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The unilateral 6-hydroxydopamine (6-OHDA) model of Parkinson's disease (PD) is one of the most commonly used in rodents. The anatomical, metabolic, and behavioral changes that occur after severe and stable 6-OHDA lesions have been extensively studied. Here, we investigated whether early motor behavioral deficits can be observed in the first week after the injection of 6-OHDA into the right substantia nigra pars compacta (SNc), and if they were indicative of the severity of the dopaminergic (DAergic) lesion in the SNc and the striatum at different time-points (day 1, 3, 5, 7, 14, 21). With this aim, we used our newly modified tail suspension swing test (TSST), the standard rotation test (RT), and immunohistochemical staining for tyrosine hydroxylase (TH). The TSST, but not the standard RT, revealed a spontaneous motor bias for the 6-OHDA-lesioned rats from the day 1 post-surgery. Both tests detected the motor asymmetry induced by (single and repeated) apomorphine (APO) challenges that correlated, in the first week, with the DAergic neuronal degeneration. The described TSST is fast and easy to perform, and in the drug-free condition is useful for the functional assessment of early motor asymmetry appearing after the 6-OHDA-lesion in the SNc, without the confounding effect of APO challenges., peer-reviewed

The behavior toward oxygen sensing of nano- composites made of the aluminum oxide-hydroxide nano- structured solid support (AP200/19) and neutral blue emitting cyclometalated iridium(III) complexes was studied. The results are compared with the same dyes immobilized in polystyrene films. Since the photoluminescence of the complexes is totally quenched for oxygen concentrations just over 10%, these systems using the blue region of the visible spectrum are promising for oxygen detection at low concentration. In particular, dyes supported into the AP200/19 provide the best sensitivity to oxygen concentration, with the possibility to detect oxygen below 1% O2 in gas (0.01 bar).

New charged cyclometalated iridium(III) complexes [Ir(ppy)2(L)](PF6) [ppy = 2-phenylpyridine; L = bis(pyrazol-1-yl)methane (for 1); L = bis(3,5-dimethylpyrazol-1-yl)methane (for 2)] were synthesized and their electrochemical and photophysical properties studied. These complexes with non-p-electron-conjugated ancillary chelates exhibit significantly blueshifted emission relative to those of commonly used derivatives with NN ancillary ligands such as bipyridine or phenanthroline. Both X-ray and theoretical analysis based on time-dependent density functional theory (TD-DFT) reveal that the binding of Ir to the bis(pyrazol-1-yl)methane ancillary ligand is much weaker than that to the phenylpyridine main ligand; the effect is enhanced in the excited state. As a result, the ancillary ligand does not participate in low-energy excitations and triplet emission, and the electronic transitions are concentrated on the main chromophoric ligands. The blueshift feature is attributed to emission originating from the main cyclometalated ligands, in contrast to emitters with the NN chromophoric ancillary ligand. In addition, complex 2 exhibits a one order of magnitude higher non-radiative decay rate than complex 1, which is attributed to the steric hindrance of the methyl groups that leads to a more loosely bound ancillary ligand.

Herein we report a series of charged iridium complexes emitting from near-UV to red using carbene-based N^C: ancillary ligands. Synthesis, photophysical and electrochemical properties of this series are described in detail together with X-ray crystal structures. Density Functional Theory calculations show that the emission originates from the cyclometallated main ligand, in contrast to commonly designed charged complexes using bidentate N^N ancillary ligands, where the emission originates from the ancillary N^N ligand. The radiative process of this series of compounds is characterized by relatively low photoluminescence quantum yields in solution that is ascribed to non-radiative deactivation of the excited state by thermally accessible metal-centered states. Despite the poor photophysical properties of this series of complexes in solution, electroluminescent emission from the bluish-green to orange region of the visible spectrum is obtained when they are used as active compounds in light-emitting electrochemical cells.

The colorimetric, fluorimetric, and electrochemical detection of mercury ions by functionalized ruthenium sensitizers in aqueous and non-aqueous solutions and on anchored TiO2 films are investigated. Mercury ions coordinate reversibly to the ruthenium sensitizers, inducing a color change and increasing the phosphorescence intensity significantly. The electrochemical data of the adsorbed sensitizer on TiO2 films show a reversible couple, owing to the percolation through electronic couplings between –NCS ligands of neighboring molecules; upon exposure to a Hg2+-containing solution, the electrical signal is appreciably reduced. The detection limit for mercury(II) ions using UV-vis spectroscopy in homogeneous aqueous solutions is estimated to be ∼ 20 ppb. The results presented herein have important implications in the development of reversible colorimetric, fluorimetric, and electrochemical on–off sensors based on nanocrystalline semiconductor films for the simple, swift, and selective detection of mercury ions in solution.

