Surface Initiated Polymerization on Pulsed Plasma Deposited Polyallylamine: A Polymer Substrate‐Independent Strategy to Soft Surfaces with Polymer Brushes

The deposition of polyallylamine (PAA) adlayers by pulsed plasma polymerization on various types of polymeric substrates has been explored as a general route to amino functionalized polymeric surfaces. These amino groups are highly suitable for anchoring an atom transfer radical polymerization (ATRP) initiator via a robust amide linkage. Subsequent surface initiated ATRP (SI‐ATRP) of monomethoxy oligo(ethylene glycol) methacrylate (MeOEGMA) resulted in polyMeOEGMA brush grafted polymer surfaces. This combined strategy of pulsed plasma polymerization with SI‐ATRP was demonstrated for five different polymeric substrates namely polyether ether ketone (PEEK), polyethylene terephthalate (PET), polyimide (PI), polypropylene (PP), and polytetrafluoroethylene (PTFE). Analysis of brush layers by attenuated total reflection infrared (ATR‐IR) spectroscopy as well as X‐ray photoelectron spectroscopy (XPS) fully corroborated the success of the proposed strategy for all substrate types.

     

Evaluation of the Electrophilicites and Band Gaps of Conductive Polymers: A New Model

It is shown that the obtained hardness and electrophilicity values of the short length oligomers for a heterocyclic conductive polymer from density functional theory method are quadraticly correlated to those obtained from semiempirical method. Therefore these quantities for all oligomers (up to 15 repeating units) are predicted using the obtained quadratic relations. Both of these predicted quantities for different oligomers are fitted to a new exponential model (Y = Y_∞ e^d/n) to estimate the electronic properties for the considered conjugated polymers. The calculated band gaps from this model show better agreement with the reported experimental data than those predicted by the previous models. Because of a wide range of variations, the electrophilicity could be a better index for investigating the doping effect in polymers than the hardness.

     

Photocatalytic decolorization of Brilliant Golden Yellow in TiO2 and ZnO suspensions

Photocatalytic decolorization of BGY, an anionic dye, has been investigated in TiO₂ and ZnO aqueous dispersions under UV-light irradiation. Spectrum of the dye has been found unaffected in the pH range 4.21–11.30. Adsorption is a prerequisite for the metal oxide-mediated photodegradation/photodecolorization and the extent of decolorization has been discussed in terms of the Langmuir–Hinshelwood model. Complete decolorization was achieved in case of UV irradiation whereas degradation of BGY was found to be about ca.75%. ZnO-mediated decolorization has appeared to be better and faster. The effects of various parameters, such as catalyst loading, pH and initial concentration of the dye on decolorization have been investigated.     

Merging tribenzotriquinacene with hexa-peri-hexabenzocoronene: a cycloheptatriene unit generated by Scholl reaction

The single-wing extension of the bowl-shaped tribenzotriquinacene (TBTQ) framework with polycondensed aromatic hydrocarbon units has been reported. In the course of a Scholl reaction, one of the three-dimensional bays of the TBTQ core has been bridged by a PAH unit to generate a seven-membered ring within the merged TBTQ-(hexa-peri-hexabenzocoronene) scaffold.     

A Theoretical Study of NBO,NICS, and 14N NQR Parameters of Adenine Tautomers in the Gas Phase via DFT

The natural bond orbital (NBO) analysis, nucleus independent chemical shift (NICS), and ¹⁴N NQR parameters of the most stable tautomers of adenine in the gas phase were predicted using density functional theory method. The NBO analysis revealed that the resonance interaction between lone pair of the nitrogen atom and empty non‐Lewis NBO increases with increasing the p character of the nitrogen lone pair. The present investigation indicated the π clouds in both the considered heterocyclic rings containing six electrons, and these tautomers has the aromatic character. The NICS study utilizing the gauge‐invariant atomic orbital method showed that there are diatropic currents in the heterocyclic rings of the tautomers, so we determined the order of overall aromaticity of these tautomers. The results of NQR parameter calculations showed three parameters are effective on nuclear quadrupole coupling constant; the p character value of lone pair electrons of nitrogens, and the related occupancies and whenever, the lone pair electrons of nitrogens participate in the formation of chemical bond and/or π system of the ring, the q_zz and consequently its χ decreases.     

Ajuganane: a new phenolic compound from Ajuga bracteosa

Phytochemical investigation of Ajuga bracteosa Wall ex Benth. (Labiatae) resulted in the isolation of a new phenolic compound, ajuganane (1) and three known compounds, 3,4'-dihydroxy-3,6,7-trimethoxyflavone, 7-hydroxy-3,6,3',4'-tetramethoxyflavone and ursolic acid. The structure of the new compound was elucidated by detailed spectroscopic (1H, 13C NMR, COSY, HMQC, HMBC), and HR-EI-MS analysis.     

Solubility of LIDOCAINE in Ionic, Nonionic and Zwitterionic Surfactants

The solubility of an anesthetic drug, LIDOCAINE, in water was investigated in the presence of ionic, nonionic and zwitterionic surfactants at 25 °C, and the solubility was found to increase linearly with the surfactant concentration. The molar solubilization ratio, R _m,s, and Gibbs free energy, DG_s^o\Delta G_{\mathrm{s}}^{\mathrm{o}} values for nonionic surfactants fall in the order DDAO > Brij 35 > Brij 30, whereas for ionic and zwitterionic surfactants the order is DDAPS > DTAB > SDS. The high negative values of the Gibbs energies in the cases of DDAO and DDAPS prove them to be better surfactants for solubilizing this drug as compared to the other surfactants.     

Solvent-free and three-component synthesis of 1H,6H-6λ5-[1,2]benzoxaphospholo[2,3-b][1,2]benzoxaphosphol-1-ones

A concise and facile synthesis of a new class of P,O-heterocycles is described. Knoevenagel condensation reaction of a salicylaldehyde and a cyclohexane-1,3-dione forms an α,β-unsaturated intermediate, which undergoes nucleophilic addition of a trialkyl phosphite under solvent-free conditions to afford the title compounds in good to excellent yields.     

Microwave-assisted reaction between 2-aminobenzoic acids, 2-hydroxybenzaldehydes,and arylboronic acids: a one-pot three-component synthesis of bridgehead bicyclo[4.4.0]boron heterocycles

A one-pot three-component synthesis of 6-aryl-8H-dibenzo[d,h][1,3,7,2]dioxazaborecin-8-ones is described. A mixture of 2-aminobenzoic acid, 2-hydroxybenzaldehyde, and arylboronic acid undergo a 1:1:1 addition reaction in CCl₄ under microwave irradiation to produce bridgehead bicyclo[4.4.0]boron heterocycles in excellent yields.     

Synthesis of diarylmethanes via a Friedel-Crafts benzylation using arenes and benzyl alcohols in the presence of triphenylphosphine ditriflate

Triphenylphosphine ditriflate (TPPD) was found to be an efficient promoter for the Friedel-Crafts benzylation of arenes with benzyl alcohols in CH₂Cl₂ at room temperature. The good yields, the 1:1 molar ratio of arene and benzyl alcohol, the benzylation of chlorobenzene as a nonactivated aromatic compound at room temperature, and no by-product formation are the main advantages of this procedure.