Tetrahedron ( IF 2.1 ) Pub Date : 2017-08-26 , DOI: 10.1016/j.tet.2017.08.046 Nozomi Saito , Higashi Kobayashi , Masahiko Yamaguchi
A water-soluble ethynylhelicene (M)-tetramer with TEG groups exhibited the inverse thermoresponse in water/triethylamine/acetone, in which heating induced the formation of double helix and cooling dissociation. In this study, we examined the solvent effect with regard to water content at temperatures between 5 and 40 °C, and showed that the inverse thermoresponse occurred in different aqueous solution systems. In acetone, the oligomer exhibited the ordinary thermoresponse: Cooling induced the formation of double helix and heating dissociation. The increase in water content to approximately 10% caused the switch to the inverse thermoresponse. Further increase inhibited the association, and did not induce the thermoresponse. When the water content was increased to approximately 50%, the inverse thermoresponse appeared as observed previously study. Two types of inverse thermoresponses, termed type I and II, appeared at high and low water contents, respectively.
中文翻译:
水性有机混合溶剂体系中水溶性螺旋烯低聚物的逆热响应
水溶性ethynylhelicene(中号具有TEG基团的)-四聚体在水/三乙胺/丙酮中表现出相反的热响应,其中加热引起双螺旋的形成和冷却离解。在这项研究中,我们研究了温度在5至40°C之间时溶剂对水分含量的影响,并显示了相反的热响应发生在不同的水溶液系统中。在丙酮中,低聚物表现出普通的热响应:冷却引起双螺旋的形成和加热解离。含水量增加到大约10%导致转换为逆热响应。进一步的增加抑制了缔合,并且没有引起热响应。当水含量增加到大约50%时,就会出现逆热响应,如先前的研究所示。