title: Novel dimeric cholesteryl-based A(LS)2 low-molecular-mass gelators with a benzene ring in the linker.
abstract: Three novel dimeric cholesteryl-based A(LS)(2) low-molecular-mass organic gelators (LMOGs) with phthaloyl, isophthaloyl, or terephthaloyl moieties in the linkers were designed and prepared. According to the linker structures, the compounds are denoted as 1 (o-), 2 (m-), and 3 (p-), respectively. Gelation tests revealed that the difference of relative positions of two cholesterol moieties in the benzene ring can produce a dramatic change in the gelation behaviors of the compounds. Importantly, 2 and 3 are more efficient gelators than 1, and their self-assembly behaviors are also very different from each other as revealed by scanning electron microscopy (SEM) measurements. Very interestingly, 2 gels xylene spontaneously at room temperature, and the sol-gel phase transition of the system is mechanically controllable. FTIR and (1)H NMR spectroscopy studies revealed that hydrogen bonding and pi-pi interactions between the molecules of the gelators play an important role in the formation and maintenance of the gels. The X-ray diffraction (XRD) analysis revealed that in the gel of 2/benzene, 2 aggregated into a layered structure with an interlayer distance of 3.54 nm, which is just the length of 2.
authors.affiliation: Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Materials Science, Shaanxi Normal University, Xi'an 710062, People's Republic of China.
authors.forename: Min
authors.initials: M
authors.lastname: Xue
authors.forename: Kaiqiang
authors.initials: K
authors.lastname: Liu
authors.forename: Junxia
authors.initials: J
authors.lastname: Peng
authors.forename: Qiuhong
authors.initials: Q
authors.lastname: Zhang
authors.forename: Yu
authors.initials: Y
authors.lastname: Fang