Coordination versatility of 1,5-bis(salicylidene)carbohydrazide in Ni(II) complexes

Versatile coordination behavior of a polydentate Schiff base ligand 1,5-bis(salicylidene)carbohydrazide (H(3)bsc) has been explored in Ni(II) complexes. [Ni(H(3)bsc)(2)](ClO4)(2) (1) center dot H2O center dot 3CH(3)CN is a bis chelate mononuclear complex of H(3)bsc in keto form, and [Ni-4(H(0.5)bsc)(2)(O2CCMe3)(3)(CH3OH)(4)](2) center dot 2H(2)O center dot 2CH(3)OH is a tetranuclear complex of H3bsc with an unusual coordination. In 2, one phenolate group of the ligand coordinates in a monodentate way and the other coordinates in a mu(2)-bridging mode to the Ni(II) center. This unusual coordination mode of the ligand stabilizes the Ni(II) complex in a tetranuclear form where the carbonyl oxygen of the ligand exists in between keto and enol form of bond order 1.5. Thus, complex 2, represents an unprecedented coordination behavior of the Schiff base ligand derived from carbohydrazides. Studies of magnetic properties of 2 are reported which reveal antiferromagnetic interaction between four Ni(II) centers. (C) 2013 Elsevier B.V. All rights reserved.