato bridges [Ni...Ni, 3.72 A], and the shared faces of the bioctahedra are linked by a tetradentate (mu 4, eta 2)-perchlorate anion and by an unusual tetradentate (mu 4, eta 2)-[H3O2]-bridge.