Anionic ligands, naming

In certain cases the kappa convention may be simplified. Donor atoms of a ligand may be denoted by adding only the italicized symbol(s) for the donor atom (or atoms) to the end of the name of the ligand. Thus, for the 1,2-dithiooxalate anion, ligand names such as 1,2-dithiooxalato-K5,K5,/ and l,2-dithiooxalato-KO,K5 may, with no possibility of confusion, be shortened to l,2-dithiooxalato-5,5 and l,2-dithiooxalato-0,5, respectively. Other examples are thiocyanato-iV and thiocyanato-5, and nitrito-iV and nitrito-O. 

The names of anionic ligands are obtained by substituting the suffix -o for the normal ending. Examples include... 

The chemical symbols of anionic ligands precede those of neutral ligands in the chemical formula of the complex (but not necessarily in its name). Thus, Cl precedes H20 and NH3. 

It is interesting to note that both Te42+ and neutral Te4 rings have been characterized as ligands, namely in the respective complexes [Te4 Nb30l6(Te2)2 ] [26] and [Te4 Cr(CO)s 4] [27]. As we will see in Section 2.7.3, effectively isolated Te4 rings are present in the anionic network of Cs4Te28 [8]. 

The names of anionic ligands always end in an o. Neutral ligands are basically unchanged. Two common exceptions in the case of neutral ligands are NH3 = ammine (note the double m), and H20 = aqua. Other common ligands and their names are listed in Appendix C. 

Alkoxides and imido are used as anionic ligands in zirconium and titanium catalysts for the polymerisation of alkenes, sometimes as the only anions, but often in combination with cyclopentadienyl ligands. Imides linked to cyclopentadienyl groups form part of the single-site catalyst developed by Dow (Chapter 10) (Figure 1.9, 1). In very different titanium catalysts, namely those used for epoxidation of alkenes, also alkoxide ligands are used (Chapter 14). 

This system is additive and was developed originally to name coordination compounds, although it can be used in other circumstances when appropriate. For a discussion, see the Nomenclature of Inorganic Chemistry, Chapter 10. The compound to be named is considered as a central atom together with its ligands, and the name is developed by assembling the individual names of the constituents. This system has also been applied to name oxoacids and the related anions. Coordination names for oxoanions are cited in the examples throughout the text, and they are presented in detail in Section 4.4.5 (p. 69). 

Finally, we must mention a number of reports concerning bis chelates, either mononuclear square planar or trinuclear octahedral, with anionic ligands which bear some resemblance to /3-diketones, namely acetophenone,1592 a -nitroketones,1593,1594 hydroxymethylenecamphor and related ligands.1595-1597... 

Additive nomenclature1 is based on the combination of element names or roots of element names and/or ligand names. The simplest and oldest additive nomenclature is binary nomenclature that expresses two components, e.g. sodium chloride. The cationic or electropositive portion of the compound expressed in a binary name is the element name unchanged or a group name ending in -ium , and the anionic or electronegative portion of a compound expressed in the name ends in -ide, -ite or -ate. The proportions of cations and anions in neutral compounds are indicated by Stock numbers or simple or multiplicative prefixes (see Section 3.3.2). Additive nomenclature denotes composition. For examples see Table 1. 

Table 4 Anionic Inorganic Ligand Names Formula Systematic name Common name...

Anionic Ligand Ligand Name Neutral Ligand Ligand Name... 

The names of anions usually end in -ide if there are monatomic or homopolyatomic, or -ate for heteropolyatomic anions and coordination compounds. Anionic ligands usually end in -o. Thus CP is chloride, I3 is triiodide and S042 is sulfate but become, chloro, triiodo and sulfato if they are coordinated as ligands. The names of complex anions are not always derived from the familiar name... 

Ligands that are anions are named with the suffix -0, as in chloro, oxalato, cyano. 

Q One thing you may have noticed in the previous example is the ending -o on the end of cyano. Most anionic ligands are written with an -o ending, like chloro, bromo, cyano, and oxo. Neutral ligands are usually given the name of the molecule. A few notable exceptions to this are NH3, known as ammine H20, known as aqua and CO, known as carbonyl. 

Surprisingly, cationic complexes of Cu(I) and Ag(I), namely, [(NHC)2M](CF3S03), have been prepared by substitution of anionic ligand of M(CF3S03)2 with two equivalents of free carbene. ... 

Anionic ligands are given an o suffix. Neutral ligands retain their usual name. Coordinated water is called aqua and coordinated ammonia is called ammine. 

Anionic ligands are named by replacing the usual ending with the suffix -o. The names of neutral ligands are unchanged. Exceptions to the latter rule are aqua (for water), ammine (for NH3), and carbonyl (for CO) (see Table 8.4). 

---