Estudio estructural de polímeros de coordinación de cu, mn, co y zn con ligante puente fumarato y ligantes auxiliares de tipo 2,2´-bipiridina

Abstract

The rational design of new compounds, focused on the search of structures with specific properties, is the aim for researchers in the field of supramolecular chemistry, where intermolecular interactions and the correct choice of building blocks play an important role. The present research has been carried out to synthesize, characterize and to study the different structures obtained in new coordination polymers having first-row transition metals, using fumarate as bridging ligand (Lb) and 2,2'-bipyridine derivatives as auxiliary ligands (La). Self-assembly reactions, in solution under ambient conditions, were used to obtain eight coordination polymers: two with Mn(II) ion, [Mn(fum)(5dmb)(OH2)2]n and {[Mn2(fum)2(4dmb)2]·H2O}n; two of Cu(II), {[Cu(fum)(5dmb)]·H2O}n, and {[Cu(fum)(4dtb)]·5H2O}n; two of Zn(II), {[Zn(fum)(4dmb)(OH2)]·H2O·CH3OH}n and {[Zn(fum)(4dtb)(OH2)]·H2O}n; and one with Co(II) ion, {[Co(fum)(4tmb)(OH2)]·2H2O}n. The obtained polymers were characterized by Elemental Analysis, IR Spectroscopy, Thermogravimetric Analysis and Single-crystal X-Ray Diffraction. Different coordination modes of the bridging ligand fumarate: monodentate (η1:η0), bidentate (η1:η1), monodentate to two metal centers (μ2-η1:η1) and bridging monodentate (μ2-η2:η0) were observed in the crystalline structures of the polymers, which generated one- (1D) and two-dimensional (2D) polymer systems. The presence of hydrogen bonds, due to water molecules coordinated directly to the central metal and/or occluded into the crystalline system, dictated the final two- (2D) or three-dimensional (3D) supramolecular structures of the compounds.