Design and synthesis of triptycene based fluorescent polymer with pendent triazole: Effect of functionality on host–guest interaction

Fluorescent materials have emerged as one of the promising candidates for chemical sensing due to their high sensitivity towards analytes that are relatively electron deficient such as nitroaromatics (NACs). Herein, four new 1,2,3‐triazole functionalized dibromo monomers ( 2‐5 ) have been synthesized. These dibromo monomers ( 2‐5 ) have been subsequently polymerized with 2,6‐diethynyltriptycene ( DET ) to yield four new ethynyl linked polymers ( P2‐P5 ) with 1,2,3‐triazole pendent. These polymers are organosoluble, amorphous in nature and have high thermal stability [T_d > 289 °C and high char yield (>73%) at 800 °C]. Interestingly these new polymers ( P2‐P5 ) are highly fluorescent in solution (Φ = 0.37–0.43 in DCM) relative to the polymer ( P1 ) that does not have the 1,2,3‐triazole motif as a pendent. The host–guest interaction between these polymers ( P1‐P5 ) and electron deficient molecules (PA and C₆₀) has been investigated. The Stern–Volmer quenching constant (K_SV) data suggest that the interaction of picric acid and polymers increases significantly in presence of 1,2,3‐triazole linked pendent group whereas in case of C₆₀, the K_SV value decrease considerably in presence of 1,2,3‐triazole linked pendent. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3725–3735     

Copper–Schiff base complex catalyzed oxidation of sulfides with hydrogen peroxide

A straightforward, efficient, and selective oxidation of sulfide to sulfoxide with 30% H₂O₂ catalyzed by copper(II)–Schiff base complex is described. The reactions proceed under mild conditions in acetonitrile at room temperature to provide a variety of aryl and alkyl sulfoxides in excellent yield.     

Synthesis and structural properties of a 1-D copper(I) coordination polymer

A coordination polymer catena-chloro(4-pyridinecarboxylic acid)copper(I): [Cu(C₆H₅ O₂N)Cl]_n (1) has been prepared directly by reacting Cu^IICl₂ 2H₂O and 4-cyanopyridine in the presence of disodium maleate under hydrothermal conditions at 140°C. Crystal data for 1 are as follows: monoclinic, P2₁/n, a = 16.4623(9) Å, b = 3.7795(2) Å, c = 24.7612(11) Å, = 101.534(1)°, V = 1509.5(1) ų, Z = 4, D _calc. = 1.955 g cm^–3, R1 = 0.0511, wR2 = 0.1060 for all 2666 reflections. In this 1-D stair-polymer, two [Cu–Cl–Cu]_n zigzag chains are held together by weak interchain Cu–Cl bonds. The 4-pyridinecarboxylic acid ligands derived from the 4-CNpy molecules coordinate to the approximately tetrahedral Cu(I) centers through pyridyl-N atoms. The carboxyl ends of 4-pyridinecarboxylic acid participate in interchain hydrogen-bonding interactions to form a 2-D supramolecular network.     

Certain transformations and special values of hypergeometric functions over finite fields

The Ramanujan Journal - In this article we find finite field analogues of certain transformations satisfied by the classical hypergeometric series. Using properties of Gauss and Jacobi sums we...     

Structural, thermal and spectroscopic properties of supramolecular coordination solids

Molecules in metal isonicotinate tetrahydrates, M(NC₅H₄-p-CO₂)₂.4H₂O with M = Mn, Fe, Co, Ni, Cu, Zn, consisting of the hexacoordinate complexestrans-[M(NC₅H₄-p-CO₂)(OH₂)₄], participate in exhaustive hydrogen-bond formation among themselves to lead to a robust 3D supramolecular network in the solid state. Solid-state diffuse reflectance UV-Vis-NIR spectra of the complexes have been assigned to ligand field and charge transfer transitions. Sharp weight loss due to dehydration, as shown by TGA of Cu(NC₅H₄-p-CO₂)₂.4H₂O, suggests the suitability of this complex for the gravimetric estimation of copper.     

Influence of Ligand Architecture on Oxidation Reactions by High‐Valent Nonheme Manganese Oxo Complexes Using Water as a Source of Oxygen

Mononuclear nonheme Mn^IV?O complexes with two isomers of a bispidine ligand have been synthesized and characterized by various spectroscopies and density functional theory (DFT). The Mn^IV?O complexes show reactivity in oxidation reactions (hydrogen‐atom abstraction and sulfoxidation). Interestingly, one of the isomers (L¹) is significantly more reactive than the other (L²), while in the corresponding Fe^IV?O based oxidation reactions the L²‐based system was previously found to be more reactive than the L¹‐based catalyst. This inversion of reactivities is discussed on the basis of DFT and molecular mechanics (MM) model calculations, which indicate that the order of reactivities are primarily due to a switch of reaction channels (σ versus π) and concomitant steric effects.     

Benzyltrimethylammoniumfluoride Hydrate: An Efficient Catalyst for One‐Pot Synthesis of Hantzsch 1,4‐Dihydropyridines and Their Aromatization

An efficient, cost‐effective and simple protocol has been developed for the synthesis of Hantzsch 1,4‐dihydropyridines and their oxidation into pyridines using benzyltrimethylammonium fluoride hydrate as an excellent catalyst under solvent‐free condition. All of the products synthesized by this method are characterized by various spectroscopic methods (IR, ¹H NMR, ¹³C NMR, and DEPT).     

Synthesis,characterization, and applications with the manifestation of antifungal activity and seed germination properties of nickel doped zinc oxide nano platform by biochemical contrivance

In the recent era, nanotechnology, a rapidly emerging field, has been explored as the most studied field worldwide. The goal of this study is to use neem leaves extract as an effective ‘reducing agent’ and ‘stabilizing agent’ in the green synthesis of bio-medically important Zn_1-XNi_XO (X = 0.00, 0.04, 0.08, 0.12) nanoparticles. The molar concentrations of nickel nitrate and zinc nitrate are varied to produce nickel-doped ZnO nanoparticles. Color change is the first indicator of nanoparticle formation during this biosynthesis. The hexagonal wurtzite structure with good crystallinity is confirmed by X-ray diffraction. FTIR analysis reveals the fact that the Zn–O stretching vibration shifts with the introduction of impurities into the ZnO matrix. UV–Vis spectra show the typical surface plasma resonance around 370 nm and the hydrodynamic diameter is larger than the size calculated from the XRD value, according to DLS. The main finding of this study is that Ni_0.12Zn_0.88O has a strong antifungal activity against and a significant growth rate after treating wheat seeds with biologically synthesized Ni_0.12Zn_0.88O nanoparticles.