A series of cobalt(II) dicyanamide (dca−) coordination polymers with substituted pyrazines (pyz) and pyrimidines (pym) as auxiliary ligands have been synthesized and structurally characterized to investigate the influence of the type and substitution pattern of the auxiliary ligand on the dimensionality and topology of the resulting frameworks. As a result of our studies, 13 novel heteroleptic cobalt(II) dicyanamide coordination polymers were obtained, and their crystal structures were determined by single-crystal X-ray diffraction. Eight of the investigated compounds exhibit a single-chain structure composed of [Co(Lpyz/pym)2]2+ units bridged via double μ1,5–dca ligands. In two complexes, neutral triple-chain topologies were observed, in which double μ1,5– and single μ1,3,5–dca bridges connect two crystallographically independent cobalt(II) ions, both being six-coordinate in tetragonally elongated octahedral environments. Two- and three-dimensional architectures were confirmed only in the case of Co(II) compounds with 2,6–Me2pyz and 4-NH2-pym co-ligand, respectively The cobalt(II) complexes described herein have also been compared with dicyanamide-based cobalt(II) systems incorporating pyrazine- and pyrimidine-like ligands. These structural relationships are of high significance for the rational design and synthesis of heteroleptic cobalt(II) dicyanamide systems.

Over the last five decades, diimine rhenium(I) tricarbonyl complexes have been extensively investigated due to their remarkable and widely tuned photophysical properties. These systems are regarded as attractive targets for design functional luminescent materials and performing fundamental studies of photoinduced processes in transition metal complexes. This review summarizes the latest developments concerning Re(I) tricarbonyl complexes bearing donor-acceptor (D-A) and donor-π-acceptor (D-π-A) ligands. Such compounds can be treated as bichromophoric systems with two close-lying excited states, metal-to-ligand charge transfer (MLCT) and intraligand-charge-transfer (ILCT). A role of ILCT transitions in controlling photobehaviour was discussed for Re(I) tricarbonyls with six different diimine cores decorated by various electron-rich amine, sulphur-based and π-conjugated aryl groups. It was evidenced that this approach is an effective tool for enhancement of the visible absorptivity, bathochromic emission shift and significant prolongation of the excited-state, opening up new possibilities in the development of more efficient materials and expand the range of their applications.

This is the first comprehensive review of rhenium(I) carbonyl complexes with 2,2′:6′,2″-terpyridine-based ligands (R-terpy)—encompassing their synthesis, molecular features, photophysical behavior, and potential applications. Particular attention has been devoted to demonstrating how the coordination mode of 2,2′:6′,2″-terpyridine (terpy-κ2N and terpy-κ3N), structural modifications of terpy framework (R), and the nature of ancillary ligands (X—mono-negative anion, L—neutral ligand) may tune the photophysical behavior of Re(I) complexes [Re(X/L)(CO)3(R-terpy-κ2N)]0/+ and [Re(X/L)(CO)2(R-terpy-κ3N)]0/+. Our discussion also includes homo- and heteronuclear multicomponent systems with {Re(CO)3(R-terpy-κ2N)} and {Re(CO)2(R-terpy-κ3N)} motifs. The presented structure–property relationships are of high importance for controlling the photoinduced processes in these systems and making further progress in the development of more efficient Re-based luminophores, photosensitizers, and photocatalysts for modern technologies.

CuCr2Se4 nanoparticles were obtained by the high-energy ball milling of CuCr2Se4 single crystals, which had a size of approximately 32 nm after 5 h of milling. Structural, magnetic, and electrical studies have shown that a reduction in CuCr2Se4 single crystals to the nanosize leads to (1) a weakening of ferromagnetic interactions, both long and short range, (2) a lack of saturation of magnetization at 5 K and 70 kOe, (3) a change in the nature of electrical conductivity from metallic to semiconductor, and (4) a reduction in the thermoelectric power factor S2σ by an order of magnitude of 400 K. The above results were considered in terms of the parameters of the band model, derived from the high-temperature expansion of magnetic susceptibility and from the diffusive component of thermoelectric power. Theoretical calculations showed a significant weakening of both the superexchange and double exchange mechanisms, a reduction in the [Cr3+,Cr4+] band width from 0.76 to 0.19 eV, and comparable values of the Fermi energy and the activation energy (0.46 eV) in the intrinsic region of electrical conductivity. The main advantage of high-energy ball milling is the ability to modify the physicochemical properties of already existing compounds for desired applications.

