Complex cations nomenclature

An additional aspect of nomenclature is the procedure of identifying the charge on a complex cation or anion by a number in parentheses after the name. The numbers indicating the charges are known as Ewens-Bassett numbers. Some examples showing both procedures for specifying charges and oxidation states are as follows ... 

Where the cation can clearly be regarded as a coordination complex, coordination nomenclature (see p. 51) is the natural choice. 

Werner did not place as much emphasis on names for complex anions as he did for complex cations and neutral entities. Consequently, such names as ferrocyanide and cobaltinitrite persisted almost to the exclusion of the more consistent hexacyanoferroate and hexanitritocobaltiate. However, it is entirely clear in papers published after those enunciating his principles for nomenclature that he inaugurated practices which are still followed today. 

The name crown arises from both the appearance of models of these compounds and their ability to crown cations by complexation. lUPAC nomenclature can be used to name these ligands however, the result is complex and cumbersome. This has been resolved by using the more illustrative Pedersen crown notation. For example in (1) dibenzo stands for both of the benzene substituents annexed to the ring, while -18- means the number of ring atoms. 

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... 

The abbreviations for the investigation methods are also taken from the nomenclature of Sillen and Martel 1 (76) aiex = anion exchange cal = calorimetry ciex = cation exchange dis = distribution between two phases est = estimate red = e.m.f. with redox electrode sp = spectrophotometry. Our selected data, rather limited in number, arise from the present status of the IAEA assessment of inorganic complexes of the actinides (12). 

The fact that metal hydrides can be acidic may seem paradoxical in view of the nomenclature that insists that all complexes with a M-H bond be referred to as hydrides regardless of whether their reactivity is hydridic or not. Not only can some metal hydrides donate a proton, but some can be remarkably acidic. Some cationic dihydrogen complexes are sufficiently acidic to protonate Et20 [8], and some dicationic ruthenium complexes have an acidity comparable to or exceeding that of HOTf [9],... 

The sections are divided by the coordination number of the reacting ion defined as the number of donor atoms that interact with the metal. The nomenclature used for the ligands is L for neutral molecules that act as ligands and X for anions that act as ligands. Most of the examples in this section will involve cations [ML ]+ or [MX ]+, but there will be a short section on bare metal anions, M . The anions of more complexity than M will be discussed in Section IV on clusters. Many reactions produce an initial product that continues to react resulting in further coordi-native changes and possibly redox changes. Tables I and II will indicate the initial reaction product and other major reaction products. 

Complex ions combine with cations or anions to form coordination complexes. These complex ions usually consist of a transition metal ion attached to ligands. You should be familiar with the basic nomenclature for coordination complexes. 

Cation complexes of cryptands were called cryptates and those of spherands, spherates. The name coronand was suggested for crown ethers and their complexes would therefore be coronates <1980ICAL45>. The latter nomenclature has proved to be acceptable to the community but it has not been universally adopted. A reasonable and systematic approach, based on principles of polymer nomenclature, has appeared but has not found wide acceptance <1984JCI266>. 

These macroblcycllc ligands (I) discovered by Lehn (13) form extremely stable cation Inclusion complexes, called cryptates. In the nomenclature system used herein. Structure I would be designated [211] when m 2 and n°=p=l. 

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