Can a Small Change in the Heterocyclic Substituent Significantly Impact the Physicochemical and Biological Properties of (Z)-2-(5-Benzylidene-4-oxo-2-thioxothiazolidin-3-yl)acetic Acid Derivatives?

Rhodanine-3-acetic acid derivatives are attractive compounds with versatile effects. What is very important is that compounds of this type have many biological properties. They are tested, among others, as fluorescent probes for bioimaging and aldose reductase inhibitors. Rhodanine-3-acetic acid derivatives also have antibacterial, antifungal and anticancer activity. The presented work demonstrates that a slight change in the five-membered heterocyclic substituent significantly affects the properties of the compounds under consideration. Three rhodanine-3-acetic acid derivatives (A-1-A-3) were obtained in the Knoevenagel condensation reaction with good yields, ranging from 54% to 71%. High thermal stability of the tested compounds was also demonstrated above 240 °C. The absorption and emission maxima in polar and non-polar solvents were determined. Then, the possibility of using the considered derivatives for fluorescence bioimaging was checked. Compounds A-1 and A-2 were successfully used as fluorescent dyes of fixed cells of mammalian origin. In addition, biological activity tests against bacteria and fungi were carried out. Our results showed that A-1 and A-2 showed the most excellent antimicrobial activity among the newly synthesized compounds, especially against Gram-positive bacteria.

Simple Donor-π-Acceptor Compounds Exhibiting Aggregation-Induced Emission as Hidden Fingerprints Detecting Agents.

Latent fingerprints are a significant carrier of information for a court expert. To detect this type of forensic trace, what is necessary is a method that is easy to use, compact, and versatile. The research aimed to investigate the physicochemical properties of luminescent substances of donor-π-acceptor systems in terms of their potential use in detecting hidden fingerprints. During the research, a group of fluorene compounds consisting of the (-CH=C(CN)(COOR)) moiety was designed and successfully synthesized. The optical, electrochemical, and aggregation-induced emission properties were studied. The aggregation-induced emission of compounds has been studied in the mixture of THF (as a good solvent) and water (as a poor solvent) with different water fractions ranging from 0% to 99%. Due to the molecular structure, substances showed different affinities to organic traces. As a result, it was noticed that all compounds showed the AIE phenomenon, while during tests on latent fingerprints, it was observed that two substances had particularly forward-looking features in this field.

The Role of Intermolecular Interaction on Aggregation-Induced Emission Phenomenon and OLED Performance.

In this work, the role of intermolecular interaction on the aggregation-induced emission (AIE) phenomenon and organic light-emitting diodes' (OLEDs) performance was investigated. During the research, a group of compounds consisting of the (-CH=C(CN)(COOR)) moiety with identical energy parameters was designed using the DFT approach and successfully synthesized. The optical, electrochemical, and aggregation-induced emission properties were studied. The aggregation-induced emission of compounds has been studied in the mixture of MeCN (as a good solvent) and water (as a poor solvent) with different water fractions ranging from 0% to 99%. Moreover, the time dependence on the AIE feature was also evaluated. Thanks to their molecular structures, almost identical behavior of these substances in dilute solutions was observed. For molecules that exhibit the strong AIE phenomenon, emission efficiency increases rapidly during aggregation. What is also very interesting is it has been shown that by introducing an appropriate substituent, one can control the degree of intermolecular interactions and "control" the length of the emitted wave. Finally, OLEDs were fabricated by the spin-coating/evaporation hybrid method. Devices showed green-blueish electroluminescence (CIE coordinates: 0.107, 0.165) with maximum luminance reaching 25 cd m-2 and EQE reaching 2%.

Photoinduced Processes in Rhenium(I) Terpyridine Complexes Bearing Remote Amine Groups: New Insights from Transient Absorption Spectroscopy.