Photochemical applications based on intermolecular photoinduced energy triplet state transfer require photosensitizers with strong visible absorptivity and extended triplet excited-state lifetimes. Using a bichromophore approach, two Re(I) tricarbonyl complexes with 2-(1-pyrenyl)-1H-imidazo[4,5-f][1,10]phenanthroline (pyr-imphen) and 1-(4-(methyl)phenyl)-2-(1-pyrenyl)-imidazo[4,5-f][1,10]phenanthroline (pyr-tol-imphen) showing extraordinary long triplet excited states at room temperature (>1000 μs) were obtained, and their ground- and excited-state properties were thoroughly investigated by a wide range of spectroscopic methods, including femtosecond transient absorption (fs-TA). It is worth noting that the designed [ReCl(CO)3(pyr-imphen)] (1) and [ReCl(CO)3(pyr-tol-imphen)] (2) complexes form a unique pair differing in the mutual chromophore arrangement due to introduction of a 4-(methyl)phenyl substituent into the imidazole ring at the H1-position, imposing an increase in the dihedral angle between the pyrene and {ReCl(CO)3(imphen)} chromophores. The magnitude of the electronic coupling between the pyrene and {ReCl(CO)3(imphen)} chromophores was found to be an efficient tool to tune the photophysical properties of 1 and 2. The usefulness of designed Re(I) compounds as triplet photosensitizers was successfully verified by examination of their abilities for 1O2 generation and triplet-triplet annihilation upconversion. The phosphorescence lifetimes, ∼1800 μs for 1 and ∼1500 μs for 2, are the longest lifetimes reported for Re(I) diimine carbonyl complexes in solution at room temperature.

Correction for ‘Nano-bismuth sulfide based dispersive micro-solid phase extraction combined with energy dispersive X-ray fluorescence spectrometry for determination of mercury ions in waters’ by Katarzyna Pytlakowska et al., J. Anal. At. Spectrom., 2021, 36, 786–795, DOI: 10.1039/D0JA00477D.

The results of magnetic and electrical measurements of ZnCr2S4 - nanoparticles (NPs) synthesized by mechanical alloying method showed an almost ideal paramagnetic state with the weak ferromagnetic short-range interactions derived from a small positive paramagnetic Curie-Weiss temperature of 0 = 0.9 K and the presence of magnetic NPs confirmed by the significantly lower value of the effective magnetic moment (mu(eff) = 2.089 mu(B)/f.u.) compared to the mu(eff) = 5.215 mu(B)/f.u. for bulk spinel as well as ntype semiconducting behavior with an extrinsic region not thermally activated and with an intrinsic region with an activation energy of 0.253 eV. Broadband dielectric spectroscopy measurements showed the relaxation processes only in the intrinsic region of the electrical conductivity, i.e. above 170 K, in which the dipole relaxation becomes faster as temperature rise. These results are interpreted in the framework of the Cole-Cole function and a hopping variable range model including structural defects. (C) 2020 Elsevier B.V. All rights reserved.

Nano-Bi2S3 as a solid sorbent for ultra-sound assisted dispersive micro-solid phase extraction of Hg(ii) ions from surface and sea waters prior to EDXRF determination.

The CuCr2S4 nanoparticles obtained by high-energy ball milling of CuS and Cr2S3 sulphides were about 3.3 nm in size. SEM images showed formation of smaller or larger agglomerates and DFT based ab-initio calculations exhibited metallic ground state with band gap of 0.8 eV width just above (similar to 0.5 eV) the Fermi level and magnetic moments located mostly at Cr sites. Measurements of magnetic susceptibility, magnetic hysteresis, electrical conductivity and thermoelectric power showed antiferromagnetic order with the Neel temperature of 40 K, superparamagnetic-like behaviour with the blocking temperature of 90 K, n-type conductivity, and a metal-insulator transition at 375 K and below this temperature the variable-range hopping in the temperature range of 108 K < T < 256 K. These results are due to the reduction of crystallite sizes to the nanometre scale, which causes narrowing of the 3d t(2g) mixed-valence band of chromium ions.

