نتایج جستجو برای: rotaxane
تعداد نتایج: 512 فیلتر نتایج به سال:
Linear molecular motors have recently attracted considerable interest. In this paper we use molecular dynamics simulations to investigate the structural and energetic properties of neutral and oxidized [2]rotaxane motors. We first consider a neutral structure to identify the stable configuration of a bistable [2]rotaxane whose ring component is on the tetrathiafulvalene (TTF) recognition site, ...
The photothermal effect is the generation of heat by molecules or particles upon high-energy laser irradiation, and near-infrared absorbers such as gold nanoparticles and organic dyes have a range of potential photothermal applications. The favourable photothermal properties of thiophene-functionalised croconaine dyes were recently discovered. The synthesis and properties of novel croconaine ro...
While the current supramolecular syntheses of [2]rotaxanes are generally efficient, the final product always retains the functional groups required for non-covalent preorganization. A short and high-yielding covalent-template-assisted approach is reported for the synthesis of a [2]rotaxane. A terephthalic acid template core preorganizes the covalently connected ring precursor fragments to induc...
A ferrocene appended rotaxane is prepared by chloride anion templation and ring closing metathesis. Upon removal of the chloride template, the rotaxane is demonstrated to be selective for chloride over more basic oxoanions by (1)H NMR spectroscopy and electrochemistry, in marked contrast to an acyclic analogue--the first example of a solution based redox-active interlocked host system capable o...
A rotaxane-based Au catalyst was developed and the effect of the mechanical bond on its behavior was studied. Unlike the non-interlocked thread, the rotaxane requires a catalytically innocent cofactor, the identity of which significantly influences both the yield and diastereoselectivity of the reaction. Under optimized conditions, Au(I) (the catalyst), Ag(I) (to abstract the Cl(-) ligand), and...
Mechanical point-chirality in a [2]rotaxane is utilized for asymmetric catalysis. Stable enantiomers of the rotaxane result from a bulky group in the middle of the thread preventing a benzylic amide macrocycle shuttling between different sides of a prochiral center, creating point chirality in the vicinity of a secondary amine group. The resulting mechanochirogenesis delivers enantioselective o...
[2]Rotaxanes based on the 1,2-bis(pyridinium)ethane subset[24]crown-8 ether motif were prepared that contain a terminal terpyridine group for coordination to a transition-metal ion. These rotaxane ligands were utilized in the preparation of a series of heteroleptic [Ru(terpy)(terpy-rotaxane)]2+ complexes. The compounds were characterized by 1D and 2D 1H NMR spectroscopy, X-ray crystallography, ...
Abstract We report a series of rotaxane‐based anion–π catalysts in which the mechanical bond between bipyridine macrocycle and an axle containing NDI unit is intrinsic to activity observed, including [3]rotaxane that catalyses otherwise disfavoured Michael addition >60 fold selectivity over competing decarboxylation pathway dominates under Brønsted base conditions. The results are rationaliz...
Femtosecond two-dimensional infrared spectroscopy has been used to investigate the coupling between the NH stretch vibrational modes of NH groups in the macrocycle and thread of a benzylic amide rotaxane as a potential time-resolved indicator of rotaxane shuttling. The peptide was used to test the two-dimensional infrared setup. We were able to observe the coupling between the asymmetric and th...
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