ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Structure and optical properties of polypyrrole oligomers prepared by solution polycondensation

Pan Wang, Mengxue Zhang, Jun Cai, and Zhixuan Chen

School of Materials and Chemical Engineering, Chuzhou University, Chuzhou, China

E-mail: pwang810@126.com

Received: 6 November 2025  Accepted: 29 December 2025

Abstract:

A series of polypyrrole oligomers (PPOs)—MPMH, MPEH, MPTH, and MPCH—were synthesized via solution polycondensation of N-methylpyrrole and para-substituted benzaldehydes to systematically explore substituent effects on their structural, optical, and electrochemical properties. MPTH showed enhanced crystallinity via π–π stacking, while MPCH formed a honeycomb-like porous structure. Optically, MPCH exhibited red-shifted excitation and emission (394/513 nm) due to a push–pull effect. The oligomers emitted violet (MPMH, MPEH), blue (MPTH), and green (MPCH) fluorescence, respectively. Electrochemically, substituents fine-tuned HOMO levels, giving band gaps of 2.0–2.4 eV suitable for visible-light emission. This study clarifies the role of substituents in modulating optoelectronic behavior, supporting the design of functional polymers for electronics and sensing.

Graphical abstract

The alternative text for this image may have been generated using AI.

Keywords: Polypyrrole oligomers; Structure; Optical properties; Quantum yield

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-025-04634-z

Chemical Papers 80 (4) 3561–3570 (2026)