A mixed‐ligand quinazoline‐based Ni(II) Schiff base complex: Synthesis,characterization, crystal structure,antimicrobial investigation and catalytic activity for the synthesis of 2H–indazolo[2,1‐b]phthalazine‐triones

A tridentate Schiff base ligand, (E)‐3‐((2‐hydroxy‐3‐methoxybenzylidene)amino)‐2‐methylquinazolin‐4(3H)‐one [HL], and its mixed‐ligand Ni(II) complex [Ni(L)(imi)], were synthesized and fully characterized using elemental analysis, FT‐IR, UV–Vis and ¹HNMR spectroscopy techniques. The structure of the synthesized ligand and complex was determined with single crystal X‐ray diffraction method. In the complex, a square planner geometry was observed around the Ni(II) central atom coordinated with the donor atoms of the Schiff base ligand and one nitrogen of imidazole group. In addition, the catalytic activity of the complex on the three‐component condensation of hydrazine hydrate with phthalic anhydride and dimedone to obtain 2H–indazolo[2,1‐b]phthalazine‐triones was investigated. Furthermore, in‐vitro antimicrobial studies were performed that indicated the great antibacterial activities of the Ni(II) complex against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus cereus bacteria.     

Conjugated Azoalkenesi Part III. Synthesis of Sone Phosphorous Azoalkenes

Recently, some of us reviewed the synthes is and chemical reactions of conjugated azoalkenes.¹ Emphasis was placed on the fact that these derivatives represent at the same time interesting products and useful intermediates in organic chemistry. In fact, conjugated azoolefins undergo a wide range of 1,4-additions, (3+2)- and (4+2)-cycloadditions allowing various functionalizations of the carbon atom adjacent to the carbonyl group, and the construction of many types of interesting five - and six-membered heterocycles, such as widely substituted pyrrole and pyridazine rings. These relevant synthetic objectives appear not to be smoothly obtained by other procedures. In addition, many of the compounds produced from conjugated azoalkenes can profitably be employed in the preparation of natural, pharmaceutical, and phytopharmaceutical products.¹     

Chemical modification of methyl cellulose with HMDI to modulate the thickening properties in castor oil

This work deals with the selective incorporation of reactive isocyanate groups into methyl cellulose in order to be used as reactive thickening agent in castor oil. Resulting gel-like dispersions may have potential applications as green lubricating greases formulated from renewable resources. Two different isocyanate-functionalized methyl cellulose-based polymers were obtained by reaction of methyl cellulose with 1,6-hexamethylene diisocyanate. The functionalization degree, from fully functionalized to a certain number of free hydroxyl groups (58:36:6 ratio between –OMe, –NCO and free –OH groups), was controlled by modifying the reagents molar ratio. These polymers were characterized through nuclear magnetic resonance of protons (¹H-NMR), Fourier transform infrared spectroscopy and thermogravimetric analysis (TGA). Thermal and rheological responses of oleogels prepared by dispersing these polymers in castor oil were studied by means of TGA analysis and small-amplitude oscillatory shear measurements. The evolution of linear viscoelasticity functions with frequency of the oleogel containing isocyanate-functionalized methyl cellulose with lower –NCO content is quite similar to that found for traditional lithium lubricating greases. In relation to long-term stability of these oleogels, the values of viscoelastic functions significantly increase during the first 7 days of ageing and then remain almost constant.     

Oxidation of α-Acetoxy Acetals with Trichloroisocyanuric Acid

α-Acetoxy acid methyl esters are prepared in excellent yields by treating aliphatic α-acetoxy dimethyl acetals with trichloroisocyanuric acid in DMF.     

Effect of permodified β‐cyclodextrin on the photophysical properties of poly[2,7‐(9,9‐dioctylfluorene)‐alt‐(5,5′‐bithiophene)] main chain polyrotaxanes

The photophysical properties of two polyrotaxanes ( PFBTh?PSβCD and PFBTh?PMeβCD ) composed of fluorene and bithiophene encapsulated into permodified β‐cyclodextrin cavities have been investigated and compared with those of the reference PFBTh . Rotaxane formation results in improvements of the thermal stability, solubility in common organic solvents, as well as better film forming ability combined with a high transparency. As expected PFBTh and its encapsulated forms absorb at wavelengths beyond 510 nm, and time‐resolved photoluminescence (PL) in solution shows a well‐define vibronic structures with a predominance of the 0‐0 transitions and an energy difference of 0.16 eV. The fluorescence lifetimes follow a monoexponential decay with a value τ = 630 ± 30 ps. Atomic force microscopy, AFM, indicated a tendency of polyrotaxanes to organize into fibers. The advancing contact angles indicated higher surface hydrophobicity and lower surface free‐energy values for polyrotaxanes compared with their unthreaded analogues. The device based on PFBTh?PSβCD: PCBM in a 1/1 w/w ratio under simulated AM 1.5G illumination at 100 mW cm^?2 exhibited improved photovoltaic parameters of cells, resulted in high V_oc (0.68 V), J_sc (1.65 mA cm^?2), FF (31.6%), and PCE (0.35) values, compared with PFBTh or PFBTh?PMeβCD , respectively. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 460–471