Spectral-luminescence and magnetic relaxation properties of lanthanide—p-sulfonatothiacalix[4]arenes in aqueous solution of surfactants

Abstract

The influence of nonionogenic, anionic and cationic surfactants on the magnetic relaxation and luminescence properties of gadolinium(III), terbium(III), and dysprosium(III) complexes with p sulfonatothiacalix[4]arene (TCAS) was studied. It was shown that the presence of both neutral and anionic surfactant does not influence the magnetic relaxation properties of GdTCAS as well as on the luminescence intensity of the TbTCAS and DyTCAS complexes. The presence of cationic surfactant at the concentration less than critical micellar concentration led to the formation of associates with stoichiometric composition with the Tb (Dy, Gd) TCAS complexes. These associates are characterized by more intensive luminescence, as compared to the initial TbTCAS and DyTCAS complexes.The ability of calix[n]arenes of recognizing different cations, anions, and neutral molecules 1,2 and participat ing in supramolecular ensembles as building blocks 3,4 attracts more and more attention among scientists work ing in the fields of analytical and bioanalytical chemistry, artificial enzymes, and self assembly membranes. 5 Since functionalization of macrocycle by sulfo groups has allowed obtaining water soluble calixarenes, the in terest in the investigation into their interactions with Ln 3+ ions (see Refs 2,6-12) possessing luminescence 13,14 and magnetic relaxation 15 properties increased.Such characteristics of the Ln calix[n]arene complex es as long lifetime of 4f luminescense, large Stoke's shift, and narrow radiation bands, make them promising as biochemical markers and probes, 16 laser and optical materials. 17 Terbium complexes with p sulfonatothia calix[n]arenes (thiacalix[4]arenesulfonates, TCAS) pos sess the most intensive luminescence among other lan thanide sulfonatocalixarene complexes. According to the literature data, TCAS coordinates lanthanide ions by sulfonate groups of the upper rim in acidic and weakly acidic media, and by phenolate groups of the lower rim in neutral and weakly basic media. 11,12The magnetic relaxation, spectrophotometric, and pH metric measurements of Gd III complexation with TCAS have allowed one to conclude that Gd III ion bind ing in acidic and weakly acidic media has outer sphere nature. In addition, the luminescence of the complex does not differ from that of aquaion. 11 At the same time the formation of highly luminescent complex in neutral and weakly basic media is governed by inner sphere co ordination of terbium to the phenolate rim of TCAS. The increase in luminescence intensity upon inner sphere coordination of lanthanide to ligands is mainly attributed to the energy transfer from the excited ligand to the emit ting level of the metal ion. However, this is not the only

Phosphineoxide-Chelated Europium(III) Nanoparticles for Ceftriaxone Detection

“…Deviation of I0/I from linear law in Stern-Volmer coordinates indicates mixed, static and dynamic, mechanism of quenching, which is typical for dark complexes formation (Figure 6b). [54,55] Limit of detection (LOD) calculated as 3σ/S (where σ is standart deviation for blank experiments and S is a slope of linear segment of luminescence intensity vs. concentration of analyte) is equal to 0.974 µM, which is comparable to the previously reported values (Table 4). For comparative purposes the luminescent response of PSS-[Eu(b)2(NO3)3] to ceftriaxone was also monitored (Figure S2).…”

Phosphineoxide-Chelated Europium(III) Nanoparticles for Ceftriaxone Detection

“…The main europium band at 612 nm demonstrated quenching for the factor of 7.23 when 87.5 μM ceftriaxone was added ( Figure 6 a). Deviation of I 0 /I from the linear law in Stern–Volmer coordinates indicates a mixed, static, and dynamic mechanism of quenching, which is typical for dark complexes formation ( Figure 6 b) [ 57 , 58 ]. In turn, the dark complex formation observed for PSS-[Eu( a ) 3 ] colloids in the presence of ceftriaxone argues for the ligand exchange disturbing the ligand-to-metal energy transfer of [Eu( a ) 3 ].…”

Aptamer-Conjugated Tb(III)-Doped Silica Nanoparticles for Luminescent Detection of Leukemia Cells

“…Calix[n]arenes coordinate lanthanide ions through covalently attached functional groups acting as antennae, enhancing both the luminescence and magnetic relaxation properties of lanthanides [21]. Indeed, terbium (III) complexes with thiacalix [4]arenesulfonate (TCAS) have the most intensive luminescence among other lanthanide-sulfocalixarene complexes [22]. TCAS coordinates Tb(III) through sulfonate groups of the upper rim in acidic/weakly acidic media and by phenolate groups of the lower rim in neutral/weakly basic media [23].…”