The use of LiN(SO2CF3)2 as salt in lithium-ion secondary cells was considered to be a promising alternative to LiPF6 salt. However, in practice this salt has never been used in rechargeable batteries due to the severe corrosion it causes to the aluminium current collector. The spinel Li4Ti5O12 has been a focus of attention for the major battery manufacturers as an alternative material for anodes instead of graphite; for cells employing this material, new electrolyte compositions can be considered which solve the corrosion problem and allow the use of imide-type salts. This work reports electrochemical studies characterizing the corrosion of aluminium electrodes polarized at high voltages in aprotic solvents containing LiSO3CF3 (LiTf) or LiN(SO2CF3)2 (LiTFSI) or LiN(SO2C2F5)2 (LiBETI) salts. Despite the observation that in common battery solvents LiTFSI causes severe corrosion of the aluminium current collector at potential around 3.7 V (vs. Li), solvents having a cyano-group showed a repassivation potential (ER) around 4.15 V (vs. Li). Based on the experimental observations made and previous literature reports, a mechanism to explain the inhibiting properties of nitriles is proposed. The nitrile-based electrolytes allow the final usage of LiTFSI in commercial batteries using LiCO2 as cathodic material on aluminium current collectors. Keywords: Aluminium corrosion, Corrosion inhibition, Imide salts, LiTFSI, Nitriles, Li-ion batteries

The recently reported heteroleptic cyclometallated iridium(III) complex [Ir(2-phenylpyridine)(2)(2-carboxy-4-dimethylaminopyridine)] N984 and its isomer N984b have been studied more in detail. While photo- and electrochemical properties are very similar, DFT/TDDFT calculations show that the two isomers have different HOMO orbital characteristics. As a consequence, solution processed OLEDs made using a mixture of N984 and isomer N984b similar to vacuum processed devices show that the isomer has a dramatic detrimental effect on the performances of the device. In addition, commonly used thermogravimetric analysis is not suitable for showing the isomerization process. The isomer could impact performances of vacuum processed OLEDs using heteroleptic cyclometallated iridium(III) complexes as dopant.

A novel ligand 4,4'-bis(carboxyvinyl)-2,2'-bipyridine (L) and its ruthenium(II) complex [Ru(II)L(2)(NCS)(2)] (K8) were synthesized and characterized by analytical, spectroscopic, and electrochemical techniques. The performance of the K8 complex as a charge transfer photosensitizer in nanocrystalline TiO(2) based solar cells was studied. When the K8 complex anchored onto a nanocrystalline TiO(2) film, we achieved very efficient sensitization yielding 77 +/-5% incident photon-to-current efficiencies (IPCE) in the visible region using an electrolyte consisting of 0.6 M methyl-N-butyl imidiazolium iodide, 0.05 M iodine, 0.05 M LiI, and 0.5 M 4-tert-butylpyridine in a 50/50 (v/v) mixture of valeronitrile and acetonitrile. Under standard AM 1.5 sunlight, the complex K8 gave a short circuit photocurrent density of 18 +/- 0.5 mA/cm(2), and the open circuit voltage was 640 +/- 50 mV with fill factor of 0.75 +/- 0.05, corresponding to an overall conversion efficiency of 8.64 +/- 0.5%.

Highly phosphorescent blue-light-emitting anionic iridium complexes (C4H9)(4)N[lr(2-phenylpyridine)(2)(CN)(2) (1), (C4H9)(4)N[Ir(2-phenyl-4-dimethylaminopyridine)(2)(CN)(2)] (2), (C4H9)(4)N[Ir(2-(2,4-difluorophenyl)-pyridine)2(CN)(2)] (3), (C4H9)(4)N[Ir(2-(2,4-difluorophenyl)-4-dimethylaminopyddine)2(CN)(2)] (4), and (C4H9)4N[lr(2-(3,5-difluorophenyl)-4-dimethylaminopyddine)2(CN)21 (5) were synthesized and characterized using NMR, UV-vis absorption, and emission spectroscopy and electrochemical methods. In these complexes color and quantum yield tuning aspects are demonstrated by modulating the ligands with substituting donor and acceptor groups on both the pyridine and phenyl moieties of 2-phenylpyridine. Complexes 1-5 display intense photoluminescence maxima in the blue region of the visible spectrum and exhibit very high phosphorescence quantum yields, in the range of 50-80%, with excited-state lifetimes of 1-4 mu s in acetonitrile solution at 298 K. DFT and time dependent-DFT calculations were performed on the ground and excited states of the investigated complexes to provide insight into the structural, electronic, and optical properties of these systems.