Pharmacological activities of aminoflavones

Aminoflavones belong to a group of flavonoids, compounds commonly found in nature. Their pharmacological and biochemical effects include cytotoxic, antioxidant and antitumor properties. The studies have shown that complexes of aminoflavons with metal ions can be potential drugs and seem to be promising in the treatment of ovarian cancer, breast cancer, lung adenocarcinoma and melanoma. In addition aminoflavones have a lower cytotoxic activity towards healthy cells than another compounds. In the view of their wide pharmacological and biological actions, they seem to have great therapeutic potential

Molecular magnetic materials

The „molecular” term appears more and more often in the materials chemistry. The Nobel Prize in 2016 was awarded to Jean-Pierre Sauvage, Sir J. Fraser Stoddart and Bernard R. Feringa „for the design and synthesis of molecular machines”. Magnetism in molecular scale, also known as molecular nanomagnetism, has been developing intensively since the second half of the last century. This branch of science involves the magnetic properties of coordination compounds of d- and f-electron metals. The paper presents results of the magnetic studies of molecular magnets of copper(II) and dysprosium(III), which have been pursuing in two doctoral thesis. The compounds form trinuclear and triangular molecules. The spin frustration phenomenon observed in the triangular relationship of copper(II) has been described. Since dysprosium(III) ion is characterized by a large magnetic anisotropy, the triangular, trinuclear coordination compound of dysprosium(III) of the formula [Dy3L5HLCl4]∙HL (where HL = 2-methoxyethanol) presents the characteristic properties of molecular magnets (SMMs) behavior. Two values of the energy barier were determined as Ueff/kB = 84,6 K and 31,2 K with the corresponding relaxation times τ0 = 1,82·10-6 s and 5,19·10-5 s. The data are probably attributed to different geometry of the coupled dysprosium ions

Preparation, characterization and X-ray analysis of [Co-2(Cl)(2)tpmc](BF4)(2). Comparative structural analysis with the complexes having analogous geometries and ligands

A novel binuclear Co(II) complex, [Co-2(Cl)(2)tpmc](BF4)(2) (tpmc=N,N,N",N"'-tetrakis(2-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane), was prepared and structurally characterized by X-ray diffraction analysis at low temperature. The complex crystallizes in P2(1)/c space group of the monoclinic crystal system, and its crystals are isomorphic with those Of [Cu-2(Br)(2)tpmc](ClO4)(2) complex. In the crystal structure the complex cations [Co-2(Cl)(2)tpmc](2+) are settled around the inversion centres. Cobalt(II) is exo coordinated with four macrocyclic N atoms, and Cl- supplements the fifth coordination site. Based on the index of trigonality, the coordination polyhedron formed around Co(II) ion is described as distorted trigonal bipyramid. Two metal centres are at a distance of 5.710 angstrom. This is the first Co(II) complex for which X-ray analysis confirmed a chair conformation of tpmc ligand. IR, EPR (X-band) and UV/VIS absorption and reflectance spectra, molar conductivities and magnetic measurements (SQUID) are used to study the investigated complex. A comparative structural analysis with some of the described Co(II) and Cu(II) complexes of analogous geometries and type of pendant azamacrocyclic ligands was also done

X-ray analyses, spectroscopic and magnetic properties of [Cu4(succinato)(tpmc)2](ClO4) 6·2C2H5OH·4H2O and [Cu2(C6H5COO)tpmc](ClO4) 3·0.5CH3OH·0.5H2O complexes

[Cu4(succinato)(tpmc)2](ClO4) 6 · 2H2O (tpmc = N,N′,N″,N‴-tetrakis-(2-pyridylmethyl)-1,4,8,11-tetraa zacyclotetradecane, succinato = dianion of succinic acid) has been prepared and characterized by elemental analysis, UV/vis, IR, EPR (X-band) spectra, conductivity and magnetization measurements (SQUID). Based on a low-temperature measurements (100(2) K), X-ray analyses of the first tetranuclear Cu(II)-tpmc complex, single crystal of which corresponded to the [Cu4(succinato)(tpmc)2](ClO4) 6·2C2H5OH·4H2O (1) and of the previously described [Cu2(C6H5COO)tpmc](ClO4) 3·0.5CH3OH·0.5H2O (2) were also done. The complexes crystallize in triclinic P over(1, ̄) (1) and monoclinic P21/c (2) space groups. The geometry around the first Cu(II) coordination sphere in the tetranuclear complex (1) is almost regular square-based pyramidal, while significant distortion around the other metallic center was observed. The angular structural parameter (τ), which is applicable to five coordinate structures as an index of degree of trigonality, was found to be 0.05 and 0.40, respectively. In the binuclear complex (2) the geometry around the first Cu(II) coordination sphere is regular square-based pyramidal (τ = 0.09), while around the other is distorted trigonal bipyramidal (τ = 0.79). In complexes (1) and (2) the bridging carboxylate groups are coordinated to metallic centres in a syn-anti mode. Weak ferromagnetic interactions are observed between copper(II) ions, connected through syn-anti monocarboxylate bridges (2J = +1.26 and +1.84 cm-1 in complexes (1) and (2), respectively). Additional antiferromagnetic interaction through succinato anion (zJ′ = -1.57 cm-1) gives finally rise to antiferromagnetic interactions, observed in magnetic measurements in tetrameric complex (1)

