Synthesis and molecular structure of the eight-coordinate complex bis( 4-amino-N,N’-disalicylidene- 1,2-phenylenediaminato)zirconium( IV), a new reagent for preparing coordination polymers

Abstract

The precursor complex bis(4-nitro-N,N’-disalicylidene- 1,2-phenylenediaminato)zirconium(IV);Zr(ndsp)2, was synthesized from the appropriate Schiff-base ligand and zirconium tetra-n-butoxide butanol complex (2:1, respectively) and then catalytically hydrogenated to produce the polymerizable diamine complex bis(4-amino-N,N’-disalicylidene- 1,2-phenylenediaminato)zirconium(IV), Zr(adsp)2. Both complexes were characterized by elemental analysis and IR, NMR, and UV-vis spectroscopy; the Zr(adsp)2 complex was further characterized by X-ray crystallography as a trisolvate. The structure of the Zr(adsp)2 complex was shown to consist of two perpendicularly disposed quadridentate ligands, similar to that of the unsubstituted complex, Zr(dsp)2, and consistent with theoretical predictions. Other details of the crystallography include the following: formula C40H30N6O4Zr*DMF*1.5C6H5CH3, space group P1, with a = 12.006 (2) A, b = 14.023 (2) A, c = 14.517 (3) A, alpha = 94.15 (1) degree, beta = 103.26 (1) degree, lambda = 99.15 (1) degree, V = 2333.7 A3, Z = 2, and D(calcd) = 1.372 g cm-3. Refinement of 600 variables using 4811 observations converged at R = 5.65%. Preliminary viscosity results on products obtained from reactions between Zr(adsp)2 and pyromellitic dianhydride or terephthaloyl chloride indicate that soluble (DMF, DMSO, NMP) oligomers are produced.