Spectroscopic characterization of N,N'-bis(salicylidene)pentane-1,3-diamine nickel(II) complex

The N2O2 tetradentate Schiff base ligand, N,N'-bis(salicylidene)pentane-1,3-diamine (Salpn), coupled with 1:2 concentration ratio of 1,3-diamino- pentane and salicylaldehyde was used to produce a series of macrocyclic Nikel(Ⅱ) complexes. In the metal complexation, it was observed that Salpn mac- rocyclic ligand can adopt more than a metal ion giv- ing an unique multinuclear metal complexes includ- ing Ni(II)Salpn and Ni(II)3(Salpn)2. Characteristic IR υ(M-O) peaks for Ni(II)Salpn and Ni(II)3(Salpn)2 were observed to be 1028cm -1 and 1024cm -1 , respec- tively. Characteristic UV-Vis absorption λmax peaks for Ni(II)3(Salpn)2 were observed to be 241nm and 401 nm. Structural characterization of Ni(II)3(Salpn)2 by NMR exhibits that the salicylidene ring moiety has two different resonance signals originated from the magnetically asymmetric diligand and trinuclear bis complex. Complete NMR signal assignments and characterizations elucidating structural features of Ni(II)3(Salpn)2 were described in detail.