thioether-linked dimers and trimers was carried out to reveal molecular designs for inducing mesophases and twist-bendnematic (NTB) phases. A five-fold approach based on molecular structural parameters including the terminal substituent, the position of the thioether bond, the nature of the bridge bond linking benzene rings in the mesogenic fragments, the nature of bonds at the linkage on the side oppose
Carbon supported hybrid catalysts for controlled product selectivity in the hydrosilylation of alkynes
作者:Max Roemer、Vinicius R. Gonçales、Sinead T. Keaveney、Indrek Pernik、Jiaxin Lian、James Downes、J. Justin Gooding、Barbara A. Messerle
DOI:10.1039/d0cy02136a
日期:——
A series of Rh- and Ir-hybrid catalysts with varying tether lengths has been prepared by immobilization of RhI, RhIII and IrIII complexes on carbon black via radical grafting. The performance of the different catalysts was assessed for the hydrosilylation of phenylacetylene with Et3SiH. The efficiency of the catalysts was dependent on the length of the tethers to the surface. The RhIII- and IrIII hybrids
Visible light-promoted ring-opening functionalization of unstrained cycloalkanols<i>via</i>inert C–C bond scission
作者:Dongping Wang、Jincheng Mao、Chen Zhu
DOI:10.1039/c8sc01763h
日期:——
light-promoted ring-opening functionalization of unstrained cycloalkanols. Upon scission of an inert cyclic C–C σ-bond, a set of medium- and large-sizedrings are readily brominated under mild reaction conditions to afford the corresponding distal bromo-substituted alkyl ketones that are hard to synthesize otherwise. The products are versatile building blocks, which are easily converted to other valuable
Controlling spontaneous chirality in achiral materials: liquid crystal oligomers and the heliconical twist-bend nematic phase
作者:M. M. Majewska、E. Forsyth、D. Pociecha、C. Wang、J. M. D. Storey、C. T. Imrie、E. Gorecka
DOI:10.1039/d1cc07012f
日期:——
ed mesogenic units connected by either linear or bent alkoxy or alkyl spacers are reported. These materials, although built from achiral molecules, show the spontaneously chiral heliconical twist-bendnematic (NTB) phase. We report the relationships between the shape of the oligomer, and the NTBphase stability, the temperature dependence of the helical pitch length and tilt angle, birefringence, and
液晶低聚物,即二聚体、三聚体和四聚体,由氰基联苯和亚苄基苯胺基介晶单元组成,通过直链或弯曲的烷氧基或烷基间隔物连接。这些材料虽然由非手性分子构成,但显示出自发的手性螺旋扭曲向列相 (N TB )。我们报告了低聚物的形状与 N TB相稳定性、螺旋螺距长度和倾斜角的温度依赖性、双折射和弹性常数之间的关系。