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The present work introduces self-assembled polystyrenesulfonate (PSS) molecules as soft nanocapsules for incorporation of Eu

The work introduces hydrophilic PSS-[Tb2(TCAn)2] nanoparticles to be applied as highly sensitive intracellular temperature nanosensors. The nanoparticles are synthesized by solvent-induced nanoprecipitation of [Tb2(TCAn)2] complexes (TCAn - thiacalix[4]arenes bearing different upper-rim substituents: unsubstituted TCA1, tert-buthyl-substituted TCA2, di- and tetra-brominated TCA3 and TCA4) with the use of polystyrenesulfonate (PSS) as stabilizer. The temperature responsive luminescence behavior of PSS-[Tb2(TCAn)2] within 293–333 K range in water is modulated by reversible changes derived from the back energy transfer from metal to ligand (M* → T1) correlating with the energy gap between the triplet levels of ligands and resonant 5D4 level of Tb3+ ion. The lowering of the triplet level (T1) energies going from TCA1 and TCA2 to their brominated counterparts TCA3 and TCA4 facilitates the back energy transfer. The highest ever reported temperature sensitivity for intracellular temperature nanosensors is obtained for PSS-[Tb2(TCA4)2] (SI = 5.25% K−1), while PSS-[Tb2(TCA3)2] is characterized by a moderate one (SI = 2.96% K−1). The insignificant release of toxic Tb3+ ions from PSS-[Tb2(TCAn)2] within heating/cooling cycle and the low cytotoxicity of the colloids point to their applicability in intracellular temperature monitoring. The cell internalization of PSS-[Tb2(TCAn)2] (n = 3, 4) marks the cell cytoplasm by green Tb3+-luminescence, which exhibits detectable quenching when the cell samples are heated from 303 to 313 K. The colloids hold unprecedented potential for in vivo intracellular monitoring of temperature changes induced by hyperthermia or pathological processes in narrow range of physiological temperatures.

The present work for the first time reports an application of the thiacalix[4]arene scaffold for the preparation of Tb3+ complexes possessing high thermal luminescence sensitivity in the physiological temperature range of 20–50 °C. Non-substituted thiacalix[4]arenes form luminescent complexes with Tb3+ ions, but they do not reveal any meaningful thermal sensitivity. To solve this problem, an upper-rim bromination of thiacalix[4]arenes, as well as distal bromination along with the embedding of two 1,3-diketone substituents are proposed as new simple synthetic approaches to enhance the thermal luminescence sensitivity of the Tb3+ complexes. A combination of mass spectrometry, NMR, UV-Vis and luminescence spectroscopy with quantum chemical calculations reveals a dimeric structure of the complexes formed by thiacalix[4]arenes with Tb3+ ions in DMF solutions. The steady-state luminescence of the Tb3+ complexes has demonstrated more than one order higher thermal sensitivity for the complexes of bromo-substituted ligands in comparison with the non-substituted thiacalix[4]arenes. The reasons for such behavior are discussed. The results highlight new opportunities for the thiacalix[4]arene platform for controlling ligand-to-metal energy transfer in terbium complexes and tuning their thermo-responsive luminescence properties.

The report introduces hybrid polyelectrolyte-stabilized colloids combining blue and green-emitting building blocks, which are citrate carbon dots (CDs) and [TbL]+ chelate complexes with 1,3-diketonate derivatives of calix[4]arene. The joint incorporation of green and blue-emitting blocks into the polysodium polystyrenesulfonate (PSS) aggregates is carried out through the solvent-exchange synthetic technique. The coordinative binding between Tb3+ centers and CD surface groups in initial DMF solutions both facilitates joint incorporation of [TbL]+ complexes and the CDs into the PSS-based nanobeads and affects fluorescence properties of [TbL]+ complexes and CDs, as well as their ability for temperature sensing. The variation of the synthetic conditions is represented herein as a tool for tuning the fluorescent response of the blue and green-emitting blocks upon heating and cooling. The revealed regularities enable developing either dual-band luminescent colloids for monitoring temperature changes within 25–50 °C through double color emission or transforming the colloids into ratiometric temperature sensors via simple concentration variation of [TbL]+ and CDs in the initial DMF solution. Novel hybrid carbon dots-terbium chelate PSS-based nanoplatform opens an avenue for a new generation of sensitive and customizable single excited dual-band nanothermometers.

Polymeric aggregates (~100 nm) based on polydiacetylenic acid doped with the luminescent TbIII complexes with the tetra- and bis-1,3-diketonate derivatives of calix[4]arenes with nonyl substituents at the lower rims are considered as potential nanosensors. The obtained colloidally stable mixed aggregates can generate a substrate-induced luminescent response in aqueous solutions of 2,2´,6´,2´´-terpyridine in the micromolar concentration range due to the coordination of the latter by TbIII ions on the aggregate surface.

