Details

Autor(en) / Beteiligte

• Kleinpeter, Erich
• Koch, Andreas

Titel

Carbones – A Classification on the Magnetic Criterion

Ist Teil von

• Chemistry, an Asian journal, 2024-01, Vol.19 (2), p.e202300826-n/a

Ort / Verlag

Germany: Wiley Subscription Services, Inc

Erscheinungsjahr

2024

Link zum Volltext

Quelle

Wiley Online Library - AutoHoldings Journals

Beschreibungen/Notizen

• Carbones (carbodiphosphoranes, bent allenes and chalcogen‐stabilized carbones) bear the same resonance contributor X+−C2−−Y+ (X+, Y+=PR3+, CR2+, SR2+, SeR2+, S+R2=NR) and exhibit unique bonding and donating properties at the central carbon atom. A classification is given on basis of both the geometry and the magnetic properties (13C chemical shift of the central carbon atom and the spatial magnetic properties, through‐space NMR shieldings (TS NMRSs), actually the anisotropy effect or the ring current effect of aromatic species). TS NMRS values have been calculated using the GIAO perturbation method employing the nucleus independent chemical shift (NICS) concept and the results visualized as iso‐chemical‐shielding surfaces (ICSS) of various size and direction. The synergy of geometry (linear or bent, orthogonal or twisted structures) and NMR characteristics (extend of the high field shift of the central carbon atom, anisotropy effect of the allene‐like C=C double bonds or the ball‐like anisotropy effect of carbone‐like central carbon atom) provides a comprehensive picture of the dominating resonance contributor. The spatial magnetic properties (TSNMRSs) of carbones and their heteroanalogues, i.e. the anisotropy effect of the carbone‐like central carbon atom (R2C2−), as measurable in 1H NMR spectroscopy, can be calculated, visualized as iso‐chemical‐shielding surfaces (ICSS) of various size and direction and employed to readily qualify and quantify the preferred resonance contributor: ball‐like anisotropy effect of central carbon atom in carbones (also bent allenes), but only the anisotropy effects of the C=C double bonds in allenes.