Adding Diversity to Diiron Aminocarbyne Complexes with Amine Ligands

Abstract

The reactions of the diiron aminocarbyne complexes [Fe2Cp2(NCMe)(CO)(μ-CO){μ-CN(Me)(R)}]CF3SO3 (R = Me, 1aNCMe; R = Cy, 1bNCMe), freshly prepared from the tricarbonyl precursors 1a–b, with primary amines containing an additional function (i.e., alcohol or ether) proceeded with the replacement of the labile acetonitrile ligand and formation of [Fe2Cp2(NH2CH2CH2OR’)(CO)(μ-CO){μ-CN(Me)(R)}]CF3SO3 (R = Me, R’ = H, 2a; R = Cy, R’ = H, 2b; R = Cy, R’ = Me, 2c) in 81–95% yields. The diiron-oxazolidinone conjugate [Fe2Cp2(NH2OX)(CO)(μ-CO){μ-CN(Me)2}]CF3SO3, 3, was prepared from 1a, 3-(2-aminoethyl)-5-phenyloxazolidin-2-one (NH2OX) and Me3NO, and finally isolated in 96% yield. In contrast, the one pot reactions of 1a-b with NHEt2 in the presence of Me3NO gave the unstable [Fe2Cp2(NHEt2)(CO)(μ-CO){μ-CN(Me)(R)}]CF3SO3 (R = Me, 4a; R = Cy, 4b) as unclean products. All diiron complexes were characterized by analytical and spectroscopic techniques; moreover, the behavior of 2a–c and 3 in aqueous media was ascertained.

Synthesis and studies of aqueous-stable diruthenium aminocarbyne complexes uncovered an N-indolyl derivative as a prospective anticancer agent

“…This outcome aligns with the general inertness previously documented for di-iron and diruthenium tris-carbonyl aminocarbyne complexes towards N-, S-and O-nucleophiles, except in the presence of a CO-removal agent as trimethylamine-N-oxide. 18,23,24,76 We moved to examine the potential interaction of the two selected complexes, applied at a final concentration of 1 mM, with BSA (at a final concentration of 30 µM) over a 48 h period, using MALDI-MS. Again, results do not show any appreciable interaction between either of the complexes and bovine serum albumin, even after 48 h incubation (Fig. S35 †).…”

FETPY: a Diiron(I) Thio–Carbyne Complex with Prominent Anticancer Activity In Vitro and In Vivo

“…The net positive charge and the robust organometallic assembly prevent oxidation in aqueous solutions, until fragmentation eventually occurs in an intracellular environment. 37,38 The subsequent, presumable release of iron(I) species determines a potent interference with the cellular redox system. 39,40 Note that Fe I is a nonendogenous oxidation state of iron, which has been rarely investigated in medicinal chemistry.…”

“…A lesson learned from Nature is that an organo-diiron core can promote cooperativity effects leading to coordination versatility and enabling unique reactivity patterns. − Specifically, [FeFe] hydrogenase enzymes are found in anaerobic organisms, where they catalyze the reversible oxidation of molecular hydrogen with great efficiency; their active site consists of a diiron unit stabilized by carbonyl and cyanide ligands and a bridging dithiolate group. The [FeFe] hydrogenase active site is indeed a fascinating and inspiring platform for the construction of diiron carbonyl compounds designed for applications in a physiological environment. , In this regard, [Fe 2 Cp 2 (CO) 4 ] is a commercially available, cost-effective, and convenient starting material to access a remarkable variety of organometallic structures with tunable properties. − Notably, cationic complexes with a bridging amino-substituted carbyne ligand (CNR 2 + , R = alkyl/aryl substituent) are straightforwardly obtained from [Fe 2 Cp 2 (CO) 4 ]. The net positive charge and the robust organometallic assembly prevent oxidation in aqueous solutions, until fragmentation eventually occurs in an intracellular environment. , The subsequent, presumable release of iron­(I) species determines a potent interference with the cellular redox system. , Note that Fe I is a nonendogenous oxidation state of iron, which has been rarely investigated in medicinal chemistry.…”