Photochromic Lanthanide(III) Materials with Ion Sensing Based on Pyridinium Tetrazolate Zwitterion

Abstract

Lanthanide(III) ion (Ln(III)) sensing has become a major research area owing to its intriguing prospect in clinic, biology, and environmental studies. However, the existing methods have limitations like requirement of expensive instrumentation, long analytical times, and sample pretreatments, revealing the necessity of other methods. In this work, by using N -methyl-4-pyridinium tetrazolate (mptz) zwitterion as an electron acceptor, we obtained several new Ln(III) compounds with electron-transfer (ET) photochromic properties: [Ln(NO 3 ) 3 (H 2 O) 4 ]·mptz [Ln = Sm ( 1 ), Eu ( 2 ), Gd ( 3 ), La ( 4 ), Ce ( 5 ), Pr ( 6 ), Nd ( 7 ), Tb ( 8 ), Dy ( 9 ), Ho ( 10 ), Er ( 11 ), Tm ( 12 ), Yb ( 13 ), Lu ( 14 )]. Notably, different Ln(III) ions in these compounds can be visually identified by their different photoinduced color changes related to the ET process. This work may not only contribute to the more understanding of the structure–photosensitivity relationships of pyridinium-based compounds, but also provide a new approach for Ln(III) ion sensing.

INVESTIGATION OF COORDINATION COMPOUNDS OF GADOLINIUM (III) WITH beta-DIKETONES

“…They are better manifested in ligands with aromatic substituents (mphpd and mbphpd). Q СRCO /QCR 0,4832/-0,1651 0,4953/ -0,1693 0,5132 /-0,4014 0,4848/-0,1723 QСRCO / QO 0,4832/-0,4296 0,4953/-0,4460 0,5132 /-0,4635 0,4848/ -0,4492 QCCH2 / QCCO -0,4988/ 0,4734 -0,501/0,4814 -0,5101 /0,4877 -0,5001 /0,4842 Q CCO /QO 0,4734/-0,4309 0,4814/-0,4311 0,4877/-0,4319 0,4842/-0,4267 QCCO -QCC-CH2 0,4734/ -0,0605 0,4814/ -0,0406 0,4877/-0,0309 0,4842/-0,0727 The lengths of the Ln-O bonds correlate quite well with those described in the literature, according to the results of X-ray diffraction analysis [23]. For the synthesized gadolinium complexes, the average length of the lanthanide-oxygen bond is approximately the same, ranging from 2.317 Ǻ to 2.2353 for Gd(dmokd)3 and Gd(mphpd)3, respectively.…”

Two Photochromic Complexes Assembled by a Nonphotochromic Ligand: Photogenerated Radical Enhanced Room-Temperature Phosphorescence

“…Moreover, the radical···Dy exchange after light irradiation significantly perturbed the ESR spectra of compound 1 with more obvious multiple resonances, further demonstrating the magnetic couplings between photogenerated radicals and Dy­(III) ions. For 2 , due to the Gd­(III) ESR signal with half-filled electronic configuration f 7 , there is a broad resonance peak with g = 2.004, and the sharp radical signal after irradiation may be blurred by the strong Gd­(III) ESR signal. , However, the intensity of the signal becomes sharper and stronger (Figure b), further confirming the generation of H 3 -TPB • radicals.…”

Manipulating On/Off Single-Molecule Magnet Behavior in a Dy(III)-Based Photochromic Complex

“…After light irradiation, the signal at low fields significantly weakened, while a sharp ESR signal at g = 2.0004 is observed for QDU-1a­(Dy) . This indicates that radicals are generated and the electrons transfer from HEDP ligand to TPT unit, resulting in the formation of O • and TPT • radicals as observed in some viologen-templated systems. − The signal variation at low fields before and after light irradiation suggests the coupling interactions between Dy­(III) ions and photogenerated radicals. The EPR spectrum for QDU-1a­(Dy) at 100 K is also measured (Figure S10), and the spectrum variation between 296 and 100 K further indicates the magnetic couplings between radicals and Dy­(III) ions.…”