This is the first comprehensive study demonstrating the antiproliferative effect of vanadium complexes bearing 8-hydroxyquinoline (quinH) ligands, including the parent and -CH3 (Me), -NO2, -Cl and -I substituted ligands, on HCT116 and A2780 cancer cell lines. To determine the structure-cytotoxicity relationships seven six-coordinate oxovanadium(v) complexes [VO(OMe)(5,7-(Me)2-quin)2] (1), [VO(OMe)(5,7-Cl2-quin)2] (2), [VO(OMe)(5,7-Cl,I-quin)2] (3), [VO(OMe)(5,7-I2-quin)2] (4), [VO(OMe)(5-NO2-quin)2] (5), [VO(OMe)(5-Cl-quin)2] (6), and [VO(OMe)(quin)2] (7) were investigated. The cytotoxicity of 8-hydroxyquinoline oxovanadium(v) complexes is higher in the A2780 cell line (lower IC50) than that observed for the widely used chemotherapeutic agent, cisplatin, while displaying low cytotoxicity for normal human primary fibroblasts. Substituents introduced into the 8-hydroxyquinoline backbone reduced the antiproliferative effect of the vanadium complexes, and the complexes with the ligand substituted only in the 5 position (5 and 6) were more cytotoxic than those with substituents in the 5,7 positions of the quin backbone (1-4). Depending on the substituent type, the cytotoxicity of 1-4 followed the trend: -Cl > -CH3 > -I. Incubation of A2780 cancer cells with IC50 concentrations of complexes 5, 6 and 7 promoted cellular detachment, possibly through membrane destabilization, and triggered apoptosis and necrosis. ROS production might be responsible for the cell death mechanism observed particularly in the A2780 cells exposed to complexes 5 and 6.

{PtCl[4'-(4-NMe2)-Ph-terpy-kappa N-3]}BPh4 center dot CH3CN (1) was synthesized and its structural, electrochemical and photophysical properties were characterized in comparison to previously described systems of [PtCl(4'-Ph-terpy-kappa N-3)](+)and [PtCl(4'-NMe2-terpy-kappa N-3)](+) to determine again the significance of the appropriate design of substituent in case of luminescence behavior of transition metal complex. The molecular formula of compound was confirmed by. X-ray analysis, elemental analysis, FT-IR and NMR studies. The geometries of ground and excited states of compound were also calculated on the basis of Density Functional Theory (DFT) method. The electrochemical properties were elucidated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The electronic absorption spectra of compound (1) in solutions are similar to those in described previously platinum(II) terpyridine coordination compounds. The photoluminescence properties were studied in various media to rationalize effects on emission properties caused by substituent, solvent polarity, concentration of solution and rigidity of media. The studied compound displays enhancement of photoluminescence properties in comparison to [PtCl(terpy-kappa N-3)](+) system, however its emission life-time in the regard to [PtCl(4'-Ph-terpy-kappa N-3)](+) and [PtCl(4'-NMe2-terpy-kappa N-3)](+) is significantly decreased. This suggest the impeded charge transfer from electron-rich NMe2 group via phenylene bridge to the terpy core due to the unfavorable, inclined geometry of excited state. As a consequence of substituent twisting on the path S-0 -> S-1 -> T-1, the interference of (ILCT)-I-3 and (MLCT)-M-3 excited state is disturbed favouring the non-radiative deactivation process of {PtCl[4'-(4-NMe2)-Ph-terpy-kappa N-3]}BPh4 center dot CH3CN.

Structural, electrical, magnetic, and specific heat measurements were carried out on ZnCr2Se4 single crystal and on nanocrystals obtained from the milling of this single crystal after 1, 3, and 5 h, whose crystallite sizes were 25.2, 2.5, and 2 nm, respectively. For this purpose, the high-energy ball-milling method was used. The above studies showed that all samples have a spinel structure, and are p-type semiconductors with less milling time and n-type with a higher one. In turn, the decrease in crystallite size caused a change in the magnetic order, from antiferromagnetic for bulk material and nanocrystals after 1 and 3 h of milling to spin-glass with the freezing temperature Tf = 20 K for the sample after 5 h of milling. The spin-glass behavior for this sample was derived from a broad peak of dc magnetic susceptibility, a splitting of the zero-field-cooling and field-cooling susceptibilities, and from the shift of Tf towards the higher frequency of the ac susceptibility curves. A spectacular result for this sample is also the lack of a peak on the specific heat curve, suggesting a disappearance of the structural transition that is observed for the bulk single crystal.

