Complexes of iron(III) and chromium(III) salen and salophen Schiff bases with bridging 1,3,5-triazine derived multidirectional ligands

摘要

Figure represented. A new synthetic route for preparing multidirectional ligands was developed by using 2,4,6-trichloro-1,3,5-triazine (cyanuric chloride) as core. The reaction included the selective substitutions of 4-aminobenzoic acid onto three chlorides of the triazine ring via a stepwise manner at 1:1, 1:2, or 1:3 equiv. and 0, 25, 130°C, respectively. An efficient synthesis of a novel class of "multidirectional ligands" has been developed based on high-yielding chloride substitutions of 2,4,6-trichloro-1,3,5-triazine by amines. Sixteen new mono-, di-, tri-, and tetra-nuclear Fe(III) and Cr(III) complexes involving tetradenta Schiff bases N,N′-bis(salicylidene)ethylenediamine-(salenH_2) or bis(salicylidene)-o-phenylenediamine-(salophenH_2) with two new 1,3,5-triazine derived multidirectional ligands were synthesized and characterized by means of elemental analysis, 1H NMR, FT-IR spectroscopy, LC-MS analysis, AAS, thermal analysis, and magnetic susceptibility measurements. The complexes were also characterized as low-spin distorted octahedral Fe(III) and Cr(III) bridged by carboxylic acids. It was understood that the [{Fe(salen)/(salophen)}_2O] and [{Cr(salen)/(salophen)} 2O] containing compounds could be represented by the electronic structure of t_(2g)~5e_g~0 and t _(2g)~3e_g~0.