THE BINUCLEAR FE(III) COMPLEX OF N,N,N',N'-TETRAKIS(2-PYRIDYLMETHYL)-2-HYDROXY-1,3-DIAMINOPROPANE - MOLECULAR AND CRYSTAL-STRUCTURE AND ITS INTERACTION WITH MONTMORILLONITE

Yellow crystals of [Fe-2(HPTP)(OH)(NO3)(2)](ClO4)(2) (HPTP = N,N,N',N'-tetrakis(2-pyridylmethyl)-2-hydroxy-1,3-diaminopropane) were grown by slow diffusion of diethylether into a solution of the complex salt in acetonitrile. Crystal data: space group R (3) over bar, a = 4280,1(15) pm, c = 1147,6(7) pm, Z = 18. The complex exhibits a binuclear Fe(III) core with (mu-oxo)(mu-alkoxo) ligands as bridging units. The nitrate anions coordinate each with a short and a long Fe-O bond. The coordination spheres of the iron atoms can be looked at as distorted edge-shearing pentagonal bipyramides. The complex cation was introduced into the interlayer region of montmorillonite by cation exchange in acetonitrile. The results of X-ray, IR- and UV/VIS experiments suggest that the cation exchange is reversible. In the interlayer region the dinuclear cations are arranged in a rather loosely packed way, thus creating channels similar to those in pillared smectites or zeolites, respectively.