Graphene and graphene-based materials have gained the greatest interest for sample handling in analytical chemistry. Graphene is a two-dimensional carbon nanomaterial which possesses sp2-hybridized carbon atoms arranged in a honeycomb pattern. It possesses the very large delocalized π-electron system that plays a dominant role in adsorption of organic compounds by formation of strong π-π stacking interaction. The graphene can be considered a non-polar, hydrophobic adsorbent, which can be applied in reversed solid-phase extraction. In contrast to hydrophobic graphene, graphene oxide (considered a derivative of graphene on the one hand, and precursor for graphene preparation on the other) is highly hydrophilic material and can therefore be applied as an adsorbent in normal solid-phase extraction for preconcentration/separation of organic compounds or metal ions. The excellent absorptive properties make graphene, graphene oxide and their derivatives favored in the analysis of analytes with a wide range of polarity using various preconcentration/separation approaches based on classical solid-phase extraction, solid-phase microextraction or dispersive micro-solid phase extraction including magnetic nanocomposites.

Chalcogenide bulk spinels with general formula CuCr 2 X 4 (X = S, Se, and Te) are ferromagnetic and p-type metallic materials with the thermoelectric figure of merit of 0.15. They can be used to dope or alloy with related semiconducting spinels. Therefore, it is expected that their nanosized crystallites display also unique properties and new potential applications. This paper presents the results of dc and ac magnetic measurements, including the higher harmonics of ac magnetic susceptibility as well as electrical conductivity and thermoelectric power of the CuCr2S4 nanospinels. These studies showed that decreasing the size of crystallites to nanometer scale leads to a dramatic change in their physical properties.

Chalcogenide spinels show a variety of physical properties and are very good candidates for electronic and high-frequency applications. We report the measurements of magnetic susceptibility, magnetic isotherm, electrical conductivity, thermoelectric power and calculations of the superexchange and double-exchange integrals made for singlecrystalline Cu[CrxHfy]Se4 spinels. The results showed a ferromagnetic order of magnetic moments below the Curie temperatures of 390K and, an increase in the splitting of the zero-field cooled and field cooled susceptibilities with increasing Hf-content below the room temperature suggesting a slight spin-frustration and a rapid transition from semiconducting to metallic state at room temperature. A quantitative evaluation of the exchange Hamiltonian showed that the total hopping integral rapidly decreased and the bandwidth of the 3d t2g band due to Cr3+ and Cr4+ ions strongly narrowed from 0.76eV for y = 0 to 0.28eV for y = 0.14. The narrowing of this band appears to be responsible for semiconducting properties of the Hf-doped CuCr2Se4 spinels below the room temperature.

ENWEndNote BIBJabRef, Mendeley RISPapers, Reference Manager, RefWorks, Zotero AMA Malicka J, Kurowska M, Kiszczak-Bochyńska E, Dudzińska M, Malicka E, Tarach J. Preliminary study of Autoimmune Polyglandular Syndrome (APS). Are they solely an endocrinological problem?. Family Medicine & Primary Care Review. 2017;19(3):239-242. doi:10.5114/fmpcr.2017.69284. APA Malicka, J., Kurowska, M., Kiszczak-Bochyńska, E., Dudzińska, M., Malicka, E., & Tarach, J. (2017). Preliminary study of Autoimmune Polyglandular Syndrome (APS). Are they solely an endocrinological problem?. Family Medicine & Primary Care Review, 19(3), 239-242. https://doi.org/10.5114/fmpcr.2017.69284 Chicago Malicka, Joanna Elżbieta, Maria Kurowska, Ewa Kiszczak-Bochyńska, Marta Dudzińska, Ewa Malicka, and Jerzy S. Tarach. 2017. "Preliminary study of Autoimmune Polyglandular Syndrome (APS). Are they solely an endocrinological problem?". Family Medicine & Primary Care Review 19 (3): 239-242. doi:10.5114/fmpcr.2017.69284. Harvard Malicka, J., Kurowska, M., Kiszczak-Bochyńska, E., Dudzińska, M., Malicka, E., and Tarach, J. (2017). Preliminary study of Autoimmune Polyglandular Syndrome (APS). Are they solely an endocrinological problem?. Family Medicine & Primary Care Review, 19(3), pp.239-242. https://doi.org/10.5114/fmpcr.2017.69284 MLA Malicka, Joanna Elżbieta et al. "Preliminary study of Autoimmune Polyglandular Syndrome (APS). Are they solely an endocrinological problem?." Family Medicine & Primary Care Review, vol. 19, no. 3, 2017, pp. 239-242. doi:10.5114/fmpcr.2017.69284. Vancouver Malicka J, Kurowska M, Kiszczak-Bochyńska E, Dudzińska M, Malicka E, Tarach J. Preliminary study of Autoimmune Polyglandular Syndrome (APS). Are they solely an endocrinological problem?. Family Medicine & Primary Care Review. 2017;19(3):239-242. doi:10.5114/fmpcr.2017.69284.

