Tetranuclear nickel(II) complexes with genuine µ3-1,1,3 and µ4-1,1,3,3 azide bridges

Unique tetranickel(II) complexes have been synthesized which incorporate genuine µ3-1,1,3 or µ4-1,1,3,3 bridging azido ligands. Identification of two distinct isomeric µ4-1,1,3,3 binding modes confirms the structural flexibility of the quadruply bridging azide.