A new Co^IIcomplex of diniconazole: synthesis, crystal structure and antifungal activity

Abstract

A new Co(II) complex of diniconazole, namely diaqua[(E)-(RS)-1-(2,4-dichlorophenyl)-4,4-dimethyl-2-(1H-1,2,4-triazol-1-yl-κN(4))pent-1-en-3-ol]cobalt(II) dinitrate dihydrate, [Co(C15H17Cl2N3O)3(H2O)2](NO3)2·2H2O, was synthesized and characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. Crystal structural analysis shows that the centrosymmetric Co(II) cation is coordinated by four diniconazole ligands and two water molecules, forming a six-coordinated octahedral structure. There are also two free nitrate counter-anions and two additional solvent water molecules in the structure. Intermolecular O-H...O hydrogen bonds link the complex cations into a one-dimensional chain. In addition, the antifungal activity of the complex against Botryosphaeria ribis, Gibberella nicotiancola, Botryosphaeria berengriana and Alternariasolani was studied. The results indicate that the complex shows a higher antifungal activity for Botryosphaeria ribis and Botryosphaeria berengriana than diniconazole, but a lower antifungal activity for Gibberella nicotiancola and Alternariasolani.

Enhanced antifungal activities of four Zn(II) complexes based on uniconazole

“…A small frontier orbital gap of a molecule is generally associated with low kinetic stability and high chemical reactivity. The energy gaps ( ΔE = E LUMO ‐E HOMO ) for complexes 1 ‐ 4 (0.0578, 0.0946, 0.1053, and 0.1245 eV, respectively) are shown to be lower than that for L (0.1274 eV), which implies that complexes have a higher chemical activity than L . A complex with a small gap is more polarized and reactive because it can easily offer electrons to the acceptor .…”

“…This leads to higher bioactivities for complex 1 than for complexes 2 ‐ 4 . In addition, the synergy level of complex 2 [uniconazole and Zn(NO 3 ) 2 ] with a molar ratio of 4:1 is better than that of complexes 3 and 4 with a molar ratio of 3:1, and the synergy level of complex 3 with ZnCl 2 is higher than that of complex 4 with ZnBr 2 , even though Cl and Br are members of the same elemental group, and complexes 3 and 4 possess the same coordination modes. Figure shows that the sequence of the synergy levels concerning the tested fungi is Botryosphaeria ribis ( I ) > Wheat gibberellic ( IV ) > Botryosphaeria berengriana ( II ) > Grape anthracnose ( III ), which implies that the antifungal activities against Botryosphaeria ribis ( I ) are improved to the greatest extent and those against Grape anthracnose ( III ) to the smallest extent after complexation.…”

“…The reason may be that the electronegativity of Cl ‐ in complex 3 is higher than that of Br ‐ in complex 4 . In addition, the electronegative group is beneficial to the biological activity . To thoroughly explore the reasons behind the increased biological activities of complexes 1 ‐ 4 , a computational investigation was conducted using DFT.…”

“…The energy difference between the HOMO and LUMO levels is an important parameter in quantum chemical calculations and is very useful for a qualitative description of the biological activity . A small frontier orbital gap of a molecule is generally associated with low kinetic stability and high chemical reactivity.…”

The enhanced biological activities of three Zn (II) complexes based on different 1,2,4‐triazole fungicides

“…Complexes play a very important role in various biological systems . The H‐1,2,4‐triazole agrochemicals, they have been used as efficient plant growth regulators and high‐efficiency systemic fungicides against a broad spectrum of fungi, which have been extensively investigated.…”