Polymorphism and Its Influence on Catalytic Activities of Lanthanide-Glutamate-Oxalate Coordination Polymers.

To study the relationship between polymorphism and catalytic activities of lanthanide coordination polymers in the cycloaddition reactions of CO2 with epoxides, the monoclinic and triclinic polymorphs of [LnIII(NH3-Glu)(ox)]·2H2O, where LnIII = LaIII (I), PrIII (II), NdIII (III), SmIII (IV), EuIII (V), GdIII (VI), TbIII (VII), and DyIII (VIII), NH3-Glu- = NH3+ containing glutamate, and ox2- = oxalate, were synthesized and characterized. Factors determining polymorphic preference, the discrepancy between the two polymorphic framework structures, potential acidic and basic sites, thermal and chemical stabilities, active surface areas, void volumes, CO2 sorption/desorption isotherms, and temperature-programmed desorption of NH3 and CO2 are comparatively presented. Based on the cycloaddition of CO2 with epichlorohydrin in the presence of tetrabutylammonium bromide under solvent-free conditions and ambient pressure, catalytic activities of the two polymorphs were evaluated, and the relationship between polymorphism and catalytic performances has been established. Better performances of the monoclinic catalysts have been revealed and rationalized. In addition, the scope of monosubstituted epoxides was experimented and the outstanding performance of the monoclinic catalyst in the cycloaddition reaction of CO2 with allyl glycidyl ether under ambient pressure has been disclosed.

Crystal structure and photoluminescent properties of a new EuIII-phthalate-acetate coordination polymer.

A new coordination polymer, poly[(acetato)aqua(µ3-phthalato)europium(III)], [Eu(C8H4O4)(CH3O2)(H2O)] n or [EuIII(phth)(OAc)(H2O)] (phth2- = phthalate and OAc- = acetate) was synthesized and characterized, revealing it to be a supra-molecular assembly of one-dimensional [EuIII(phth)(OAc)(H2O)] chains. Each chain is built up of edge-sharing distorted tricapped trigonal-prismatic TPRS-{EuIIIO9} building motifs and assembled in a regular fashion through hydrogen-bonding and aromatic π-π inter-actions. The fully deprotonated phth2- ligand was shown to be an effective sensitizer, promoting the characteristic 5 D 0→7 FJ (J = 1-4) emissions of EuIII even in the presence of the non-sensitizing OAc- group.

Lanthanide Coordination Polymers of Mixed Phthalate/Adipate for Ratiometric Temperature Sensing in the Upper-Intermediate Temperature Range.

Based on the mixed phthalate (phth2-) and adipate (ad2-), [Nd2(ad)(phth)2(H2O)4] (I) and [Ln(ad)0.5(phth)(H2O)2] (Ln = EuIII (II), GdIII (III), TbIII (IV), DyIII (V), ErIII (VI), TmIII (VII), 1EuIII:10TbIII (VIII), 3EuIII:10TbIII (IX), and 5EuIII:10TbIII (X)) were synthesized and characterized. Complexes VIII-X show excellent ratiometric temperature sensing behavior in physiological and higher temperature ranges (303-423 K) rendered by the TbIII-to-EuIII energy transfer process. The efficiency of the process as illustrated through the lifetime measurements depends on both the EuIII:TbIII mole ratio and the temperature. The performance of X in terms of relative sensitivity ( Sr), temperature resolution, and measurement repeatability were determined, revealing the maximum Sr ( Sm) of 1.21%·K-1 at 303 K with reliable temperature resolution and excellent repeatability.