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An oxalate complex of vanadyl(IV) (Bu4N)2[VO(C2O4)2] (I) was synthesized and used as a vanadium precursor. The synthesis and characterization of the double complex salts [Pt(NH3)4][VO(H2O)(C2O4)2]·2H2O (III) and {[Pt(NH3)4][VO(C2O4)2]}n (IV) were carried out. The complexes obtained were characterized by IR and diffuse reflectance spectroscopy, single-crystal and powder X-ray diffraction, and EPR. The magnetic properties of I, III, and IV were also studied. The process of thermal decomposition of the synthesized complexes in reducing and inert atmospheres was studied, and the composition of the released gases was determined. Thermal decomposition of the salts in a hydrogen atmosphere at 600 °C resulted in the formation of a bimetallic solid solution, Pt0.6V0.4. [ABSTRACT FROM AUTHOR]

The synthetic approaches for the preparation of trans(NO,OH)-cis(NO2,NO2)-[RuNO(L)2(NO2)2OH], where L = ethyl nicotinate (I) and methyl nicotinate (II), are reported. The structures of the complexes are characterized by X-ray diffraction and analyzed by Hirshfeld surface analysis. Both compounds show a nitric oxide release reaction under 445 or 532 nm irradiation of dimethyl sulfoxide (DMSO) solutions, which is studied by combined ultraviolet-visible- (UV-vis), infrared- (IR), and electron paramagnetic resonance (EPR) spectroscopy and density functional theory (DFT) calculations. The charge transfer from the OH–Ru–NO chain and nitrite ligands to the antibonding orbitals of Ru–NO is responsible for the photo-cleavage of the ruthenium–nitrosyl bond. The elimination of NO leads to a side reaction, namely the protonation of the parent hydroxyl compound. The cytotoxicity and photo-induced cytotoxicity investigations of both compounds on the breast adenocarcinoma cell line MCF-7 reveal that (I) and (II) are cytotoxic with IC50 values of 27.5 ± 2.8 μM and 23.3 ± 0.3 μM, respectively. Moreover, (I) shows an increase of the toxicity after light irradiation by 7 times (IC50 = 4.1 ± 0.1), which makes it a prominent target for deeper biological investigations. [ABSTRACT FROM AUTHOR]

Reaction of Cp2TiCl2 (Cp = η5-C5H5) with sodium 3,6-di-tert-butylcatecholate (Na2Cat36) leads to mononuclear complex [Cp2TiCat36], while the isomeric sodium 3,5-di-tert-butylcatecholate (Na2Cat35) gives the mixed-valence binuclear complex [Cp2Ti(μ-Cat35)2TiCp]. The latter was characterized by EPR spectroscopy and magnetic susceptibility measurements, and shown to be a Ti-centred radical. DFT calculations confirm that the unpaired electron is located on the Ti atom from the TiCp2 fragment. [ABSTRACT FROM AUTHOR]

The photolysis products of the [Rh(NH3)5(NO2)](NO3)2 complex in aqueous solutions were studied by electron paramagnetic resonance (EPR), UV-visible (UV-vis), and 15N nuclear magnetic resonance (15N NMR) spectroscopies. Aqueous solutions of [Rh(NH3)5(NO2)](NO3)2 became blue when exposed to UV irradiation under an oxygen-containing atmosphere while aqueous solutions of [Rh(NH3)5(NO2)](NO3)2 with additives of NaNO2 turned orange under the same conditions. Photolysis of degassed [Rh(NH3)5(NO2)](NO3)2 solutions did not lead to any change of their color. It was suggested that, as a result of the photolysis, the complex decomposed with the formation of a NO2 fragment and a fragment containing Rh(ii). In the presence of molecular oxygen in solution, a superoxide complex, [Rh(NH3)5O2]2+, was formed, in which electron transfer from the metal ion to O2 took place. [ABSTRACT FROM AUTHOR]

Paramagnetic cuboidal cluster [W3(GaBr)0.81(μ3-S)4(dppe)3Br3] was synthesized by treatment of the electron precise [W3(μ3-S)(μ-S)3(dppe)3Br3]Br with [Ga(η5-C5Me5)]6 and studied by EPR spectroscopy and magnetic measurements. [ABSTRACT FROM AUTHOR]

