Front Cover

Abstract

The cover image is based on the Full Paper Synthesis, reactivity and preliminary biological activity of iron(0) complexes with cyclopentadienone and amino‐appended N‐heterocyclic carbene ligands by Andrea Cingolani et al., https://doi.org/10.1002/aoc.4779. Illustration Credit: Rita Mazzoni and Elena Gigli.

Cyclopentadienone–NHC iron(0) complexes as low valent electrocatalysts for water oxidation

“…Iron complexes employed in this work as electrocatalysts for water oxidation are summarized in Chart 1. Complexes 1, 57 2, 63 3, 4, and 5 were prepared following a synthetic strategy of our group. 57,70 A complete description of the synthesis and characterization of novel complexes 3, 4, and 5 is available in the experimental and SI (Figure S10-S21).…”

“…The bonding parameters and overall structure of 4 is similar to those reported in the literature for related Fe and Ru complexes. 57,63 In particular, the Fe 4) Å] corresponds essentially to a double bond. 71 The Fe(1)-C( 21) bond [1.978(3) Å] is in the typical range for the interaction between Fe(0) and a N-heterocyclic carbene.…”

“…Reagents: Fe 2 (CO) 9 (Strem), methyl iodide, silver oxide, 1methylimidazole, trifluoroboric acid, octa-1,7-dyine, dipropargyl ether, (Alpha Aesar) were used as purchased. 1,3-Dimethylimidazolium iodide, 61 1-methyl-3-(2hydroxypropyl)imidazolium bromide, 1,8bis(trimethylsilyl)octa-1,7-diyne, (oxybis(prop-1-yne-3,1diyl))bis(trimethylsilane), 62 triscarbonyl 63 and triscarbonyl-(4,6bis(trimethylsilyl)-1H-cyclopenta[c]furan-5(3H)-one)iron, 64 were prepared following procedures reported in the literature. NMR spectra were recorded using Varian Inova 300 ( (6) (0.048 g, 0.103 mmol), trimethylammine-N-oxide (0.012 g, 0.155 mmol), 3-(2-hydroxypropyl)-1-methylimidazole bromide (0.022 g, 0.103 mmol), and silver oxide (0.037 g, 0.160 mmol) were added to the reaction vessel and dissolved in acetonitrile (8 mL).…”

“…Furthermore, CO release, favoured by the coordinating amino group, was already observed. 63 In order to shed some light on the peculiar behaviour of complexes 2 and 5, CV of 2 was also recorded in phosphate buffer aqueous solution at pH 2 (Figure 3). Under these conditions 2 is soluble in water and the amino group is totally protonated, hence being unsusceptible to be involved in any side reactions.…”

(Cyclopentadienone)iron Complexes: Synthesis, Mechanism and Applications in Organic Synthesis

“…Simultaneously, Mazzoni and co‐workers [162] also reported an efficient strategy for synthesis of iron‐NHC complexes, which involves transmetallation between nitrile ligated CPDICs and in situ generated silver‐NHC complexes. Later, they functionalized these complexes by introducing a pendant amino group in the carbene ligand in order to influence its steric, electronic and solubility properties [163,164] . The photophysical properties were exclusively studied in both organic and aqueous solvents.…”