Crystal structure and Hirshfeld surface analysis of the fungicide metconazole

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-(1<i>H</i>-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, <i>gem</i>-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 (1<i>S</i>,5<i>R</i>) 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 <i>cis</i>-metconazole [(1<i>S</i>,5<i>R</i>)/(1<i>R</i>,5<i>S</i>)], determined in the monoclinic space group <i>P</i>2₁/<i>c</i> with two independent mol-ecules in the asymmetric unit (<i>Z</i>' = 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 <i>b</i> 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).