13458-62-3Relevant academic research and scientific papers
Isomeric squaraine-based [2]pseudorotaxanes and [2]rotaxanes: Synthesis, optical properties, and their tubular structures in the solid state
Xue, Min,Su, Yong-Sheng,Chen, Chuan-Feng
, p. 8537 - 8544 (2010)
On the basis of formation of [2]pseudorotaxane complexes between triptycene-derived tetralactam macrocycles la and lb and squaraine dyes, construction of squaraine-based [2]rotaxanes through clipping reactions were studied in detail. As a result, when two symmetrical squaraines 2d and 2e were utilized as templates, two pairs of isomeric [2]rotaxanes 3a-b and 4a-b as diastereomers were obtained, owing to the two possible linking modes of triptycene derivatives. It was also found, interestingly, that when a nonsymmetrical dye 2 g was involved, there existed simultaneously three isomers of [2]rotaxanes in one reaction due to the different directions of the guest threading. The 1H NMR and 2D NOESY NMR spectra were used to distinguish the isomers, and the yield of [2]rotaxane 5 a with the benzyl group in the wider rim of the host la was found to be higher than that of another isomer 5 b with an opposite direction of the guest, which indicated the partial selection of the threading direction. The X-ray structures of 3 b and 4 a showed that, except for the standard hydrogen bonds between the amide protons of the hosts and the carbonyl oxygen atoms of the guests, multiple Ji-Ji stacking and C-H-ji interactions between triptycene subunits and aromatic rings of the guests also participated in the complexation. Crystallographic studies also revealed that the [2]rotaxane molecules 3 b and 4 a further self-assembled into tubular structures in the solid state with the squaraine dyes inside the channels. In the case of 4 a, all the nonsymmetrical macrocyclic molecules pointed in one direction, which suggests the formation of oriented tubular structures. Moreover, it was also found that the squaraines encapsulated in the triptycenederived macrocycles were protected from chemical attack, and subsequently have potential applications in imaging probes and other biomedical areas.
Squaraine-derived rotaxanes: Sterically protected fluorescent near-IR dyes
Arunkumar, Easwaran,Forbes, Christopher C.,Noll, Bruce C.,Smith, Bradley D.
, p. 3288 - 3289 (2005)
A squaraine dye with bulky end groups is employed as the thread component in two Leigh-type amide rotaxanes. The rotaxanes are synthesized in a simple two-step process. X-ray crystal structures of the rotaxanes show that the pyridyl-containing macrocycle
Squaraine rotaxanes with boat conformation macrocycles
Fu, Na,Baumes, Jeffrey M.,Arunkumar, Easwaran,Noll, Bruce C.,Smith, Bradley D.
experimental part, p. 6462 - 6468 (2010/01/16)
(Chemical Equation Presented) Mechanical encapsulation of fluorescent, deep-red bis(anilino)squaraine dyes inside Leigh-type tetralactam macrocycles produces interlocked squaraine rotaxanes. The surrounding macrocycles are flexible and undergo rapid excha
