Diiron Aminocarbyne Complexes with NCE− Ligands (E = O, S, Se)

Abstract

Diiron μ-aminocarbyne complexes [Fe2Cp2(NCMe)(CO)(μ-CO){μ-CN(Me)(R)}]CF3SO3 (R = Xyl, [1aNCMe]CF3SO3; R = Me, [1bNCMe]CF3SO3; R = Cy, [1cNCMe]CF3SO3; R = CH2Ph, [1dNCMe]CF3SO3), freshly prepared from tricarbonyl precursors [1a–d]CF3SO3, reacted with NaOCN (in acetone) and NBu4SCN (in dichloromethane) to give [Fe2Cp2(kN-NCO)(CO)(μ-CO){μ-CN(Me)(R)}] (R = Xyl, 2a; Me, 2b; Cy, 2c) and [Fe2Cp2(kN-NCS)(CO)(μ-CO){μ-CN(Me)(CH2Ph)}], 3 in 67–81% yields via substitution of the acetonitrile ligand. The reaction of [1aNCMe–1cNCMe]CF3SO3 with KSeCN in THF at reflux temperature led to the cyanide complexes [Fe2Cp2(CN)(CO)(μ-CO){μ-CNMe(R)}], 6a–c (45–67%). When the reaction of [1aNCMe]CF3SO3 with KSeCN was performed in acetone at room temperature, subsequent careful chromatography allowed the separation of moderate amounts of [Fe2Cp2(kSe-SeCN)(CO)(μ-CO){μ-CN(Me)(Xyl)}], 4a, and [Fe2Cp2(kN-NCSe)(CO)(μ-CO){μ-CN(Me)(Xyl)}], 5a. All products were fully characterized by elemental analysis, IR, and multinuclear NMR spectroscopy; moreover, the molecular structure of trans-6b was ascertained by single crystal X-ray diffraction. DFT calculations were carried out to shed light on the coordination mode and stability of the {NCSe-} fragment.

Mixed valence triiron complexes from the conjugation of [FeIFeI] and [FeII] complexes via intermolecular carbyne/alkyne coupling

“…In the NMR spectra, the two N-methyl groups show two resonances (e.g., at 3.74 and 3.55 ppm in the 1 H spectrum), in line with the partial double-bond character of the alkylidene-nitrogen bond. 69 The presence of the alkenyl moiety is evident from the characteristic chemical shifts of the CH unit [δ( 1 H) = 7.66 ppm; δ( 13 The structure of 4a1 was ascertained by X-ray diffraction analysis (Fig. 3), which demonstrated its close relation to previously reported five-membered metallacycle complexes.…”

“…, at 3.74 and 3.55 ppm in the 1 H spectrum), in line with the partial double-bond character of the alkylidene-nitrogen bond. 69 The presence of the alkenyl moiety is evident from the characteristic chemical shifts of the CH unit [ δ ( 1 H) = 7.66 ppm; δ ( 13 C) = 146.7 ppm]; these signals are substantially shifted with respect to the corresponding signals in [2a1] + (4.68 and 53.5 ppm, respectively). The Fe–C–N carbon resonates at 262.2 ppm in 4a1 , whereas it occurs at 225.2 ppm in [2a1] + , in accord with its increased amino-alkylidene over iminium nature in 4a1 .…”

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

“…These unprecedented 13 C{ 1 H} NMR data allow us to observe a peculiar upfield shift of the resonances of the [M 2 (CO) 2 (μ-CO){μ-CN}] core on going from Fe to Ru (μ-CO and μ-CN: −22/26 ppm, t-CO: −12 ppm). 26,52 The structures of [ 2a–d ]CF 3 SO 3 and [ 2g ]CF 3 SO 3 were ascertained by X-ray diffraction on single crystals (Fig. 1 and Table 1).…”

Triiron Complex with N-Ferrocenyl Aminocarbyne Ligand Bridging a Diiron Core: DFT, Electrochemical, and Biological Insights

“…The experimentally detected cis/trans ratio (=5 in CDCl 3 solution) is significantly lower than the theoretical value (11, in CHCl 3 as a continuous medium). In general, the cis/trans isomerization for cationic tris-carbonyl μ-aminocarbyne complexes is not accessible at least up to 50 °C. , Therefore, to promote a potential isomerization process, solutions of [2]­CF 3 SO 3 in various solvents were heated ( Table ). The greatest change in the cis/trans ratio was achieved by refluxing an acetone solution of [2]­CF 3 SO 3 for 2.5 h, resulting in an 18:1 cis/trans ratio.…”