The present review is aimed at highlighting outlooks for cyclophanic 1,3-diketones as a new type of versatile ligands and building blocks of the nanomaterial for sensing and bioimaging. Thus, the main synthetic routes for achieving the structural diversity of cyclophanic 1,3-diketones are discussed. The structural diversity is demonstrated by variation of both cyclophanic backbones (calix[4]arene, calix[4]resorcinarene and thiacalix[4]arene) and embedding of different substituents onto lower or upper macrocyclic rims. The structural features of the cyclophanic 1,3-diketones are correlated with their ability to form lanthanide complexes exhibiting both lanthanide-centered luminescence and magnetic relaxivity parameters convenient for contrast effect in magnetic resonance imaging (MRI). The revealed structure–property relationships and the applicability of facile one-pot transformation of the complexes to hydrophilic nanoparticles demonstrates the advantages of 1,3-diketone calix[4]arene ligands and their complexes in developing of nanomaterials for sensing and bioimaging.

The present work for the first time reports an application of the thiacalix[4]arene scaffold for the preparation of Tb3+ complexes possessing high thermal luminescence sensitivity in the physiological temperature range of 20-50 °C. Non-substituted thiacalix[4]arenes form luminescent complexes with Tb3+ ions, but they do not reveal any meaningful thermal sensitivity. To solve this problem, an upper-rim bromination of thiacalix[4]arenes, as well as distal bromination along with the embedding of two 1,3-diketone substituents are proposed as new simple synthetic approaches to enhance the thermal luminescence sensitivity of the Tb3+ complexes. A combination of mass spectrometry, NMR, UV-Vis and luminescence spectroscopy with quantum chemical calculations reveals a dimeric structure of the complexes formed by thiacalix[4]arenes with Tb3+ ions in DMF solutions. The steady-state luminescence of the Tb3+ complexes has demonstrated more than one order higher thermal sensitivity for the complexes of bromo-substituted ligands in comparison with the non-substituted thiacalix[4]arenes. The reasons for such behavior are discussed. The results highlight new opportunities for the thiacalix[4]arene platform for controlling ligand-to-metal energy transfer in terbium complexes and tuning their thermo-responsive luminescence properties.

Hydrophilic colloids (PSS-[Ln2(TCAi)2] and PSS-[LnCAi], where i = 1, 2, or 3 and Ln = Gd or Tb) were prepared by precipitation of Gd(III) or Tb(III) complexes with tetrathiacalix[4]arenes (TCAi) and calix[4]arenes bearing two 1,3-diketone groups (CAi) from dimethylformamide to an aqueous solution of poly(sodium 4-styrenesulfonate) (PSS). Dynamic light scattering and transmission electron microscopy demonstrated the formation of nanoparticles coated by the polymer. Luminescence decay measurements on Tb(III)-based colloids allowed hydration numbers of 2 and 4 per metal ion to be determined for PSS-[Ln2(TCAi)2] and PSS-[LnCAi] samples, respectively. Longitudinal and transverse water proton relaxivity values measured at 20.8 MHz were remarkably high for the PSS-[GdCAi] colloids but unexpectedly low for the PSS-[Gd2(TCAi)2] ones. 1H fast field cycling nuclear magnetic resonance relaxometry was applied to shed light on the origin of the different relaxation enhancement in the investigated systems. Extremely slow exchange with the bulk of water molecules coordinated to Gd(III) and the scarce accessibility of Gd(III) sites to water were highlighted as the main causes of limited relaxivity.

The temperature and substrate dependent luminescence of terbium complexes with calix[4]arene derivatives makes them promising building blocks of nanosensors. Thus, calix[4]arene 1,3-diketones in 1,3-alternate and cone isomeric forms bearing buthyl, dodecyl, nonyl and bromine substituents are introduced as ligands forming luminescent Tb3+ complexes in basified DMF solutions. The structure variation of the ligands allows to highlight buthyl-substituted derivative of calix[4]arene 1,3-diketone in 1,3-alternate isomeric form as the optimal structure. The detailed studies of the complex stoichiometry by means of UV-Vis and H1 NMR diffusion spectroscopy methods reveal 2:2 stoichiometry as the main for the calix[4]arene 1,3-diketones in 1,3-alternate isomeric form. The predominance of 2:2 over 1:1 and 1:2 (Tb:L) complex stoichiometries for the buthyl-substituted ligand was confirmed by comparison of the quantum chemically calculated thermochemical parameters of their complex formation. However, the 2:2 complex formation is either restricted for their dodecyl-substituted derivative or interferes with the 1:2 stoichiometry for the bromo-substituted counterpart. The conversion of the Tb3+ complexes from the DMF solutions to the PSS-stabilized colloids through the solvent-exchange procedure reveals the unfavorable effect of the nonyl- and dodecyl-substituted ligands on aggregation behavior of the colloids. Thus, 2:2 terbium complex with buthyl-substituted ligand in 1,3-alternate isomeric form is the optimal basis for production of the luminescent PSS-colloids with high colloid stability. The Tb3+- luminescence of the colloids exhibit the enhanced sensitivity to both environmental pollutant glyphosate with LOD = 1.97 nM and temperature changes within the physiological temperature range with SI = −4.67 K-% at 323 K.

