Siedzielnik M, Pawłowska M, Daśko M, Kleinschmidt H, Dołęga A. Reactions of cobalt(ii) chloride and cobalt(ii) acetate with hemisalen-type ligands: ligand transformation, oxidation of cobalt and complex formation. Preliminary study on the cytotoxicity of Co(ii) and Co(iii) hemisalen complexes.
RSC Adv 2023;
13:8830-8843. [PMID:
36936819 PMCID:
PMC10018370 DOI:
10.1039/d2ra07089h]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 03/08/2023] [Indexed: 03/18/2023] Open
Abstract
Several molecular cobalt(ii) complexes, one Co(ii) coordination polymer and one ionic cobalt(iii) complex with imine hemisalen ligands were synthesized. The hemisalen ligands were synthesized from o-vanillin (oVP) and diverse aminopyridines (compounds HL1-HL4) or aminophenol (compound HL5). It was observed that cobalt(ii) chloride in dry acetonitrile catalyzes a transformation of HL1 and HL3 instead of complex formation. The conversion of these imines proceeded via self-cyclization to N-2''-pyridyl-2,6-dioxo-9-aza-[c,g]di-2'-methoxybenzo nonan or its methyl derivative as the major product. The remaining reactions were performed using imines HL1-HL5 and cobalt(ii) acetate Co(Ac)2 in methanol or DMSO/acetonitrile resulting in forming a series of cobalt complexes. The following series of compounds was obtained: two similar tetrahedral molecular Co(ii) complexes [Co(L1)2] and [Co(L3)2], one trinuclear, mixed-ligand Co3(Ac)2(L4)2(oVP)2, one coordination polymer {Co(L2)2}∞ and finally one octahedral anionic Co(iii) complex [HNEt3][Co(L5)3]. The latter complex formed in a cobalt(ii) acetate reaction with a hemisalen HL5 derived from oVP and 2-aminophenol. The molecular structures of all compounds were confirmed by X-ray diffraction, and the cytotoxicity of Co(ii) and Co(iii) complexes towards cancer cell lines HCT116, HL-60 and normal cell line MRC-5 was studied.
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