Photophysical properties of two Re(I) complexes [ReCl(CO)3(R-C6H4-terpy-κ2N)] with remote amine groups, N-methyl-piperazinyl (1) and (2-cyanoethyl)methylamine (2), were investigated. The complexes show strong absorption in the visible region corresponding to metal-to-ligand charge transfer (1MLCT) and intraligand-charge-transfer (1ILCT) transitions. The energy levels of 3MLCT and 3ILCT excited-states, and thus photoluminescence properties of 1 and 2, were found to be strongly affected by the solvent polarity. Compared to the parent chromophore [ReCl(CO)3(C6H5-terpy-κ2N)] (3), both designed complexes show significantly prolonged (by 1-2 orders of magnitude) phosphorescence lifetimes in acetonitrile and dimethylformamide, contrary to their lifetimes in less polar chloroform and tetrahydrofuran, which are comparable to those for 3. The femtosecond transient absorption (fsTA) measurements confirmed the interconversion between the 3MLCT and 3ILCT excited-states in polar solvents. In contrast, the emissive state of 1 and 2 in less polar environments is of predominant 3MLCT nature.

Controlling of Photophysical Behavior of Rhenium(I) Complexes with 2,6-Di(thiazol-2-yl)pyridine-Based Ligands by Pendant π-Conjugated Aryl Groups.

The structure-property correlations and control of electronic excited states in transition metal complexes (TMCs) are of high significance for TMC-based functional material development. Within these studies, a series of Re(I) carbonyl complexes with aryl-substituted 2,6-di(thiazol-2-yl)pyridines (Arn-dtpy) was synthesized, and their ground- and excited-state properties were investigated. A number of condensed aromatic rings, which function as the linking mode of the aryl substituent, play a fundamental role in controlling photophysics of the resulting [ReCl(CO)3(Arn-dtpy-κ2N)]. Photoexcitation of [ReCl(CO)3(Arn-dtpy-κ2N)] with 1-naphthyl-, 2-naphthyl-, 9-phenanthrenyl leads to the population of 3MLCT. The lowest triplet state of Re(I) chromophores bearing 9-anthryl, 2-anthryl, 1-pyrenyl groups is ligand localized. The rhenium(I) complex with appended 1-pyrenyl group features long-lived room temperature emission attributed to the equilibrium between 3MLCT and 3IL/3ILCT. The excited-state dynamics in complexes [ReCl(CO)3(9-anthryl-dtpy-κ2N)] and [ReCl(CO)3(2-anthryl-dtpy-κ2N)] is strongly dependent on the electronic coupling between anthracene and {ReCl(CO)3(dtpy-κ2N)}. Less steric hindrance between the chromophores in [ReCl(CO)3(2-anthryl-dtpy-κ2N)] is responsible for the faster formation of 3IL/3ILCT and larger contribution of 3ILCTanthracene→dtpy in relation to the isomeric complex [ReCl(CO)3(9-anthryl-dtpy-κ2N)]. In agreement with stronger electronic communication between the aryl and Re(I) coordination centre, [ReCl(CO)3(2-anthryl-dtpy-κ2N)] displays room-temperature emission contributed to by 3MLCT and 3ILanthracene/3ILCTanthracene→dtpy phosphorescence. The latter presents rarely observed phenomena in luminescent metal complexes.

A fundamental role of the solvent polarity and remote substitution of the 2-(4-R-phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline framework in controlling the ground- and excited-state properties of Re(I) chromophores [ReCl(CO)3(R-C6H4-imphen)].

