4‐(4‐Fluoro‐3‐phenoxy­phen­yl)‐6‐(4‐fluoro­phen­yl)‐2‐oxo‐1,2‐dihydro­pyridine‐3‐carbonitrile and the 6‐(4‐methyl­phen­yl)‐ analogue

The crystal structures of the title compounds, viz. C₂₄H₁₄F₂N₂O₂, (I), and C₂₅H₁₇FN₂O₂, (II), respectively, have been determined in order to unravel the role of an ordered F atom in generating stable supra­molecular assemblies. On changing the substitution from fluorine to a methyl group, C—H⋯F inter­actions are replaced by C—H⋯π inter­actions, revealing the importance of such weak inter­actions when present alongside N—H⋯O and C—H⋯O hydrogen bonds. The dihedral angle between the planes of the 4‐fluoro­phenyl ring and the pyridine ring is 26.8 (1)° in (I), while that between the planes of the 4‐methyl­phenyl and pyridine rings is 29.5 (1)° in (II).     

Synthesis of 4-(2-chloroethyl)-2,3-dihydro[1,4]oxazino[2,3-b]quinoline and 4-(2-chloroethyl)2,3-dihydropyrido[2,3-b][1,4]oxazine

The title compounds were synthesized from 3-[bis(2-hydroxyethyl)amino]quinolin-2(1H)-one 11a and 3-[bis(2-hydroxyethyl)amino]pyridin-2(1H)-one 18 respectively. The preparation involved a tandem chlorination/cyclization reaction.     

A family of oxorhenium(v) complexes incorporating chelated monoanionic ONN reduced Schiff base and dianionic ONNO tetradentate ligands: synthesis, spectroscopic and electrochemical studies

The green colored complexes of the type Re(V)O(L(SB))Cl(2), 1, have been synthesised by reacting NBu(4)[ReOCl(4)] with HL(SB) in dry ethanol. Here, L(SB)(-) are the deprotonated forms of N-(2-hydroxybenzyl)-2-picolylamine (HL(SB)(1)); N-(2-hydroxybenzyl)-N',N'-dimethylethylenediamine (HL(SB)(2)) and N-(2-hydroxybenzyl)-N',N'-diethylethylenediamine (HL(SB)(3)). Similarly, NBu(4)[ReOCl(4)] reacted with N,N-bis(2-hydroxybenzyl)-2-picolylamine (H(2)L(1)); N,N-bis(2-hydroxybenzyl)-N',N'-dimethylethylenediamine (H(2)L(2)); N,N-bis(2-hydroxybenzyl)-N',N'-diethylethylenediamine (H(2)L(3)); [N-(2-hydroxybenzyl)-N-(2-pyridylmethyl)]-2-aminoethanol (H(2)L(4)); [N-(2-hydroxybenzyl)-N-(2-pyridylmethyl)]-2-methyl-2-amino-1-propanol (H(2)L(5)); N,N-bis(1-hydroxyethyl)-2-picolylamine (H(2)L(6)), to give the monochloro complexes Re(V)O(L)Cl, 2. The X-ray structures of the complexes are reported. The molecular structures observed in the solid state are preserved in solution ((1)H NMR). In acetonitrile solution the Re(V)O(L)Cl, 2, display a one-electron couple, Re(VI)O(L)Cl(+)-Re(V)O(L)Cl, near 1.0 V vs SCE. The electrogenerated hexavalent complexes [Re(VI)O(L)Cl]ClO(4), 3, are paramagnetic and display sextet EPR spectra in solution at room temperature (A(av) approximately 417 (G), g approximately 1.914).     

Palladium catalyzed atom-efficient cross-coupling reactions of triarylbismuths with aryl bromides

Aryl bromides (3 equiv) were coupled efficiently with triarylbismuths (1 equiv) in an atom-efficient way using the Pd(OAc)₂/PPh₃ catalytic system in the presence of K₃PO₄ as base in DMF at 90 °C, providing excellent yields of the cross-coupled biaryls in short reaction times.     

Studies on defect formation in femtosecond laser-irradiated PMMA and PDMS

We report here our results on the spectroscopic and elemental analysis of femtosecond (fs) laser-modified regions in polymers of polymethylmethacrylate (PMMA) and polydimethylsiloxane (PDMS) in the context of defect formation and emission in the visible region. Different physical and chemical models are used to explain the changes in modified regions. We found that the emission intensity, recorded from the fs-modified regions of polymers, decreased over time to a constant value. We also demonstrate that these materials are suitable for the preparation of the microstructures en route for light guiding applications. The fs laser-irradiated regions exhibited paramagnetic behavior as was confirmed from electron spin resonance studies through the formation of peroxide-type free radicals. Raman mapping was performed in the modified regions which consisted of defects and found that the modulations in intensity are predominant in the central portion of the structure compared to edges. Elemental analysis has been performed in the modified regions using field emission scanning electron microscope instrument and energy-dispersive X-ray absorption spectroscopy to estimate the percentage contents of individual elements which resulted in defect formation such as paramagnetic and optical centers.     

Synthesis,Characterization, Electrochemical and Antimicrobial Studies of Iron(II) and Nickel(II) Macrocyclic Complexes

Russian Journal of Electrochemistry - Herein, we synthesized [12] membered pyridine based transition metal macrocyclic complexes [MIILCl2] (M = Fe(II) and Ni(II), L = 6,12,5,11-tetraphenyl...