# Dicopper(II) Schiff base aminobenzoates with discrete molecular and 1D-chain polymeric structures

Mukherjee, Arindam and Saha, Manas K and Nethaji, Munirathinam and Chakravarty, Akhil R (2004) Dicopper(II) Schiff base aminobenzoates with discrete molecular and 1D-chain polymeric structures. In: Polyhedron, 23 (13). pp. 2177-2182.

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A16Dicopper(II)_Schiff_base.pdf

Dicopper(II) complexes $[Cu_2L(O_2CC_6H_4-o-NH_2)]$ (1) and $[Cu_2L(O_2CC_6H_4-p-NH_2)]$ (2) are prepared from a reaction of $[Cu_2-L(O_2CMe)]$ with the corresponding aminobenzoic acid and a base in MeOH, where L is a trianionic pentadentate Schiff base ligand N,N'-(2-hydroxypropane-1,3-diyl)bis(salicylaidimine). The complexes are structurally characterized by X-ray crystallography. The crystal structures show the presence of an asymmetrically dibridged ${Cu^{II}_2(\mu-OR)(\mu-O_2CR)}$ core where the endogenous monoatomicbridging alkoxo group is derived from the Schiff base and theaminobenzoate ligand displays syn-syn bridging mode. The Cu...Cuseparation and Cu-OR-Cu bond angle in 1 and 2 are 3.472(1) \AA, $131.02{(18)}^{\circ}$ and 3.511(1) \AA, $132.20{(17)}^{\circ}$, respectively. The o-aminobenzoate complex is discrete dimeric nature. The pendant o-amino group is involved in an intramolecular hydrogenbonding interaction with one carboxylate oxygen atom. The crystalstructure of the p-aminobenzoate species 2 shows the formation of aone-dimensional polymeric chain resulting from the axial binding of thependant p-amino group to one copper center belonging to another dimericunit. Magnetic studies show that both the complexes areantiferromagnetic in nature giving a singlet-triplet energy separation of - 130 and - 150 $cm^{-1}$ for 1 and 2, respectively. The 1 D chaincomplex 2 magnetically behaves like the discrete dimeric complex 1.