Quinone-Bodipy H-bonding interaction over π-stacking in toluene.

Quinone type compounds (o-chloranil, p-chloranil and DDQ) demonstrate excellent H-bonding interactions with a meso-phenol Bodipy dye (1) in both ground and excited state in a non-polar toluene medium. The spectroscopic detection of isosbestic absorption occurs with both quinones and fullerenes, but only quinones form isoemissive complexes with dye 1. (1)H NMR study and Monte Carlo global minima searching justified the above mentioned results with efficiency.

Synthesis and photophysics of selective functionalized π-conjugated, blue light emitting, highly fluorescent C7-imidazo indolizine derivatives.

A new family of novel highly fluorescent π-conjugated, C7-imidazole based indolizine derivatives has been prepared in good to excellent yields, catalysed by l-proline in acetonitrile. These are π-conjugated, C7-imidazole based indolizine derivatives covering the emission wavelength range 423-449 nm in acetonitrile with high quantum yields at 25 °C. A thorough photophysical study of all the compounds has been carried out to understand the π-conjugated electronic effect of the imidazole moiety fused at the C7 position on the indolizine motif. In addition, a comparative photophysical study of three selective fluorophores was also carried out in a wide variety of solvents at 25 °C. Finally, the molecular orbitals of the two representative compounds were investigated through DFT calculations to illustrate the pi-conjugate effect.

Microbes and microbial strategies in carcinogenic polycyclic aromatic hydrocarbons remediation: a systematic review.

Degradation, detoxification, or removal of the omnipresent polycyclic aromatic hydrocarbons (PAHs) from the ecosphere as well as their prevention from entering into food chain has never appeared simple. In this context, cost-effective, eco-friendly, and sustainable solutions like microbe-mediated strategies have been adopted worldwide. With this connection, measures have been taken by multifarious modes of microbial remedial strategies, i.e., enzymatic degradation, biofilm and biosurfactant production, application of biochar-immobilized microbes, lactic acid bacteria, rhizospheric-phyllospheric-endophytic microorganisms, genetically engineered microorganisms, and bioelectrochemical techniques like microbial fuel cell. In this review, a nine-way directional approach which is based on the microbial resources reported over the last couple of decades has been described. Fungi were found to be the most dominant taxa among the CPAH-degrading microbial community constituting 52.2%, while bacteria, algae, and yeasts occupied 37.4%, 9.1%, and 1.3%, respectively. In addition to these, category-wise CPAH degrading efficiencies of each microbial taxon, consortium-based applications, CPAH degradation-related molecular tools, and factors affecting CPAH degradation are the other important aspects of this review in light of their appropriate selection and application in the PAH-contaminated environment for better human-health management in order to achieve a sustainable ecosystem.

Non-covalent interactions between epinephrine and nitroaromatic compounds: A DFT study.

Here, we present a density functional theory (DFT) study of hydrogen bonding and π-π stacking interactions between epinephrine and different aromatic nitro-compounds in gas phase as well as in methanol solvent. Detail investigations of hydrogen bonding and π-π interactions are performed and confirmed on the basis of theoretical IR spectra, natural bond orbital (NBO) analysis, non-covalent interaction (NCI), chemical reactivity descriptors and electronic spectra. Among different functionals used for the calculation, the results obtained from ωB97XD functional are found to be more suitable to describe the hydrogen bonding and π-π stacking phenomenon for our considered systems. Weakening of hydrogen bonding and π-π stacking interaction on solvent incorporation is observed. Electronic transition between different orbitals and transition probabilities of epinephrine and nitro-aromatic complexes are described using time dependent density functional theory (TD-DFT) method.

Spectroscopic and theoretical studies of charge-transfer interaction of 1-(2-pyridylazo)-2-napthol with nitroaromatics.

1-(2-Pyridylazo)-2-napthol (hereafter 1Q) is widely used as a chelating ligand applied in chelatometric, spectrophotometric analysis of metal ions. It appeared from the literature survey that no inclusion complex of 1Q was reported with nitroaromatics. The formation of charge-transfer complex gives an opportunity to improve the physico-chemical properties of different donors. So the complex of 1Q with 4-nitrophenol (4-NP), 2,4-dinitrophenol (2,4-DNP), picric acid (PA), and 3,5-dinitrosalicylic acid (3,5-DNSA) was described in this work in methanol medium. The ground and excited state binding constants and other spectroscopic data have been determined using UV-vis and fluorescence spectroscopic studies. All the complexes have been synthesized and characterized using FT-IR, 1H NMR, and elemental analysis. Spectroscopic data reveal that 1Q joins by a N+HO- type hydrogen bond with nitroaromatics. Job's plot of the continuous variation of absorbance indicates that stoichiometry of CT-complex was 1:1. Thermal stability of the synthesized complex has determined by TGA-DTA analysis. Energy-minimization DFT calculation further supported the formation of the H-bonded charge-transfer adduct.

Recognition of steric factor in external association of xanthenocrown-5 and bis-napthalenocrown-6 with bis(benzimidazolium)propane borontetrafluoride.

This is the first report of charge transfer band for crown-axel H-bonding interaction in acetonitrile medium. Monte Carlo simulation established external association of small cavity crown with BBIM-propane dication axels. Resonance energy, binding constant and ratiometric detection of association of xanthenocrown-5 (1) and bis-napthalenocrown-6 (2) with bis-(benzimidazolium)propane borontetrafluoride (3a-3d) in acetonitrile determined the effect of steric factor towards association.

Charge transfer in the electron donor-acceptor complexes of a meso-phenol BODIPY dye with chloranils and fullerenes.

UV-Vis spectral investigations of electron donor-acceptor complexes of laser dye 2,6-Diethyl-4,4-difluoro-1,3,5,7-tetramethyl-8-(4'-hydroxyphenyl)-4-bora-3a,4a-diaza-s-indecene (1c) with chloranils and fullerenes are reported in toluene medium. Well defined charge transfer (CT) absorption bands have been located in the visible region. Oscillator strengths, transition dipole and resonance energies of the CT complexes have been estimated. Vertical ionization potential of 1c has been determined utilizing Mulliken's equation. A possible mechanism for the interaction between electronic subsystems of chloranils, [60]- and [70]fullerenes with three different BODIPY dyes (1a, 1b and 1c shown in Fig. 1) have been discussed in comparing the parameters like degree of charge transfer and binding constant in nonpolar toluene. Comparison of 1c complexes is done with DFT/B3LYP/6-31G optimized gas phase geometries.