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首页> 外文期刊>Polymers for advanced technologies >Surrogate-stoppered [2] rotaxanes: a new route to larger interlocked architectures
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Surrogate-stoppered [2] rotaxanes: a new route to larger interlocked architectures

机译：替代物塞住的[2]轮烷：通向更大的互锁体系结构的新途径

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摘要

A novel synthetic strategy for exchanging stoppers on rotaxanes, without them losing their integrity as interlocked molecules, is presented. The surrogate-stoppered [2]rotaxane contains one inert stopper and a triphenylphosphonium group attached to a benzylic position as a second reactive stopper in the dumbbellshaped component which contains an ammonium (NH{sub}2{sup}+) ion recognition site, encircled by a crown ether (24C8 or 25C8) component. The strategy for exchanging stoppers relies upon the ability of a benzylic triphenylphosphonium function to undergo a Wittig reaction with a bulky aromatic aldehyde to form a 'stilbenoid' [2]rotaxane as a mixture of cis and trans isomers, without the occurrence of any dethreading of the crown ether ring component. The C=C double bonds can then be hydrogenated, using Adams' catalyst, to afford a new covalently modified [2]rotaxane with two inert stoppers. Utilizing this strategy, larger interlocked molecular structures including a two-stationed [2jrotaxane and a branched [4]rotaxane have been prepared. Furthermore, initial studies, aimed at using this methodology to gain access to poly[n]rotaxane architectures, are presented. Two ammonium ion/crown ether-based [2]rotaxane monomers-each incorporating (i) a dumbbell-shaped component, possessing the surrogate benzylic triphenylphosphonium stopper, and (ii) a crown ether ring component, bearing an aldehyde function on a fused benzenoid ring-undergo a sequence of Wittig reactions in which the surrogate benzylic triphenylphosphonium stopper is exchanged for a crown ether ring component either, (i) in the same rotaxane molecule, to give cyclic daisy-chains by an intramolecular, chain-terminating reaction or, (ii) in another rotaxane molecule, to give acyclic daisy chains by an intermolecular chain-propagating reaction.
机译：提出了一种新颖的合成策略，用于交换轮烷上的塞子，而不会失去它们作为互锁分子的完整性。带有塞子的[2]轮烷含有一个惰性塞子和一个连接在苄基上的三苯基phosph基团，作为哑铃型组件中的第二个反应性塞子，其中包含铵（NH {sub} 2 {sup} +）离子识别位点由冠醚（24C8或25C8）组成。交换塞子的策略依赖于苄基三苯基phosph官能团与庞大的芳族醛进行Wittig反应以形成顺式和反式异构体混合物的“ stilbenoid” [2]轮烷的能力，而不会发生冠醚环成分。然后可以使用Adams的催化剂将C = C双键氢化，得到带有两个惰性塞子的新型共价改性的[2]轮烷。利用这种策略，已经制备了更大的互锁分子结构，包括两工位的[2_紫杉烷和支链的[4]紫杉烷。此外，提出了旨在使用这种方法获得聚[n]轮烷结构的初步研究。两种基于铵离子/冠醚的[2]轮烷单体，每一种都包含（i）哑铃状组分，具有取代的苄基三苯基phosph塞子，和（ii）冠醚环组分，在稠合的苯并类化合物上具有醛官能进行一系列Wittig反应，其中将替代的苄基三苯基phosph终止子交换为冠醚环组分，或者（i）在同一轮烷分子中，通过分子内链终止反应产生环状雏菊链，或者（ii）在另一个轮烷分子中，通过分子间链增长反应产生无环雏菊链。

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