Iron(III) Pincer Complexes as a Strategy for Anticancer Studies

Abstract

[Fe(NCN) 2 ]PF 6 (1·PF 6 ) [NCHN = 1,3-di(pyridin-2-yl)benzene] was readily obtained by a transmetalation reaction between [Fe 3 (CO) 12 ] and Hg(NCN)Cl followed by a metathesis reaction with KPF 6 . X-ray diffraction, electron paramagnetic resonance spectroscopy, and cyclic voltammetry studies confirmed

Excited‐State Kinetics of an Air‐Stable Cyclometalated Iron(II) Complex

“…for the effects of exchanging an N‐donor by a cyclometalating ligand could not be confirmed experimentally so far. Although aryl carbanion ligands in the form of 2‐phenylpyridine, 1,3‐di(2‐pyridinyl)benzene, and 6‐phenyl‐2,2′‐bipyridine (Hpbpy already found applications in the context of noble metal complexes, air‐ and water‐stable cyclometalated Fe II compounds, allowing for photochemical applications, are lacking up to date . With this work we will fill this gap and present a) a synthetic access to heteroleptic, cyclometalated [Fe(N^N^N)(N^N^C cm )] + complexes, here in the form of [Fe(pbpy)(tpy)] + (tpy=2,2′:6′,2′′‐terpyridine) and b) thoroughly investigate the ground‐ and excited‐state characteristics in comparison to the prototypical complex [Fe(tpy) 2 ] 2+ to prove the high potential of cyclometalating ligands for increasing MLCT lifetimes.…”

Dibromine Promoted Transmetalation of an Organomercurial by Fe(CO)5: Synthesis, Properties, and Cytotoxicity of Bis(2-C6H4-2′-py-κC,N)dicarbonyliron(II)

“…In particular, ruthenium (RDCs) and osmium compounds (ODCs) bearing cyclometalated 2-phenylpyridine ligand revealed strikingly promising anticancer properties, and conceivable mechanisms of action were explored. − These complexes show high cytotoxicity and bypass standard resistance mechanisms by inducing the endoplasmic reticulum stress pathway. Hence, in attempts to expand the cyclometalation strategy on nontoxic iron, we succeeded in preparing the iron­(II) and iron­(III) pincer complexes [Fe­(NCN) 2 ] and [Fe­(NCN) 2 ]­PF 6 (NCN = 1,3-di­(pyridyn-2-yl)­benzene) . Tested on colon, lung, and gastric cancer cell lines, the latter displayed a much higher cytotoxic activity than cisplatin, comparable to that observed for structurally similar ruthenium and osmium derivatives. , Studies on how [Fe­(NCN) 2 ]­PF 6 could cause the cell death suggested a caspase-independent pathway involving endoplasmic reticulum (ER) stress and autophagy.…”

Novel Cyclometalated Fe(II) Complex with NCN Pincer and BODIPY‐Appended 4'‐Ethynyl‐2,2':6',2”‐terpyridine as Mitochondria‐Targeted Photodynamic Anticancer Agents

“…Recently a class of iron(III) catecholates was reported that showed photocytotoxicity with the complexes primarily localizing in the nucleus or mitochondria of HeLa and HaCaT cells . Moreover, new NCN pincer iron(III) complexes have been reported as cytotoxic assays in human colon cancer (HCT‐15), lung cancer (SKLU), and gastric cancer (AGS, KATOIII) cells with IC 50 values more than cisplatin for all cell lines …”

“…[43,44] Many BODIPY conjugates are well documented to target the mitochondria of cancer cells and have been explored in photodynamic therapy (PDT) . Also iron pincer complexes have been prepared and studied against several cancer cell lines . With an objective to specifically target the mitochondria of the cells and also with the aim of enhancing the photophysical and photobiological properties of BODIPY ligands in cyclometalated Fe(II) complexes, we have designed and prepared new pincer iron complex including potentially mitochondria targeting organic BODIPY moiety andalso tridentate ligands for the stabilization of metalated iron compound with potentialcytotoxic properties.…”

“…[20][21][22] Moreover, new NCN pincer iron(III) complexes have been reported as cytotoxic assays in human colon cancer (HCT-15), lung cancer (SKLU), and gastric cancer (AGS, KATOIII) cells with IC 50 values more than cisplatin for all cell lines. [23] Recently, ferrocenyl (Fc) groups linked to borondipyrromethenes (BODIPYs) via a spacer located at mesoposition have been published during recent years. [24][25][26][27][28][29][30][31][32][33] Moreover, BODIPY derivatives have been developed for biological labeling, cellular imaging, photodynamic therapy (PDT) agents, and fluorescence sensing, unique narrow emission with high quantum yield in biological and medical fields.…”