Ansa‐Bridged Bis(benzene) Titanium Complexes

Taking advantage of an improved synthesis of [Ti(η⁶‐C₆H₆)₂], we report here the first examples of ansa‐bridged bis(benzene) titanium complexes. Deprotonation of [Ti(η⁶‐C₆H₆)₂] with nBuLi in the presence of N,N,N′,N′′,N′′‐pentamethyldiethylenetriamine (pmdta) leads to the corresponding 1,1′‐dilithio salt [Ti(η⁶‐C₆H₅Li)₂] ? pmdta that enables the preparation of the first one‐ and two‐atom‐bridged complexes by simple salt metathesis. The ansa complexes were fully characterized (NMR spectroscopy, UV/Vis spectroscopy, elemental analysis, and X‐ray crystallography) and further studied electrochemically and computationally. Moreover, [Ti(η⁶‐C₆H₆)₂] is found to react with the Lewis base 1,3‐dimethylimidazole‐2‐ylidene (IMe) to give the bent sandwich complex [Ti(η⁶‐C₆H₆)₂(IMe)].     

Exergoeconomic analysis of a thermochemical copper–chlorine cycle for hydrogen production using specific exergy cost (SPECO) method

The manner is investigated in which exergy-related parameters can be used to minimize the cost of a copper–chlorine (Cu–Cl) thermochemical cycle for hydrogen production. The iterative optimization technique presented requires a minimum of available data and provides effective assistance in optimizing thermal systems, particularly in dealing with complex systems and/or cases where conventional optimization techniques cannot be applied. The principles of thermoeconomics, as embodied in the specific exergy cost (SPECO) method, are used here to determine changes in the design parameters of the cycle that improve the cost effectiveness of the overall system. The methodology provides a reasonable approach for improving the cost effectiveness of the Cu–Cl cycle, despite the fact that it is still in development. It is found that the cost rate of exergy destruction varies between $1 and $15 per kilogram of hydrogen and the exergoeconomic factor between 0.5 and 0.02 as the cost of hydrogen rises from $20 to $140 per GJ of hydrogen energy. The hydrogen cost is inversely related to the exergoeconomic factor, plant capacity and exergy efficiency. The results are expected to assist ongoing efforts to increase the economic viability and to reduce product costs of potential commercial versions of this process. The impact of the results are anticipated to be significant since thermochemical water splitting with a copper–chlorine cycle is a promising process that could be linked with nuclear reactors to produce hydrogen with no greenhouse gases emissions, and thereby help mitigate numerous energy and environment concerns.     

Microencapsulated oleic–capric acid/hexadecane mixture as phase change material for thermal energy storage

Journal of Thermal Analysis and Calorimetry - Thermal energy storage systems provide efficiency in order to have better utilization of energy sources while protecting the environment. Thermal...     

Intramolecular hydrogen bonding and tautomerism in N-(3-pyridil)-2-oxo-1-naphthylidenemethylamine

N-(3-pyridil)-2-oxo-1-naphthylidenemethylamine (C₁₆H₁₂N₂O) was studied by elemental analysis, IR, ¹H NMR, and UV–visible techniques and X-ray diffraction methods. The UV–visible spectrum of the compound was investigated in solutions effect polarity. The polarity of the some solvents was modifierly the additional (CF₃COOH) and [(C₂H₅)₃N]. The compound is in tautomeric equilibrium (phenol-imine O–H···N and keto-amine O···H–N forms) in polar and nonpolar solvents. The keto-amine form is observed in basic solutions of DMSO, ethanol, chloroform, benzene, cyclohexane, and in acidic solutions of chloroform and benzene, but not in acidic solutions of DMSO and ethanol. The compound crystallizes in the monoclinic, space group P2₁/a with a = 7.010(5) Å, b = 13.669(4) Å, c = 12.764(4) Å, = 101.23(4)°, V = 1199.6(10) ų, Z = 4, D _c = 1.375 g/cm³, (Mo K) = 0.088 mm^–1, R = 0.045 for 1658 reflections [I > 2(I)]. The title compound is not planar two Schiff base moieties A [C1–C11, O1] and B [N1, C12, C13, N2, C14, C15, C16] are inclined at an angle of 27.4(1)° reflecting mainly the twist about C12–N1 [C11–C12–N1–C13, 29.7(2)°]. There is a strong intramolecular hydrogen bond (O–H···N) of 2.529(2) Å.     

