Synthesis and characterization of new cardo poly(bisbenzothiazole)s containing cyclohexylidene units

A new diaminobenzenethiol 1,1-bis(4-amino-3-mercaptophenyl) cyclohexane dihydrochloride (BAMPCH · 2HCl) containing the bulky pendant cyclohexylidene group was synthesized from cyclohexanone in three steps. Its chemical structure was characterized by ¹H NMR, ¹³C NMR, MS, FT-IR and EA. Aromatic poly(bisbenzothiazole)s (PBTs) were prepared from the new monomer and five aromatic dicarboxylic acids by direct polycondensation. The inherent viscosities were in the range of 0.78-2.04 dL/g. These polymers exhibited good solubility and thermal stability. Most of the prepared PBTs were soluble in various polar solvents. The decomposition temperatures at 10% weight loss were in the range of 482-518 °C in nitrogen. X-ray diffractograms of PBTs showed that all polymers were amorphous.     

Synthesis and characterization of polybinaphthalene incorporating chiral (R) or (S)-1,1′-binaphthalene and oxadiazole units by Heck reaction

Chiral conjugated polymers P-1 and P-2 were synthesized by the polymerization of (R)-3,3′-diiodo-2,2′-bisbutoxy-1,1′-binaphthalene ((R)-M-1) and (S)-3,3′-diiodo-2,2′-bisbutoxy-1,1′-binaphthalene ((S)-M-1) with 2,5-bis(4-vinylphenyl)-1,3,4-oxadiazole (M-2) under Pd-catalyzed Heck coupling reaction, respectively. Both monomers and polymers were analysed by NMR, MS, FT-IR, UV, DSC-TG, fluorescent spectroscopy, GPC and CD spectra. The chiral conjugated polymers exhibit strong Cotton effect in their circular dichroism (CD) spectra indicating a high rigidity of polymer backbone. CD spectra of polymers P-1 and P-2 are almost identical and have opposite signs for their position. These polymers have strong blue fluorescence.     

Convexity of solutions and estimates for fully nonlinear elliptic equations

The starting point of this work is a paper by Alvarez, Lasry and Lions (1997) concerning the convexity and the partial convexity of solutions of fully nonlinear degenerate elliptic equations. We extend their results in two directions. First, we deal with possibly sublinear (but epi-pointed) solutions instead of 1-coercive ones; secondly, the partial convexity of C² solutions is extended to the class of continuous viscosity solutions. A third contribution of this paper concerns C^1,1 estimates for convex viscosity solutions of strictly elliptic nonlinear equations. To finish with, all the tools and techniques introduced here permit us to give a new proof of the Alexandroff estimate obtained by Trudinger (1988) and Caffarelli (1989).     

A novel method for thiiranation of alkenes with 1,1′-dithiobis(1H-1,2,4-triazole)

Eight alkenes reacted with 1,1′-dithiobis(1H-1,2,4-triazole) 4 at −15 °C to form the corresponding thiiranes in moderate to good yields. The thiiranations of anti- and syn-9,9′-bibenzonorbornenylidenes and cis- and trans-cyclooctenes with 4 proceeded with retention of configuration of the starting alkenes.     

Facile synthesis of 6-iodo-2,2′-dipivaloyloxy-1,1′-binaphthyl, a key intermediate of high reactivity for selective palladium-catalyzed monofunctionalization of the 1,1′-binaphthalene core

A high-yielding procedure for selective monoiodination of 2,2′-dihydroxy-1,1′-binaphthyl (BINOL) is reported. 6-Iodo-2,2′-dipivaloyloxy-1,1′-binaphthyl, obtained in three steps starting from BINOL in 88% overall yield, proved to be a highly efficient substrate in various palladium-catalyzed coupling (Stille, Heck, Sonogashira, and Suzuki coupling) and carbonylation reactions compared to the analogous 6-bromo derivative.     

Synthesis of Dinaphtho-dioxaphosphepin-4-oxides, Epoxides and Bisphosphonates

A few new seven-membered phosphorus heterocyclic compounds and bis-phosphonates (5a—5g, 5f’, 5g’, 9 and 10) were prepared by the reaction of 4-bromo dioxaphosphepin (2) with various Grignard reagents followed by their oxidation with H2O2. All the compounds were thoroughly characterized by elemental analysis, IR, 1H, 13C, 31P NMR and mass spectral data. Their antimicrobial activity was evaluated and some of them possess significant activity.     

含联吡啶，Eu(III)或Gd(III)的手性高分子配合物的合成及荧光性质研究

手性高分子P–1由(R)-5,5′-二溴-6,6′-二(4-三氟甲基苯基)-2,2′-二正辛氧基-1,1′-联萘(R–M–1)和5,5′-二乙烯基-2,2′-联吡啶(M–2)通过Pd催化的Heck偶合反应合成得到,高分子配合物P-2和P-3由高分子P-1与Eu(TTA)3·2H2O和Gd(TTA)3·2H2O (TTA– = 2-噻吩甲酰三氟丙酮)反应生成。手性高分子P-1能发射强的蓝色荧光,这是由于手性重复单元(R)-6,6′-二(4-三氟甲基苯基)-2,2′-二正辛氧基-1,1′-联萘和单元2,2′-联吡啶通过亚乙烯基桥连形成共轭高分子结构造成的。在不同的激发波长激发下,含Eu(III)的高分子配合物P–2不仅显示高分子荧光,还可显示Eu(III) (5D0→7F2)特征荧光。含Gd(III)的高分子配合物P–3仅发射高分子荧光。基于高分子及含RE(III)的高分子配合物的荧光性质研究发现,共轭高分子并没有把能量转移到Eu(III)或Gd(III) 配合物部分,只发射它自身的荧光,含Eu(III)的高分子配合物P–2发射Eu(III) (5D0→7F2)特征荧光能量主要来源于配阴离子TTA–。     

Ferrous methanesulfonate as an efficient and recyclable catalyst for chemoselective synthesis of 1,1-diacetate from aldehydes

Ferrous methanesulfonate catalysing the conversion of aromatic,heteroaromatic,unsaturated,and aliphatic aldehydes to 1,1- diacetates at room temperature under solvent-free condition has been developed.The catalytic activity of seventeen metal methanesulfonates was compared under the same condition,ferrous methanesufonate proved to be the best.It can be easily recovered and reused for several times without distinct deterioration in catalytic activity.During the competitive protection between a ketone and ...     

灰色GM(1,1)模型的改进模型在房地产价格指数预测中的应用

提出了一种结合非线性回归技术的灰色GM(1,1)模型的改进模型.利用我国的房地产价格指数预测作为研究对象,用以验证所提方法的有效性和准确性.根据实证结果,说明了新的改进模型有效提高了经典灰色模型的预测精度.