The present work for the first time introduces PDA-based vesicles as convenient supporters of luminescent water insoluble Tb3+ complexes. The specific cyclophanic structure of the ligands, where upper and lower calix[4]arene rims are decorated by nonyl- and chelating groups correspondingly provides both complex formation with Tb3+ ions with the coordination of the latter via two 1,3-diketonate groups and self- or mixed aggregation of the complexes. The conditions of the self-aggregation of the Tb3+ complexes are revealed, although the self-aggregates are unstable being converted into the nanosized precipitates which tend to further aggregation and phase separation. The complexes exhibit Tb(III)-centered luminescence which tends to change in time following the phase separation processes. The embedding of the Tb3+ complexes into the PDA-based vesicles results in the mixed aggregates with significant Tb(III)-centered luminescence and significant colloidal stability. The latter arises from high negative electrokinetic potential values due to exterior carboxylic/carboxylate groups of the PDA vesicles.

This is the first report on the synthesis and characterization of tetra-1,3-diketone derivatives of tetrthia- and calix[4]arenes substituted by acetylacetonyl or dipivaloylmethanyl moieties at the upper rim and bearing hydroxyl groups at the lower rim as ligands for Tb3+ complexes. The spatial structure and tautomeric content for the synthesized ligands have been determined by means of X-ray, IR and NMR spectroscopy. Comparison of the sensitizing properties of tetrathiacalix[4]arenes and their calix[4]arene analogues on the Tb3+-centered luminescence in DMF solutions has been performed. A substantial enhancement of the luminescent properties of Tb3+- complexes with tetra-1,3-diketone ligands promoted by the tetrathiacalix[4]arene scaffold was established.

The present work introduces an impact of polyelectrolyte-based hydrophilic shell on magnetic relaxivity and luminescence of hard cores built from isostructural complexes of Tb(III) and Gd(III) in the core-shell aqueous colloids. Microscopic and scattering techniques reveal "plum pudding" morphology of the colloids, where polyelectrolyte-coated ultrasmall (5nm) hard cores form aggregates in aqueous solutions. Interaction of bovine serum albumin (BSA) with the colloids provides a tool to modify the polyelectrolyte-based shell, which is the reason for the improvement in both aggregation behavior of the colloids and their relaxivity. The modification of the hydrophilic polyelectrolyte-based shell enables to tune the longitudinal relaxivity from 5.9 to 23.3mM

Novel bis- and tetra-1,3-diketo derivatives of calix[4]arene with nonyl substituents at the lower rim have been synthesized. Their conformational and tautomeric composition have been determined; spectral parameters and complex formation properties with Tb3+ have been studied. Substitution of two 1,3-diketo groups with bromine under going from tetra- to bis 1,3-diketone derivatives was resulted in twofold increase luminescence intensity in their terbium complexes. Lifetime of the excited state of the terbium luminescence of the corresponding complexes as well as lifetime of excited triplet level of the 1,3-diketonate ligands have been determined.

The present work introduces the synthesis and characterization of upper rim dibromo-substituted bis-1,3-diketone calix[4]arenes with hydroxy and propyloxy groups at the lower rim as ligands for Gd3+ and Tb3+ complexes. The dibromo-substitution does not affect 1:1 complex formation with the lanthanide ions arising from their coordination via two 1,3-diketonate groups incorporated at the upper rim of the calix[4]arene. The analysis of the time-resolved luminescence spectra of the Gd3+ complexes clearly demonstrates the notable enhancement of the decay time of the ligand triplet state, while the energy of the triplet state for the new dibromo-bis-1,3-diketones remains practically unchanged versus its non-substituted analogues. The latter tendency points to the heavy-atom effect on the energy transfer from the excited state to vibration levels of the dibromo-substituted ligand resulting in a decreased radiationless decay contribution. Measurements of Tb3+-centered luminescence indicate a better antenna effect (∼1.7) of dibromo-calix[4]arenes compared with its non-substituted counterpart.

