Synthesis, characterisation and cryomagnetic studies of a novel homonuclear Nd(III) Schiff base dimer

A novel homodinuclear complex [NdIII(L)(NO3)]2 (1) has been synthesised [H2L = N1,N3- bis(salicylideneimino)diethylenetriamine, a pentadentate Schiff base with N3O2 donor set] and characterised with spectroscopic and micro-analytical techniques. Single crystal X-ray diffraction study reveals a centrosymmetric binuclear neutral entity [space group, P21/n; a = 12.911(5); b = 11.938(5); c = 13.960(5) Å; Z = 4] where Nd(III) metal centers are bridged together by two phenoxo oxygen atoms each coming from the two ligands. The most interesting fact is that two similar “salen” moieties of each ligand are behaving completely different in their coordination. In the doubly deprotonated ligand (L2−), one phenoxo oxygen is mono coordinated to the metal, whereas its immediate neighbour on the other end bridges the two Nd(III) centers. The distance between the Nd(III) centers is found to be 3.884(3) Å. Temperature dependence (2–300 K) magnetic susceptibility study suggests the presence of an antiferromagnetic interaction operating via two phenoxo bridges.