Impact of tunable 2-(1-indol-3-yl)acetonitrile based fluorophores towards optical, thermal and electroluminescence properties.

Herein, we have synthesized 4,5-diphenyl-1-imidazole and 2-(1-indol-3-yl)acetonitrile based donor-π-acceptor fluorophores and studied their optical, thermal, electroluminescence properties. Both the fluorophores exhibit high fluorescence quantum yield ( = <0.6) and good thermal stability ( = <300 °C), and could be excellent candidates for OLED applications.

Half-sandwich Ru(η-p-cymene) complexes featuring pyrazole appended ligands: Synthesis, DNA binding and in vitro cytotoxicity.

Organometallic Ru(II)-arene complexes have emerged as potential alternatives to platinum appended agents due to their wide range of interesting features such as stability in solution and solid, significant activity, less toxicity and hydrophobic property of arene moiety, etc. Hence, a series of Ru(II)-p-cymene complexes, [(η-p-cymene)Ru(η-N,N-L1)Cl]Cl (1), [(η-p-cymene)Ru(η-N-L2)Cl] (2) and [(η-p-cymene)Ru(η-N-L3)Cl] (3) were prepared from pyrazole based ligands [2-(1H-pyrazol-3-yl)pyridine (L1), 3-(furan-2-yl)-1H-pyrazole (L2) and 3-(thiophen-2-yl)-1H-pyrazole (L3)], and [RuCl-(η-p-cymene)] dimer. The new Ru(II)-p-cymene complexes were well characterized by elemental analysis, and spectroscopic (FT-IR, UV-Visible, H NMR, C NMR and mass) and crystallographic methods.

Biomolecular Interaction, Anti-Cancer and Anti-Angiogenic Properties of Cobalt(III) Schiff Base Complexes.

Two cobalt(III) Schiff base complexes, trans-[Co(salen)(DA)](ClO) (1) and trans-[Co(salophen)(DA)](ClO) (2) (where salen: N,N'-bis(salicylidene)ethylenediamine, salopen: N,N'-bis(salicylidene)-1,2-phenylenediamine, DA: dodecylamine) were synthesised and characterised using various spectroscopic and analytical techniques. The binding affinity of both the complexes with CT-DNA was explored adopting UV-visible, fluorescence, circular dichroism spectroscopy and cyclic voltammetry techniques. The results revealed that both the complexes interacted with DNA via intercalation as well as notable groove binding.

Evaluation of the Leaf Essential Oil from and Its Larvicidal and Repellent Activity against Dengue Fever Vector -An Experimental and Molecular Docking Investigation.

is a mosquito vector that spreads dengue fever and yellow fever worldwide in tropical and subtropical countries. Essential oil isolated from is found to have larvicidal and repellent action against this vector. The dried leaves were subjected to hydrodistillation using a clevenger-type apparatus for 4 h.

Structure and Reactivity of Pd Complexes in Various Oxidation States in Identical Ligand Environments with Reference to C-C and C-Cl Coupling Reactions: Insights from Density Functional Theory.

Bonding and reactivity of [(N4)Pd CHX] complexes have been investigated at the M06/BS2//B3LYP/BS1 level. Feasible mechanisms for the unselective formation of ethane and methyl chloride from mono-methyl Pd complexes and selective formation of ethane or methyl chloride from Pd complexes are reported here. Density functional theory (DFT) results indicate that Pd is more reactive than Pd and Pd in different oxidation states that follow different mechanisms.

Are cucurbiturils better drug carriers for bent metallocenes? Insights from theory.

Bent metallocenes (BM) have anti-tumor properties but they face a serious drug efficacy problem due to poor aqueous solubility and rapid hydrolysis under physiological conditions. These two problems can be fixed by encapsulating them in host molecules such as cyclodextrin (CD), cucurbituril (CB) etc. Experimentally, CD-BM, CB-BM host-guest complexes have been investigated to check the efficiency of the drug delivery and efficiency of the encapsulated drug.

A multispectroscopic and molecular docking investigation of the binding interaction between serum albumins and acid orange dye.