New bis-1,3-diketone derivatives of calix[4]arene (3–5) have been synthesized with good yields by the addition of a sodium salt of acetylacetone, 1-benzoylacetone and dibenzoylmethane to 5,17-bis-(bromomethyl)-25,26,27,28-tetrahydroxycalix[4]arenes. The structural properties of the obtained compounds and their complexes have been established by means of IR, UV-Vis, NMR spectroscopy and quantum-chemical calculations. The complex ability of bis-1,3-diketones towards Al3+, Ni2+, Cu2+ and lanthanide ions (Nd3+, Eu3+, Tb3+) has been investigated by using a liquid–liquid extraction method. The UV-Vis data indicate thermodynamically favorable 1:1 complex formation of the ligands with Tb3+ in alkaline DMF, although the time required for the equilibration reveals the difference between calix[4]arenes bearing acetylaceton-, benzoylaceton- and dibenzoylmethane-substituents. The steric hindrance effect on keto–enol transformation is the reason for the difference. The ligand-centered emissions of Gd3+ complexes with benzoylaceton- and acetylaceton-substituted calix[4]arenes reveal them both as more convenient antennae for red and infra-red than for green lanthanide luminescence. Indeed, the benzoylaceton-substituted counterpart sensitizes Yb3+-centered luminescence to a good extent. Nevertheless, the luminescence of Tb3+ is sensitized by the acetylaceton-substituted counterpart to a better extent than that of Yb3+, while only poor red Eu3+ emission is observed under sensitization by both the ligands.

The present work highlights the key aspects of the influence of calix[4]arene and tetrathiacalix[4]arene scaffolds on the structural and photophysical properties of Tb3+ complexes with tetra-1,3-diketone derivatives of the macrocycles in DMF solutions. The equilibrium forms of Tb3+ complexes with unsubstituted and functionalized by acetylacetonyl groups at the upper rim of calix[4]arenes and thiacalix[4]arenes are revealed from UV-, NMR, MALDI TOF mass spectroscopy, quantum-chemical calculations at the DFT level and luminescence spectroscopy data. In alkaline DMF solutions, the ligands form predominantly 1 : 1 complexes with Tb3+ ions. However, the replacement of a calix[4]arene-scaffold by a thiacalix[4]arene-scaffold in the tetra-1,3-diketone derivatives shifts the equilibrium forms of Tb3+ complexes from monomeric to the dimeric ones. DFT calculations in combination with experimental data reveal the most reliable structures of complexes. The quantitative analysis of the photophysical parameters in correlation with the structural features of the complexes highlights the specific inner-sphere environment of Tb3+ ions in the dimeric complexes with the thiacalix[4]arene derivatives as a reason for greater sensitization of Tb3+-centered luminescence.

Two novel calix[4]arene macrocyclic ligands functionalized with four 1,3-diketone groups at the upper and hydroxyl ( 3 ) or propyloxy-groups ( 6 ) at the lower rims were synthesized and characterized using NMR, IR spectroscopy, mass spectrometry, and elemental analysis. UV–vis spectrophotometry and ESI mass spectrometry studies indicate 1:1 complex formation of ligands 3 and 6 with Ln(III) (Ln=Tb, Yb) in alkaline DMF solutions resulted from coordination of Ln(III) with 1,3-diketonate groups. Luminescence study of Ln(III) complexes with 3 and 6 reveals significant difference in antenna effects of their deprotonated forms on both Tb(III)- and Yb(III)-centered luminescence. Comparison of ligand-centered emission for ligands 3 and 6 points to the latter as more efficient antenna for Tb(III) and Yb(III). Different conformational behavior of ligands 3 and 6 in alkaline media is assumed as a reason for the experimentally observed difference in sensitization pathways in Ln(III) complexes with 3 and 6 .

New bifunctional derivatives of 1,3-alternate tetrathiacalix[4]arene decorated with carboxylic, ester, hydrazide and/or hydrazone groups have been synthesized with good yields using the tetrathiacalix[4]arene derivatives with incorporated pairs of carboxylic and ester groups as versatile building blocks. The structural peculiarities of the obtained bifunctional compounds have been investigated by means of X-ray analysis, IR and NMR spectroscopy. The recognition ability of the synthesized macrocycles towards some alkali, alkali-earth and transition metal ions has been investigated applying a solvent extraction method. The results showed that the structure of a calix[4]arene platform as well as the nature of functional substitutes located on opposite sides of the macrocycle are critical for the coordination properties of the synthesized compounds.

Correction for ‘A simple synthetic approach to enhance the thermal luminescence sensitivity of Tb3+ complexes with thiacalix[4]arene derivatives through upper-rim bromination’ by Sergey N. Podyachev, et al., Dalton Trans., 2020, 49, 8298–8313, DOI: 10.1039/D0DT00709A.

The authors describe new ligands with two 1,3-diketone groups and two heteroaromatic (pyridyl or quinolyl) moieties embedded to the upper and lower rims of dibromo-substituted calix[4]arene scaffold. The ligands bind Tb(III) ions in alkaline DMF solutions to form 1:1 complexes. The strong Tb(III)-centered luminescence (with excitation/emission peaks at 330/545 nm) of the complexes results from efficient ligand-to-metal energy transfer. The complexes were incorporated into polystyrenesulfonate (PSS) colloids by diluting a DMF solution of the complex with aqueous solution of PSS. The luminescence of the colloids is quenched by copper(II), and this was used to develop a method for its fluorometric determination in nanomolar concentrations. The lower limit of detection is 0.88 nM. Quenching is a result of (a) ion exchange which converts the terbium complexes into their copper counterparts, and (b) energy transfer from Tb(III) to Cu(II) complexes. The low cytotoxicity of the colloidal nanoprobe conceivably makes it a promising tool for use in cellular imaging. Graphical abstract New calix[4]arene derivative provide efficient binding sites for Tb(III) and Cu(II) ions. The Tb(III) complexes were embedded to core-shell nanoparticles by solvent-mediated aggregation followed by polystryrenesulfonate deposition. The nanoparticles exhibit luminescence response on copper ions in nanomolar concentration range.

