NOPR Community:

Synthesis, molecular structure and TD-DFT studies on N'-(pyridine-2-ylmethylene)acetohydrazide nickel(II) complexes

Tue, 15 Dec 2015 10:13:32 GMT

Title: Synthesis, molecular structure and TD-DFT studies on N'-(pyridine-2-ylmethylene)acetohydrazide nickel(II) complexes Authors: Patel, Ram N; Singh, Yogendra Pratap; Singh, Yogendra; Butcher, Raymond J Abstract: Nickel(II) complexes of a Schiff base derived from 2-pyridinecarboxyldehyde and acetylhydrazide, viz., [Ni(L)₂].(NO₃)₂.H₂O (1) and [Ni(HL)(L)].ClO₄.(H₂O)₂(2) (where L = N'-(pyridine-2-ylmethylene)acetohydrazide), have been synthesized and characterized by physicochemical techniques as well as by single crystal X-ray structural analysis. The supramolecular architecture in both complexes (1) and (2) are totally guided by complicated H-bondings. The molecular structures and spectral properties of the ligand and the complexes have been explained by DFT and TD-DFT calculations. The electronic excitation energies of these complexes calculated at TD-DFT levels are in agreement with values deduced from the experimental UV-visible spectra. Page(s): 1459-1465

Synthesis, characterization and DFT calculations of N,O Schiff base complex of copper(II)

Tue, 01 Dec 2015 00:00:00 GMT

Title: Synthesis, characterization and DFT calculations of N,O Schiff base complex of copper(II) Authors: Dey, Sudipto; Ghosh, Koushik; Halder, Shibashis; Rizzoli, Corrado; Roy, Partha Abstract: Mononuclear copper(II) complex of the Schiff base, 2-methoxy-6-(3-morpholinopropyl-iminomethyl) phenol, [Cu(HL)₂](ClO₄)₂].H₂O (1) has been synthesized and characterized by elemental analysis and different spectroscopic techniques. The structure of (1) is confirmed by single crystal X-ray diffraction analysis. The complex (1) crystallizes in the monoclinic space group P21/n. The crystal structure of the mononuclear complex exhibits two Schiff base ligands bound to the copper atom and two perchlorate ions as non-coordinating species. Both the ligands in (1) are zwitterions where nitrogen atom of the morpholine ring is protonated. Fluorescence spectral study shows that HL displays an emission band at 535 nm on excitation at 418 nm. The presence of Cu²⁺ ion in complex (1) quenches its emission intensity. DFT and TDDFT calculations have been carried out to investigate the spectral transitions. Page(s): 1451-1458

Pyrene-appended Schiff base as a turn-on fluorescence sensor for Al³⁺ detection and interaction with DNA

Tue, 15 Dec 2015 10:06:46 GMT

Title: Pyrene-appended Schiff base as a turn-on fluorescence sensor for Al³⁺ detection and interaction with DNA Authors: Panda, Uttam; Das, Kuheli; Dutta, Paramita; Sinha, Chittaranjan Abstract: Pyrene appended Schiff base, 1,3-bis-((E)-pyrene-1-ylmethyleneamino)propan-2-ol (HL) fluoresces at 419 nm and 508 nm in DMF solution upon excitation at 344 nm. The addition of Al³⁺ results in a significant 100 fold increase of its fluorescent intensity with the emission maximum red shifted from 421 nm to 508 nm with intense green emission. This phenomenon may be attributed to the formation of a 1:2 stoichiometric [Al₂Cl₅(L)] complex, which has been supported by Jobs, NMR titration and mass spectral data. The complexation inhibits the photo-induced electron transfer process and the cheletropic enhancement of fluorescence mechanism is responsible for the turn-on fluorescence sensitivity. The limit of detection of Al³⁺ (7.42×10^-8 M) is the second lowest in the series of pyrene functionalized chemosensor. Both HL and its Al³⁺ complex, [Al₂Cl₅(L)], show DNA stacking interaction (binding constant K_b 9.8×10⁴ M^-1 (of HL) and 3.8×10⁴ M^-1 (of [Al₂Cl₅(L)]). Page(s): 1446-1450

Synthesis of zinc sulfide nanoparticles stabilized by sodium dodecylsulfate micelles and evaluation of photocatalytic activity

Tue, 15 Dec 2015 10:00:46 GMT

Title: Synthesis of zinc sulfide nanoparticles stabilized by sodium dodecylsulfate micelles and evaluation of photocatalytic activity Authors: Devi, Longjam Meerabai; Negi, Devendra P S Abstract: Zinc sulfide nanoparticles have been synthesized using sodium dodecylsulfate micelles as a stabilizing agent. The as-prepared nanoparticles are characterized by ultraviolet-visible spectroscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and transmission electron microscopy. The photocatalytic activity of the ZnS nanoparticles has been evaluated by monitoring the degradation of methyl orange with a UV-visible spectrophotometer. The effect of ZnS concentration on the photocatalytic degradation of the dye has been investigated. Under optimum experimental conditions, 98% of the dye is degraded in the presence of the photocatalyst during 10 min of irradiation with ultraviolet light. The turnover frequency for methyl orange degradation per mg of ZnS is calculated to be 6×10¹³molecules s^-1. The effect of SDS concentration on the photocatalytic degradation of the dye has also been investigated. The results suggest that SDS micelles do not catalyze the degradation of the dye. The mechanism of the photocatalytic degradation of methyl orange has been discussed. Page(s): 1440-1445

NOPR Community:

Synthesis, molecular structure and TD-DFT studies on N'-(pyridine-2-ylmethylene)acetohydrazide nickel(II) complexes

Synthesis, characterization and DFT calculations of N,O Schiff base complex of copper(II)

Pyrene-appended Schiff base as a turn-on fluorescence sensor for Al3+ detection and interaction with DNA

Synthesis of zinc sulfide nanoparticles stabilized by sodium dodecylsulfate micelles and evaluation of photocatalytic activity

Pyrene-appended Schiff base as a turn-on fluorescence sensor for Al³⁺ detection and interaction with DNA