Benzimidazolium-based new simple ratiometric fluorescent sensor for selective detection of dihydrogenphosphate

A series of pyridine-coupled benzimidazolium-based receptors 1, 2 and 3 have been designed and synthesised. In the series, only receptor 1 is structurally appealing in the selective recognition of H₂PO₄^?  in CHCl₃ as well as in CH₃CN over a series of other anions. The ratiometric change in emission with a triplet band at 420 nm is the distinctive feature of selective recognition of H₂PO₄^?  in CHCl₃. In CH₃CN, a ‘turn on’ response is selectively observed. Binding studies have been carried out using fluorescence, UV–vis, ¹H NMR and ³¹P NMR spectroscopic techniques. Experimental results have been correlated with the theoretical findings.     

Cooperative Catalysis by Palladium and a Chiral Phosphoric Acid: Enantioselective Amination of Racemic Allylic Alcohols

Cooperative catalysis by [Pd(dba)₂] and the chiral phosphoric acid BA1 in combination with the phosphoramidite ligand L8 enabled the efficient enantioselective amination of racemic allylic alcohols with a variety of functionalized amines. This catalytic protocol is highly regio‐ and stereoselective (up to e.r. 96:4) and furnishes valuable chiral amines in almost quantitative yield.     

Electrically Controlled Eight‐Spin‐Qubit Entangled‐State Generation in a Molecular Break Junction

The generation of spin‐based multi‐qubit entangled states in the presence of an electric field is one of the most challenging tasks in current quantum‐computing research. Such examples are still elusive. By using non‐equilibrium Green′s function‐based quantum‐transport calculations in combination with non‐collinear spin density functional theory, we report that an eight‐spin‐qubit entangled state can be generated with the high‐spin state of a dinuclear Fe(II) complex when the system is placed in a molecular break junction. The possible gate operation scheme, gating time, and decoherence issues have been carefully addressed. Furthermore, our calculations reveal that the preservation of the high spin state of this complex is possible if the experimentalists keep the electric‐field strength below 0.78 V nm^?1. In brief, the present study offers a unique way to realize the first example of a multi‐qubit entangled state by electrical means only.     

A goal programming model for the best possible solution to loan allocation problems

In this paper, we propose a multi-criteria decision making approach to address the problem of finding the best possible solution in credit unions. Sensitivity analysis on the priority structure of the goals has been performed to obtain all possible solutions. The study uses the Euclidean distance method to measure distances of all possible solutions from the identified ideal solution. The possible optimum solution is determined from the minimum distance between the ideal solution and other possible solutions of the problem.     

Selective CO2 Adsorption in a Supramolecular Organic Framework

Considering the rapidly rising CO₂ level, there is a constant need for versatile materials which can selectively adsorb CO₂ at low cost. The quest for efficient sorptive materials is still on since the practical applications of conventional porous materials possess certain limitations. In that context, we designed, synthesized, and characterized two novel supramolecular organic frameworks based on C‐pentylpyrogallol[4]arene (PgC₅) with spacer molecules, such as 4,4′‐bipyridine (bpy). Highly optimized and symmetric intermolecular hydrogen‐bonding interactions between the main building blocks and comparatively weak van der Waals interactions between solvent molecules and PgC₅ leads to the formation of robust extended frameworks, which withstand solvent evacuation from the crystal lattice. The evacuated framework shows excellent affinity for carbon dioxide over nitrogen and adsorbs ca. 3 wt % of CO₂ at ambient temperature and pressure.     

Cadmium–halide and mixed cadmium–halide–dicyanamide polymers mediated by ancillary 2-aminoalkyl-pyridine ligands: Synthesis,X-ray single crystal structures and luminescence property

A series of mixed halide–dicyanamide and halide complexes of cadmium(II) mediated by 2-aminoalkyl-pyridine ligands [2-aminomethylpyridine (ampy) and 2-aminoethylpyridine (aepy)] have been synthesized. Five of them, [CdCl(dca)(aepy)]_n (1), [CdBr(dca)(ampy)]_n (2), [CdCl(dca)(ampy)]_n (3) (dca = dicyanamide); [CdI₂(aepy)]_n (4), and [CdI₂(ampy)]_n (5), (dca = dicyanamide) have been characterized by X-ray single crystal structure analysis. The structural determination shows that the compounds are 1D coordination polymers, with the exception of 3 that gives origin to a 2D sheet-like network. The ampy and aepy ligands (also with the occurrence of dca anions in 1–3) reveal to be useful ancillary fragments for the construction of unprecedented Cd–halide polymeric species. The crystal packing shows that the dimensionality of all compounds is enlarged to 2D, and 3D in the case of complex 3, through π–π interactions occurring between the pyridine rings. All the species exhibit interesting luminescence property in solution as well in solid state which is originated from ligand-centered π–π^∗ transitions. The fluorescence band maxima and fluorescence efficiency (in methanol) are found to be dependent not only on the pyridine ligand but also on the type of halide, and the co-ligand. Solid state luminescent study implies that π–π interactions occurring between pyridine rings are also important in controlling the fluorescence intensity. Amongst the synthesized complexes reported, complex 5 exhibits the highest fluorescence efficiency in methanol.     

Pd PEPPSI-IPr-mediated reactions in metal-coated capillaries under MACOS: the synthesis of indoles by sequential aryl amination/Heck coupling

A method has been devised for the microwave-assisted, continuous-flow preparation of indole alkaloids by a two-step aryl amination/cross-coupling sequence of bromoalkenes and 2-bromoanilines. This process requires both the presence of a metal-lined flow tube (a 1180 micron capillary) and the Pd PEPPSI-IPr catalyst; without either, the catalyst or the film, there is zero turnover of this catalytic process. A silver film has been shown to provide some conversion (48-62 %), but optimal results (quantitative) across a variety of bromoalkenes and bromoanilines were achieved by using a highly porous palladium film. Possible roles for the Pd film are considered, as is the interplay of the catalyst and the film.     

Synthesis,crystal structure and antibacterial activity of four mononuclear Schiff base complexes of copper(II) and nickel(II)

Transition Metal Chemistry - Three mononuclear copper(II) complexes, viz. [CuL1] (1), [CuL2] (2), [CuL3] (3), and one nickel(II) complex, viz.[NiL3] (4) where...     

Hydrazine selective dual signaling chemodosimetric probe in physiological conditions and its application in live cells

A rhodamine–cyanobenzene conjugate, (E)-4-((2-(3′,6′-bis(diethylamino)-3-oxospiro[isoindoline-1,9′-xanthene]-2-yl)ethylimino)methyl)benzonitrile (1), which structure has been elucidated by single crystal X-ray diffraction, was synthesized for selective fluorescent “turn-on” and colorimetric recognition of hydrazine at physiological pH 7.4. It was established that 1 detects hydrazine up to 58 nM. The probe is useful for the detection of intracellular hydrazine in the human breast cancer cells MCF-7 using a fluorescence microscope. Spirolactam ring opening of 1, followed by its hydrolysis, was established as a probable mechanism for the selective sensing of hydrazine.