The present work reports ultra-small polyelectrolyte-coated water insoluble Tb(III) complex species with bright Tb(III)-centered luminescence resulted from efficient ligand-to-metal energy transfer as efficient labels for Hep-2 cells. The flow cytometry data revealed the enhanced cellular uptake of negatively charged nanoparticles coated by the polystyrenesulfonate (PSS)-monolayer versus the positively charged nanoparticles. The latter are obtained by layer-by-layer deposition of polyethyleneimine (PEI) onto PSS-coated ones. Confocal and TEM images of Hep-2 cells exposed by the colloids confirm favorable cell internalization of the PSS- compared to PEI-PSS-coated colloids illustrating unusual charge-effect. Dynamic light scattering data indicate significant effect of the biological background exemplified by serum bovine albumin and phosphatidylcholine-based bilayers on the exterior charge and aggregation behavior of the colloids. The obtained results reveal the PSS-coated nanoparticles based on water insoluble Tb(III) complex as promising cell labels.

In the course of systematic study of self-organization and properties of diluted solutions of biologically active compounds (BACs), an unknown phenomenon has been discovered. Using a complex of physicochemical methods, it has been shown for the first time that diluted aqueous solutions of many BACs in a wide range of calculated concentrations (10–6–10–20 mol/L), prepared by serial tenfold dilution from a stock solution, are self-organized disperse systems in which the disperse phase is represented by nanosized molecular ensembles (up to 400 nm) denominated nanoassociates [1].

The present work introduces an origin of sensing function of polyelectrolyte-coated colloids based on Tb(III) complexes with calix[4]resorcinarene cavitand bearing four 1,3 -diketone groups at the upper rim. The Tb(III)-centered luminescence of the colloids remains unchanged at pH 3–9, although the Tb(III) complexes are highly pH-dependent in DMF solutions. Both colloidal and luminescent properties of the colloids are stable within one month at least, which reveals stability of complex-based hard nanotemplates and soft polyelectrolyte deposition. The chelating substrates (catechol, tetracycline and fluoroquinolone derivatives) induce quick and reproducible luminescent response of the complex-based colloids without any detectable changes of their colloidal properties. The ternary complex formation at the interface of the colloids is the reason for their luminescent response on the substrates in aqueous solutions. Both the insolubility of the Tb(III)-containing cores and the shielding and/or buffer effect of the polyelectrolyte coating affect the interfacial complex formation, which results in more selective luminescent response of the colloids on the tetracycline and fluoroquinolone antibiotics in comparison with the complexes in solutions.

Novel 6-methyluracil derivatives with ω-(substituted benzylethylamino)alkyl chains at the nitrogen atoms of the pyrimidine ring were designed and synthesized. The numbers of methylene groups in the alkyl chains were varied along with the electron-withdrawing substituents on the benzyl rings. The compounds are mixed-type reversible inhibitors of cholinesterases, and some of them show remarkable selectivity for human acetylcholinesterase (hAChE), with inhibitory potency in the nanomolar range, more than 10,000-fold higher than that for human butyrylcholinesterase (hBuChE). Molecular modeling studies indicate that these compounds are bifunctional AChE inhibitors, spanning the enzyme active site gorge and binding to its peripheral anionic site (PAS). In vivo experiments show that the 6-methyluracil derivatives are able to penetrate the blood-brain barrier (BBB), inhibiting brain-tissue AChE. The most potent AChE inhibitor, 3 d (1,3-bis[5-(o-nitrobenzylethylamino)pentyl]-6-methyluracil), was found to improve working memory in scopolamine and transgenic APP/PS1 murine models of Alzheimer's disease, and to significantly decrease the number and area of β-amyloid peptide plaques in the brain.

Complexation of metal cations with acyclic and macrocyclic nucleobase derivatives containing uracil and 2-thiocytosine units linked by polymethylene spacers was studied. The investigated compounds have demonstrated high extraction selectivity for the Ag+ ion over a large number of competitive cations (Na+, Ca2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+). The structure and composition of Ag+ complexes have been investigated by a variety of physical-chemical methods. The crystal structures of three Ag+ complexes with 2-thiocytosine have been established by X-ray analysis. To refine the composition of the complexes formed in solution, the self-diffusion coefficients have been determined by NMR spectroscopy. For the estimation of the most reliable complex structures, the combined analysis of NMR data and DFT calculations was successfully applied. It was shown that the tendency of 2-thiocytosine moieties to form N1-nitrogen coordinated complexes and the presence of a polymethylene spacer between amine groups in the pyrimidinophanes provides the formation of Ag+ mediated duplex-type multi-component complexes.