The interaction of Acid Orange 10 (AO10) with bovine serum albumin (BSA) was investigated comparatively with that of human serum albumin (HSA) using multispectroscopic techniques for understanding their toxic mechanism. Further, density functional theory calculations and docking studies have been carried out to gain more insights into the nature of interactions existing between AO10 and serum albumins. The fluorescence results suggest that AO10 quenched the fluorescence of BSA through the combination of static and dynamic quenching mechanism.

Surfactant-cobalt(III) complexes: The impact of hydrophobicity on interaction with HSA and DNA - insights from experimental and theoretical approach.

To develop surfactant-based metallodrugs, it is very important to know about their hydrophobicity, micelle forming capacity, their interaction with biomacromolecules such as proteins and nucleic acids, and biological activities. Here, diethylenetriamine (dien) and tetradecylamine ligand (TA) based surfactant-cobalt(III) complexes with single chain domain, [Co(dien)(TA)Cl]ClO (1) and double chain domain [Co(dien)(TA)Cl](ClO) (2) were chosen to study the effect of hydrophobicity on the interaction with human serum albumin and calf thymus DNA. The obtained results showed that (i) single chain surfactant-cobalt(III) complex (1) interact with HSA and DNA via electrostatic interaction and groove binding, respectively; (ii) double chain surfactant-cobalt(III) complex (2) interact with HSA and DNA via hydrophobic interaction and partial intercalation, respectively, due to the play of hydrophobicity by single and double chain domains.

Structural elucidation and physicochemical properties of mononuclear Uranyl(VI) complexes incorporating dianionic units.

Two derivatives of organouranyl mononuclear complexes [UO2(L)THF] (1) and [UO2(L)Alc] (2), where L = (2,2'-(1E,1'E)-(2,2-dimethylpropane-1,3-dyl)bis(azanylylidene, THF = Tetrahydrofuran, Alc = Alcohol), have been prepared. These complexes have been determined by elemental analyses, single crystal X-ray crystallography and various spectroscopic studies. Moreover, the structure of these complexes have also been studied by DFT and time dependent DFT measurements showing that both the complexes have distorted pentagonal bipyramidal environment around uranyl ion.

Elucidating the structures and cooperative binding mechanism of cesium salts to the multitopic ion-pair receptor through density functional theory calculations.

Designing new and innovative receptors for the selective binding of radionuclides is central to nuclear waste management processes. Recently, a new multi-topic ion-pair receptor was reported which binds a variety of cesium salts. Due to the large size of the receptor, quantum chemical calculations on the full ion-pair receptors are restricted, thus the binding mechanisms are not well understood at the molecular level.

Insights from the computational studies on the oxidized as-isolated state of [NiFeSe] hydrogenase from D. vulgaris Hildenborough.

A density functional theory study of the active site structure and features of the oxygen tolerant [NiFeSe] Hase in the oxidized as-isolated state of the enzyme D. vulgaris Hildenborough (DvH) is reported here. The three conformers reported to be present in the X-ray structure (PDB ID: ) have been studied.

Luminescent Re(I) terpyridine complexes for OLEDs: what does the DFT/TD-DFT probe reveal?

The electronic structure and spectroscopic properties of a series of rhenium(I) terpyridine complexes were investigated using density functional theory (DFT) and time dependent density functional theory (TD-DFT) methods. The influence of different substituent groups on the optical and electronic properties of Re(I) terpyridine complexes has also been explored. The reorganization energy calculations show that the substituted Re(I) terpyridine complexes are better electron transport materials with high quantum efficiency in OLED devices due to their high electron transport mobility and low λ(electron) values, whereas the unsubstituted complex shows relatively balanceable charge transfer abilities with the higher efficiency in organic light emitting devices (OLEDs).

Novel uranyl(VI) complexes incorporating propylene-bridged salen-type N2O2-ligands: a structural and computational approach.

