Chiral complexes nomenclature

Figure 3 Topological forms possible for ligands (178-184) in an octahedral complex, [M XY(N4)]"+ The R, R-nomenclature is valid for (178) and (180) but should be assigned for each individual polyamine. The alternative (chirality independent) nomenclature is based on X having a higher priority than Y...

The metal center in (i9 -C5H5)M(L)(CO)(allyl) can be considered pseudotetrahedral and characterized by the (R) and (5) nomenclature. Neutral chiral complexes of this type have been prepared previously, e.g., phosphine carbonyl derivatives (21, 75) and nitrosyl halide derivatives prepared by carbonyl displacement from nitrosyl cations by iodide (57, 60). Each of the diastereomers produced by the addition of a prochiral allyl moiety to the chiral metal center exhibit endo-exo isomerism. The endo-exo equilibration depends on charge and the neutral nitrosyl iodides rearrange rapidly compared to the cationic nitrosyls. 

Macropolycyclic ligands, 2,942 classification, 2,917 metal complexes binding sites, 2, 922 cavity size, 2,924 chirality, 2, 924 conformation, 2,923 dimensionality, 2, 924 electronic effects, 2, 922 shaping groups, 2,923 structural effects, 2,922 molecular cation complexes, 2,947 molecular neutral complexes, 2,952 multidentate, 2,915-953 nomenclature, 2,920 Macro tetrolide actins metal complexes, 2,973 Macrotricycles anionic complexes, 2,951 cylindrical... 

Figure 27. Epoxide hydrolase catalyzed kinetic resolution of c/.v-2-ethyl-3-methyloxirane and formation of 2i ,3f -2,3-pentanediol as monitored by complexation gas chromatography on 0.08 M nickel(II) bis[3-(heptafluorobutanoyl)-(1 / )-camphorate] in methylpolysiloxane [25 m x 0.25 mm (i.d.) glass capillary column. 95CC, 1.1 bar nitrogen]191 2,3-pentanediol as acetonides 0.14 M nickel(ll) bis[3-(heptafluo-robutanoyl)-(l /t,2S)-pinan-4-onatc]151 in SE-30. Note that there is a change in the numbering of the chiral carbon atoms of the oxiranc vs. the diol due to nomenclature requirements.

There are, in fact, currently three somewhat different nomenclature conventions being used to designate the chirality of a metal complex. Ultimately, when applied correctly, these conventions all give the same information on chiral structure and can be interrelated. The application of the different nomenclature systems depends to some extent on how closely the structures can be compared to tetrahedral carbon structures, how easy the nomenclature rules are to apply, and somewhat on keeping well-known previously applied historical nomenclature. 

Avnir et al. llbl have examined the classical definitions and terminology of chirality and subsequently determined that they are too restrictive to describe complex objects such as large random supermolecular structures and spiral diffusion-limited aggregates (DLAs). Architecturally, these structures resemble chiral (and fractal) dendrimers therefore, new insights into chiral concepts and nomenclature are introduced that have a direct bearing on the nature of dendritic macromolecular assemblies, for example, continuous chirality measure44 and virtual enantiomers. ... 

Figure 2.36 The nomenclature for the regiochemistry of additions must rely on a more complex system if (5,6)-adducts are to be considered, too. Moreover, the compound s chirality must be regarded for the derivatives concerned.

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