Polyelectrolyte-coated nanoparticles consisting of terbium and gadolinium complexes with calix[ 4] arene tetra-diketone ligand were first synthesized. The antenna effect of the ligand on Tb(III) green luminescence and the presence of water molecules in the coordination sphere of Gd(III) bring strong luminescent and magnetic performance to the core-shell nanoparticles. The size and the core-shell morphology of the colloids were studied using transmission electron microscopy and dynamic light scattering. The correlation between photophysical and magnetic properties of the nanoparticles and their core composition was highlighted. The core composition was optimized for the longitudinal relaxivity to be greater than that of the commercial magnetic resonance imaging (MRI) contrast agents together with high level of Tb(III)-centered luminescence. The tuning of both magnetic and luminescent output of nanoparticles is obtained via the simple variation of lanthanide chelates concentrations in the initial synthetic solution. The exposure of the pheochromocytoma 12 (PC 12) tumor cells and periphery human blood lymphocytes to nanoparticles results in negligible effect on cell viability, decreased platelet aggregation and bright coloring, indicating the nanoparticles as promising candidates for dual magneto-fluorescent bioimaging. Funding Agencies|Swedish Institute scholarship; President of Russian Federation [MK-4456.2015.3]; Russian Government Program of Competitive Growth of Kazan Federal University; Swedish Research Council [621-2011-4395]; Royal Academy of Sciences [FOA12 V-111]; Kempe Foundation; Swedish Foundations Consolidator Fellowship; LTU Labbfonden Program

Self-organization and physicochemical properties of highly diluted solutions (10−11–10−2 mol L−1) in aqueous DMF (30 vol.% DMF) of a series of octasubstituted amphiphilic calix[4]resorcinols (CRs 1–4, where 1 is CR with carboxymethyl groups, 2 is its potassium salt, and 3 and 4 are CRs with acetylhydrazide and tris(hydroxymethyl)methylamide fragments) stored both under natural conditions and in the absence of external physical fields (geomagnetic and low-frequency electromagnetic) were studied by a complex of methods (dynamic light scattering, electrophoresis, tensiometry, conductometry, and pH metry). The studied solutions of CRs 1–4 are dispersed systems in which micelles (for CRs 1, 2, and 4), supramolecular domains (for CRs 1–4), and nanoassociates (for CRs 2–4) are formed, depending on hydrophilicity and nature of functional groups of CRs in various concentration ranges. The new approach to studying highly diluted solutions made it possible to explain for the first time the reasons for the nonmonotonic changes in the physicochemical properties and surface activity of aqueous-dimethylformamide highly diluted solutions of amphiphilic calix[4]resorcinols (10−4–10−7 mol L−1) from the viewpoint of the formation and rearrangement of supramolecular domains and nanoassociates.

New acylhydrazones containing sterically hindered phenolic fragments with different degrees of steric shielding were synthesized by reactions of 2,2′,2″-[benzene-1,3,5-triyltris(oxy)]triacetic acid trishydrazide with hydroxybenzaldehydes. According to the NMR data, the products in solution exist as relatively stable conformational cis/trans isomers with respect to the C(O)-NH bond.

The work presents the synthesis of a novel calix[4]resorcinarene cavitand bearing four 1,3-diketone groups at the upper rim and its complex formation with Tb(III) ions in DMF and DMSO solutions. Electrospray ionization mass spectra, 1H NMR, UV-Vis and luminescence spectra indicate a long (three hours at least) equilibration time for the complex formation between the cavitand and Tb(III) in alkaline DMF and DMSO solutions. These results are explained by the restricted keto–enol conversion, resulting from the steric hindrance effect of the methylenedioxy-groups linking the benzene rings within the cavitand framework. A facile synthetic route to convert luminescent Tb(III) complexes of various stoichiometries into luminescent hydrophilic colloids is disclosed in this work. The route is based on the reprecipitation of the Tb(III) complexes from DMF to aqueous solutions with further polyelectrolyte deposition without prior separation of the luminescent complexes. The luminescent colloids exhibit high stability over time and in buffer systems, which is a prerequisite for their applicability in analysis and biolabeling.

264 Recently, we have discovered a new phenomenon that opens the way to elucidating the mechanism of the effect of weak action of different nature on living organisms [1–5]. This phenomenon, referred to as “effect of ultralow concentrations and electromag netic fields” [2], consists in the formation of nano sized molecular ensembles, so called nanoassociates, in aqueous solutions of low concentrations. The nanoassociate formation is responsible for the emer gence of unique physicochemical properties of dilute solutions and, which is especially important, corre lates with bioeffects of these solutions [3, 4]. Forma tion of nanoassociates is initiated by a solute under certain conditions, the most essential among which are the presence of external electromagnetic fields and a definite structure of a substance [5].

