Crystal Structure and Molecular Conformational Studies of Allyl 6-Amino-5-cyano-4-(4-fluorophenyl)-2-methyl-4H-pyran-3-carboxylate

Crystallography Reports - The allyl 6-amino-5-cyano-4-(4-fluorophenyl)-2-methyl-4H-pyran-3-carboxylate, C17H15FN2O3, compound adopts a triclinic crystal system with the sp. gr. $$P\bar {1}$$, Z =...     

Kinetics and Thermodynamics of Formation and Electron‐Transfer Reactions of Surfactant Cobalt(III) Complexes Containing Polypyridyl Ligands with Fe(CN)64− in Microheterogeneous Environment

The electron‐transfer reaction of some surfactant cobalt(III) complexes, cis‐[Co(ip)₂(C₁₂H₂₅NH₂)₂]³⁺ 1 , cis‐[Co(dpq)₂(C₁₂H₂₅NH₂)₂]³⁺ 2 , and cis‐[Co(dpqc)₂(C₁₂H₂₅NH₂)₂]³⁺ 3 (ip = imidazo[4,5‐f][1,10]phenanthroline, dpq = dipyrido[3,2‐d:2′‐3′‐f]quinoxaline, dpqc = dipyrido[3,2‐a:2′,4′‐c](6,7,8,9‐tetrahydro)phenazine, C₁₂H₂₅NH₂ = dodecylamine) with the Fe(CN)₆^4? ion has been investigated in microheterogeneous media (micelles, β‐cyclodextrin) at different temperatures by the spectrophotometric method under pseudo‐first‐order conditions using an excess of the reductant. Experimentally, the reaction was found to be second order and the electron transfer postulated as an outer sphere. The rate constant for the electron‐transfer reaction in micelles was found to increase with an increase in the initial concentration of the surfactant–cobalt(III) complex. This peculiar behavior of dependence of the second‐order rate constant on the initial concentration of one of the reactants has been attributed to the presence of various concentrations of micelles under different initial concentrations of the surfactant–cobalt(III) complex in the reaction medium. Inclusion of the long aliphatic chain of the surfactant complex ion into β‐cyclodextrin leads to decrease in the rate constant. Kinetic data and activation parameters are interpreted in terms of an outer‐sphere electron‐transfer mechanism. All these results have been interpreted in terms of the hydrophobic effect and the reactants with the opposite charge.     

Optical,theoretical and mechanical studies on sodium acid phthalate crystal

The semiorganic crystal of sodium acid phthalate (NaAP) single crystals was grown in the solvent of water by slow evaporation method at room temperature. The single crystal X-ray diffraction studies showed the crystal belongs to orthorhombic system. The optical absorption spectrum reveals that the crystal has good transparency in entire visible region. The hardness number of the material is measured by microhardness tester. The fluorescence green colour emission exhibits is semiorganic. The SHG efficiency of NaAP crystal confirms NLO behaviour of green colour emission to provide frequency doubling process for photo electronic applications.     

Four cocrystals of thymine with phenolic coformers: influence of the coformer on hydrogen bonding

Cocrystals are molecular solids composed of at least two types of neutral chemical species held together by noncovalent forces. Crystallization of thymine [systematic name: 5‐methylpyrimidine‐2,4(1H,3H)‐dione] with four phenolic coformers resulted in cocrystal formation, viz. catechol (benzene‐1,2‐diol) giving thymine–catechol (1/1), C₅H₆N₂O₂·C₆H₆O₂, (I), resorcinol (benzene‐1,3‐diol) giving thymine–resorcinol (2/1), 2C₅H₆N₂O₂·C₆H₆O₂, (II), hydroquinone (benzene‐1,4‐diol) giving thymine–hydroquinone (2/1), 2C₅H₆N₂O₂·C₆H₆O₂, (III), and pyrogallol (benzene‐1,2,3‐triol) giving thymine–pyrogallol (1/2), C₅H₆N₂O₂·2C₆H₆O₃, (IV). The resorcinol molecule in (II) occupies a twofold axis, while the hydroquinone molecule in (III) is situated on a centre of inversion. Thymine–thymine base pairing is common across all four structures, albeit with different patterns. In (I)–(III), the base pair is propagated into an infinite one‐dimensional ribbon, whereas it exists as a discrete dimeric unit in (IV). In (I)–(III), the two donor N atoms and one carbonyl acceptor O atom of thymine are involved in thymine–thymine base pairing and the remaining carbonyl O atom is hydrogen bonded to the coformer. In contrast, in (IV), just one donor N atom and one acceptor O atom are involved in base pairing, and the remaining donor N atom and acceptor O atom of thymine form hydrogen bonds to the coformer molecules. Thus, the utilization of the donor and acceptor atoms of thymine in the hydrogen bonding is influenced by the coformers.     

Sequential change in one-pot,three-component protocol: A stepping stone in heterocyclic synthesis

Two different heterocycles, thiazole-2-imines and imidazole-2-thiones, have been conveniently synthesized by just altering the sequential order (1 + 2 + 3 or 1 + 3 + 2) when combining the same components [aryl amine (1), aryl isothiocyanate (2), and phenacyl bromide (3)] in one-pot, three-component protocols. The third possible sequential order of combination (2 + 3 + 1) chemoselectively affords thiazole-2-imine. The finding is a stepping stone in the synthetic applicability of sequential one-pot, three-component protocols.