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1 Parent Structures
1.1.4
Multivalent Substituent Groups
Multivalent substituent groups of acyclic hydrocarbons are designated by
attaching the suffixes ... idene and ... idyne to the name of the corresponding monovalent group insofar as the free valences are at the same C
atom. Multiple occurrence of such structural elements is taken into
account with suitable multiplicative infixes. Methylene, =CH2 or -CHn is
retained as trivial name; the group =CH- is sometimes still called methine
or methyne.
HC= Methylidyne, H2C=C= Vinylidene, (CH3hC= Isopropylidene,
=C-CHrCH =CH -C= Pent-2-ene-l,4-bis(ylidyne),
=C-C=C-CH =
But-2-yne-l-yliden-4-ylidyne,
l)--!
Pmpano-l,2,3-tdyl,
~
4
~~~
1
2
~
r ~ Butane-l,4-diyl-2-ylidene,
~
JVV\r
~ = C - b -CH= ~ Propane-2,2-diyl-l-yliden -3-ylidyne.
I
JVV\r
Hydrocarbon chains with free valences at each terminal C atom are frequently still called trimethylene-, tetramethylene-, etc. instead of alkanel-w-diyl groups, the systematically correct designation. Unsaturated substituent groups of this kind are named by replacing the terminal syllable
... ene with .•. enylene. The trivial terms ethylene for -CH2-CHn propylene for H3C-CH-CHn and vinylene for -CH=CH- are still frequently
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