Bis(thiosemicarbazone) Complexes of Cobalt(III). Synthesis, Characterization, and Anticancer Potential

Abstract

Nine bis(thiosemicarbazone) (BTSC) cobalt(III) complexes of the general formula [Co(BTSC)(L)]NO were synthesized, where BTSC = diacetyl bis(thiosemicarbazone) (ATS), pyruvaldehyde bis(thiosemicarbazone) (PTS), or glyoxal bis(thiosemicarbazone) (GTS) and L = ammonia, imidazole (Im), or benzylamine (BnA). These compounds were characterized by multinuclear NMR spectroscopy, mass spectrometry, cyclic voltammetry, and X-ray crystallography. Their stability in phosphate-buffered saline was investigated and found to be highly dependent on the nature of the axial ligand, L. These studies revealed that complex stability is primarily dictated by the axial ligand following the sequence NH > Im > BnA. The cellular uptake and cytotoxicity in cancer cells were also determined. Both the cellular uptake and cytotoxicity were significantly affected by the nature of the equatorial BTSC. Complexes of ATS were taken up much more effectively than those of PTS and GTS. The cytotoxicity of the complexes was correlated to that of the free ligand. Cell uptake and cytotoxicity were also determined under hypoxic conditions. Only minor differences in the hypoxia activity and uptake were observed. Treatment of the cancer cells with the copper-depleting agent tetrathiomolybdate decreased the cytotoxic potency of the complexes, indicating that they may operate via a copper-dependent mechanism. These results provide a structure-activity relationship for this class of compounds, which may be applied for the rational design of new cobalt(III) anticancer agents.

Hydrazone-based cobalt complexes toward multielectron redox and spin crossover

“…[7][8][9][10] For the purpose of potential application, it is of paramount importance to tune the donor type and ligand eld strength of the ligands available to form the cobalt coordination sphere. [11][12][13] Just recently, Yang et al reported the redox tuning and electronic effects of proximal nonredox active cations in cobalt Schiff-base complexes. The tunability in the reversible redox potential was ascribed to the control of the absolute energy of the molecular orbital participating in electron transfer.…”

Synthesis, structure elucidation, DNA binding and molecular docking studies of novel copper(II) complexes of two 1,3,4‐thiadiazolethiosemicarbazone derivatives

“…[ 12 ] Thiosemicarbazone‐metal complexes exhibit a wide range of pharmaceutical applications. [ 13,14 ] Especially, copper complexes of thiosemicarbazone ligands present a variety of biological activities. [ 15,16 ] Another sulfur and nitrogen containing ligand is thiadiazole which known with their efficient application in agricultural, pharmaceutical, and materials chemistry.…”

Yeni 5-(Dietilamino)-2-[((2-merkapto-1H-benzo[d]imidazol-5-il)imino)metil]fenol Bileşiğinin Yapısal, Elektronik ve Spektroskopik Özelliklerinin İncelenmesi

“…Bu ilginin nedeni, benzimidazol yapısının kimyasal olarak aktif olması ve türevlerinin farklı biyolojik etki göstermesidir. Bu farmasötik etkiler arasında antiprotozol, antiülser, antikanser, antitüberküloz, antikonvülzan, antidiyabetik, antihipertansif, antioksidan, analzejik, antiinflamatuar ve tirozin kinaz inhibitörü gibi birçok özellik yer almaktadır (Rajarajeswari et al, 2013;Song et al, 2014;Tajika et al, 2014;Banerjee and Chakravarty, 2015;Ghosh et al, 2015;Tajika et al, 2015;Halder et al, 2016;Sethi and Ahuja, 2016;Singh et al 2016;Yan et al, 2016;King et al, 2017;Horaka et al, 2018;Menteşe vd., 2019;Ramezani et al, 2019). Bu yüzden, yeni benzimidazol türevli Schiff bazlarının geniş bir uygulama alanına sahip olması bu bileşiklerin araştırılmasını daha da önemli hale getirmektedir.…”