A Novel Trinuclear Nickel(II) Salicylaldimine Complex: Synthesis, Structural Characterization, Bioactivity Profile against Bacterial, Fungal and Breast Cancer Cells and Effects on Wheat Germination Indices

Abstract

The complex [Ni3L6]•1.56CH2Cl2 (HL = (E)-2-(((3,4-dimethylphenyl)imino)methyl)phenol) was isolated in the monoclinic C 2/c space group. All nickel atoms are six-coordinate with a nickel atom bound to only O-phenol atoms, while the two terminal cations are surrounded by N3O3 atoms. This complex and its ligand (20 mg/mL in DMSO) were tested as antimicrobials. Against two fungi, the complex and amphotericin B caused 13 and 21 mm inhibition diameters, respectively, in Candida albicans plates. Against four bacteria, the ligand inhibited only Staphylococcus aureus with a 10 mm diameter, and the complex induced inhibitions with 10–13 mm (ampicillin afforded 21–26 mm inhibitions). Against cancer (MCF-7) and normal (BHK) cells, the ligand provided virtual inactivity, but great activities (IC50 = 5.44 and 11.61 μM, respectively) were shown by the complex. Doxorubicin afforded activities with IC50 = 9.66 and 36.42 μM in these cells, respectively. The ligand and its complex offered 100% germination of a drought-sensitive wheat cultivar (90% for control), but, under drought, the complex, ligand and control gave germination with 85, 75 and 95%, respectively. Under normal irrigation and drought, the control and complex afforded 100% germination, and the ligand afforded 95% germination for a drought-resistive wheat cultivar.