The extraction ability of phenyl hydrazone derivatives of cone- and 1,3-alternate tetrathiacalix[4]arenes towards to some alkali, alkaline earth, transition and heavy metal ions has been investigated by picrate extraction method. The synthesized cone-tetrathiacalix[4]arene hydrazones show a high efficiency coupled with an excellent selectivity towards for Ag+ and Hg2+ ions. The stoichiometry of complexes and the extraction constants have been determined. The influence of calix[4]arene platform’s structure and the electron donor substituents in phenyl fragments on the extraction efficiency has been discussed.

1,3-Alternate and cone stereoisomers of tetrathiacalix[4]arene and 4-tert-butyltetrathiacalix[4]arene functionalized by carbohydrazide groups reacted with 3,5-di-tert-butyl-4-hydroxybenzaldehyde to give the corresponding hydrazones having sterically hindered phenol fragments.

A new strategy for the synthesis of bifunctional compounds, based on 1 , 3 - alternate tetrathiacalix[4]arene precursors functionalized by pairs of carboxylic acid and ester groups located on opposite sides of the macrocycle platform is described. These building blocks were prepared by the Cs 2 CO 3 induced selective hydrolysis of tetrathiacalix[4]arene tetraester derivatives. A mechanism for the selective hydrolysis is suggested. The structures of the compounds are elucidated by NMR spectroscopic analysis and X-ray single crystal diffraction.

The IR, 1 H and 13 C NMR data, as well as conformation and dynamic behaviour of tetrathiacalix[4]arenes functionalized by hydrazone fragments are reported. The influence of isomers of thiacalix[4]arenes, the removal of tert -butyl groups from upper rim of macrocycle and the replacement of a phenyl substituents in the hydrazone fragments by 2-pyridyl ones on conformational properties of the compounds are discussed. The structural peculiarities of the cone isomer of 25,26,27,28-tetrakis[N 2 -(2-pyridinylmethylidene)hydrazinocarbonylmethyloxy]-2,8,14,20-tetrathiacalix[4]arene and the 1 , 3-alternate isomer of 25,26,27,28-tetrakis[N 2 -(benzylidene)hydrazinocarbonylmethyloxy]-2,8,14,20-tetrathiacalix[4]arene in solution are compared with their crystal structures obtained by X-ray analysis. The correlation between extraction efficiency data obtained for these compounds earlier and the conformational features of calix[4]arene hydrazone derivatives studied in this work was performed.

The recognition ability of pyridinyl hydrazone derivatives of cone- and 1,3-alternate tetrathiacalix[4]arenes towards transition and alkali metals has been investigated by picrate extraction method. The stoichiometry of complexes and the extraction constants have been determined. It has been found that hydrazones do not extract alkali metal ions but show an excellent affinity towards transition and heavy metal cations. The removal of tert-butyl groups from calix[4]arene platform in the case of cone and 1,3-alternate isomers leads to an increase of d-ion extraction selectivity or efficiency.

Reactions of 1,3-alternate stereoisomers of tetrathiacalix[4]arene and 4-tert-butyltetrathiacalix[4]-arene, functionalized by hydrazide groups, with benzaldehyde and pyridin-2-carbaldehyde gave new tetrathiacalix[ 4]arene tetrahydrazone derivatives as promising receptors for transition and toxic heavy metal ions.

New de-tert-butyltetrathiacalix[4]arenes with acetylhydrazide substituents in cone and 1,3-alternate conformations have been synthesised with good yield by the hydrazinolysis of calix[4]arene ester derivatives. The recognition ability of synthesised macrocycles towards transition and alkali metals has been investigated by the picrate extraction method. The stoichiometry of complexes and the extraction constants have been determined. It has been found that tetrahydrazides do not extract alkali metal ions, but show an excellent affinity towards transition and heavy metal cations. The 1,3-alternate conformer of de-tert-butyltetrathiacalix[4]arene has revealed a remarkable selectivity for Ni2+ and Ag+ in the row of d-elements and for Cd2+ ion among the toxic heavy metals. The experimental data show that the removal of tert-butyl groups from tetrathiacalix[4]arene framework leads to the drastic improvement of extraction efficiency and selectivity of new tetrahydrazides.

The structural peculiarities of tetrathiacalix[4]arenes with acetylhydrazide substitutes in cone and 1,3-alternate conformations have been determined by means of X-ray analysis, IR and NMR spectroscopy. The structural and molecular modeling data were used in the interpretation of binding properties of calix[4]arene tetrahydrazides. The quantum-chemical calculations at the DFT level using the PBE exchange–correlation functional were performed for the complexation of 1,3-alternate conformer of tetrathiacalix[4]arene with Ag+ ion. It was shown that the removal of tert-butyl groups from tert-butyltetrathiacalix[4]arene platform facilitates a bis-ligand coordination of the metal ion and leads to a remarkable increase of Ag+ extraction efficiency.

