Functional Transition And Rare-Earth Coordination Polymers Assembled Via Metalloligands

Construction of heterometallic coordination polymers is one of the most active areas of materials research.The intense interest in this field is justified not only by their versatile network topologies but also by their special chemical and physical properties such as catalytic behavior,magnetic,optoelectronic properties. The use of metal complexes as ligands is an elegant way to assemble the complexed structures of heterobimetallic coordination polymers.In this thesis,we have prepared a series of transition and rare-earth heterometallic coordination polymers by the reactions of the matalloligands with the second metal cations.These complexes have been characterized through elemental analysis,IR,and X-ray diffration crystallography.The luminescent properties of some compounds were studied.The neutral square-planar complexes[Pt(RNH₂)₂(NHCOR)₂]act as metalloligands and make bonds to closed-shell TI(â… )ions to afford one and two-dimensional platinum-thallium polymers based on heterobimetallic backbones. A series of heteronuclear Pt(â…¡)-Tl(â… )compounds have been synthesized and structurally characterized.The strcture of the Pt-Tl compoud are dependent on both counteranions and the amine substituents.The compound[Pt(NH₃)₂-(NHCO^tBu)₂Tl]X₂(X=NO₃^-,ClO₄^-)adopt one dimensional zigzag chain structures consisting of repeatedly stacked[Pt(NH₃)₂(NHCO^tBu)₂Tl]⁺ units,whereas [Pt(NH₃)₂(NHCO^tBu)₂Tl]X₂(X = PF₆^-)consists of a helical chain.The polymeric [{Pt(DACH)(NHCO^tBu)₂}₂Tl₂]²⁺(R = CH₃,^tBu)complexes adopt helical structures, which are generated around the crystallographic 2₁ screw axis.The complexes derived from[Pt(NH₃)₂(CO^tBu)₂]and the trinuclear complexes[{Pt(RNH₂)-(NHCO^tBu)₂}₂Tl]⁺ do not emit at room temperature but are luminescent at 77K, whereas the polymeric Pt-Tl complexes containing 1,2-diaminocyclohexane are intensively luminescent at both room temperature and 77K.Seven Pt-Ag coordination polymers were synthesized from the corresponding [Pt(RNH₂)(NHCO^tBu)₂]and Ag salts,and their structures were determined by X-ray crystallography.The Pt-Ag units aggregate into one-dimensional chains based on Pt-Ag backbones.These polymers are constructed by the Pt-Ag interactions and the coordination of amidate oxygen atoms to Ag ions.Pyridyl-substitutedβ-diketonate is a prospective multifunctional precursor.We prepared seven lanthanide complexes of pyridyl-substitutedβ-diketonate ligand. X-ray diffraction analysis revealed that reactions of 1-(pyridin-4-yl)-butane-1,3-dione with Ln ions afford one-dimensional polymers,whereas Ln complexes of 1,3-di(pyridin-3-yl)propane-1,3-dione display two-dimensional networks(Ln = Nd,La)and dinuclear complex(Ln = Eu).Two Eu(â…¢)complex are highly selective and sensitive chemosensors for Hg²⁺.These Eu-containing materials show fluorscent enhancement only for Hg²⁺.The complexation of other metal ions leads to fluorescence quenching or no response.The pyridyl group of the lanthanide complexes of pyridyl-substitutedβ-diketonate ligand could be easily involved in the formation of extended coordition frameworkes with Ag ions.Five mixed Ln-Ag complexes were synthesized and characterized by X-ray crystal diffraction and photoluminescent spectroscopy.These compounds exhibit 2-dimensional grid networks or one dimensional chain strctures.