The synthesis of the tetradentate dianionic ligand, H2L (2,2'-(1E,1'E)-(2,2-dimethylpropane-1,3-dyl)bis(azanylylidene)bis(methanylylidene)diphenol), from 2,2-dimethyl-1,3-diaminopropane and its reaction with UO2(CH3COO)2·2H2O in a 1:1 molar ratio in methanol to produce the complex [UO2(L)(CH3OH)] are reported. The isolated compounds have been characterized by elemental analysis, ionization mass spectrometry (ESI-MS), UV/Vis, FT-IR, (1)H- and (13)C-NMR, DEPT-135 spectroscopy, TGA and single-crystal X-ray diffraction. As shown by X-ray crystallography, the coordination geometry around the uranium centre is distorted pentagonal bipyramidal with two imine nitrogen atoms, two phenolic oxygen atoms and one methanol O atom occupying equatorial sites, together with two axial oxo groups.

Influence of self-assembly on intercalative DNA binding interaction of double-chain surfactant Co(III) complexes containing imidazo[4,5-f][1,10]phenanthroline and dipyrido[3,2-d:2'-3'-f]quinoxaline ligands: experimental and theoretical study.

A new class of surfactant Co(III) complexes, cis-[Co(ip)2(C12H25NH2)2](ClO4)3 (1) and cis-[Co(dpq)2(C12H25NH2)2](ClO4)3 (2) (ip = imidazo[4,5-f][1,10]phenanthroline, dpq = dipyrido[3,2-d:2'-3'-f]quinoxaline), have been synthesized and characterized by various spectroscopic and physico-chemical techniques. The critical micelle concentration (CMC) values of these complexes in aqueous solution were obtained from conductance measurements. The specific conductivity data (at 303, 308, 313, 318 and 323 K) served for the evaluation of the temperature-dependent CMC and the thermodynamics of micellization (ΔG(0)(m), ΔH(0)(m) and ΔS(0)(m)).

Are Re(i) phenanthroline complexes suitable candidates for OLEDs? Answers from DFT and TD-DFT investigations.

The electronic structure and spectroscopic properties of seven recently reported rhenium(i) phenanthroline complexes were investigated theoretically by density functional theory (DFT) and time dependent density functional theory (TD-DFT) methods. All the seven complexes are shown here to be better electron transport materials with high quantum efficiency in OLED devices due to their high electron transport mobility and low λ(electron) values. Particularly, among these seven chosen complexes the difference between λhole and λ(electron) for tricarbonyl Re(i) complexes is smaller, suggesting that these complexes have a better hole- and electron-transport balance in OLED devices.

Surfactant-copper(II) Schiff base complexes: synthesis, structural investigation, DNA interaction, docking studies, and cytotoxic activity.

A series of surfactant-copper(II) Schiff base complexes (1-6) of the general formula, [Cu(sal-R2)2] and [Cu(5-OMe-sal-R2)2], {where, sal=salicylaldehyde, 5-OMe-sal=5-methoxy- salicylaldehyde, and R2=dodecylamine (DA), tetradecylamine (TA), or cetylamine (CA)} have been synthesized and characterized by spectroscopic, ESI-MS, and elemental analysis methods. For a special reason, the structure of one of the complexes (2) was resolved by single crystal X-ray diffraction analysis and it indicates the presence of a distorted square-planar geometry in the complex. Analysis of the binding of these complexes with DNA has been carried out adapting UV-visible-, fluorescence-, as well as circular dichroism spectroscopic methods and viscosity experiments.

Atomic partitioning of M-H2 bonds in [NiFe] hydrogenase--a test case of concurrent binding.

The possibility of simultaneous addition of η(2)-H2 to both the metals (Ni and Fe) in the active site of the as isolated state of the enzyme (Ni-SI) is examined here by an atom-by-atom electronic energy partitioning based on the QTAIM method. Results show that the 4LS state prefers H2 removal than addition. Destabilization of the atomic basins of the thiolate bridges and decrease of the electrophilicity of the Fe and Ni, resulting in poor back donation to the CO ligand, are the bottlenecks that hamper dihydrogen activation simultaneously.

A new turn in codon-anticodon selection through halogen bonds.

