Page 181 - Nomenclature of Inorganic Chemistry (IUPAC Recommendations 2005)

C O O R D I N A T I O N C O M P O U N D S IR-9.2

The two platinum atoms are equivalent and receive lower central atom locants than
palladium by rule (a).

Examples:

11.
N N
(OC) Rh Rh(CO) 2
2
N Me N
Me Me
N Me N
(OC) Rh N N Rh(CO) 2
2

3
1
cyclo-tetrakis(m-2-methylimidazolido-kN :kN )tetrakis(dicarbonylrhodium)

12.
N N
(OC) Rh Rh(CO)(PMe )
2
3
1 4
N Me N
Me Me
N Me N
3 2
(Me P)(OC)Rh N N Rh(CO) 2
3

2
2
cyclo-hexacarbonyl-1k C,2k C,3kC,4kC-tetrakis(m-2-methyl-1H-imidazol-l-ido)-
2 1
3
3
2
1
1
3
2 3
2
1
1:3k N :N ;1:4k N :N ;2:3k N :N ;2:4k N :N -bis(trimethylphosphane)-
3kP,4kP-tetrarhodium
IR-9.2.5.7 Polynuclear clusters: symmetrical central structural units
The structural f eatures of complex p olynuclear entities m ay be communicated u sing the
concept of a central structural unit (CSU). Only the metal atoms are considered for this
purpose. For nonlinear c lusters, descriptors such as triangulo, tetrahedro and
dodecahedro are used to describe c entral structural u nits in simple cases, as has already
been exemplified above. However, synthetic chemistry has advanced far beyond the
limited range of central structural units associated with this usage. A m ore comprehensive
CSU descriptor and a n umbering system, the CEP (Casey, Evans, Powell) system, h as
been developed specifically for fully triangulated polyboron polyhedra (deltahedra). 8
These CEP descriptors may be used in general as systematic alternatives to the traditional
descriptors for fully triangulated polyhedra (deltahedra). Examples are listed in Table
IR-9.1.

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