Response of a Tethered Zn-Bis-Terpyridine Complex to an External Mechanical Force: A Computational Study of the Roles of the Tether and Solvent

• Published in: The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory Vol. 129; no. 15; pp. 3423 - 3434
• Main Authors: Ghose, Shouryo, Duwez, Anne-Sophie, Fustin, Charles-André, Remacle, Françoise
• Format: Journal Article Web Resource
• Language: English
• Published: United States American Chemical Society 17.04.2025; American Chemical Society (ACS)
• Subjects: A: Structure, Spectroscopy, and Reactivity of Molecules and Clusters; Chemistry; Chimie; mechanochemistry, metal transition complexes; Physical, chemical, mathematical & earth Sciences; Physique, chimie, mathématiques & sciences de la terre
• ISSN: 1089-5639; 1520-5215; 1520-5215
• DOI: 10.1021/acs.jpca.4c08639

Polymeric materials containing weak sacrificial bonds can be designed to engineer self-healing and higher toughness, improve melt-processing, or facilitate recycling. However, they usually exhibit a lower mechanical strength and are subject to creep and fatigue. For improving their design, it is of interest to investigate their mechanical response on the molecular scale. We report on a computational study of the response to a mechanical external force of a Zinc­(II) bis-methyl phenyl-terpyridine ([Zn-bis-Terpy]2+) complex included in a cyclic poly­(ethylene glycol) (PEG) tether designed to maintain the two partners of the metal–ligand bonds in close proximity after the rupture of the complex. The mechanical response is studied as a function of the pulling distortion by using the CoGEF isometric protocol, including interactions with a polar solvent (DMSO). We show that tethering favors recombination but destabilizes the complex before bond rupture because of the interactions of the PEG units with Terpy ligands. Similar effects occur between the DMSO molecules and the complex. Our results on the molecular scale are relevant for single-molecule force spectroscopy experiments. Interactions of the complex with solvent molecules and/or with the tether lead to a dispersion of the rupture force values, which could obscure the interpretation of the results.