Keto–enol tautomerism, conformations, and structure of 1-[N-(4-chlorophenyl)]aminomethylidene-2(1H)naphthalenone

1-[N-(4-chlorophenyl)]aminomethylidene-2(1H)naphthalenone (C₁₇H₁₂NOCl) (1) was synthesized and the crystal structure was determined. Compound 1 crystallizes in the monoclinic space group P2₁/n with a = 4.761(3) Å, b = 20.347(1) Å, c = 13.773(2) Å, = 92.89(3)°, V = 1332.4(3) ų, Z = 4, D _c = 1.404 g cm^–3, (Mo K) = 0.28 mm^–1, and R = 0.036 for 2680 reflections [I > 2(I)]. Molecule 1 is not planar, and the dihedral angle between the naphthaldeyde plane A [C1–C11, 01] and the 4-chloroaniline plane B [C12–C17, C11, N1] is 20.1(3)°. An intramolecular hydrogen bond occurs between the hydroxyl oxygen and imine nitrogen atoms [2.528(3) Å]. IR, ¹H NMR, and UV measurements and AM1 semiempirical quantum mechanical calculations support the keto form found in the X-ray structure.     

Synthesis,Spectroscopic Studies and Structure of 2-[(Benzo[<Emphasis Type="Italic">d</Emphasis>]thiazol-2-ylamino)methyl]phenol

Abstract  

Schiff base (E)-2-[(benzo[d]thiazol-2-ylimino)methyl]phenol (1) has been synthesized from the reaction of 2-hydroxy-benzaldehyde with 2-aminobenzothiazole. The 2-[(benzo[d]thiazol-2-ylamino)methyl]phenol (2) was prepared reduction of the Schiff base 1 with sodium borohydride. The compounds 1 and 2 have been characterized by elemental analysis, FT-IR, ¹H-NMR, ¹³C-NMR and UV–visible spectroscopic techniques. The structure of the compound 2 has also been examined crystallographically. The compound 2 crystallizes in the monoclinic space group P2/c. The unit cell parameters were found as a = 10.017(1), b = 11.725(1), c = 10.341(1) ?, V = 1208.1(1) ?³, D _x = 1.409 g cm⁻³ and Z = 4. The crystal structure was solved by direct methods and refined by the full-matrix least squares method and found as R ₁ = 0.0308 and wR ₂ = 0.0818 for 2032 for the observed reflections [I > 2σ(I)].     

N,N,N′,N′‐Tetra­methyl­ethyl­enedi­ammonium dichloride

The structure of the title compound, C₆H₁₈N₂²⁺.2Cl^?, has been determined and has a centre of symmetry. The mol­ecule has strong intermolecular hydrogen bonding between each Cl^? and an N—H bond [Cl?N = 3.012 (3) Å].     

Preparation and characterization of activated carbon from pine cone by microwave-induced ZnCl2 activation and its effects on the adsorption of methylene blue

In this work, activated carbon prepared from pine cone (PCAC) with ZnCl₂ as an activation agent under microwave radiation was investigated. The activation step was performed at the microwave input power of 400 W and radiation time of 5 min. The properties of activated carbon were characterized by N₂ adsorption Brunauer–Emmett–Teller (BET), scanning electron microscopy and Fourier transform infrared spectroscopy. Results showed that the BET surface area, Langmuir surface area, and total pore volume of PCAC were 939, 1,486 m²/g and 0.172 cm³/g, respectively. Adsorption capacity was demonstrated by the iodine numbers. The adsorptive property of PCAC was tested using methylene blue dye. Equilibrium data was best fitted by the Langmuir isotherm model, showing a monolayer adsorption capacity of 60.97 mg/g. The pseudo-first- and pseudo-second-order kinetic models were examined to evaluate the kinetic data, and the rate constants were calculated. Adsorption of the dyes followed pseudo-first order kinetics. Thermodynamic parameters such as free energy, enthalpy and entropy of dye adsorption were obtained.     

Catalytic methanolysis of hydrazine borane: a new and efficient hydrogen generation system under mild conditions

Safe and efficient hydrogen storage is a major obstacle for using hydrogen as an energy carrier. Therefore, intensive efforts have been focused on the development of new materials for chemical hydrogen storage. Of particular importance, hydrazine borane (N(2)H(4)BH(3)) is emerging as one of the most promising solid hydrogen carriers due to its high gravimetric hydrogen storage capacity (15.4 wt%) and low molecular weight. Herein, we report metal catalyzed methanolysis of hydrazine borane (N(2)H(4)BH(3), HB) as a fast hydrogen generation system under mild conditions. When trace amounts of nickel(ii) chloride (NiCl(2)) is added to the methanol solution of hydrazine borane ([HB]/[Ni] ≥ 200) the reaction solution releases 3 equiv. of H(2) with a rate of 24 mol H(2) (mol Ni min)(-1) at room temperature. The results reported here also includes (i) identification of the reaction products by using ATR-IR, DP-MS, (1)H and (11)B NMR spectroscopic techniques and the establishment of the reaction stoichiometry, (ii) investigation of the effect of substrate and catalyst concentrations on the hydrogen generation rate to determine the rate law for the catalytic methanolysis of hydrazine borane, (iii) determination of the activation parameters (E(a), ΔH(#), and ΔS(#)) for the catalytic methanolysis of hydrazine borane by using the temperature dependent rate data of the hydrogen generation.