A series of Re(I) carbonyl complexes with the 1H-imidazo[4,5-f][1,10]phenanthroline (imphen) ligand functionalized with electron-donating amine groups attached to the imidazole ring via phenylene linkages were designed to investigate the impact of remote amine substituents on the ground- and excited-state properties of [ReCl(CO)3(R-C6H4-imphen)]. The complexes [ReCl(CO)3(R-C6H4-imphen)] belong to the family of [ReCl(CO)3(diimine)] systems, but contrary to strongly related phenanthroline Re(I) carbonyl complexes with a rich history in coordination chemistry, they are really sparse. The effects of electron-rich N-donor groups in [ReCl(CO)3(R-C6H4-imphen)] were fully studied with the use of cyclic voltammetry, absorbance and emission spectroscopy, and transient absorption spectroscopy, and they were simulated by density functional theory. The attachment of electron-rich amine groups to C6H5-imphen resulted in a decrease in oxidation potentials and a noticeable bathochromic shift of the longest absorption wavelength of [ReCl(CO)3(R-C6H4-imphen)] compared with the parent compound [ReCl(CO)3(C6H5-imphen)] due to a significant destabilization of the HOMO energy level. Regarding the excited-state properties, the triplet emission red-shift of [ReCl(CO)3(R-C6H4-imphen)] induced by appended electron-rich N-donor groups was accompanied by a significant increase in excited state lifetimes, up to a 12-fold enhancement compared with the parent chromophore. The lifetime prolongation of [ReCl(CO)3(R-C6H4-imphen)] bearing amine substituents was rationalized by the population of the ligand-localized triplet state, while the solvent-dependent photoluminescence characteristics of [ReCl(CO)3(R-C6H4-imphen)] were correlated with strong hydrogen bonding interactions between the acidic imidazole NH proton and highly polar solvents. The present findings are of high importance for understanding and controlling the excited-state nature of transition metal complexes.

Impact of the Anthryl Linking Mode on the Photophysics and Excited-State Dynamics of Re(I) Complexes [ReCl(CO)3(4'-An-terpy-κ2N)].

Rhenium(I) complexes with 2,2':6',2″-terpyridines (terpy) substituted with 9-anthryl (1) and 2-anthryl (2) were synthesized, and the impact of the anthryl linking mode on the ground- and excited-state properties of resulting complexes [ReCl(CO)3(4'-An-terpy-κ2N)] (An─anthryl) was investigated using a combination of steady-state and time-resolved optical techniques accompanied by theoretical calculations. Different attachment positions of anthracene modify the overlap between the molecular orbitals and thus the electronic coupling of the anthracene and {ReCl(CO)3(terpy-κ2N)} chromophores. Following the femtosecond transient absorption, the lowest triplet excited state of both complexes was found to be localized on the anthracene chromophore. The striking difference between 1 and 2 concerns the triplet-state formation dynamics. A more planar geometry of 2-anthryl-terpy (2), and thus better electronic communication between the anthracene and {ReCl(CO)3(terpy-κ2N)} chromophores, facilitates the formation of the 3An triplet state. In steady-state photoluminescence spectra, the population ratio of 3MLCT and 3An was found to be dependent not only on the anthryl linking mode but also on solvent polarity and excitation wavelengths. In dimethyl sulfoxide (DMSO), compounds 1 and 2 excited with λexc > 410 nm show both 3MLCT and 3An emissions, which are rarely observed. Additionally, the abilities of the designed complexes for 1O2 generation and light emission under the external voltage were preliminary examined.

In-Depth Studies of Ground- and Excited-State Properties of Re(I) Carbonyl Complexes Bearing 2,2':6',2″-Terpyridine and 2,6-Bis(pyrazin-2-yl)pyridine Coupled with π-Conjugated Aryl Chromophores.

