Luminescence Resonance Energy Transfer in Heterodinuclear Ln^III Complexes for Sensing Biologically Relevant Anions

Abstract

Dinuclear lanthanide(III) complexes of the macrocycles 1,4-bis[1-4,7,10-tris(carbamoylmethyl)-1,4,7,10-tetraazacyclododecane]-m-xylene (1) and 1,3-bis[1-4,7,10-tris(carbamoylmethyl)-1,4,7,10-tetraazacyclododecane]-p-xylene (2)

Concentration-Independent pH Detection with a Luminescent Dimetallic Eu(III)-Based Probe

“…Lanthanide-based probes overcome many of the limitations associated with organic fluorophores because they offer atomic-based emissions that do not photobleach, emit line-like bands (<20 nm bandwidth), have large Stokes shifts, and exhibit long luminescence lifetimes (ms). Due to these advantages, many examples of lanthanide-based probes have been reported for the detection of biologically important cations, 1 anions, 2 neutral species, 3 proteins and peptides, 4 and DNA. 5 Many of these probes rely on the ratio of two emission peaks to determine analyte concentration, but the luminescence-decay rate of Eu(III)-containing complexes should enable the determination of analyte concentration without knowledge of probe concentration or extinction coefficient.…”

Multilanthanide Systems for Medical Imaging Applications

“…Another possible advantage of multilanthanide complexes is Ln-sensitized luminescence [80]. In these systems, interactions at each lanthanide can be interrogated separately for ratiometric sensing, wherein the response of the probe can be determined without determining the concentration of the probe [83]. Further, some multilanthanide complexes are known to display different properties than their monometallic analogs such as a response to or cleavage of DNA and RNA for reasons that are not well understood [48, 83, 84].…”

“…In these systems, interactions at each lanthanide can be interrogated separately for ratiometric sensing, wherein the response of the probe can be determined without determining the concentration of the probe [83]. Further, some multilanthanide complexes are known to display different properties than their monometallic analogs such as a response to or cleavage of DNA and RNA for reasons that are not well understood [48, 83, 84]. Yet, while the study of interactions between multilanthanide luminescent probes and DNA is still in its infancy, this class of compounds has the potential to generate useful tools for gene sensing or for therapy in the medical field.…”

“…9). Complexes 28 and 30–40 contain aromatic groups that function as antennas within these linkers [83–87]. The efficiency of energy transfer depends in part on the Ln-antenna distance; therefore, antennas that coordinate to the Ln ion such as the pyridyl ligands in 32 are expected to better sensitize Ln emission than those that transfer energy through space.…”

“…Due to the wide variety of possible antenna-lanthanide combinations, the study of multilanthanide luminescent probes is expected to expand in the future. Another interesting observation in multilanthanide luminescent probes is that a single fluorophore is capable of sensitizing two Ln ions as demonstrated in complexes 28 and 33–40 [83–85]. The knowledge gained from studying how multiple lanthanide ions are sensitized by a single antenna is likely to indicate how macromolecular systems can be designed with multiple lanthanide ions excited by a single antenna.…”