Applying the Crystalline Sponge Method to Agrochemicals: Obtaining X-ray Structures of the Fungicide Metalaxyl-M and Herbicide S-Metolachlor

The crystalline sponge method is a technique that provides the ability to elucidate the absolute structure of noncrystalline or hard to crystallize compounds through single-crystal X-ray diffraction by removing the need to obtain crystals of the target compound. In this study the crystalline sponges {[(ZnX_{2})_{3}(2,4,6-tris(4-pyridyl)-1,3,5-trazine)_{2}].x(solvent)}n (X = I, Br) were used to obtain X-ray structures of the agrochemical active ingredients metalaxyl-M and S-metolachlor. The effect of the temperature used during guest uptake and the influence of changing the host framework ZnX_{2} nodes on guest encapsulation were investigated. Additionally, three compounds containing chemical fragments similar to those of metalaxyl-M and S-metolachlor (phenylacetaldehyde, N-ethyl-o-toluidine, and methyl phenylacetate) were also encapsulated. This allowed for the effect of guest size on the position that guests occupy within the host frameworks to be examined. The disorder experienced by the guest compounds was documented, and an analysis of the intermolecular host–guest interactions (CH···π and π ···π) used for guest ordering within the host frameworks was also undertaken in this study

Encapsulation of Aromatic Compounds and a Non-Aromatic Herbicide into a Gadolinium-Based Metal–Organic Framework via the Crystalline Sponge Method

The crystalline sponge method (CSM) is a procedure that has the potential to remove the need to have good-quality single crystals of the target compound by soaking said compound into a crystalline metal–organic framework (MOF). To increase the range of compounds that can be employed with the CSM, a range of different MOFs must be investigated. In this study we have explored the use of a lanthanide-based MOF, RUM-2, recently shown to have potential as a CSM host. Specifically, we have successfully formed five novel inclusion complexes with the four aromatic guests: 2-phenylethanol, benzyl acetate, benzyl benzoate, and vanillin and the non-aromatic herbicide molinate. A detailed analysis of the effect of size on the positions guest molecules sit within the pores of the MOF was performed. The π···π, CH···π, hydrogen-bonding, and coordination host–guest and guest–guest interactions utilized in guest ordering were also investigated, and the disorder experienced by guest molecules was documented