In the current work, comprehensive photophysical and electrochemical studies were performed for eight rhenium(I) complexes incorporating 2,2':6',2″-terpyridine (terpy) and 2,6-bis(pyrazin-2-yl)pyridine (dppy) with appended 1-naphthyl-, 2-naphthyl-, 9-phenanthrenyl, and 1-pyrenyl groups. Naphthyl and phenanthrenyl substituents marginally affected the energy of the MLCT absorption and emission bands, signaling a weak electronic coupling of the appended aryl group with the Re(I) center. The triplet MLCT state in these complexes is so low lying relative to the triplet 3ILaryl that the thermal population of the triplet excited state delocalized on the organic chromophore is ineffective. The attachment of the electron-rich pyrenyl group resulted in a noticeable red shift and a significant increase in molar absorption coefficients of the lowest energy absorption of the resulting Re(I) complexes due to the contribution of intraligand charge-transfer (ILCT) transitions occurring from the pyrenyl substituent to the terpy/dppy core. At 77 K, the excited states of [ReCl(CO)3(Ln-κ2N)] with 1-pyrenyl-functionalized ligands were found to have predominant 3ILpyrene/3ILCTpyrene→terpy character. The 3IL/3ILCT nature of the lowest energy excited state of [ReCl(CO)3(4'-(1-pyrenyl)-terpy-κ2N)] was also evidenced by nanosecond transient absorption and time-resolved emission spectroscopy. Enhanced room-temperature emission lifetimes of the complexes [ReCl(CO)3(Ln-κ2N)] with 1-pyrenyl-substituted ligands are indicative of the thermal activation between 3MLCT and 3IL/3ILCT excited states. Deactivation pathways occurring upon light excitation in [ReCl(CO)3(4'-(1-naphthyl)-terpy-κ2N)] and [ReCl(CO)3(4'-(1-pyrenyl)-terpy-κ2N)] were determined by femtosecond transient absorption studies.

Square planar Au(III), Pt(II) and Cu(II) complexes with quinoline-substituted 2,2':6',2″-terpyridine ligands: From in vitro to in vivo biological properties.

Cancer is the second leading cause of death worldwide. Cisplatin has challenged cancer treatment; however, resistance and side effects hamper its use. New agents displaying improved activity and more reduced side effects relative to cisplatin are needed. In this work we present the synthesis, characterization and biological activities of three complexes with quinoline-substituted 2,2':6',2″-terpyridine ligand: [Pt(4'-(2-quin)-terpy)Cl](SO3CF3) (1), [Au(4'-(2-quin)-terpy)Cl](PF6)2·CH3CN (2) and [Cu(4'-(2-quin)-terpy)Cl](PF6) (3). The three complexes displayed a high antiproliferative activity in ovarian carcinoma cell line (A2780) and even more noticeable in a colorectal carcinoma cell line (HCT116) following the order 3 > 2 > 1. The complexes IC50 are at least 20 × lower than the IC50 displayed by cisplatin (15.4 µM) in HCT116 cell line while displaying at the same time, much reduced cytotoxicity in a normal dermal fibroblast culture. These cytotoxic activities seem to be correlated with the inclination angles of 2-quin unit to the central pyridine. Interestingly, all complexes can interact with calf-thymus DNA (CT-DNA) in vitro via different mechanisms, although intercalation seems to be the preferred mechanism at least for 2 and 3 at higher concentrations of DNA. Moreover, circular dichroism (CD) data seems to indicate that complex 3, more planar, induces a high destabilization of the DNA double helix (shift from B-form to Z-form). Higher the deviation from planar, the lower the cytotoxicity displayed by the complexes. Cellular uptake may be also responsible for the different cytotoxicity exhibited by complexes with 3 > 2 >1. Complex 2 seems to enter cells more passively while complex 1 and 3 might enter cells via energy-dependent and -independent mechanisms. Complexes 1-3 were shown to induce ROS are associated with the increased apoptosis and autophagy. Moreover, all complexes dissipate the mitochondrial membrane potential leading to an increased BAX/BCL-2 ratio that triggered apoptosis. Complexes 2 and 3 were also shown to exhibit an anti-angiogenic effect by significantly reduce the number of newly formed blood vessel in a CAM model with no toxicity in this in vivo model. Our results seem to suggest that the increased cytotoxicity of complex 3 in HCT116 cells and its potential interest for further translation to pre-clinical mice xenografts might be associated with: 1) higher % of internalization of HCT116 cells via energy-dependent and -independent mechanisms; 2) ability to intercalate DNA and due to its planarity induced higher destabilization of DNA; 3) induce intracellular ROS that trigger apoptosis and autophagy; 4) low toxicity in an in vivo model of CAM; 5) potential anti-angiogenic effect.

Carbazole effect on ground- and excited-state properties of rhenium(i) carbonyl complexes with extended terpy-like ligands.

