Issue 43, 2021

Intermolecular interactions and solubility behavior of multicomponent crystal forms of 2,4-D: design, structure analysis, and solid-state characterization

Abstract

2,4-Dichlorophenoxyacetic acid (2,4-D) is a kind of plant growth regulator which exhibits hormesis effects at low dosages, while high dosages adversely affect the exposed organisms and act as herbicide. 2,4-D has low solubility, therefore, it is a good candidate for crystal engineering research to improve its solubility. This paper presents the preparation of five new multicomponent crystals of 2,4-D, including three salts with imidazole (IMZ), 2-aminopyridine (AAP), and 3-aminopyridine (BAP), and two cocrystals with isonicotinamide (ISO) and pyrazinamide (PYM) as coformers (CCFs). The five multicomponent crystals were first characterized by single-crystal X-ray diffraction, powder X-ray diffraction, differential scanning calorimetry, and thermogravimetric analysis. Molecular interactions, crystal packing, and structure similarity analyses performed using Hirshfeld surface and CrystalCMP confirmed the charge-assisted H-bonding sites and structural similarity among the solved crystal structures. The stability tests show that all five multi-component crystals exhibit excellent stability within 12 weeks under accelerated storage conditions (40 °C and 75% RH). Moreover, all the five multicomponent crystals of 2,4-D exhibit increased solubility, especially (2,4-D)+(IMZ) that increased the solubility of the resulting salt by 70 times compared to the free acid 2,4-D. From the perspective of single-crystal structure and intermolecular interaction, the reasons for these changes in physical and chemical properties are further clarified.

Graphical abstract: Intermolecular interactions and solubility behavior of multicomponent crystal forms of 2,4-D: design, structure analysis, and solid-state characterization

Supplementary files

Article information

Article type
Paper
Submitted
12 اگست 2021
Accepted
23 ستمبر 2021
First published
24 ستمبر 2021

CrystEngComm, 2021,23, 7615-7627

Intermolecular interactions and solubility behavior of multicomponent crystal forms of 2,4-D: design, structure analysis, and solid-state characterization

L. Fang, Y. Xiao, C. Zhang, Z. Gao, S. Wu, J. Gong and S. Rohani, CrystEngComm, 2021, 23, 7615 DOI: 10.1039/D1CE01080H

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements