Driving a sustainable application of s-triazine ametryn and atrazine herbicides through multicomponent crystals with improved solubility

Author(s)

da Silva, Amandha Kaiser ^[1] ; Diniz, Luan F. ^[2] ; Tenorio, Juan C. ^[3] ; Nazario, Carlos E. D. ^[1] ; Ribeiro, Caue ^[4] ; Carvalho Jr, Paulo S.

Affiliation

^[1] Univ Fed Mato Grosso do Sul, Inst Quim, BR-79074460 Campo Grande, MS - Brazil

^[2] Univ Fed Minas Gerais, Fac Farm, Dept Prod Farmaceut, Lab Controle Qualidade, BR-31270901 Belo Horizonte, MG - Brazil

^[3] Univ Estadual Campinas, Inst Quim, BR-13083970 Campinas, SP - Brazil

^[4] EMBRAPA Instrumentacao, Natl Nanotechnol Lab Agribusiness LNNA, BR-13560970 Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: CrystEngComm; v. 23, n. 24, p. 4252-4263, JUN 28 2021.
• Web of Science Citations: 0

Abstract

Atrazine (ATZ) and ametryn (AMT) are poorly soluble s-triazine herbicides widely used worldwide as the main weed control (WC) method in crops. Herein, we report the highly soluble multicomponent crystals of these s-triazine herbicides, which were fabricated with the aim to provide safer and more eco-friendly formulations. The crystallization of ATZ with fumaric acid yielded hydrated (ATZ-H(2)Fum center dot H2O) and dehydrated (ATZ-H(2)Fum) cocrystals with an herbicide : acid ratio of 2 : 1, whereas the combination of AMT with nitric and trifluoracetic acids resulted in the formation of two 1 : 1 salts (AMT-NO3 and AMT-TFA, respectively). All solid forms were characterized in terms of their structural (single-crystal/powder X-ray diffraction and infrared spectroscopy), and physicochemical properties (thermal stability, phase transition, and solubility). Similarities between the crystal arrangements of these compounds could be seen in the formation of 1D-chains by the association of the s-triazine herbicide molecules and the ionizable portion of coformers. Thus, the crystal structures featured hydrophilic domains, breaking the original hydrophobic packing of the pure herbicides and, hence, increasing significantly the melting point and modifying the solubility compared to the parent forms. The new crystals ATZ-H(2)Fum, AMT-NO3, and AMT-TFA were 6-fold, 22-fold, and 14-fold, respectively, more soluble than their corresponding pure forms. The implication of these findings complies with enhanced sustainability in the crop production, whereby the herbicidal formulation utilizes highly soluble compounds, which could decrease the presence of undissolved solids or adjuvants, and thereby, reduce the dosage needed for WC. (AU)

• FAPESP's process: 16/09198-6 - Designing and characterization of solid modifications of agrochemical ingredients herbicides with lower environmental impact
• Grantee: Paulo de Sousa Carvalho Júnior
• Support Opportunities: Scholarships in Brazil - Post-Doctoral