Synthesis of water-soluble potassium salts of carboxymethyl derivatives of calix[4]pyrogallols and dodeca(carboxylatomethyl)tetramethylcalix[4]pyrogallol (L) complexes with transition metal ions (Cu2+, Fe3+, La3+) is described. Their structures in the solid state and in solution were characterized by NMR spectroscopy, ESR, and IR spectroscopy. Calix[4]pyrogallol dodecacarboxylates exist in the rccc-configuration. Calix[4]pyrogallol with methyl substituents at the lower rim in a wide range concentrations exists in water predominantly in the dimeric form. The obtained polynuclear transition metal complexes possess less symmetric structure than potassium salt of calix[4]pyrogallol (K12L). All studied complexes contain water molecules bound by rather strong hydrogen bonds. At room temperature the Fe4L complex is characterized by the environment of the Fe3+ ions close to octahedral. The absence of signals in the ESR spectrum of the Cu6L complex indicates the strong antiferromagnetic interaction Cu2+-Cu2+.

A series of new calix[4]resorcinarenes (rccc-isomer) and resorcinols functionalized by acetylhydrazone binding fragments have been synthesized. The IR and NMR data and stereochemical behaviour of hydrazones are reported and compared with the results of earlier investigations. The barriers of rotation of hydrazone fragments for some octahydrazone derivatives of calix[4]resorcinarenes and their resorcinol analogues have been determined by NMR-measurements. The complexing behaviour of bis- and octahydrazones has been studied by liquid–liquid extraction towards the s-metal ions (Li+, Na+, K+, Cs+ and Ca2+), p-metal ions (Pb2+), d-metal ions (Co2+, Ni2+, Cu2+, Zn2+, Cd2+ and Hg2+) and f-metal ions (La3+, Gd3+ and Lu3+). The stoichiometry of complexes and the extraction constants have been determined. It has been established that octahydrazones do not extract alkali metal cations but show excellent selectivity towards transition and soft heavy metal cations (especially Hg2+ or Pb2+).

The 1 H, 13 C and 15 N NMR data, conformation and dynamic behaviour of the new tetrathiacalix[4]arenes functionalized by hydrazide and hydrazone groups are reported and compared with the result of earlier investigations of 4- tert -butylphenoxyacetylhydrazones. The unusual fact of formation of N , N ′-diacetylhydrazine bridge and factors leading to its formation in the cone conformer of calixarene has been discussed. The barriers of rotation of hydrazone fragments of tetrathiacalix[4]arenes were determined by NMR-measurements at various temperatures. The structure of 1,3 - alternate conformer of 5,11,17,23-tetra- tert -butyl-25,26,27,28-tetrakis[hydrazinocarbonylmethyl]-2,8,14,20-tetrathiacalix[4]arene in solution is compared with crystal structure obtained by the X-ray analysis.

The binding properties of the cone conformer of O,O,O,O-tetrakis[hydrazinocarbonylmethyl]-4-tert-butylcalix[4]arene, the cone and the 1,3-alternate conformers of the corresponding thia analogue have been evaluated by means of liquid–liquid extraction for a large variety of metal ions. The extraction constants and the stoichiometries of the complexes formed have been determined. Comparison of the extraction properties of calix[4]arenes with their acyclic monomeric analogue clearly demonstrated, that the preorganization of acetylhydrazide groups on the calix[4]arene platform is the cause for a significant improvement of its binding properties. The presence of additional “soft” nitrogen binding sites in acetylhydrazide derivatives of calix[4]arenes compared to their amide derivatives leads to a shift from their classical selectivity for alkali and alkaline earth cations to transition metals. The cone conformer of tetrathiacalix[4]arene shows higher selectivity in a series of d-metal ions compared with its “c...

The aggregation behavior of carbazoylmethyl derivatives of pyrogallol and calix[4]pyrogallol was studied by conductometry and dynamic light scattering in water-DMF media. The formation of mixed nanoaggregates in the presence of cationic surfactants was revealed. The effect of structural preorganization of these compounds on their reactivity in the acylation by 4-nitrophenylacetate and the catalytic activity in the hydrolysis of phosphorus acid esters was studied.

A series of new calix[4]phenols, calix[4]resorcinols and calix[4]pyrogallols with acetylhydrazide substitutes has been␣synthesized with high yields by hydrazinolysis of ester group containing calix[4]arenes. The synthesized calix[4]phenols adopt the cone conformation while the calix[4]resorcinol and calix[4]pyrogallol derivatives prefer the boat conformation. The amide fragment of the hydrazide groups predominantly exists in the trans-conformation. The binding ability of synthesized calix[4]arenes toward transition and alkali metals by solvent extraction has been investigated.