The Effect of Supports of Glassy–Carbon and Activated Graphite Foil on the Electrochemical Behavior of Composite Coatings Based on Polyaniline and Its N-Substituted Derivatives

Russian Journal of Electrochemistry - Abstract—Hybrid polymer nanomaterials are synthesized based on polyaniline (PAni) and its N-substituted derivative...     

Synthesis of Nanoparticles in a Pulsed-Periodic Gas Discharge and Their Potential Applications

Conditions for the synthesis of three types nanoparticles (SnO₂, Al₂O₃, and Ag) with typical sizes in the range of 4 to 10 nm and a performance of 0.4 g/h are employed in a pulsed-periodic gas discharge in an atmosphere of air. Spherical Ge nanoparticles with a characteristic size of 13 nm are synthesized by these means for the first time with a performance of around 10 mg/h. The specific energy consumption in the synthesis of nanoparticles is for these materials in the range of 2000 to 5000 kW h/kg. The prospects for using tinoxide nanoparticles in sensor components and jets of silver nanoparticles for aerosol printing are discussed. The merits and demerits of the pulsed gas-discharge method among other gas-phase approaches to the synthesis of nanoparticles are analyzed for the current level of development.

     

Thiocyanates of rare-earth elements with tetramethylphenanthroline

Molecular [M(NCS)₃(H₂O)(Me₄Phen)₂] · (Me₄Phen) · 0.75EtOH and anionic [H(Me₄Phen)][М(NCS)₄(Me₄Phen)₂] complexes are synthesized using thiocyanates М(NCS)₃ · 6H₂O (M = Y, Eu, Tb) and 3,4,7,8-tetramethyl-1,10-phenanthroline (Me4Phen). The complexes are characterized by IR spectroscopy and elemental, X-ray phase, and X-ray diffraction analyses (CIF files CCDC no. 1498178–1498184). The thermoanalytical study shows that the solvate molecules Me₄Phen are localized in the internal coordination sphere of the molecular complexes at 195–250°C. The magnetic behavior of the Eu and Tb complexes is governed by the nature of the Ln ion.     

Synthesis,structure, and ESR spectra of the new heteronuclear complex {Li4(VO)2[(OOC)2C(H)Bu]4(H2O)8}·H2O

The reaction of an aqueous solution of vanadyl sulfate VOSO₄·3H₂O, butylmalonic acid (H₂Bumal = C₄H₁₀(COOH)₂), and lithium carbonate at pH ～4–5 gave crystals of the complex Li₄(VO)₂(Bumal)₄(H₂O)₈]·H₂O (1). The structure of complex 1 was established by X-ray diffraction analysis. The molecule of complex 1 consists of two mononuclear bischelate dianionic units {VO(Bumal)₂(H₂O)} linked by four lithium ions to form the hexanuclear heterometallic {V₂Li₄} structure. The crystals and an ethanolic solution of compound 1 were studied by ESR spectroscopy.     

Crystal structure and magnetic properties of a new heterometallic complex of Pd(II)-Cu(II) with 1-aminoethylidene-1,1-diphosphonic acid

A heterometallic complex of Pd(II)-Cu(II) with 1-aminoethylidene-1,1-diphosphonic (AEDP) acid (C₄H₂₂CuN₂O₁₆P₄Pd) _n (I) is synthesized. Single crystals of compound I are obtained; its crystal structure is determined by X-ray crystallography. The crystals are orthorhombic, space group Pbcn, a = 18.366(3) Å, b = 9.7661(17) Å, c = 20.198(4) Å, V = 3622.8(11) ų, Z = 8, d _x = 2.376 g/cm³. The compound crystallizes as a coordination polymer; the square environment of Pd(II) is formed by nitrogen atoms of amino groups and oxygen atoms of phosphonic groups, while at two non-equivalent copper atoms the octahedral environment is formed by oxygen atoms of phosphonic groups and water molecules. The crystal structure of compound I is characterized by the formation of a branched network of hydrogen bonds. Based on the analysis of the temperature dependence of the magnetic susceptibility it is found that for the heterometallic complex of Pd(II)-Cu(II) with AEDP antiferromagnetic interactions between the paramagnetic centers are dominant.     

