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This article aims to discuss the possible use of other indicators of external vulnerability in addition to traditional ones, showing indications of financial fragility in the international insertion of the economies of emerging countries, specifically the so-called BRICS. The analysis presented for the BRICS (Brazil, Russia, India, China and South Africa) was limited to identifying foreign currency flows, leading to an analysis that can lead to conclusions regarding the greater or lesser degree of exposure of these economies to fluctuation in financing flows. In principle, if the accumulation of reserves is originated using third-party resources, in addition to representing a cost (particularly for countries with much higher domestic than foreign interest rates), their ability to maintain that liquidity inventory is not equal for all BRICS countries. As seen under this aspect, China and Russia seem to have greater autonomy in managing their reserves than the BIS (Brazil, India, and South Africa) countries.

The triply chloro-bridged binuclear complexes [Ph3X=O···H···O=XPh3][Ru2Cl7(XPh3)2]·0.5(CH2Cl2)(H2O) (X = As or P) were obtained from [RuCl3(XPh3)2DMA]·DMA (DMA = dimethylacetamide) CH2Cl2/Et2O solution. The structures were characterized by X-ray diffraction studies. The complexes are formed from two Ru atoms bridged by three chloride anions. The two ruthenium atoms are also coordinated to two non-bridging Cl atoms and an AsPh3or PPh3ligand respectively. As an interesting feature, the cations of these complexes are protons, trapped in a very short hydrogen bond between two triphenylarsine or triphenylphosphine oxide molecules.

The triply halide-bridged binuclear complexes [Ru2Cl5(CO)(AsPh3)3] (AsPh3 = triphenylarsine), [Ru2Cl5(CO)(PPh3)2(AsPh3)] (PPh3 = triphenylphosphine), [Ru2Cl5(CO)(AsPh3)2(PPh3)], [Ru2 Br5(CO)(PPh3)3], [Ru2Cl5(CO)(P{p-tol}3)2(PPh3)] (P{p-tol}3 = tri-p-tolylphosphine) and [Ru2 Br2Cl3(PPh3)2(AsPh3)] were prepared from the precursor compounds ttt-[RuX2(CO)2(P)2] (X = Cl or Br) and [RuY3(P')2S]·S (Y = Cl or Br; P=PPh3, AsPh3 or P{p- tol}3 and P' = AsPh3 or PPh3; S=DMA or MeOH, where DMA = N,N'-dimethylacetamide). The molecular structures of the binuclear complexes [Ru2Cl5(CO)(AsPh3)3] (P21/c), [Ru2Br5(CO)(PPh3)3] (P21/c) and ttt-[RuCl2(CO)2(PPh3)2] (P1) were determined by X-ray diffraction methods. The complexes are always formed by two Ru atoms bridged through three halide anions, two of which are × type (from the RuII precursor) and the other is Y type (from the rutheniumIII precursor) confirming our previously suggested mechanism for obtaining this class of complexes. The RuII atom is also coordinated to a carbon monoxide molecule and two P ligands from the ttt-starting isomer whereas the RuIII atom is bonded to two non-bridging Y halides and one P' molecule. The presence of RuIII was confirmed by EPR data, a technique that was also useful to suggest the symmetry of the complexes. The absence of intervalence charge-transfer transitions (IT) in the near infrared spectrum confirms that the binuclear complexes have localized valence. The IR spectra of the complexes show; (CO) bands close to 1970 cm-1 and ν(Ru-Cl) or(Ru-Br) bands at about 230-380 cm-1 corresponding to halides at terminal or bridged positions. Two widely separated redox processes, RuII/RuII←RuII/RuIII→RuIII/RuIII, were observed by cyclic voltammetry and differential pulse voltammetry.

An arene-ruthenium (II) complex - [Ru(η6-p-cymene)(ampy)Cl]PF6, where ampy is 2-(aminomethyl)pyridine - was synthesized and used in the construction of a modified carbon ceramic electrode (Ru-CCE) for determining paracetamol (PCT) by square wave voltammetry (SWV). The modified electrode, constructed by sol–gel methods, provides a considerable enhancement of PCT oxidation. Under the optimized working conditions, the peak current is linear to the PCT concentration in the ranges of 1.99 × 10−6–3.10 × 10−5mol L−1with a detection limit of 5.83 × 10−7mol L−1. The Ru-CCE showed good repeatability and reproducibility (RSD < 4%), long-term stability (>12 months). Lastly, the proposed sensor was used for the determination of PCT in pharmaceutical formulations, offering a promising tool for quality control.