Single-site binding of pyrene to poly(ester-imide)s incorporating long spacer-units: prediction of NMR resonance-patterns from a fractal model,Chemical Science

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Single-site binding of pyrene to poly(ester-imide)s incorporating long spacer-units: prediction of NMR resonance-patterns from a fractal model
Chemical Science ( IF 7.6 ) Pub Date : 2020-10-09 , DOI: 10.1039/d0sc03730c
Marcus Knappert _{1,

2,

3,

4} , Tianqi Jin _{1,

2,

3,

4} , Scott D. Midgley _{1,

2,

3,

4} , Guanglu Wu _{4,

5,

6,

7} , Oren A. Scherman _{4,

5,

6,

7} , Ricardo Grau-Crespo _{1,

2,

3,

4} , Howard M. Colquhoun _{1,

2,

3,

4}

Affiliation

Co-polycondensation of the diimide-based diols N,N′-bis(2-hydroxyethyl)hexafluoroisopropylidene-diphthalimide, (HFDI), and N,N′-bis(2-hydroxy-ethyl)naphthalene-1,4,5,8-tetracarboxylic-diimide, (NDI), with aliphatic diacyl chlorides ClOC(CH₂)_xCOCl (x = 5 to 8) affords linear copoly(ester-imide)s. Such copolymers interact with pyrene via supramolecular binding of the polycyclic aromatic at NDI residues. This interaction results in upfield complexation shifts and sequence-related splittings of the NDI ¹H NMR resonances, but gives a very different final resonance-pattern from the copolymer where x = 2. Computational modelling of the polymer with x = 5 suggests that each pyrene molecule binds to just a single NDI residue rather than by intercalation between a pair of NDI's at a tight chain-fold, as was found for x = 2. The new single-site binding model enables the pattern of ¹H NMR resonances for copolymers with longer spacers (x = 5 to 8) to be reproduced and assigned by simulation from sequence-specific shielding factors based on a type of fractal known as the last-fraction Cantor set. As this type of fractal also enables an understanding of pairwise binding systems, it evidently provides a general numerical framework for supramolecular sequence-analysis in binary copolymers.

中文翻译：

site与掺入长间隔单元的聚（酯-酰亚胺）的单点结合：从分形模型预测NMR共振模式

二酰亚胺基二醇N，N'-双（2-羟乙基）六氟异亚丙基-二邻苯二甲酰亚胺（HFDI）和N，N'-双（2-羟乙基）萘-1,4,5的共缩聚带有脂肪族二酰氯ClOC（CH ₂）_x COCl（x = 5至8）的8-四羧酸-二酰亚胺（NDI ）提供了线性共聚（酯-酰亚胺）。这样的共聚物通过NDI残基上的多环芳族化合物的超分子结合与pyr相互作用。这种相互作用导致NDI ¹ H NMR共振的高场络合位移和与序列有关的分裂，但最终的共振模式与共聚物不同，其中x= 2与聚合物的计算建模X = 5表明每个芘分子结合只是一个单一的NDI一对NDI的的之间的残基，而不是由插在紧链倍，作为被发现的X = 2的新单位结合模型使得具有更长间隔基（x = 5至8）的共聚物的¹ H NMR共振图可以通过基于特定分形类型（称为最后分数）的序列特异性屏蔽因子的模拟进行复制和分配康托集。由于这种类型的分形也可以理解成对的结合体系，因此显然为二元共聚物中的超分子序列分析提供了一个通用的数值框架。

更新日期：2020-10-19

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