Reactivity of an All‐Ferrous Iron–Nitrogen Heterocubane under Reductive and Oxidative Conditions

Abstract

The reactivity of the all-ferrous FeN heterocubane [Fe4 (Ntrop)4 ] (1) with i) Brønsted acids, ii) σ-donors, iii) σ-donors/π-acceptors, and iv) one-electron oxidants has been investigated (trop = 5H-dibenzo[a,d]cyclo-hepten-5-yl). 1 showed self-re-assembling after reactions with i) and proved surprisingly inert in reactions with ii) and iii), with the exception of CO. Reductive and oxidative cluster degradation was observed in reactions with CO and TEMPO, respectively. These reactions yielded new cluster compounds, namely a trinuclear bis(μ3 -imido) 48 electron complex in the former case and a tetranuclear all ferric μ-oxo-μ-imido species in the latter case. Characterization techniques include NMR and in situ IR spectroscopy, single crystal X-ray analysis, Mössbauer spectroscopy, cyclic voltammetry, magnetic susceptibility measurements, and DFT calculations.

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

“…The IR spectra of 2a and 2c (in CH 2 Cl 2 , 2300–1500 cm −1 spectral region) were similar to that of 2b , consisting of three bands related to the coordinated cyanate ligand and the terminal and bridging carbonyl ligands (e.g., at 2242, 1986, and 1818 cm −1 , respectively, in the case of 2a ). The major stability of N -coordination (compared to O -coordination) of the {NCO} moiety was as expected for a low-valent iron center [ 45 , 46 , 47 ]; otherwise, the preference for O -coordination of potential N - and O -donors is commonly observed with high-valent metal complexes [ 48 , 49 , 50 ]. Note that O -coordination towards the Fe I center in related systems has been rarely observed and only as part of a coordination by means of multidentate hydrocarbyl ligands [ 51 , 52 ].…”

Synthesis and Characterization of Ion Pairs between Alkaline Metal Ions and Anionic Anti-Aromatic and Aromatic Hydrocarbons with π-Conjugated Central Seven- and Eight-Membered Rings

“…All compounds containing the trop ‒ anion show strongly shielded signals for all protons in the 1 H NMR spectra. In the dimer of the trop radical [ 23 ], namely C 15 H 11 − C 15 H 11 = trop 2 [ 42 ] (entry 1, Table 1 ), which has an electronic structure reminiscent of the conjugated hydrocarbon cis -stilbene, the olefinic protons 1 H ol and the benzylic proton 1 H bz attached to the central seven-membered ring are observed in the normal range at δ = 7.06 ppm and δ = 4.73 ppm. In the ion pairs, Mtrop , these resonances are significantly shifted to lower frequencies to δ ( 1 H ol ) < 2.6 ppm and δ ( 1 H bz ) < 0.56 ppm (M = Li, Na, K, entries 2–4, Table 1 ).…”