2-(2,4-Di-fluoro-phen-yl)-4,5-dimethyl-1-(4-methyl-phen-yl)-1H-imidazole monohydrate.

The asymmetric unit of the title compound, C18H16F2N2·H2O, contains two independent mol-ecules (A and B), and two independent water mol-ecules of crystallization. In mol-ecule A, the imidazole ring makes dihedral angles of 47.46 (7) and 60.

Synthesis and physico-chemical studies of cyclometalated heteroleptic iridium(III) complexes.

Phosphorescent studies of 2-arylimidazole heteroleptic cyclometalated iridium(III) complexes with picolinic acid as the ancillary ligand were made. The observed experimental data reveals that these complexes possess dominantly (3)MLCT and (3)π-π* excited states and the solvent shift of these complexes are interpreted by Reichardt-Dimroth and Marcus solvent functions. The results are consistent with prior assignments on the absorption band to a metal-to-ligand charge transfer excited state associated with chelating ligand.

Fluorescence spectral studies of some imidazole derivatives.

The photophysical properties of imidazole derivatives namely 2-(2,4-difluorophenyl)-4,5-dimethyl-1-p-tolyl-1H-imidazole and N,N-dimethyl-4-(4,5-dimethyl-2-phenyl-1H-imidazol-1-yl)benzenamine, synthesized from an unusual four components assembling, were studied in several solvents. Polarization also plays major role in the increase of excited-state dipole moment (μ(e)). From the spectral results, it was found that there is equilibrium between neutral species and monocationic (MC) species in polar aprotic and polar protic solvents.

Synthesis, spectral studies and solvatochromic analysis of novel imidazole derivatives.

Bioactive imidazole derivatives were synthesized and characterized by spectral techniques. The photophysical properties of imidazole derivatives were studied in several solvents. The observed spectral shift is attributed to a loss of planarity in the excited state provided by the non-co-planarity of the aryl rings attached to C(2) and N(1) atoms of the imidazole ring.

Light-emitting materials from cyclometalated heteroleptic iridium(III) complexes--A physicochemical study.

Phosphorescent studies of 2-arylimidazole heteroleptic cyclometalated iridium(III) complexes with picolinic acid as the ancillary ligand were made. The observed experimental data reveal that these complexes possess dominantly (3)MLCT and (3)π-π* excited states and the solvent shift of these complexes is interpreted by Reichardt-Dimroth and Marcus solvent functions. The results are consistent with prior assignments on the absorption band to a metal-to-ligand charge transfer excited state associated with chelating ligand.

Luminescent study on the binding interaction of bioactive imidazole with bovine serum albumin-A static quenching mechanism.

Novel bioactive imidazole derivatives were synthesized and characterized by NMR spectra, mass and CHN analysis. The interaction between the imidazole derivative and bovine serum albumin (BSA) was investigated by fluorescence and UV-vis absorption spectroscopy. The fluorescence quenching of BSA by the imidazole derivatives may be due to the formation of imidazole-BSA complex.

Synthesis, crystal structure, Kamlet-Taft and Catalan solvatochromic analysis of novel imidazole derivatives.

Novel imidazole derivatives were synthesized and its crystal structure has been studied by single crystal XRD analysis. The photophysical properties of these imidazole derivatives were studied in several solvents, which include a wide range of apolar, polar and protic media. The observed lower fluorescence quantum yield may be due to an increase in the non-radiative deactivation rate constant.

Physicochemical studies of bioactive heterocycles of some novel imidazole derivatives as sensitive NLO materials.

Some novel imidazole derivatives were developed as highly sensitive chemisensors for transition metal ions. A prominent fluorescence enhancement was found in the presence of transition metal ions such as Hg(2+), Pb(2+), Cu(2+), Zn(2+), Co(2+) and Fe(2+) and this was suggested to result from the suppression of radiationless transitions from the n-π* state in the chemisensors. By DFT calculation HOMO-LUMO energies were calculated, the electric dipole moment (μ) and the hyperpolarizability (β) of the investigated molecules have been studied experimentally and also theoretically.

A physiochemical study of azo dyes: DFT based ESIPT process.

Azo linked dye derivatives were synthesized and characterized by NMR, mass and elemental analysis. An excited state intramolecular proton transfer (ESIPT) in hydroxy Schiff base has been analyzed, and found that two distinct ground state isomers of I and II are responsible for the observed dual emission. DFT calculation on energy, dipole moment, charge distribution of the rotamers in the ground and excited states support the ESIPT process.

Physicochemical studies of some novel Y-shaped imidazole derivatives--a sensitive chemisensor.

Some novel Y-shaped imidazole derivatives were developed for highly sensitive chemisensors for transition metal ions. A prominent fluorescence enhancement was found in the presence of transition metal ions such as Hg(2+), Pb(2+) and Cu(2+) and it is due to the suppression of radiationless transitions from the n-π* state in the chemisensors. The HOMO-LUMO energies, electric dipole moment (μ) and the first-hyperpolarizability (β) values of the investigated molecule have been studied theoretically which reveal that the synthesized molecules have microscopic non-linear optical (NLO) behaviour with non-zero values.

Synthesis and physicochemical studies of some novel picrate derivatives.

