Isolobality

Isolobal (from Greek: isos = equal, lobos = lobe) is the name for electronically equivalent fragments within a molecule . The term was introduced by Roald Hoffmann and others in 1976.

The CH ₃ fragment is isolobal to the Mn (CO) ₅ fragment (CO ligands are not shown).

Molecular fragments are “isolobal” if the number, symmetry , energy and shape of the frontier orbitals are similar and these are occupied by the same number of electrons .

The isolobal analogy allows a uniform view of inorganic , organic and organometallic structures.

Examples

• the CH ₃ fragment is isolobal to the Mn (CO) ₅ fragment; Ethane is isolobal to dimanganese decacarbonyl
• the CH ₂ fragment is isolobal to the Fe (CO) ₄ fragment; Cyclopropane is isolobal to triiron dodecacarbonyl
• the CH fragment is isolobal to the Co (CO) ₃ fragment
• the CH fragment is isolobal to the BH ^- fragment

See also

• isoelectronic
• Isosteria

Individual evidence

1. ^ Roald Hoffmann: Building Bridges Between Inorganic and Organic Chemistry (Nobel Lecture). In: Angewandte Chemie International Edition in English. 21, 1982, pp. 711-724, doi : 10.1002 / anie.198207113 .
2. ↑ Entry on Isolobal. In: Römpp Online . Georg Thieme Verlag, accessed on June 13, 2014.