Study of Triple System Calcium Iodide-HMTA-Water

Research relevance: synthesis, physicochemical studies of complexes bioactivity with salts of biometals and organic ligands are of great interest for bio-coordination chemistry. Materials and research methods: isothermal method was used to study heterogeneous equilibria at 25 °C. The concentration limits of compounds existence and the types of their solubility have been established. Research objectives: to investigate compounds of hexamethylenetetramine with salts of biometals with organic ligands in order to reduce toxicity, increase the bioactivity and bioavailability of coordination compounds. Research results: concentration limits of compounds existence and types of their solubility have been established. Conclusions: in obtained complexes, HMTA ligand contains four equivalent electron donor nitrogen atoms.

Ultrahard magnetism from mixed-valence dilanthanide complexes with metal-metal bonding

Magnetic effects of lanthanide bonding Lanthanide coordination compounds have attracted attention for their persistent magnetic properties near liquid nitrogen temperature, well above alternative molecular magnets. Gould et al . report that introducing metal-metal bonding can enhance coercivity. Reduction of iodide-bridged terbium or dysprosium dimers resulted in a single electron bond between the metals, which enforced alignment of the other valence electrons. The resultant coercive fields exceeded 14 tesla below 50 and 60 kelvin for the terbium and dysprosium compounds, respectively. —JSY

Changes in micro- and central hemodynamic parameters in rats under the action of acetylsalicylic acid and its coordination compounds with metals

Introduction. The cutaneous blood circulation is a representative model both for studying the mechanisms of vascular diseases and for assessing the current state of the central hemodynamics in preclinical researches of various chemical compounds. Aim. The changes in the parameters of cutaneous microcirculation and central hemodynamics (heart rate and blood pressure) were studied in the animals under the action of acetylsalicylic acid and its coordination compounds with cations of cobalt, zinc, nickel and manganese at a dose of 20 mg/kg. Materials and methods. The research was conducted using the laser Doppler flowmetry method on the Lazma-MC device (manufactured by RPE Lazma, Russia) and the NIBP200A system (Biopac Systems, Inc., USA). Results. The study shows that animals develop bradycardia, and microcirculation and central hemodynamics change in two ways after the introduction of acetylsalicylic acid and the tested metal salicylates. These ways are hypotension-related hyperemia (acetylsalicylic acid and cobalt salicylate) and ischemia (zinc, nickel and manganese salicylates) associated with hypertension. Conclusion. The obtained data confirm the cardiotropic activity of new coordination compounds. The data also prove that the generation of the acetylsalicylic acid derivatives allows enhancing it physiological effects, as well as obtaining completely new molecules. The molecules are different from the precursor one and are necessary for the production of effective drugs.

Two new bis(pyridine)-bis(amide)-based copper(II) coordination compounds for the electrochemical detection of trace Cr(VI) and efficient electrocatalytic oxygen evolution

Two new metal-organic compounds (MOCs) [Cu(L)0.5(3-nba)2] (1) and [Cu(L)(2,5-tdc)] (2) have been hydrothermally synthesized by employing the ligand N,N′-di(3-pyridyl)adipoamide (L) and two carboxylic acids (3-Hnba = 3-nitrobenzoic acid, 2,5-H2tdc = 2,5-thiophenedicarboxylic acid) as ligands. Compound 1 displays a metal-organic chain-like structure formed by the {Cu2(3-nba)4} double-paddle wheel units and the µ 2-bridging L ligands. The adjacent polymeric chains form a supramolecular layered structure through hydrogen bonding. Compound 2 shows a 3D metal-organic polymeric framework derived from Cu-L layers and µ 2-bridging 2,5-tdc ligands, which presents a 3,5-connected {4.62}{4.66.83} topology. The electrochemical and electrocatalytic behavior of the two compounds has been studied in detail. Carbon paste working electrodes modified with compounds 1 and 2 can be used as highly selective sensors for detecting traces Cr(VI). Both electrodes show also electrocatalytic performance in oxygen evolution reactions (OERs).

Crystal structures of 3/4-pyridyl-based thiosemicarbazones and related Cu and Ni coordination compounds

In this investigation, the crystal structures of the thio-ligands 3-formylpyridine 4-phenylthiosemicarbazone (C13H12N4S, 1) and 4-benzoylpyridine 4-ethylthiosemicarbazone (C15H16N4S, 2), and of two new coordination compounds, chlorido(3-formylpyridine 4-phenylthiosemicarbazone-κS)bis(triphenylphosphane-κP)copper(I) acetonitrile monosolvate, [CuCl(C13H12N4S)(C18H15P)2]·CH3CN, 3, and bis(3-formylpyridine 4-ethylthiosemicarbazonato-κ2 N 1,S)nickel(II), [Ni(C9H11N4S)2], 4, are reported. In complex 3, the thio-ligand coordinates in a neutral form to the Cu atom through its S-donor atom, and in complex 4, the anionic thio-ligand chelates to the Ni atom through N- and S-donor atoms. The geometry of complex 3 is distorted tetrahedral [bond angles 99.70 (5)–123.23 (5)°], with the P—Cu—P bond angle being the largest, while that of complex 4 is square planar, with trans-S—Ni—S and N—Ni—N bond angles of 180°.