Complexation of metal ions with the novel 2-hydroxy-1-naphthaldehyde-derived diamine Schiff base carrying a macrobicyclic moiety with N2O2S2 mixed donor in acetonitrile-dichloromethane

A new Schiff base containing a macrobicyclic moiety was designed and synthesized by reaction of the corresponding macrobicyclic diamine compound and 2-hydroxy-1-naphthaldehyde. The influence of metal cations such as Zn²⁺, Mn²⁺, Fe²⁺, Fe³⁺, Co²⁺, Ni²⁺ and Pb²⁺ on the spectroscopic properties of the 2-hydroxy-1-naphtyl group linked to the macrobicyclic moiety with N₂O₂S₂ mixed donor was investigated in acetonitrile-dichloromethane solution (9.5/0.5) by means of absorption and emission spectrometry. Emission spectra undergo a marked blue shift and enhancement of naphtyl fluorescence in the presence of Fe³⁺ and Zn²⁺. The presence of Pb²⁺, Mn²⁺, Fe²⁺, Co²⁺ and Ni²⁺ caused a quenching of naphtyl fluorescence. Especially, the quenching was higher than 90% in case of the interaction of Ni²⁺ and Co²⁺ with the ligand. The results of spectrophotometric and spectrofluorimetric titration experiments disclosed the complexation properties of the novel ligand with Zn²⁺, Co²⁺ and Ni²⁺ cations.     

Bearing condition diagnosis and prognosis using applied nonlinear dynamical analysis of machine vibration signal

In this paper, we introduce a modified form of the correlation integral developed by Grassberger and Procaccia referred to as the partial correlation integral, which can be computed in real time. The partial correlation integral algorithm is then used to analyze machine vibration data obtained throughout a life test of a rolling element bearing. From the experimental results, the dimensional exponent (an approximation of the correlation dimension) as computed from the partial correlation integral algorithm tends to increase as time progresses and the useful remaining life of the bearing is decreasing. The dimensional exponents of a healthy bearing and a bearing close to failure are statistically different. We also propose a computational scheme for bearing condition monitoring (diagnosis and prognosis) using the dimensional exponent integrated with a surrogate data testing technique. As a result, we can characterize the condition of the bearing from the results of the surrogate data test and furthermore, we provide some preliminary evidence that the dimensional exponent can be used to predict the failure of rolling element bearings in rotating machinery from real-time vibration data.     

Solutions of Two-Mode Bosonic and Transformed Hamiltonians

We have constructed the quasi-exactly-solvable two-mode bosonic realization of SU(2). Two-mode boson Hamiltonian is defined through a differential equation which is solved by quantum Hamilton-Jacobi formalism. The squeezed states of two-mode boson systems are characterized through canonical transformation. The illustrated concept of squeezed boson systems has been applied two-mode bosonic Hamiltonian which is a squeezed one and is determined through a differential equation. This differential equation is solved and energy eigenvalues are found approximately.     

Calculation of current–voltage characteristics of a Cu (II) complex/n-Si/AuSb Schottky diode

In this study, Cu (II) complex/n-Si structure has been fabricated by forming a thin organic Cu (II) complex film on n-Si wafer. It has been seen that the structure has clearly shown the rectifying behaviour and can be evaluated as a Schottky diode. The contact parameters of the diode such as the barrier height and the ideality factor have been calculated using several methods proposed by different authors from current–voltage (I–V) characteristics of the device. The calculated barrier height and ideality factor values from different methods have shown the consistency of the approaches. The obtained ideality factor which is greater than unity refers the deviation from ideal diode characteristics. This deviation can be attributed to the native interfacial layer in the organic/inorganic interface and the high series resistance of the diode. In addition, the energy distribution of the interface state density (N_ss) in the semiconductor band gap at Cu (II) complex/n-Si interface obtained from I–V characteristics range from 2.15 × 10¹³ cm⁻² eV⁻¹ at (E_c − 0.66) eV to 5.56 × 10¹² cm⁻² eV⁻¹ at (E_c − 0.84) eV.     

Spectroscopic Studies and Crystal Structure of 3-[(2-morpholinoethylimino)methyl]benzene-1,2-diol

Abstract Schiff base 3-[(2-morpholinoethylimino)methyl]benzene-1,2-diol has been synthesized from the reaction of 4-(2-aminoethyl)morpholine with 2,3-dihydroxybenzaldehyde. The title compound has been characterized by elemental analysis, IR, ¹H-NMR, ¹³C-NMR and UV–visible techniques. The structure of the compound also has been examined crystallographically. For the compound exist as dominant form of enol-imines in both the solutions and solid state. The crystal structure has been solved by direct methods and refined by full-matrix least squares. The title compound crystallize in the monoclinic space group P2₁/n with a = 12.085(1), b = 8.256(1), c = 13.650(1) ?, β = 108.56(1)°, V = 1291.1(2) ?³, D _x = 1.288 g cm⁻³, respectively (R ₁ = 0.0336 and wR ₂ = 0.0922 for 2117 reflections [I > 2σ(I)]. Index abstract Intramolecular hydrogen bonding is important on the tautomeric properties and the type of aldehyde plays a vital role of the enol-imine and keto-amine properties of the Schiff base ligand.      