Direct Evidence of Significantly Different Chemical Behavior and Excited‐State Dynamics of 1,7‐ and 1,6‐Regioisomers of Pyrrolidinyl‐Substituted Perylene Diimide

Novel bay‐functionalized perylene diimides with additional substitution sites close to the perylene core have been prepared by the reaction between 1,7(6)‐dibromoperylene diimide 6 (dibromo‐PDI) and 2‐(benzyloxymethyl)pyrrolidine 5 . Distinct differences in the chemical behaviors of the 1,7‐ and 1,6‐regioisomers have been discerned. While the 1,6‐dibromo‐PDI produced the corresponding 1,6‐bis‐substituted derivative more efficiently, the 1,7‐dibromo‐PDI underwent predominant mono‐debromination, yielding a mono‐substituted PDI along with a small amount of the corresponding 1,7‐bis‐substituted compound. By varying the reaction conditions, a controlled stepwise bis‐substitution of the bromo substituents was also achieved, allowing the direct synthesis of asymmetrical 1,6‐ and 1,7‐PDIs. The compounds were isolated as individual regioisomers. Fullerene (C₆₀) was then covalently linked at the bay region of the newly prepared PDIs. In this way, two separate sets of perylene diimide–fullerene dyads, namely single‐bridged (SB‐1,7‐PDI‐C₆₀ and SB‐1,6‐PDI‐C₆₀) and double‐bridged (DB‐1,7‐PDI‐C₆₀ and DB‐1,6‐PDI‐C₆₀), were synthesized. The fullerene was intentionally attached at the bay region of the PDI to achieve close proximity of the two chromophores and to ensure an efficient photoinduced electron transfer. A detailed study of the photodynamics has revealed that photoinduced electron transfer from the perylene diimide chromophore to the fullerene occurs in all four dyads in polar benzonitrile, and also occurs in the single‐bridged dyads in nonpolar toluene. The process was found to be substantially faster and more efficient in the dyads containing the 1,7‐regioisomer, both for the singly‐ and double‐bridged molecules. In the case of the single‐bridged dyads, SB‐1,7‐PDI‐C₆₀ and SB‐1,6‐PDI‐C₆₀, different relaxation pathways of their charge‐separated states have been discovered. To the best of our knowledge, this is the first observation of photoinduced electron transfer in PDI‐C₆₀ dyads in a nonpolar medium.     

Cobalt-doped chalcopyrites CuInSe2: the synthesis and magnetic properties

Two series of samples of the composition CuIn_1?XCo_XSe₂ (m-series) and Cu_1?X/2In_1?X/2Co_XSe₂ (d-series) were prepared by solid-state synthesis and their magnetic properties were investigated. It was shown that cobalt is much better incorporated into the chalcopyrite matrix of the d-series samples, thus providing the onset of paramagnetic properties. Quenching allows the concentration of the incorporated cobalt to increase, which leads to the onset of weak ferromagnetism.

     

Molecular Magnets Based on Mononuclear Aqua and Aqua-Chloro Lanthanide (Tb,Dy, Er,Yb) Complexes with Bipyridine

Russian Journal of Coordination Chemistry - The complexes [Tb(Bipy)2(H2O)2Cl2]Cl (I), [Ln(Bipy)(H2O)6]Cl3·2H2O·0.5Bipy (Ln = Dy (II), Yb (IV)), [Er(Bipy)2(H2O)3Cl]Cl2·2H2O (III), and...     

Generation of a Hetero Spin Complex from Iron(II) Iodide with Redox Active Acenaphthene-1,2-Diimine

The reaction of the redox active 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene (dpp-BIAN) and iron(II) iodide in acetonitrile led to a new complex [(dpp-BIAN)Fe^III₂] (1). Molecular structure of 1 was determined by the single crystal X-ray diffraction analysis. The spin state of the iron cation in complex 1 at room temperature and the magnetic behavior of 1 in the temperature range of 2–300 K were studied using Mossbauer spectroscopy and magnetic susceptibility measurements, respectively. The neutral character of dpp-BIAN in 1 was confirmed by IR and UV spectroscopy. The electrochemistry of 1 was studied in solution and solid state using cyclic voltammetry. The generation of the radical anion form of the dpp-BIAN ligand upon reduction of 1 in a CH₂Cl₂ solution was monitored by EPR spectroscopy.