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The ruthenium(II) compounds cis-[Ru(bpy)2(4-bzpy)(CO)](PF6)2 (I) and cis-[Ru(bpy)2(4-bzpy)(Cl)](PF6) (II) (4-bzpy=4-benzoylpyridine, bpy=2,2'-bipyridine) were synthesized and characterized by spectroscopic and electrochemical techniques. The crystal structure of II was determined by X-ray diffraction. The photochemical behavior of I in aqueous solution shows that irradiation with ultraviolet light (365nm) releases both CO and 4-bzpy leading to the formation of the cis-[Ru(bpy)2(H2O)2]2+ ion as identified by NMR and electronic spectroscopy. Carbon monoxide release was confirmed with the myoglobin method and by gas chromatographic analysis of the headspace. CO release was not observed when aqueous I was irradiated with blue light (453nm). Changes in the electronic and 1H NMR spectra indicate that I undergoes photoaquation of 4-bzpy to form cis-[Ru(bpy)2(CO)(H2O)]2+. Blue light irradiation of aqueous II released the coordinated 4-bzpy to give the cis-[Ru(bpy)2(H2O)(Cl)]2+ ion. When the latter reaction was carried out in the presence of the nucleobase guanine, Ru-guanine adducts were formed, indicating that the metal containing photoproduct may also participate in biologically relevant reactions. The photochemical behavior of I indicates that it can release either CO or 4-bzpy depending on the wavelength chosen, a feature that may have therapeutic application.

The synthesis and structural characterization of three families of coordination complexes synthesized from 4′‐phenyl‐2,2′:6′,2′′‐terpyridine (8, Ph‐TPY), 4′‐(4‐chlorophenyl)‐2,2′:6′,2′′‐terpyridine (9, ClPh‐TPY) and 4′‐(4‐methoxyphenyl)‐2,2′:6′,2′′‐terpyridine (10, MeOPh‐TPY) ligands with the divalent metals Co2+, Fe2+, Mn2+ and Ni2+ are reported. The compounds were synthesized from a 1:2 mixture of the metal and ligand, resulting in a series of complexes with the general formula [M(R‐TPY)2](ClO4)2 (where M = Co2+, Fe2+, Mn2+ and Ni2+, and R‐TPY = Ph‐TPY, ClPh‐TPY and MeOPh‐TPY). The general formula and structural and supramolecular features were determinated by single‐crystal X‐ray diffraction for bis(4′‐phenyl‐2,2′:6′,2′′‐terpyridine)nickel(II) bis(perchlorate), [Ni(C21H15N3)2](ClO4)2 or [Ni(Ph‐TPY)2](ClO4)2, bis[4′‐(4‐methoxyphenyl)‐2,2′:6′,2′′‐terpyridine]manganese(II) bis(perchlorate), [Mn(C22H17N3O)2](ClO4)2 or [Mn(MeOPh‐TPY)2](ClO4)2, and bis(4′‐phenyl‐2,2′:6′,2′′‐terpyridine)manganese(II) bis(perchlorate), [Mn(C21H15N3)2](ClO4)2 or [Mn(Ph‐TPY)2](ClO4)2. In all three cases, the complexes present distorted octahedral coordination polyhedra and the crystal packing is determined mainly by weak C—H...π interactions. All the compounds (except for the Ni derivatives, for which FT–IR, UV–Vis and thermal analysis are reported) were fully characterized by spectroscopic (FT–IR, UV–Vis and NMR spectroscopy) and thermal (TGA–DSC, thermogravimetric analysis–differential scanning calorimetry) methods. [ABSTRACT FROM AUTHOR]

The water‐soluble compound [Ru3O(CH3COO)6(4‐ampy)3]Cl (1, 4‐ampy=4‐aminopyridine) was evaluated in terms of its biologically relevant properties. Compound 1 participates in a hydrogen bonding network which includes the NH2 substituents of the ancillary ligands, methanol molecules, the Cl− counter‐ion, and a non‐conventional hydrogen bond with the neighboring 4‐ampy molecules′ π‐cloud, as determined by X‐ray measurements. One protonation equilibrium was observed at pH values below 2.3. Additionally, the compound exhibited a partition coefficient value of −0.86 (±0.07), indicating that it is highly hydrophilic. At 37 0C and pH=7.4 (phosphate buffer), compound 1 shows moderate (Ksv=2.4 104 M−1) and spontaneous (ΔG=−26.4 kJ mol−1) binding to human serum albumin (HSA) through ground‐state association, which involves formation of hydrogen bonds (ΔH=−35.7 kJ mol−1 and, ΔS=−29.8 J mol−1 K−1). Molecular docking calculations support the formation of hydrogen bonds between 1 and HSA, and suggest subdomain IIA (site I), which contains the Trp‐214 residue, as the primary interactive pocket, in agreement with the experimental static fluorescence quenching mechanism. Furthermore, a preliminary assay reveals that 1 has low cytotoxicity towards human glioblastoma U87‐MG cells. [ABSTRACT FROM AUTHOR]

