2.2 Nomenclature Types for Substituted Systems
107
2.2.7.5
Radical Anions (Anion Radicals)
These species can again be derived in four different ways by:
a) Addition of an electron to a neutral structure,
b) subtraction of a hydron from a radical,
c) concomitant addition of a hydride ion to and abstraction of a hydrogen
atom from a parent structure,
d) simultaneous abstraction of a hydron and a hydrogen atom from a parent structure, occasionally involving, as in the case of arenes, a formal
dihydrogenation.
Naming can then occur either descriptively as ... radical anion (a) or
strictly operationally with suffix combinations such as ... uidyl (c) and
... idyl (d). Designations reflecting formation mode b) would lead to
the suffix combination ... ylide which, regrettably, has already been earmarked as class name for Wittig reagents and must therefore be avoided
here (see 2.2.7.7). Delocalization is treated exactly as in the case of analogous radical cations.
[C2H4Jo e
• •• 8
vgl.
•• e
~
H2C-CH2
H3C-~H
a) Ethene radical anion
c) Ethenuidyl
d) Ethanidyl
Ethan-2-id-l-yl
Ethan-l-id-l-yl
oe
e .
•• e
[H3C- CH3J
vs. H4C-CHz
~H2
a) Ethane radia) ,V-Methane radical anion
cal anion
c) Ethanuidyl
Ethan-2-uid-l-yl
c) ,V-Methanuidyl
d) Methanidyl
•
..
Pyridine radical anion
1,4-Dihydropyridin-l-id-4-yl
With reference to Table 11, more complex radical ions, for example of the
ketyl type, can be named systematically without difficulties.