(1)H and (13)C NMR spectra were recorded for some novel picrate derivatives derived from some 3,3-methyl-2,6-diarylpiperidin-4-ones and 3-benzyl-2,6-diarylpiperidin-4-one. The difference in the chemical shift of equatorial methylene proton and axial methylene proton at C(5) [Δ = δ(eq)-δ(ax)] is highly negative which is in contrast to the value observed in the corresponding parent piperidin-4-ones and this is attributed to the syn 1,3-diaxial interaction between the axial N-H bond and axial hydrogen at C-5. The effect of protonation on the chemical shifts was studied in detail.

Physicochemical studies of green phosphorescent light-emitting materials from cyclometalated heteroleptic iridium(III) complexes.

A series of novel imidazole ligands were synthesized and characterized. Phosphorescence studies of series of heteroleptic cyclometalated iridium(III) complexes reveal that these complexes possess dominantly (3)MLCT and (3)π-π* excited states and the solvent shifts of these complexes are interpreted by Richardt-Dimroth and Marcus solvent functions. The results consistent with prior assignments on the absorption band to a metal-to-ligand charge transfer excited state associated with chelating ligand.

Fluorescence resonance energy transfer from a bio-active imidazole derivative 2-(1-phenyl-1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl)phenol to a bioactive indoloquinolizine system.

Novel donor imidazole derivative, 2-(1-phenyl-1H-imidazo [4,5-f][1,10]phenanthrolin-2-yl)-phenol (PIPP) was screened as highly sensitive chemisensor for transition metal ions and it can be used as a "multi-way" optically switchable material. Solvatochromic effects on the fluorescence behaviour of PIPP were studied in different solvents. The fluorescence of PIPP was highly sensitive to both the polarity as well as protic nature of the solvent.

An intramolecular charge transfer fluorescent probe: synthesis, structure and selective fluorescent sensing of Cu+2.

A series of substituted imidazoles have been synthesized in very good yield under solvent free condition by grinding 1,2-diketone, aromatic aldehyde and ammonium acetate in the presence of molecular iodine as the catalyst. The short reaction time, good yield and easy workup make this protocol practically and economically attractive and characterized by NMR spectra, X-ray, mass and CHN analysis. An excited state intramolecular proton transfer (ESIPT) process in hydroxy imidazoles (dpip and dptip) have been studied using emission spectroscopy and it was detected that the two distinct ground state rotamers are responsible for the normal and the tautomer emissions.

Physicochemical studies of molecular hyperpolarizability of imidazole derivatives.

A series of substituted imidazoles have been synthesized in very good yield under solvent free condition by grinding 1,2-diketone, arylaldehyde, arylamine and ammonium acetate in the presence of molecular iodine as the catalyst. The short reaction time, good yield and easy workup make this protocol practically and economically attractive and the imidazoles are characterized by NMR spectra, X-ray, mass and CHN analysis. The push-pull character of series of imidazoles have been analyzed by the quotient of the occupations of the bonding (π) and anti-bonding (π*) orbitals of the central linking -N=C-C=C- unit.

Evidence for strong mixing between the LC and MLCT excited states in some heteroleptic iridium(III) complexes.

The synthesis, structure and photophysical properties of series of new luminescent cyclometalated Iridium (III) complexes are reported. The cyclometalated ligand used here is 2-aryl imidazole and the auxiliary ligand is acetyl acetone (acac). The crystal structure of the complex (dmdpi)(2)Ir(acac) (5) show that the Iridium(III) ion resides in a distorted octahedral environment.

Synthesis, structure, luminescent and intramolecular proton transfer in some imidazole derivatives.

A group of novel 2-aryl imidazole derivatives were synthesized and characterized by NMR spectra, X-ray, mass and CHN analysis. An excited state intramolecular proton transfer (ESIPT) process in hydroxy imidazoles (dmip and dmtip) have been studied using emission spectroscopy and it was detected that the two distinct ground state rotamers of I and II are responsible for the normal and the tautomer emission respectively. In hydrocarbon solvent, the tautomer emission predominates over the normal emission for both dmip and dmtip.

Iridium(III) complexes with orthometalated phenylimidazole ligands subtle turning of emission to the saturated green colour.

A series of novel six iridium complexes (1-6) bearing two substituted phenylimidazole and an additional acetylacetone as the third co-auxilary ligand are reported. The lowest absorption band for all iridium complexes consist of a mixture of heavy atom Ir(III) enhanced (3)MLCT and (3) π-π* transitions and the phosphorescent peak wavelength can be fine-tuned to cover the spectral range 455-518 nm with high quantum efficiencies. The peak wavelength of the dopants can be finely tuned depending upon the electronic properties of the substituents.

Synthesis and photophysics of some novel imidazole derivatives used as sensitive fluorescent chemisensors.

Some novel imidazole derivatives were developed for highly sensitive chemisensors for transition metal ions. Since these compounds are sensitive to different external stimulations such as UV irradiation, heat, increasing pressure and changing the environmental pH causing colour change and so they can be used as a 'multi-way' optically switchable material. A prominent fluorescence enhancement was found in the presence of transition metal ions such as Hg(2+), Pb(2+) and Cu(2+) and this was suggested to result from the suppression of radiationless transitions from the n-π* state in the chemisensors.