A range of salicyladimines were reacted with nickel(II) to form mononuclear Schiff base complexes, [Ni(sal)₂(H₂O)₂], where upon reaction with NO3- ions form bi- or tri-nuclear complexes. Short alkyl chains (R= methyl, ethyl, n-propyl) give rise to trinuclear compounds while bulkier chain alkyl and aryl groups (R= i-propyl, phenyl) form binuclear nickel complexes. Formation of the bi versus trinuclear core depends on the N-aminosalicylaldimine ligand, which allows for a measurement of the steric restrictions of the complexes. While the trinuclear complexes form under low steric restrictions, continuing adjustment of the binuclear ligand environment may act as a new model for urease, or other nickel enzymes.