Page 31 - Nomenclature of Inorganic Chemistry (IUPAC Recommendations 2005)

O R G A N O M E T A L L I C C O M P O U N D S IR-10.2

Table IR-10.2 Names for ligands forming several metal–carbon single bonds

Ligand formula Systematic name as Systematic name as Acceptable
anionic ligand neutral ligand alternative name

CH 2 methanediido methanediyl methylene
CH 2 CH 2 ethane-1,2-diido ethane-1,2-diyl ethylene
CH 2 CH 2 CH 2 propane-1,3-diido propane-1,3-diyl
CH 2 CH 2 CH 2 CH 2 butane-1,4-diido butane-1,4-diyl

HC methanetriido methanetriyl

CH CH ethane-1,1-diido ethane-1,1-diyl
3

CH C ethane-1,1,1-triido ethane-1,1,1-triyl
3
CH¼CH ethene-1,2-diido ethene-1,2-diyl
H 2 C C ethene-1,1-diido ethene-1,1-diyl

C C ethyne-1,2-diido ethyne-1,2-diyl
C 6 H 4 benzenediido benzenediyl phenylene
(-1,2-diido, etc.) (-1,2-diyl, etc.) (1,2-, etc.)

IR-10.2.3.1 The mu (m) convention

Organic l igands forming more than one metal–carbon bond can be either chelating, if
coordinating to one metal atom, or bridging, if coordinating to two or more metal atoms.
A b ridging b onding m ode is indicated by the Greek letter m (Sections IR-9.2.5.2 and
IR-10.2.3.4).

H 2 H 2
C C
H C CH 2 H C CH 2
2
2
M M M
μ-propane-1,3-diyl propane-1,3-diyl
(bridging) (chelating)

The number of metal atoms connected by a b ridging l igand is indicated by a r ight
subscript, m n , w here n $ 2, though t he bridging i ndex 2 i s n ot normally indicated.

H 3
C
H 3
C M M
M M M
μ-methyl μ 3 -methyl

The name methylene for CH 2 can only be used in connection with a b ridging b onding
mode (m-methylene), whereas a CH 2 ligand bonding to one metal only has a m etal–carbon
double b ond and should b e n amed as methylidene (see Section IR-10.2.4).

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