The synthesis and characterization of 22-membered diazapentathia macrocycles and investigation of their ion extraction capability from aqueous media

Two new macrocyclic ligands, (5) and (6), containing nitrogen–sulfur donor atoms were designed and synthesized in a multi-step reaction sequence. Ion extraction capability of macrocycles (5) and (6) were investigated involving solvent extraction of metal picrates such as Ag⁺, Hg²⁺, Cd²⁺, Zn²⁺, Cu²⁺, Ni²⁺, Mn²⁺, Co²⁺ and Pb²⁺ from aqueous phase to the organic phase. The metal picrate extractions were carried out at 25 ± 0.1 °C and extractions were measured by u.v.–visible spectrometry. The extractability and selectivity of the mentioned metal picrates were evaluated depending on the organic solvents used for extraction. The extraction constant (log K_ex) and the complex composition of each metal complex were determined using spectroscopic methods.     

Conformational analysis and crystal structure of (<Emphasis Type="Italic">E</Emphasis>)-3-methyl-4-(<Emphasis Type="Italic">p</Emphasis>-tolyldiazenyl)phenol

The single crystal X-ray diffraction analysis of the title compound, C₁₄H₁₄N₂O, reveals that an interesting intermolecular or extended structure (hydrogen-bonded polymeric zigzag chains) is formed by linking its monomer units with O–H···N type intermolecular hydrogen bonds. The compound crystallizes in the monoclinic space group P2₁/n with a = 5.8151(5) Å, b = 18.106(1) Å, c = 11.515(1) Å  and β = 96.891(7)°. In order to understand better its structural aspects in solid state, quantum chemical (PM3) calculations were performed on a part of the extended structure of the title compound containing ten monomers. To determine in vacuo conformational flexibility of the compound, molecular energy profile of the title compound was obtained with respect to a selected torsional degree of freedom and the pedal angle varied from ?180° to +180° in every 10°. The results from the computational study suggest that hydrogen-bonding properties in the crystal lattice is fundamental in determining the crystallographically observed conformation of the title compound.     

Crystallographic and conformational analysis of (<Emphasis Type="Italic">E</Emphasis>)-2-isopropyl-4-(<Emphasis Type="Italic">p</Emphasis>-tolyldiazenyl)phenol

The molecular and crystal structures of the title compound, C₁₆H₁₈N₂O, were characterized and determined by single crystal X-ray diffraction method in addition to spectroscopic means such as IR, UV–VIS and ¹H NMR. The compound crystallizes in orthorhombic space group P bca, with a = 9.3350(5) Å, b = 23.4878(13) Å, c = 26.5871(12) Å, Z = 16, D _calc. = 1.1591(1) g/cm³, μ (MoK_α) = 0.073 mm^?1. Monomers of the compound in the crystal structure are linked into C(7) and C(8) chains generated by translation along the [1 0 0] direction with the aid of O–H···N type H-bonds which serve to the stabilization of periodic organization of the molecules beside major and minor component in the disordered azo fragment. In order to describe conformational flexibility and the crystal packing effects on the molecular conformation, potential barriers regarding the rotation along both Ar–N bonds were calculated by varying the related torsional degrees of freedom in every 10° ranging from ?180° to +180° via quantum chemical calculations at DFT/B3LYP level.     

Solid-liquid interfacial energy for solid succinonitrile in equilibrium with succinonitrile dichlorobenzene eutectic liquid

The equilibrated grain boundary groove shapes for solid succinonitrile (SCN) in equilibrium with the succinonitrile (SCN) dichlorobenzene (DCB) eutectic liquid were directly observed. From the observed grain boundary groove shapes, the Gibbs-Thomson coefficient and solid-liquid interfacial energy for solid SCN in equilibrium with the SCN DCB eutectic liquid have been determined to be (5.43 ± 0.27) × 10⁻⁸ K m and (7.95 ± 0.80) × 10⁻³ J m⁻² with present numerical method and Gibbs-Thomson equation, respectively. The grain boundary energy of SCN rich phase of the SCN DCB eutectic system has been determined to be (14.77 ± 1.77) × 10⁻³ J m⁻² from the observed grain boundary groove shapes. Thermal conductivity of eutectic solid phase and eutectic liquid phase at the eutectic melting temperature have also been measured to be 0.269 and 0.231 W/K m, respectively.