The ground- and excited-state properties of three novel complexes [ReCl(CO)3(Ln-κ2N)] bearing 2,2':6',2''-terpyridine, 2,6-di(thiazol-2-yl)pyridine and 2,6-di(pyrazin-2-yl)pyridine functionalized with 9-carbazole attached to the central pyridine ring of the triimine core via phenylene linkage were investigated by spectroscopic and electrochemical methods and were simulated using density functional theory (DFT) and time-dependent DFT. To get a deeper and broader understanding of structure-property relationships, the designed Re(i) carbonyl complexes were compared with previously reported analogous systems - without any groups attached to the phenyl ring and bearing pyrrolidine instead of 9-carbazole. The results indicated that attachment of the N-carbazolyl substituent to the triimine core has less influence on the nature of the triplet excited state of [ReCl(CO)3(Ln-κ2N)] than the pyrrolidine group. Additionally, the impact of the ligand structural modifications on the light emission of the Re(i) complexes under external voltage was preliminarily examined with electroluminescence spectra of diodes containing the synthesized new molecules in an active layer.

Photoluminescence enhancement of Re(i) carbonyl complexes bearing D-A and D-π-A ligands.

Three Re(i) carbonyl complexes [ReCl(CO)3(Ln)] bearing 2,2'-bipyridine, 2,2':6',2''-terpyridine, and 1,10-phenanthroline functionalized with diphenylamine/or triphenylamine units (L1-L3) were synthesized to explore the impact of highly electron donating units appended to the imine ligand on the thermal and optoelectronic properties of Re(i) systems. Additionally, for comparison, the ligands L1-3 and parent complexes [ReCl(CO)3(bipy)], [ReCl(CO)3(phen)] and [ReCl(CO)3(terpy-κ2N)] were investigated. The thermal stability was evaluated by differential scanning calorimetry. The ground- and excited-state electronic properties of the Re(i) complexes were studied by cyclic voltammetry and differential pulse voltammetry, absorption and emission spectroscopy, as well as using density-functional theory (DFT). The majority of the compounds form amorphous molecular materials with high glass transition temperatures above 100 °C. Compared to the unsubstituted complexes [ReCl(CO)3(bipy)], [ReCl(CO)3(phen)] and [ReCl(CO)3(terpy-κ2N)], the HOMO-LUMO gap of the corresponding Re(i) systems bearing modified imine ligands is reduced, and the decrease in the value of the ΔEH-L is mainly caused by the increase in HOMO energy level. In relation to the parent complexes, all designed Re(i) carbonyls were found to show enhanced photoluminescence, both in solution and in solid state. The investigated ligands and complexes were also preliminarily tested as luminophores in light emitting diodes with the structures ITO/PEDOT:PSS/compound/Al and ITO/PEDOT:PSS/PVK:PBD:compound/Al. The pronounced effect of the ligand chemical structure on electroluminescence ability was clearly visible.

Platinum(II) coordination compounds with 4'-pyridyl functionalized 2,2':6',2″-terpyridines as an alternative to enhanced chemotherapy efficacy and reduced side-effects.

Two platinum(II) coordination compounds, [PtCl(4'-R1-terpy)](SO3CF3) (1) and [PtCl(4'-R2-terpy)](SO3CF3) (2), with 4'-(2-pyridyl)-2,2':6',2″-terpyridine (4'-R1-terpy) or 4'-(3-pyridyl)-2,2':6',2″-terpyridine (4'-R2-terpy) were synthesized and the impact of the pendant pyridyl ring on the structure and cytotoxic activity of Pt(II)-terpyridine complexes was explored. The single-crystal X-ray diffraction analysis confirmed square planar coordination of the cations [PtCl(4'-Rn-terpy)]+. The mode of binding of 1 and 2 to calf thymus DNA was examined by UV-Vis absorption titration, ethidium displacement assay and reaction with 9-ethylguanine, and the mixed covalent-intercalative mode was demonstrated. The cytotoxicity of the Pt(II) complexes against six cancer cell lines and three normal ones was determined using MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay and compared to cisplatin. The IC50 values for the compound 2 towards the cancer cell lines are in the low micromolar range. Most remarkably, 2 was over 4 times more effective than 1 and cisplatin against non-small lung adenocarcinoma (A549), and its selectivity index was ~60-80 times higher than that for 1 and cisplatin. The mechanisms underlying the loss of viability under treatment of 2 was further investigated including F-actin staining, mitotic index analysis, cytometric cell cycle analysis, Fluorescein isothiocyanate (FITC) -conjugated Annexin V antibody and propidium iodide (PI) staining, measurements of reactive oxygen species (ROS) in cells, analysis of changes in the mitochondrial mass and potential and quantitative real time polymerase chain reaction (qRT-PCR) genes analysis. The compound 2 was found to have a pro-oxidative effect by strong stimulation of cells for the production of reactive oxygen species and cytostatic effect through cell cycle arrest.

