The design of responsive luminescent lanthanide probes and sensors

Abstract

The design principles that guide the creation of responsive lanthanide luminescent probes are defined, classified and exemplified.

Spin-flip luminescence

“…Photoactive complexes are both fundamentally interesting and highly valuable in many applications, e.g., optical devices, catalysis and biomedicine [1][2][3][4]. Traditionally there is an excessive reliance on compounds containing precious transition metal ions like Ru II , Ir III , Os II or Pt II due to their favorably high intrinsic ligand field splitting and strong spin-orbit coupling (SOC) [5][6][7][8][9]. In most cases, the emissive states are of charge transfer (CT) character, be it metal-toligand (MLCT), ligand-to-metal (LMCT), ligand-to-ligand (LL'CT) or intra-ligand charge transfer (ILCT), while metalcentered (MC) states are often non-emissive and facilitate non-radiative deactivation [10,11].…”

“…Beyond the d 3 electronic configuration, spin-flip emission is also conceivable in octahedral d 2 , d 4 and d 8 complexes, but examples are much less prevalent in the literature than for d 3 complexes. In this review, we outline the theoretical frame required to understand spin-flip luminescence with respect to ligand field theory, symmetry, intersystem crossing (ISC) and relaxation pathways using various well-described Cr III complexes.…”

Synthesis of bright water-soluble circularly polarized luminescence emitters as potential sensors

“…To determine if our system can be best described as “sensors” or “activity-based probes”, 13 we tested the reversibility of our system. When the pH was reversed back to 8.0, the initial g lum value was recovered (Fig.…”

Chiral Dinuclear EuIII, TbIII, and YIII Complexes Supported by P‐Stereogenic Linear Tetraphosphine Tetraoxide

“…Chiral lanthanide(III) complexes have attracted surging attention in developing photo-functional materials by the use of chiroptical properties with an aim of probing and sensing various chiral biomolecules. [1][2][3][4][5][6][7][8] Besides the chiral multidentate ligand systems developed for photoluminescent lanthanide complexes, such as C-chiral O,N-donor ligands of 3-fluoroalkanoyl-d-camphorate, [9][10][11][12] pyridine-2,6-bis(carboxamides), [13][14][15] pyridine-2,6-bis(oxazolines), [16][17][18] and so on, multidentate phosphine oxides are thought to be promising as their steric bulkiness could prevent the high-energy vibrational solvent molecules from coordinating to the metal center and the low vibrational energy of phosphoryl group suppress nonradiative deactivation of the 4f-4f excited states. In this regards, an axischiral diphosphine dioxide, (R/S)-2,2'-bis(diphenylphosphoryl)-1,1'-binaphthyl ((R/S)-BINAPO), was used to induce chiral property on Eu(hfa) 3 chromophore (hfaH = 1,1,1,5,5,5-hexafluoropentane-2,4-dione), [11,19] and however, other phosphine oxides including P-stereogenic multidentate phosphine oxides have no longer been investigated hitherto.…”

“…The absolute configuration was determined by an X-ray crystallographic analysis with Flack parameter near to zero on [Ce((S,S)-dpmppm(=O) 4 )(NO 3 ) 3 ] (CeL4 SS NO 3 ) (Figure S7, Tables S1), which was prepared by reacting Ce(NO 3 ) 3 • 6H 2 O with the tetraphosphine tetraoxide of the second fraction (Scheme 1), and revealed a 10-coordinate mononuclear Ce(III) structure ligated by one (S,S)-dpmppm(=O) 4 and three η 2 nitrate anions. The IR spectra of L4 RR and L4 SS showed an intense P=O stretching vibration at around 1193 cm À 1 , and in the 31 P{ 1 H} NMR spectra in CDCl 3 , two multiplet resonances are observed at δ 24.5 and 29.5 ppm in a 1 : 1 ratio (Figure S9). The CD spectra exhibited mirror images of the Cotton effects at 278 and 265 nm, corresponding to the UV absorption bands around 273 and 266 nm ascribable to π-π* transitions of the phosphine oxide (Figure S13).…”