The chemical reaction of 4-bromo-benzoyl-chloride and 2-amino-thia-zole in the presence of potassium thio-cyanate yielded a white solid formulated as C15H10BrN3OS2, which consists of 4-bromo-benzamido and 2-benzo-thia-zolyl moieties connected by a thio-urea group. The 4-bromo-benzamido and 2-benzo-thia-zolyl moieties are in a trans conformtion (sometimes also called s-trans due to the single bond) with respect to the N-C bond. The dihedral angle between the mean planes of the 4-bromo-phenyl and the 2-benzo-thia-zolyl units is 10.45 (11)°. The thio-urea moiety, -C-NH-C(=S) -NH- fragment forms a dihedral angle of 8.64 (12)° with the 4-bromo-phenyl ring and is almost coplanar with the 2-benzo-thia-zolyl moiety, with a dihedral angle of 1.94 (11)°. The mol-ecular structure is stabilized by intra-molecular N-H⋯O hydrogen bonds, resulting in the formation of an S(6) ring. In the crystal, pairs of adjacent mol-ecules inter-act via inter-molecular hydrogen bonds of type C-H⋯N, C-H⋯S and N-H⋯S, resulting in mol-ecular layers parallel to the ac plane. [ABSTRACT FROM AUTHOR]

Lapachol (lap) is widely studied due to its biological application, as well as its importance in the coordination chemistry field. The structure of cis and trans isomers of new ruthenium(III) complex [RuCl2(PPh3)2(lap)] is reported here. The complexes present one molecule of the natural product lapachol, coordinated as bidentate by oxygen atoms, two monodentate triphenylphosphines and two chlorido ligands in a cis or trans configurations. All neutral complexes were characterized by single-crystal X-ray diffraction and these data were compared with Density Functional Theory (DFT) data results. This study highlights the stereochemistry and structural versatility of metal complexes containing lapachol as ligand. [ABSTRACT FROM AUTHOR]

A three-dimensional terbium(III) coordination polymer of formula [Tb(bttb)0.5(2,5-pzdc)0.5]n (1) [H4bttb = 1,2,4,5-tetrakis(4′-carboxyphenyl)benzene and H2-2,5-pzdc = 2,5-pyrazinedicarboxylic acid] was obtained under hydrothermal conditions. The bttb4− tetraanion in 1 adopts the bridging and chelating–bridging pseudo-oxo coordination modes while the 2,5-pzdc2− dianion exhibits a rather unusual bis-bidentate bridging pseudo-oxo coordination mode, both ligands being responsible for the stiffness of the resulting 3D structure. Solid-state photoluminescent measurements illustrate that 1 exhibits remarkable green luminescence emission, the most intense band occurring in the region of 550 nm (5D4 → 7F5) with lifetimes at the millisecond scale. Thermometric performances of 1 reveal a maximum relative sensitivity (Sm) of 0.76% K−1 at 295 K (δT = 0.05 K), constituting a TbIII ratiometric solid luminescent thermometer over the physiological temperature range. Variable-temperature static (dc) magnetic susceptibility measurements for 1 in the temperature range 2.0–300 K show the expected behavior for the depopulation of the splitted mJ levels of the 7F7 ground state of the magnetically anisotropic terbium(III) ion plus a weak antiferromagnetic interaction through the carboxylate bridges. No significant out-of-phase magnetic susceptibility signals were observed for 1 in the temperature range 2.0–10.0 K, either in the absence or presence of a static dc magnetic field. [ABSTRACT FROM AUTHOR]

This study addressed the formation of co‐crystals from Quercetin and Curcumin by mechanochemical treatment employing ball mill grinding. The binary system was initially studied using molecular complementarity and hydrogen bond propensity analysis structural tools available in Mercury software. This study was performed from CCDC reported structural data for Curcumin and Quercetin dihydrate used as starting reagents. Reaction conditions, such as Quercetin: Curcumin molar ratio, grinding time, and solvent‐assisted variables, were optimised to synthesise a new solid phase from the binary system. The synthesised product was characterised by differential scanning calorimetry, thermogravimetric analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, and powder X‐ray diffraction techniques. Finally, to compare the anti‐oxidant capacities from the pure components, eutectic mixtures previously reported and the new crystalline phase was evaluated in vitro using the 1,1‐diphenyl‐2‐pycril‐hydrazylhydrate radical inhibition method. The co‐crystal phase and eutectic mixtures present higher anti‐oxidant activity with values around 5.0 mg/L compared to pure Quercetin (3,444 mg/L) and Curcumin (9,141 mg/L), using only half of the molecules. These results indicate Quercetin molecule is synergically active with the Curcumin molecule in the binary mixtures. [ABSTRACT FROM AUTHOR]