Alternative Procedure for the Synthesis of (+)-Tavacpallescencine Precursor

A conversion of dimethylbenzo[d]suberone prepared from 5-chlorovaleric acid into butenolide, a precursor of tavacpallescencine, was described.     

Synthesis and Characterization of Nano-Crystalline Fluorine-Doped Tin Oxide Thin Films by Sol-Gel Method

Thin films of fluorine-doped tin-oxide (FTO) were prepared by sol-gel dip-coating technique. Stannous chloride (SnCl₂2H₂O) and hydrogen fluoride (HF) were mixed with isopropyl alcohol to serve as source solution. X-ray diffraction (XRD) spectrum showed all the peaks of the crystalline SnO₂. Analysis of XRD spectrum showed the particle size to be nearly 6 nm, which indicated the nanocrystalline structure of the films. Strain calculation by integral breadth (IB) method from XRD data showed a value of 0.010. UV-Visible spectrophotometric measurement showed high transparency of the films in the visible region and the band gap was calculated to be 3.34 eV. The room temperature resistivity of the films were of the order of 1 cm. Fluorine concentration in the films was determined from energy dispersive X-ray (EDX) study. Current-voltage (I-V) characteristics at high temperatures showed the Poole-Frenkel effect of thermionic emission. SEM study indicated the existence of fine grains in the film. FT-IR spectroscopy showed strong Sn—O and Sn—O—Sn bonding.     

A new end-on (μ1,1) azido bridged [Zn2(L)2(Na)N3]n 1D chain derived from a trinuclear zinc complex: syntheses,crystal structures,photoluminescence properties and DFT study

A bicompartmental N₂O₄ donor symmetric Schiff base ligand has been deployed to synthesize a trinuclear zinc complex [Zn₃(L)₂Cl₂], which upon treatment with sodium azide produces a new μ_1,1-azido-bridged 1-D polymer [Zn₂(L)₂(Na)N₃]_n. Both complexes have been characterized using IR, NMR, UV–vis, and X-ray diffraction techniques. In order to have better understanding of electronic transitions of the complexes, a time-dependent DFT study has been performed. Lifetime measurements have also been performed to learn about the stability of excited states of both complexes. The average fluorescence decay lifetime has been found to be 1.42 and 0.59 ns for 1 and 2, respectively. In Hirshfeld surface mapping, X?H/H?X (X = O, Cl) contacts are found to be only 2.7% of the total surface, which indicates that no significant X?H/H?X contacts are present in either of the complexes. Unconventional interactions such as C–H?π and π?π stacking interactions are found in supramolecular architectures of both complexes.     

Synthesis,characterization and fluorescence properties of hexanuclear zinc(II) complexes

Two hexanuclear zinc(II) complexes, [Zn₆(L¹)₂(μ₂-OH)₂(μ₂-CH₃COO)₈] · CH₃CN (1 · CH₃CN) and [Zn₆(L²)₂(μ₂-OH)₂(μ₂-CH₃COO)₈] · 4CH₃CN (2 · 4CH₃CN), where HL¹ = 4-methyl-2,6-bis(cyclohexylmethyliminomethyl)-phenol and HL² = 4-methyl-2,6-bis(1-naphthalylmethyliminomethyl)-phenol, have been synthesized and characterized by elemental analysis, FT-IR and fluorescence spectroscopic methods, and by X-ray diffraction analysis. In the asymmetric unit of complex 1, two of the three zinc atoms have pentacoordinate geometries and the other is tetrahedrally coordinated, whereas the three distinct Zn atoms in complex 2 adopt three different coordination environments, namely distorted octahedral, trigonal bipyramidal and tetrahedral. The fluorescence properties of the ligands and complexes have been investigated.     

Absorption spectroscopic study of synergistic extraction of praseodymium with benzoyl acetone in presence of crown ether

The extraction behaviour of Pr(III) from aqueous nitric acid medium employing benzoylacetone has been studied in presence of two crown ethers, viz., 15-crown-5 and benzo-15-crown-5 in chloroform medium using UV-vis absorption spectroscopy. The binary equilibrium constant (logk(ex)) for the complex [Pr(benzoylacetonate)(NO3(-))2(H(2)O)] in organic phase was found to be 1.170. The overall equilibrium constants (logK) for the ternary species [Pr(benzoylacetonate)(crown ether)(NO3(-))(2)] were estimated to be 4.01 and 4.41 for 15-crown-5 and benzo-15-crown-5, respectively. The trend in the equilibrium constant values were very much in accordance with the nature of substitution of the donor moiety. The extraction of Pr(III) by the benzoylacetone-crown ether combination was maximum at pH 3.0 and extraction decreases with increase in pH. It has been found that the extent of extraction of Pr(III) in organic phase as the binary as well as ternary complex [Pr(benzoylacetonate)(NO3(-))(2)(H(2)O)] and [Pr(benzoylacetonate)(crown ether)(NO3(-))(2)] increases with increase in concentration of the ligand. Similar trend is observed in the extraction by only donors. Enthalpies and entropies of formation for the ternary extraction process have been estimated. In addition, the effect of NaNO(3) as foreign salt was also studied and it was observed that with increase in ionic strength, percentage extraction increases.