Effect of thienyl units in cyanoacrylic acid derivatives toward dye-sensitized solar cells.

A series of heterocyclic donor-acceptor systems were synthesized and well characterized by using 1H, 13C NMR, FT-IR, and elemental analysis. They were designed to investigate the effect of thiophene and cyanoacrylic acid number units on the thermal, optical, electrochemical and finally photovoltaic properties of dye-sensitized solar cells prepared with the selected compounds. The effect of chemical structure on their properties was demonstrated. They showed the beginning of thermal decomposition between 230 and 270 °C. The compounds absorbed the radiation in the range of 300-500 nm or 200-400 nm. They were electrochemically active and varied in energy band gap from 3.40 to 1.58 eV. Additionally, their optimized geometry, HOMO-LUMO levels, ionization potential, and electron affinity were evaluated using density functional theory. The photovoltaic devices based on TiO2 sensitized with the obtained molecules exhibited low power conversion efficiency, which was the highest for the device containing the symmetrical molecule with bithiophene structure. Under co-sensitization, the cell made of the same compound gave significant enhancement of efficiency of 6.3% being higher to that of the individual device prepared from dye N719 (5.75%). Moreover, the effects of immersion time of TiO2 electrode in the dye solution and co-sensitization methods were tested. The surface morphology of photoanode was investigated using atomic force microscopy.

Thermal, spectroscopic, electrochemical, and electroluminescent characterization of malononitrile derivatives with triphenylamine structure.

Three push-pull molecules with linear, quadrupolar and tripodal arrangements, consisting of triphenylamine (electro-donor) substituted with malononitrile groups (electro-acceptor), were synthesized with high yield by a simple procedure. Impact of the number of malononitrile substituents on optoelectronic properties was investigated with cyclic voltammetry, absorption and emission spectroscopy, as well as density functional theory calculation. The derivatives formed amorphous materials and exhibited low energy band gaps ranging from 2.06 to 2.49 eV. UV-Vis absorption and photoluminescence emission spectra were investigated in solutions (CHCl3, NMP) and in solid-state as thin films and two kinds of blends (with PMMA and PVK:PBD). Quantum yield of photoluminescence was dependent on the molecule structure, solvent, and solid-state layer formulation. The compounds exhibited high photoluminescence quantum yield in the range of 15-42% and 12-59% in solid-state as film and blend with PMMA (1 wt%), respectively, being promising for applications in light emitting diodes. The diodes with active layer consisting of neat derivatives and compounds molecularly dispersed in PVK:PBD (50:50 wt%) matrix showed orange and green electroluminescence.

Spectroscopy, electrochemistry and antiproliferative properties of Au(iii), Pt(ii) and Cu(ii) complexes bearing modified 2,2':6',2''-terpyridine ligands.

