Radical metallacyclopropene: synthesis, structure and aromaticity

Abstract

Metallaaromatics are an important class of aromatic compounds, showing diverse and interesting aromatic properties. Radical rhenabenzofurans 1-3 with a fused metallacyclopropene unit are reported, containing d1 Re centers. Computational studies...

Preparation and Aromaticity of Rhenacycloprop-2-ene-containing Polycyclic Compounds

“…The sum of angles in 5MR is 540.07°, close to the ideal value of 540°. The Re–C(1) (1.966(4) Å) and Re–C(2) (1.957(3) Å) bond distances are slightly different, and both are typical of ReC bonds. − ,− The C(1)–C(2) (1.352(5) Å) bond is similar to those of aromatic scandacyclopropenes . The Re–O bond (2.125(2) Å) is comparable to known rhenafuran complexes (1.981–2.191 Å). − These structural features, including conjugated C–C and C–O bond lengths (C2–C8, and O1), suggest a possibly delocalized metallatricycle.…”

“…Aromaticity study of metallacycloprop-1-ene complexes has been reported recently, − and they show mainly σ-aromaticity. Such work on metallacycloprop-2-ene complexes is less developed though η 2 -alkyne complexes have been widely studied. ,− Since many fused metallacycloprop-1-enes are aromatic, − herein we present the synthesis and characterization of fused five- and six-membered oxa-rhenacycles with a metallacycloprop-2-ene unit, as well as their aromaticity investigation.…”

Aza-metallacycles with a heptavalent Re (d0) center

“…We have previously reported nonaromatic rhenabenzofurans containing a Re( v ) metal center, determined by an X-ray photoelectron spectroscopy (XPS) experiment. 15 Subsequently, we work on the construction of Re( vii )-metallacycles. Herein, the synthesis and characterization of conjugated aza-metallacycles with a Re( vii ) center from the facile oxidation of amino complexes are detailed.…”

“…16 The Re–C bond length (2.090(7) Å), C–C bond length (1.359(9) Å) and C–P bond length (1.767(7) Å) in the alkenyl ylide unit are close to those of other rhenacycles with exocyclic alkenyl ylide structures. 15,17,18 The oxo ligand ReO (1.669(5) Å) is trans to NH 2 , and it can be identified in the IR spectra ( ν (ReO) = 992 cm −1 , KBr disk).…”