Magnetic, electrochemical and antimicrobial properties of some Cu(II) complexes with TPMC

Three complexes: [Cu-2(C6H5COO)tpmc](ClO4)(3)center dot CH3OH, (A), (tpmc = N,N',N'',N''' tetrakis(2-pyridilmethyl)-1,4,8,11-tetraazacyclotetradecane), [Cu-2(Hpht)tpmc](ClO4)(3)center dot 3H(2)O (H(2)pht = phtalic acid) (B) and [Cu-4(ipht)(tpmc)(2)](ClO4)(6)center dot NaClO(4)center dot 2CH(3)CN(H(2)ipht = isophtalic acid) (C) previously described were investigated by magnetic measurements, cyclic voltammetry (CV) and were tested towards some strains of microorganisms. It is found that all three complexes were electrochemically stable in the investigated ranges. The least stable was mu-ipht-complex (C) due to the reaction of central ion, which is seen from weak peaks in its cyclic voltammogram. Complexes were characterized by variable temperature magnetic measurements (4.2-300 K) and the observed data were successfully simulated by the equation based on the spin Hamiltonian operator, (H) over cap = -2J (S) over cap (1)(S) over cap (2), giving the ferromagnetic exchange parameters J = 0.92 cm(-1) for A, J = 0.55 cm(-1) for B and J = 0.65 cm(-1) for C. For the complex C model of molecular magnet with two magnetically isolated dimeric subunits was used. These results indicate the presence of weak ferromagnetic spin exchange interaction between the Cu-II magnetic centers within each molecule

Magnetic, electrochemical and antimicrobial properties of some Cu(II) complexes with TPMC

Three complexes: [Cu-2(C6H5COO)tpmc](ClO4)(3)center dot CH3OH, (A), (tpmc = N,N',N'',N''' tetrakis(2-pyridilmethyl)-1,4,8,11-tetraazacyclotetradecane), [Cu-2(Hpht)tpmc](ClO4)(3)center dot 3H(2)O (H(2)pht = phtalic acid) (B) and [Cu-4(ipht)(tpmc)(2)](ClO4)(6)center dot NaClO(4)center dot 2CH(3)CN(H(2)ipht = isophtalic acid) (C) previously described were investigated by magnetic measurements, cyclic voltammetry (CV) and were tested towards some strains of microorganisms. It is found that all three complexes were electrochemically stable in the investigated ranges. The least stable was mu-ipht-complex (C) due to the reaction of central ion, which is seen from weak peaks in its cyclic voltammogram. Complexes were characterized by variable temperature magnetic measurements (4.2-300 K) and the observed data were successfully simulated by the equation based on the spin Hamiltonian operator, (H) over cap = -2J (S) over cap (1)(S) over cap (2), giving the ferromagnetic exchange parameters J = 0.92 cm(-1) for A, J = 0.55 cm(-1) for B and J = 0.65 cm(-1) for C. For the complex C model of molecular magnet with two magnetically isolated dimeric subunits was used. These results indicate the presence of weak ferromagnetic spin exchange interaction between the Cu-II magnetic centers within each molecule

The effect of the outer-sphere cations on the photophysical and magnetic properties of rare earth complexes with 2,2,2-trichloro-N-(diphenylphosphoryl)acetamide

Two series of rare earth coordination compounds have been synthesized (Na[RE(L4)] (labeled as 1RE) and PPh4[RE(L4)] (labeled as 2RE), where RE = Y3+, Eu3+, Tb3+, L = 2,2,2-trichloro-N-(diphenylphosphoryl)acetamide) to determine the possibility of modifying their photophysical and magnetical properties by changing the counterion. The crystal structure of 1RE was determined based on the single-crystal X-ray diffraction and the crystal structure of 2RE was determined based on quantum chemistry computational procedures. Characterization of the physicochemical properties of the compounds was carried out using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), 1H and 31P NMR spectroscopy as well as FT-IR, absorption and luminescence spectroscopy in the temperature range of 300 - 77 K. The rate constants of radiative (Arad) and non-radiative (Anrad) transitions, intrinsic (QLnLn) and overall (QLnL) emission quantum yields, sensitization efficiency (ηsens), the experimental and theoretical intensity parameters (Ωλ), the forward (WS, WT) and backward (WbS, WbT) intramolecular energy transfer (IET) rates were determined. Magnetic properties of Tb3+ compounds were studied in a constant field of 0.5 T in the temperature range of 1.8–300 K. Dynamic AC magnetic susceptibility measurements were carried out as a function of temperature and frequency for 1Tb and 2Tb. Only in the case of 2Tb, in the presence of an external DC field, a slight temperature dependence of in-phase χ′ and out-of-phase χ'' susceptibility was recorded. Based on experimental and theoretical results, the significant effect of counterion on the photophysical and magnetic properties of RE chelates has been demonstrated and clarified, providing valuable guidance for the design of bifunctional electromagnetic radiation converters