Volume 62, Issue 38 e202308780
Research Article

A Single-Crystal Monomer to Single-Crystal Polymer Reaction Activated by a Triplet Excimer in a Zipper Mechanism

Lanxin Long

Lanxin Long

Department of Pharmacy, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China, 610072 Chengdu, P. R. China

These authors contributed equally to this work.

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Dr. Samara Medina Rivero

Dr. Samara Medina Rivero

Department of Physical Chemistry, University of Málaga, Andalucia-Tech Campus de Teatinos s/n, 29071 Málaga, Spain

Department of Physics & Astronomy, University of Sheffield, S3 7RH Sheffield, UK

These authors contributed equally to this work.

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Fanxi Sun

Fanxi Sun

Department of Pharmacy, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China, 610072 Chengdu, P. R. China

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Prof. Dongsheng Wang

Prof. Dongsheng Wang

Department of Pharmacy, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China, 610072 Chengdu, P. R. China

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Dr. Dimitri Chekulaev

Dr. Dimitri Chekulaev

Department of Physics & Astronomy, University of Sheffield, S3 7RH Sheffield, UK

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Prof. Claire Tonnelé

Corresponding Author

Prof. Claire Tonnelé

Donostia International Physics Center (DIPC), 20018 Donostia, Euskadi, Spain

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Prof. David Casanova

Prof. David Casanova

Donostia International Physics Center (DIPC), 20018 Donostia, Euskadi, Spain

Ikerbasque Foundation for Science, 48009 Bilbao, Euskadi, Spain

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Prof. Juan Casado

Corresponding Author

Prof. Juan Casado

Department of Physical Chemistry, University of Málaga, Andalucia-Tech Campus de Teatinos s/n, 29071 Málaga, Spain

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Prof. Yonghao Zheng

Corresponding Author

Prof. Yonghao Zheng

Department of Pharmacy, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China, 610072 Chengdu, P. R. China

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First published: 02 August 2023

Graphical Abstract

A novel understanding of the topochemical polymerization of bisindenedione in a single crystal has been proposed. The mechanism involves the formation of a triplet excimer, which evolves into a bonded triplet state, followed by propagation and termination.

Abstract

A combined experimental and theoretical study focused on the elucidation of the polymerization mechanism of the crystal monomer to crystal polymer reaction of a bisindenedione compound in the solid state. The experimental description and characterization of the polymer product have been reported elsewhere and, in this article, we address the first detailed description of the polymerization process. This reaction pathway consists of the initial formation of a triplet excimer state that relaxes to an intermolecularly bonded triplet state that is the starting point of the propagation step of the polymerization. The overall process can be visualized in the monomer starting state as an open zipper in which a cursor or slider is formed by light absorption and the whole zipper is then closed by propagation of the cursor. To this end, variable-temperature electron spin resonance (ESR), femtosecond transient absorption spectroscopy, and vibrational Raman spectroscopic data have been implemented in combination with quantum chemical calculations. The presented mechanistic insight is of great value to understand the intricacies of such an important reaction and to envisage and diversify the products produced thereof.

Conflict of interest

The authors declare no conflict of interest.

Data Availability Statement

The data that support the findings of this study are available in the supplementary material of this article.

The full text of this article hosted at iucr.org is unavailable due to technical difficulties.