Conjugation of Nitrogen-Linked Phthalein Polymers by Forming Ions in the Backbone upon Protic Acid Addition

IF 5.2 1区化学 Q1 POLYMER SCIENCE

Macromolecules Pub Date : 2025-06-13 DOI:10.1021/acs.macromol.4c03172

Daniel J. Frazier, Daniel M. Knauss

{"title":"Conjugation of Nitrogen-Linked Phthalein Polymers by Forming Ions in the Backbone upon Protic Acid Addition","authors":"Daniel J. Frazier, Daniel M. Knauss","doi":"10.1021/acs.macromol.4c03172","DOIUrl":null,"url":null,"abstract":"Polymers with amine linkages composed of the halochromic phthalein moiety are prepared from n-octylamine, aniline, 4-hexylaniline, and p-anisidine with a dibromofunctionalized phthalein monomer via Buchwald–Hartwig polyaminations. Characterization with thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) showed excellent thermal stability with onset degradation temperatures in air above 360 °C and high thermal transitions with Tgs up to 256 °C. Treating the polymers with a protic acid converts the nitrogen-linked phthalein structure into a conjugated form through the generation of ions in the backbone, which is supported by ultraviolet–visible (UV–vis) spectra that display evidence of carbocation species and reduced optical energy gaps, with the lowest energy gap observed at 1.45 eV. Cyclic voltammetry (CV) provides estimations of the energy levels for each polymer with deep highest occupied molecular orbital (HOMO) levels ranging from −5.37 to −5.47 eV. Additionally, electron paramagnetic resonance (EPR) spectroscopy detected air-stable unpaired electrons in the protic acid-treated polymers, which suggests resonance between a closed-shell ionic form and an open-shell radical form that is expected to yield intriguing electrical and magnetic properties.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"27 1","pages":""},"PeriodicalIF":5.2000,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Macromolecules","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1021/acs.macromol.4c03172","RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"POLYMER SCIENCE","Score":null,"Total":0}

引用次数: 0

Abstract

Polymers with amine linkages composed of the halochromic phthalein moiety are prepared from n-octylamine, aniline, 4-hexylaniline, and p-anisidine with a dibromofunctionalized phthalein monomer via Buchwald–Hartwig polyaminations. Characterization with thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) showed excellent thermal stability with onset degradation temperatures in air above 360 °C and high thermal transitions with T_gs up to 256 °C. Treating the polymers with a protic acid converts the nitrogen-linked phthalein structure into a conjugated form through the generation of ions in the backbone, which is supported by ultraviolet–visible (UV–vis) spectra that display evidence of carbocation species and reduced optical energy gaps, with the lowest energy gap observed at 1.45 eV. Cyclic voltammetry (CV) provides estimations of the energy levels for each polymer with deep highest occupied molecular orbital (HOMO) levels ranging from −5.37 to −5.47 eV. Additionally, electron paramagnetic resonance (EPR) spectroscopy detected air-stable unpaired electrons in the protic acid-treated polymers, which suggests resonance between a closed-shell ionic form and an open-shell radical form that is expected to yield intriguing electrical and magnetic properties.

Abstract Image

查看原文本刊更多论文

质子酸加成后在主链上形成离子的氮联酞聚合物的偶联

以正辛胺、苯胺、4-己苯胺、对苯胺和二溴功能化的酞单体为原料，经Buchwald-Hartwig聚胺法制备了由卤代酞部分组成的胺键聚合物。通过热重分析（TGA）和差示扫描量热法（DSC）表征表明，具有优异的热稳定性，在360°C以上的空气中起始降解温度和高达256°C的高热转变。用质子酸处理聚合物后，通过在主链中产生离子，将氮连接的酞菁结构转化为共轭形式，这得到了紫外可见光谱的支持，该光谱显示了碳正离子的存在和光学能隙的减小，在1.45 eV处观察到最低的能隙。循环伏安法（CV）提供了每种聚合物的深最高已占据分子轨道（HOMO）能级的估计，范围为−5.37至−5.47 eV。此外，电子顺磁共振（EPR）光谱在质子酸处理的聚合物中检测到空气稳定的未成对电子，这表明封闭壳离子形式和开放壳自由基形式之间的共振有望产生有趣的电学和磁性能。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

来源期刊

Macromolecules 工程技术-高分子科学

CiteScore

9.30

自引率

16.40%

发文量

942

审稿时长

2 months

期刊介绍： Macromolecules publishes original, fundamental, and impactful research on all aspects of polymer science. Topics of interest include synthesis (e.g., controlled polymerizations, polymerization catalysis, post polymerization modification, new monomer structures and polymer architectures, and polymerization mechanisms/kinetics analysis); phase behavior, thermodynamics, dynamic, and ordering/disordering phenomena (e.g., self-assembly, gelation, crystallization, solution/melt/solid-state characteristics); structure and properties (e.g., mechanical and rheological properties, surface/interfacial characteristics, electronic and transport properties); new state of the art characterization (e.g., spectroscopy, scattering, microscopy, rheology), simulation (e.g., Monte Carlo, molecular dynamics, multi-scale/coarse-grained modeling), and theoretical methods. Renewable/sustainable polymers, polymer networks, responsive polymers, electro-, magneto- and opto-active macromolecules, inorganic polymers, charge-transporting polymers (ion-containing, semiconducting, and conducting), nanostructured polymers, and polymer composites are also of interest. Typical papers published in Macromolecules showcase important and innovative concepts, experimental methods/observations, and theoretical/computational approaches that demonstrate a fundamental advance in the understanding of polymers.