Naming Coordination Compounds

It is worth to mention that both coordination compounds, namely [Ca(7)2]DBTA and [Ca(H20)](12)DBTA form conglomerates with their enantiomers, respectively. Thus, optical resolution of racemic DBTA by preferential crystallization of these coordination complexes is also possible. [26, 27]... 

Complex-formation titration — A method based on the -> titration between a metal ion and electron-pair donor species to form coordination compounds named -> complexes. The donor species is usually called complexing agent or ligand and it can have one or several pairs of unshared electrons available to bond a metal species [i]. 

In Werner s lifetime no system was used to name coordination compounds. Names of the compounds were commonly based on colors and names of discoverers. As the field expanded and more coordination compounds were identified, an orderly system of nomenclature became necessary. A simplified version of this system is summarized by the following rules. 

Nomenclature before Werner (to 1897)- The Lavoisierian system of nomenclature, even with the Berzelius modifications, provided no suitable names for that class of compounds which later was designated coordination compounds. Names based on the patterns for double salts and addition compounds were not satisfactory because the properties of these materials were not those consistent with the patterns provided. Consequently, names based on properties, especially color (Table I), or the names of prominent investigators became popular (2) because they, at least, did not commit the user to any theory of their structure. The developments in organic chemistry after 1860 did not contribute to the understanding of these strange compounds, so there was no carry-over to them of the nomenclature developments in organic chemistry. 

Even though both Hohenberg-Kohn and Kohn-Sham papers have been subsequently recognized as extremely important for Chemistry, that recognition came late in the community of theoretical chemists. Meanwhile, the MS-Xa method received much more attention. Por example, in 1970, Johnson and Smith addressed polyatomic molecules such as perchlorate and sulphate ions for the first time [13]. A landmark application of MS-Xa was the first investigation by Johnson and Smith of the electronic structure of a coordination compound, namely the permanganate ion [22]. The interest in the MS-Xa method for calculating the electronic structure of transition metal complexes increased rapidly and realistic results were soon obtained [23-25]. 

Atoms of nine elements have been identified in this chapter as capable of being donor atoms in coordination compounds. Name eight of these elements. What do they have in common that allows the atoms to be donor atoms ... 

Naming coordination compounds Naming inorganic compounds Naming organic compounds Organic functional groups Oxidation states (common)... 

Oxidation Number of Metals in Coordination Compounds Naming Coordination Compounds... 

PROCEDURE FOR... Naming Coordination Compounds EXAMPLE 24.3 Naming Coordination Compounds Name the following compound [Cr(H20)5Cl]Cl2. EXAMPLE 24.4 Naming Coordination Compounds Name the following compoun K3[Fe(CN)6l. 

Esters. Esters of inorganic acids are named as the salts for example, ( 113)2804, dimethyl sulfate. However, if it is desired to specify the constitution of the compound, the nomenclature for coordination compounds should be used. 

Naming a Coordination Compound. To name a coordination compound, the names of the ligands are attached directly in front of the name of the central atom. The ligands are listed in alphabetical order regardless of the number of each and with the name of a ligand treated as a unit. Thus diammine is listed under a and dimethylamine under d. The oxidation number of the central atom is stated last by either the oxidation number or charge number. 

Ternary compounds are also named by citing the more electropositive constituent first. The various oxidation states of the more electropositive element are designated by a system of prefixes and terminations added to a stem characteristic of the element, except in the case of coordination compounds (qv). Examples are as follows (see Chlorine oxygen acids and salts) ... 

Coordination compounds are named in much the same way as simple ionic compounds. The cation is named first, followed by the anion. Examples include... 

The names of coordination compounds can become awesomely long because the identity and number of each type of ligand must be included. In most cases, chemists avoid the problem by using the chemical formula rather than the name itself. For instance, it is much easier to refer to [FeCl(H20)5]+ than to pen-taaquachloroiron(II) ion, its formal name. However, names are sometimes needed, and they can be constructed and interpreted, in simple cases at least, by using the rules set out in Toolbox 16.1. Table 16.4 gives the names of common ligands and their abbreviations, which are used in the formulas of complexes. 

HOWTO NAME (/-METAL COMPLEXES AND COORDINATION COMPOUNDS... 

The name of a coordination compound (as distinct from a complex cation or anion) is built in the same way as that of a simple compound, with the cation named before the anion ... 

EXAMPLE 16.1 Sample exercise Naming complexes and coordination compounds... 

Which of the following coordination compounds can have cis and trans isomers If such isomerism exists, draw the two structures and name the compound. 

Originally, compounds containing coordination complexes were given common names such as Prussian blue (KFe[Fe (CN)g ]), which is deep blue, or Reinecke s salt (NH4[Cr (NH3)2 (NCS)4]), named for its first maker. Eventually, coordination compounds became too numerous for chemists to keep track of all the common names. To solve the nomenclature problem, the International Union of Pure and Applied Chemistry (lUPAC) created a systematic procedure for naming coordination compounds. The following guidelines are used to determine the name of a coordination compound from its formula, or vice versa ... 

Follow the guidelines for naming coordination compounds. Break the complex ion down one piece at a... 

Example provides more practice in working with the names of coordination compounds. Our Chemical Milestones Box describes the detective work that led to the birth of coordination chemistry. 

Functionally substituted phosphines play an important role as ligands in a great variety of phosphorus coordination compounds. They have some interesting features that distinguish them from other phosphine ligands, namely (a) the presence of other heteroatoms bearing lone electron pairs in addition to phosphorus (b) the presence of functional groups able to form bonds with a metal with the participation of its valence electrons ... 

The number of rules that need to be followed in naming coordination compounds is small, but they are sufficient to permit naming the majority of complexes. The rules will be stated and then illustrated by working through several examples. 

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