A mononuclear manganese(ii) complex with a chelating 4-(3,5-diphenyl-1H-pyrazol-1-yl)-6-(piperidin-1-yl)pyrimidine ligand (L), [MnL2Cl2]·H2O, shows intriguing excitation wavelength-dependent emission. Depending on the excitation wavelength, the complex demonstrates three emission bands with the maxima at 380 nm, 440 nm and 495 nm. The 380 nm and 440 nm emissions originate from the π→π* and n →π* ligand-centered transitions. The long-wave 495 nm emission with microsecond lifetimes is related to the d–d transitions and/or metal-to-ligand and halogen-to-ligand charge transfer. The emission behavior of this complex is strongly temperature-dependent: upon cooling from 300 K down to 77 K, the intensity of emission considerably increases. The enhancement of the luminescence upon cooling is accompanied by the appearance of the vibrational structure. This complex is the first example of manganese(ii) complexes demonstrating excitation wavelength-dependent emission. [ABSTRACT FROM AUTHOR]

We report the direct facile high-temperature synthesis and investigation of heterometallic rhenium–molybdenum cluster K6[Re3Mo3S8(CN)4(CN)2/2] (1) with a new {Re3Mo3S8} core. Dissolution of polymeric compound 1 resulted in subsequent oxidation and formation of stable 23e paramagnetic anionic cluster complex [Re3Mo3S8(CN)6]6−. [ABSTRACT FROM AUTHOR]

The synthetic approaches for the preparation of trans (NO,OH)- cis (NO 2 ,NO 2 )-[RuNO(L) 2 (NO 2 ) 2 OH], where L = ethyl nicotinate (I) and methyl nicotinate (II), are reported. The structures of the complexes are characterized by X-ray diffraction and analyzed by Hirshfeld surface analysis. Both compounds show a nitric oxide release reaction under 445 or 532 nm irradiation of dimethyl sulfoxide (DMSO) solutions, which is studied by combined ultraviolet-visible- (UV-vis), infrared- (IR), and electron paramagnetic resonance (EPR) spectroscopy and density functional theory (DFT) calculations. The charge transfer from the OH-Ru-NO chain and nitrite ligands to the antibonding orbitals of Ru-NO is responsible for the photo-cleavage of the ruthenium-nitrosyl bond. The elimination of NO leads to a side reaction, namely the protonation of the parent hydroxyl compound. The cytotoxicity and photo-induced cytotoxicity investigations of both compounds on the breast adenocarcinoma cell line MCF-7 reveal that (I) and (II) are cytotoxic with IC 50 values of 27.5 ± 2.8 μM and 23.3 ± 0.3 μM, respectively. Moreover, (I) shows an increase of the toxicity after light irradiation by 7 times (IC 50 = 4.1 ± 0.1), which makes it a prominent target for deeper biological investigations.

A mononuclear manganese(ii) complex with a chelating 4-(3,5-diphenyl-1H-pyrazol-1-yl)-6-(piperidin-1-yl)pyrimidine ligand (L), [MnL 2 Cl 2 ]·H 2 O, shows intriguing excitation wavelength-dependent emission. Depending on the excitation wavelength, the complex demonstrates three emission bands with the maxima at 380 nm, 440 nm and 495 nm. The 380 nm and 440 nm emissions originate from the π → π* and n → π* ligand-centered transitions. The long-wave 495 nm emission with microsecond lifetimes is related to the d-d transitions and/or metal-to-ligand and halogen-to-ligand charge transfer. The emission behavior of this complex is strongly temperature-dependent: upon cooling from 300 K down to 77 K, the intensity of emission considerably increases. The enhancement of the luminescence upon cooling is accompanied by the appearance of the vibrational structure. This complex is the first example of manganese(ii) complexes demonstrating excitation wavelength-dependent emission.

We report the direct facile high-temperature synthesis and investigation of heterometallic rhenium-molybdenum cluster K6[Re3Mo3S8(CN)4(CN)2/2] (1) with a new {Re3Mo3S8} core. Dissolution of polymeric compound 1 resulted in subsequent oxidation and formation of stable 23e paramagnetic anionic cluster complex [Re3Mo3S8(CN)6](6-).