Tuning of the Network Dimensionality and Photoluminescent Properties in Homo- and Heteroleptic Lanthanide Coordination Polymers

Abstract

Targeted synthesis, through a heteroleptic methodology, has resulted in three types of lanthanide (Ln) coordination polymers (CPs) with tailored dimensionality, tunable photoluminescent colors, and distinct luminescence quenching upon UV and X-ray irradiation. The homoleptic Ln(tpbz)(NO 3 ) 2 [CP-1; tpbz = 4-(2,2′:6′,2″-terpyridin-4′-yl)benzoate] is assembled from Ln cations and bridging tpbz ligands, accompanied by the decoration of NO 3 − anions, forming a one-dimensional (1D) chain structure. The presence of ancillary dicarboxylate linkers, 1,4-benzenedicarboxylate (bdc) and 2,5-thiophenedicarboxylate (tdc), promotes additional bridging between 1D chains to form a two-dimensional layer and a three-dimensional framework for Ln(tpbz)(bdc) (CP-2) and Ln(tpbz)(tdc) (CP-3), respectively. The multicolor and luminescence properties of the obtained CPs were investigated, displaying typical red Eu III -based and green Tb III -based emissions. The Sm III -bearing CP-1−CP-3, however, exhibit diverse ratiometric Ln IIIand ligand-based emissions, with the photoluminescent colors varying from pink to orange to cyan. Notably, the Tb III -containing CP-1−CP-3 display distinct luminescence quenching upon continuous exposure to UV and X-ray irradiation. To our best knowledge, CP-2-Tb represents one of the most sensitive UV dosage probes (3.2 × 10 −7 J) among all CPs.

Structure–Property Relationships in Photoluminescent Bismuth Halide Organic Hybrid Materials

“…Even though these simultaneous emissions likely result from competitive pathways, they also afford compositional PLCT as a function of Eu doping percentage. Variation of Ln doping percentages to achieve PLCT is a well-established design strategy in luminescent materials literature, , yet to the best of our knowledge, the Eu-doped Bi-halide organic hybrid materials reported herein provide one of the first examples of emissive color tuning within hybrid materials that can be achieved upon visible excitation.…”

Combined Experimental/Theoretical Study on the Luminescent Properties of Homoleptic/Heteroleptic Erbium(III) Anilate-Based 2D Coordination Polymers

“…33 The ability of ClCNAn 2− as an antenna toward NIR-emitting Ln III ions was studied by some of us in both bulk-sized 2D CPs, formulated as [Ln 2 (ClCNAn) 3 (DMF) 6 ] n •(DCM) x (Ln = Yb, Nd, and Er; DMF = N,N-dimethylformamide; DCM = dichloromethane), and their related 2D ultrathin nanosheets obtained via solventassisted exfoliation methods by the top-down approach. 30 A promising synthetic strategy to tune the structure and photophysical properties of Ln-CPs is the use of a suitable combination of mixed ligands 34 to provide heteroleptic CPs, despite the fact that these mixed-ligand materials are scarcely studied, 35 probably because of synthetic issues. The first ligand acts as an antenna to sensitize Ln III emission, while the second ligand works as an ancillary bridging ligand for the construction of multidimensional networks.…”

“…A promising synthetic strategy to tune the structure and photophysical properties of Ln-CPs is the use of a suitable combination of mixed ligands to provide heteroleptic CPs, despite the fact that these mixed-ligand materials are scarcely studied, probably because of synthetic issues. The first ligand acts as an antenna to sensitize Ln III emission, while the second ligand works as an ancillary bridging ligand for the construction of multidimensional networks.…”

The coordination chemistry of benzhydrazide with lanthanide(iii) ions: hydrothermalin situligand formation, structures, magnetic and photoluminescence sensing properties

“…metal–ligand ratio, solvent, temperature, time, and pH) may also affect the final structure and coordination number of lanthanide assemblies. 3 A large number of lanthanide coordination complexes with fascinating structures and interesting properties have been reported. However, establishing a structure–property relationship in these materials is of great importance in the field of materials science and still remains a challenging task in crystal engineering.…”