Spectroscopic studies and quantum chemical investigations of (3,4-dimethoxybenzylidene) propanedinitrile.

The Fourier Transform Infrared (FTIR), Ultra-Violet Visible (UV-Vis) spectroscopy and Thermogravimetric (TG) analysis of (3,4-dimethoxybenzylidene) propanedinitrile have been carried out and investigated using quantum chemical calculations. The molecular geometry, harmonic vibrational frequencies, Mulliken charges, natural atomic charges and thermodynamic properties in the ground state have been investigated by using Hartree Fock Theory (HF) and Density Functional Theory (DFT) using B3LYP functional with 6-311G(d,p) basis set. Both HF and DFT methods yield good agreement with the experimental data. Vibrational modes are assigned with the help of Vibrational Energy Distribution Analysis (VEDA) program. UV-Visible spectrum was recorded in the spectral range of 190-800nm and the results are compared with the calculated values using TD-DFT approach. Stability of the molecule arising from hyperconjugative interactions, charge delocalization have been analyzed using natural bond orbital (NBO) analysis. The results obtained from the studies of Highest Occupied Molecular Orbital (HOMO) and Lowest Unoccupied Molecular Orbital (LUMO) are used to calculate molecular parameters like ionization potential, electron affinity, global hardness, electron chemical potential and global electrophilicity.

Fluorescent probe 7-(prop-2-yn-1-yloxy)-2H-chromen-2-one: Experimental and DFT based approach to photophysical properties.

Compound 7-(prop-2-yn-1-yloxy)-2H-chromen-2-one was synthesized by Pechmann condensation reaction and characterized by various spectroscopic techniques. The structure of title compound was confirmed by single crystal X-ray diffraction. The compound crystallized in the orthorhombic system with P 21 21 21 space group and the corresponding lattice parameters were found to be a=4.0138 (11) Å, α=90°; b=23.536 (6) Å, ß=90°; c=10.93 (2) Å, γ=90°. The crystal packing of molecule showed that intermolecular hydrogen bonds C3-H3⋯O3 [D=3.53 Å], C-13-H13⋯O2 [D=3.67 Å] and intermolecular short interaction between C1-H1⋯C1-H1 [2.68 Å] forms a dimeric unit which finally stabilizes the crystal packing in three dimensional network in the molecule. Absorption and emission spectra shows that compound is fluorescent with good Stoke shift values ranging between 57 and 62 nm. Thermal analysis further supports by TGA, DTA. The photophysical results show that the compound exhibits change in fluorescence quantum yield with change in solvent polarity. The structural parameters and the vibrational wave numbers obtained from the optimized geometry of the compound from DFT-B3LYP calculations employing 6-311G (d,p) basis set are in good agreement with the experimental data. UV-Vis spectrum calculated by employing time dependent density functional theory (TD-DFT) is also in very good agreement with the experiment for all solvents.

Synthesis, crystal structure, photoluminescence, and DFT studies of bis(1,10-phenanthroline)di(κ(2)OO' nitrato)cadmium(II) [Cd(phen)2(NO3)2].

A cadmium 1,10-phenanthroline complex, [Cd(phen)2(NO3)2] has been synthesized by and its crystal structure determined. The compound is monoclinic, C2/c, a=11.5008(2), b=15.3523(2), c=13.2767(2)Å, ß=103.610(2), Z=4. The compound is monomeric with a octacoordinate cadmium ion bonded to two bidentate 1,10-phenanthroline molecules and two bidentate nitrate units. The metal ion is bis-chelated by two N-heterocycles as well as by two nitrate ions in a distorted dodecahedral CdN4O4 coordination environment. The complex is thermally stable up to 110°C. Photophysical investigation reveals that complex is luminescent in the solid state. The molecular geometry, harmonic vibrational frequencies and bonding features of complex [Cd(phen)2(NO3)2] in the ground-state have been calculated by using the density functional B3LYP method with 3-21G (d, p) as higher basis set. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecule. Finally the calculation results were applied to simulate infrared spectrum of the title compound which show good agreement with observed spectrum.