Crystal structure and Hirshfeld surface analysis of the fungicide metconazole

Abstract

Metconazole is a systemic triazole fungicide that inhibits the ergosterol bio-synthesis pathway. It is widely used in agriculture to control fungal infections, including rusts, fusarium and septoria diseases. The mol-ecular structure is a three-ring system, namely, 5-(4-chlorobenz-yl)-2,2-dimethyl-1-(1H-1,2,4-triazol-1-ylmeth-yl)cyclo-pentan-1-ol, C₁₇H₂₂ClN₃O, consisting of a cyclo-pentan-1-ol with 1,2,4-triazol-1-ylmethyl, gem-dimethyl and 4-chloro-benzyl groups attached at the 1-, 2- and 5-positions of the cyclo-penta-nol ring. It has two stereocentres (cyclo-penta-nol positions 1 and 5) leading to four stereoisomers, with the (1S,5R) form being the most bioactive. Despite its agricultural significance, detailed crystallographic data remain scarce. This study reports the crystal structure and Hirshfeld surface analysis of racemic cis-metconazole [(1S,5R)/(1R,5S)], determined in the monoclinic space group P2₁/c with two independent mol-ecules in the asymmetric unit (Z' = 2). Both exhibit similar conformations, with minor differences in the cyclo-penta-nol ring puckering and the torsion angles between the three rings. The crystal packing consists of 2₁-screw-related hy-dro-gen-bonded chains parallel to the b axis, with additional weak C-H⋯N and C-H⋯Cl contacts linking adjacent mol-ecules. Hirshfeld surface analysis indicates that inter-molecular inter-actions are dominated by contacts involving hy-dro-gen (96.1 and 96.7% for the two mol-ecules).

Keywords: Hirshfeld surface analysis; conazole; crystal structure; fungicide; metconazole; triazole.

Figure 1

An ellipsoid plot (50% probability) of cis-metconazole. H atoms are drawn as small circles of fixed arbitrary radius.

Figure 2

A least-squares overlay of the two symmetry-independent mol­ecules of cis-metconazole.

Figure 3

A partial packing plot, viewed down [103], showing O—H⋯N hy­dro­gen bonds, as well as C—H⋯N and C—H⋯Cl contacts, as dotted cyan lines.

Figure 4

Hirshfeld surface two-dimensional fingerprint plots for each independent mol­ecule, arranged in pairs for mol­ecules A and B, respectively. (a)/(b) H⋯H, (c)/(d) H⋯Cl, (e)/(f) H⋯C and (g)/(h) H⋯N contacts. Reciprocal contacts are included in each case.