Structural, spectroscopic and electrochemical properties of six complexes [AuCl(L1)](PF6)2·CH3CN (1), [AuCl(L2)](PF6)2 (2), [PtCl(L1)](BPh4)·CH3CN (3), [PtCl(L2)](SO3CF3) (4), [CuCl2(L1)] (5) and [CuCl2(L2)]·CH3CN (6) with modified 2,2':6',2''-terpyridine ligands, 4'-(4-methoxyphenyl)-2,2':6',2''-terpyridine (L1) and 4'-(4-methoxynaphthalen-1-yl)-2,2':6',2''-terpyridine (L2) were thoroughly investigated and a significant role of the substituent (4-methoxyphenyl or 4-methoxynaphthalen-1-yl) and the metal center was demonstrated. The naphthyl-based substituent was found to increase the emission quantum yield of the luminescent Au(iii) and Pt(ii) complexes. Furthermore, the antiproliferative potential of the reported complexes was examined towards human colorectal (HCT116) and ovarian (A2780) carcinoma cell lines as well as towards normal human fibroblasts. The Au(iii) complex 2 and Cu(ii) complex 5 were found to have a higher antiproliferative effect on HCT116 colorectal and A2780 ovarian carcinoma cells when compared with the Pt(ii) complex with the same ligand (4). The order of cytotoxicity in both cell lines is 2 > 6 > 1 > 3 > 4. Complex 2 seems to be more cytotoxic towards HCT116 and A2780 cancer cell lines with IC50 values 300× and 130× higher in normal human fibroblasts compared to the respective cancer cells. The viability loss induced by the complexes agrees with Hoechst 33258 staining and the typical morphological apoptotic characteristics like chromatin condensation and nuclear fragmentation and flow cytometry assay. The induction of apoptosis correlates with the induction of reactive oxygen species (ROS). Fluorescence microscopy analysis indicates that after 3 h of incubation, complexes 1-4 are localized inside HCT116 cells and the high levels of internalization correlate with their cytotoxicity.

Synthesis, spectroscopic, electrochemical and computational studies of rhenium(i) tricarbonyl complexes based on bidentate-coordinated 2,6-di(thiazol-2-yl)pyridine derivatives.

Nine rhenium(i) complexes possessing three carbonyl groups together with a bidentate coordinated 2,6-di(thiazol-2-yl)pyridine derivative were synthesized to examine the impact of structure modification of the triimine ligand on the photophysical, thermal and electrochemical properties of [ReCl(CO)3(4-Rn-dtpy-κ2N)]. The Re(i) complexes were fully characterized using IR, 1H and 13C, HRMS-ESI and single crystal X-ray analysis. Their thermal properties were evaluated using DSC and TGA measurements. Photoluminescence spectra of [ReCl(CO)3(4-Rn-dtpy-κ2N)] were investigated in solution and in the solid state, at 298 and 77 K. Both emission wavelengths and quantum yields of [ReCl(CO)3(4-Rn-dtpy-κ2N)] were found to be structure-related, demonstrating a crucial role of the substituent attached to the 2,6-di(thiazol-2-yl)pyridine skeleton. In order to fully understand the photophysical properties of [ReCl(CO)3(4-Rn-dtpy-κ2N)], density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations were performed. Furthermore, the complexes which showed appropriate solubility in chloroform were tested as an emissive active layer in OLED devices.

222Rn and 226Ra activity concentrations in groundwaters of southern Poland: new data and selected genetic relations.

Since 2008, the authors have been conducting research into 222Rn and 226Ra activity concentrations in shallow circulation groundwaters in southern Poland. Measurements have been performed with a liquid-scintillation method and ultra low-level liquid-scintillation spectrometers α/ß Quantulus 1220. The research carried out so far has demonstrated that in the Sudetes groundwaters with high activity concentrations of 222Rn and 226Ra are common. In other studied areas in southern Poland no shallow circulation groundwaters with high radon or radium concentrations have been found yet. The conducted research has demonstrated that the activity concentration of 222Rn dissolved in shallow circulation groundwaters in the Sudetes depends chiefly on the amount of radon, which after being released as gas from reservoir rocks is dissolved in waters flowing through these rocks. At the same time, the concentration of 222Rn dissolved in some shallow circulation groundwaters in the Carpathians is influenced significantly by the amount of radon produced from the decay of its parent ion 226Ra2+ dissolved in these waters.