Constructing Organometallic Architectures from Aminoalkylidyne Diiron Complexes

Abstract

The chemistry of diiron complexes has seen a recent renaissance, due to the prominent role played by the element iron in the development of sustainable synthetic processes and the cooperative effects provided by two metal centers working in concert, that is a concept amazingly exploited by Nature. Aminoalkylidyne derivatives of [Fe 2 Cp 2 (CO) 4 ] are a convenient scaffold to grow organic fragments; in particular, the facile re-[a] received his PhD degree in Chemistry from the University of Bologna in 2003, then he moved to the University of Pisa in 2006, where he is currently Professor of Inorganic Chemistry. He has co-authored over 150 papers in international journals, dealing with several aspects of the coordination chemistry of transition metal compounds. He was awarded the Nasini Prize by the Italian Chemical Society in 2014, for his contribution to the chemistry of group 5 and 6 metal compounds and to the exploration of unconventional modes of metal mediated C-C bond formation. 3990 Scheme 7. Coupling of isocyanide ligands promoted by acetylide addition to aminoalkylidyne complexes. (a) R = Xyl, R′ = Ph; R = Xyl, R′ = 4-C 6 H 4 Me; R = Me, R′ = Ph. (b) γ-Al 2 O 3 , R′ = SiMe 3 . [51]Eur. 3991Scheme 8. Base-assisted coupling of aminoalkylidyne ligand (R = Me, Xyl or 4-C 6 H 4 OMe) with (a) alkenes (R′ = H, R′′ = CN, CO 2 Me, Ph; R′ = R′′ = CO 2 Et) [53] and (b) allenes (R′ = R′′ = Me; R′ = Me, CO 2 Et, R′′ = H). [54] Scheme 9. Synthesis of vinyliminium complexes via alkyne insertion into Fe-μ-carbyne bond. Inset: possible forms of isomerism. [61][62][63] Eur.

Bond Forming Reactions Involving Isocyanides at Diiron Complexes

“…As a consequence, the bridging amino alkylidyne ligand in 4 can undergo nucleophilic addition at the bridging carbon to form the corresponding aminocarbene complexes 5 and 6 (Scheme 3) [54]. Very recently, the synthesis and isolation of diiron bridging aminoalkylidyne complexes of type 4 have been reinvestigated in order to provide a most convenient access to these complexes [52], which have been proved to be very versatile species and valuable starting materials for obtaining a number of organometallic complexes [52,53]. Although the bridging CNRR' ligand is usually described as a bridging carbyne (alkylidyne), the >C-N interaction displays some double bond character (C-N bond distances are usually around 130 ppm), and the ligand shows some iminium, or azavinilydene, character.…”

“…In both synthetic routes leading to 11, the overall remarkable result is the coupling of an alkyne with a bridging isocyanide, accompanied (assisted) by N alkylation. Finally, it is worth noting that the convenient access to 11, by alkyne-isocyanide assembly, has made it possible to fully investigate the huge potential of bridging vinyliminium ligands as versatile and extremely valuable precursors of a large variety of new organometallic species [30,53,[73][74][75].…”

Anticancer Potential of Diiron Vinyliminium Complexes

“…Herein, we report a series of diiron complexes with a bridging vinyliminium ligand as a novel family of cytotoxic organometallic compounds (Figure ). The complexes can be obtained on gram scales from Fe 2 Cp 2 (CO) 4 by the stepwise assembly of isocyanide and alkyne units, and display acceptable water solubility and stability. Spectro‐electrochemical studies, reactive oxygen species (ROS) analysis and investigations on the interaction with biomolecules have been conducted to ascertain a possible mode of action.…”

Mono-, Di- and Tetra-iron Complexes with Selenium or Sulphur Functionalized Vinyliminium Ligands: Synthesis, Structural Characterization and Antiproliferative Activity

“…Former findings indicate that the vinyliminium ligand in type 1 compounds displays a versatile and rich chemistry, offering much scope for derivatization [43][44][45]. Herein, we will describe the synthesis and the characterization of a series of S-and Se-functionalized derivatives [42][43][44][45][46][47]. Cytotoxicity data concerning both cancer and non-cancer cell lines and experiments aimed to clarify the mechanism of action of the compounds are described.…”