Synthesis and characteristics of a novel pseudorotaxane with the diarylethene as the functional stopper

A Visible–Near‐Infrared Light‐Responsive Host–Guest Pair with Nanomolar Affinity in Water

“…Diarylethenes (DAE) have attracted considerable interest owing to their outstanding photochromic properties . In previously reported CBn:DAE complexes, the macrocycle binds to peripheral groups decorating the DAE rather than the photoactive unit, precluding significant differences in the stability of the complexes upon switching between the open and closed forms . Preliminary experiments suggested that CB7 binds 1 through the pyridinium units with 2:1 stoichiometry and moderate affinity (above the μ m range) for both 1 o and 1 c forms (see Supporting Information, SI, Figures S4–S7).…”

“…[42] In previously reported CBn:DAE complexes, the macrocycle binds to peripheralgroups decorating the DAE rather than the photoactive unit, precluding significant differences in the stabilityo f the complexesu pons witching between the open and closed forms. [43][44][45] Preliminary experimentss uggested that CB7 binds 1 through the pyridinium units with 2:1s toichiometry and moderate affinity (above the mm range) for both 1o and 1c forms (see Supporting Information, SI, Figures S4-S7). ESI-MS experiments also showed that both 1o and 1c form 1:1c omplexes with CB8 (see the SupportingI nformation, FigureS8), which is supported by UV/Vis titrations( Figure 1 www.chemeurj.org spectralchanges with well-defined isosbestic points can be observed, indicatingt hat CB8 forms stable (K > 1 10 7 m À1 )1 :1 host-guest complexes with 1o and 1c.I np articular,t he spectrum of 1o undergoes ac a.…”

Threading-gated photochromism in [2]pseudorotaxanes

“…Despite the widespread use of bis(thienyl)ethenes as molecular photoswitches,19 only a few examples of [2]pseudorotaxanes20 and [2]rotaxanes21 containing this moiety as a structural component or signalling unit have been reported. As such, we report herein the design and synthesis of 4,5-bis(benzothienyl)-2-phenylimidazolium axles and show that their association with 24-crown-8 ethers results in significant enhancement of the photochromic properties of the axles.…”

Photo-responsive [2]catenanes: synthesis and properties

“…6 Tian et al found that the dithienylethene unit could be used as a stopper in the construction of rotaxane. 7 Subsequently, they reported a multi-state [2]rotaxane based on the dithienylethene unit which could alter intercomponent interactions in a photochromic multi-state [2]rotaxane. 8 Recently, Liu and coworkers reported a [2]pseudorotaxane formed from an unsymmetrical diarylperfluorocyclopentene and a Eu 3+ complex of terpyridinyldibenzo-24-crown-8, which revealed dual-stimulus luminescence lanthanide molecular switching behavior modulated by host-guest interaction and optical stimuli.…”