The halogen bond is relatively a less characterized intermolecular interaction compared to the hydrogen bond and the structure, stability and electronic structures of halogenated base pairs, particularly at the wobble junction have been investigated using DFT. Three halogens, namely Cl, Br and I, have been tested for their role in such situations with uracil as the anticodon base. Computed results reveal that when halogen atoms replace protons in the hydrogen bonding positions they induce lot of geometric changes that flip some of the observed base pairs into unobserved base pairs and vice versa.

Highly emissive luminogens based on imidazo[1,2-a]pyridine for electroluminescent applications.

A search for novel organic luminogens led us to design and synthesize some N-fused imidazole derivatives based on imidazo[1,2-a]pyridine as the core and arylamine and imidazole as the peripheral groups. The fluorophores were synthesized through a multicomponent cascade reaction (A(3) coupling) of a heterocyclic azine with an aldehyde and alkyne, followed by Suzuki coupling and a multicomponent cyclization reaction. All of the compounds exhibited interesting photophysical responses, especially arylamine-containing derivatives, which displayed strong positive solvatochromism in the emission spectra that indicated a more polar excited state owing to an efficient charge migration from the donor arylamine to the imidazo[1,2-a]pyridine acceptor.

On the nature of hypercoordination in dihalogenated perhalocyclohexasilanes.

Hypercoordination in silicon has long been reviewed. Dihalogenated perhalocyclohexasilane inverse sandwich complexes (ISCs) are the only group of hypercoordinate Si complexes with anion donors that contact six neutral silicon atoms; opening prospective applications in Si self-assembled nanostructures. Hypercoordinate bonds in 16 such ISCs were studied and their anion ring interactions have been understood with respect to halides.

Sequence selectivity of azinomycin B in DNA alkylation and cross-linking: a QM/MM study.

Azinomycin B--a well-known antitumor drug--forms cross-links with DNA through alkylation of purine bases and blocks tumor cell growth. This reaction has been modeled using the ONIOM (B3LYP/6-31+g(d):UFF) method to understand the mechanism and sequence selectivity. ONIOM results have been checked for reliability by comparing them with full quantum mechanics calculations for selected paths.

Designing benzosiloles for better optoelectronic properties using DFT & TDDFT approaches.

Like siloles, benzosiloles have low lying LUMOs due to σ*-π* conjugation between Si and the butadiene moiety but are more amenable for structural tuning. In total, 27 benzosiloles, 12 of them already synthesized and another 15 newly reported here, have been investigated using DFT and TDDFT calculations with an aim to check their suitability for optoelectronic applications. Our results show that all these molecules have excellent π-conjugation throughout.

A combined experimental and computational study on the sulfoxidation by high-valent iron bispidine complexes.

Iron-bispidine complexes are efficient catalysts for the oxidation of thioanisole to phenylmethylsulfoxide with iodosylbenzene as oxidant. With the tetradentate bispidine ligand L(1) (L(1) = 2,4-pyridyl-3,7-diazabicyclo[3.3.

Spectroscopic studies on TiO(2) enhanced binding of Hypocrellin B with DNA.

The binding of Hypocrellin B-TiO(2) chelate with DNA has been studied by using absorption, steady state fluorescence, cyclic voltammetry, time resolved fluorescence and laser flash photolysis measurements. The experimental results show that the presence of TiO(2) nanoparticles increases the binding of Hypocrellin B with DNA. The groove binding mode is confirmed by spectroscopic and docking studies.

Antitumor activity of bent metallocenes: electronic structure analysis using DFT computations.

The antitumor activities of bent metallocenes [Cp-M-Cp](2+) (M = Ti, V, Nb, Mo) and complexes of them with guanine, adenine, thymine and cytosine nucleotides have been probed using electronic structure calculations. DFT/BP86 calculations have revealed that the bent metallocene-nucleotide interaction strongly depends on the stability of the hydrolyzed form of the bent metallocene dichloride [Cp(2)M](2+) species, and in turn the stability of the [Cp(2)M](2+) species strongly depends on the electronic structure of [Cp(2)M](2+). Detailed electronic structure and Walsh energy analyses have been carried out for the hydrolyzed forms of four [Cp-M-Cp](2+) (M = Ti, V, Nb, Mo) species to find out why the bent structure is unusually stable.