We describe a novel solid phase sorbent that was synthesized by coupling graphene oxide (GO) to ethylenediamine (EDA). This nanomaterial (referred to as GO-EDA) is capable of adsorbing the ions of iron, cobalt, nickel, copper, zinc and lead. The ethylenediamine-modified graphene oxide was characterized by X-ray photoelectron spectroscopy, scanning electron microscopy and Fourier transform infrared spectroscopy. The analytical procedure relies on (a) sorption of metal ions on GO-EDA dispersed in aqueous samples; (b) filtering, and (c) direct submission of the filter paper to energy-dispersive X-ray fluorescence spectrometry. This kind of dispersive micro-solid phase extraction was optimized with respect to pH values, concentration of GO-EDA, contact time, and the effects of interfering ions and humic acid on recovery of determined elements. Under optimized conditions, the recoveries of spiked samples range from 90 to 98 %. The detection limits are 0.07, 0.10, 0.07, 0.08, 0.06 and 0.10 ng mL−1 for Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Pb(II), respectively. The method has a relative standard deviation of <6 %, and its accuracy was verified by analysis of two standard reference materials [LGC6016 (estuarine water) and BCR-610 (groundwater)]. It was successfully applied to the determination of trace amounts of these metal ions in water samples.

Graphene oxide (GO) is a novel material with excellent adsorptive properties. However, the very small particles of GO can cause serious problems is solid-phase extraction (SPE) such as the high pressure in SPE system and the adsorbent loss through pores of frit. These problems can be overcome by covalently binding GO nanosheets to a support. In this paper, GO was covalently bonded to spherical silica by coupling the amino groups of spherical aminosilica and the carboxyl groups of GO (GO@SiO2). The successful immobilization of GO nanosheets on the aminosilica was confirmed by scanning electron microscopy and X-ray photoelectron spectroscopy. The spherical particle covered by GO with crumpled silk wave-like carbon sheets are an ideal sorbent for SPE of metal ions. The wrinkled structure of the coating results in large surface area and a high extractive capacity. The adsorption bath experiment shows that Cu(II) and Pb(II) can be quantitatively adsorbed at pH 5.5 with maximum adsorption capacity of 6.0 and 13.6 mg g(-1), respectively. Such features of GO nanosheets as softness and flexibility allow achieving excellent contact with analyzed solution in flow-rate conditions. In consequence, the metal ions can be quantitatively preconcentrated from high volume of aqueous samples with excellent flow-rate. SPE column is very stable and several adsorption-elution cycles can be performed without any loss of adsorptive properties. The GO@SiO2 was used for analysis of various water samples by flame atomic absorption spectrometry with excellent enrichment factors (200-250) and detection limits (0.084 and 0.27 ng mL(-1) for Cu(II) and Pb(II), respectively).

In the past three years, we have seen intense interest grow in graphene (G) and graphene oxide (GO) as new sorbents in analytical chemistry. This article focuses on the adsorptive properties of G and GO and their application in preconcentrating organic compounds and trace-metal ions, including trace analysis of water, food, biological and environmental samples using chromatography and spectroscopy techniques. Some methods of modification or chemical functionalization of G and GO are also discussed. The article shows that G, GO and their derivatives or composites can be very attractive as sorbents due to their adsorption capacities being much higher than those of any of the currently reported sorbents. (C) 2013 Elsevier Ltd. All rights reserved.