Microcrystalline Core–Shell Lanthanide-Based Coordination Polymers for Unprecedented Luminescent Properties

Abstract

Microcrystalline core–shell powders of lanthanide-based coordination polymers with general chemical formula ([Ln­(cpbOH)]∞)1–x @([Ln′(cpbOH)]∞) x with Hcpb = 1,4-carboxyphenylboronic acid have been synthesized and structurally characterized. Their luminescent properties have been studied. They are drastically different from those of heterolanthanide coordination polymers, also called “molecular alloys”, that present the same crystal structure and chemical composition. Study of the photophysical properties of core–shell lanthanide-based coordination polymers reveals that it is possible to control efficiently the intermetallic energy transfers between lanthanide ions. Furthermore, multiemissive compounds, under unique irradiation, in both visible and infrared regions are easily feasible. Core–shell microstructured lanthanide-based coordination polymers have also been prepared with terephthalic (H2bdc) and trimesic (H3tma) acids as ligands for evidencing that lanthanide-ion-based coordination compounds are excellent candidates for 3D molecular epitaxial growth.

Luminescence properties of lanthanide complexes-based molecular alloys

“…Indeed, in segregated compounds, inter-metallic energy transfers are weak. [72] In order to quantify these inter-metallic energy transfers, Tb of an acceptor ion are related to inter-metallic energy transfers efficiency (ET) according to the relationship: [14] = 1 − 0 (1)…”

Monitoring Fe(II) Spin-State Equilibria via Eu(III) Luminescence in Molecular Complexes: Dream or Reality?

“…In this context, Eu­(III) and Tb­(III) have been exhaustively used as luminescent probes because of their strong, easily detectable, long-lived, and well-understood visible emission . For instance, Eu­(III) and Tb­(III) stains have been used for probing point mutations in DNA, labeling proteins, improving contrast in optical microscopy, sensing local chiral environments, quantifying analytes in complex media, and designing colored phosphors . In inorganic and coordination chemistry, the latter visible lanthanide probes were intensively exploited for monitoring intermetallic d – f communications operating in (supra)­molecular assemblies .…”

Design and properties of multiple-emitter luminescent metal–organic frameworks

“…43,88 For example, core-shell structured [Eu(cpb)] 0.5 *[Tb(cpb)] 0.5 (cpb 3À = 1,4-carboxyphenylboronate) displayed a yellow emission color compared to the red emission of the solid solution multiemitter [Tb 0.5 Eu 0.5 (cpb)]. 21 The identical 5 D 0 and 5 D 4 lifetime of the core-shell sample to that of the single [Eu(cpb)] and [Tb(cpb)] phase, respectively, as well as the constant emission intensity ratio of I Eu /I Tb over the temperature range clearly indicated the negligible intermetallic energy transfer in the core-shell sample. Whereas for the solid-solution sample, the reduced 5 D 4 lifetime compared to [Tb(cpb)], as well as the gradually decreased I Eu /I Tb as the temperature increased, indicated the presence of Tb 3+ to Eu 3+ energy transfer.…”

“…2,19,20 Even if there is an interparticle or interlayer phase boundary in a so-called multi-heterostructured emitter (see below) one could still view this as a single LMOF phase since the different phases are constructed on the lattice match between MOFs with similar topologies. 21,22 (2) They benefit from the modifiable pore surface of MOFs, such that the chromophore moieties can be integrated into the MOF matrix by post-synthetic modification (PSM). [23][24][25][26][27] This provides possibilities for creating multi-emitter LMOFs, in which the multiple emission is added through the PSM-chromophore to a pristine single-emitter LMOF or even a non-luminescent MOF.…”