Skeletal replacement nomenclature

So, in substitutive nomenclature we take a parent hydride or a functional parent, whose name form a root of a term to be created, and replace the hydrogens with substituents, whose names become prefixes or suffixes. Can we do the same with other atoms apart from hydrogens, for the naming purposes?

Yes we can.

(a)	(b)

pentaethylene glycol (trivial) 3,6,9,12-tetraoxatetradecane-1,14-diol (replacement + substitutive) tetradecane

Functional parents

There is a small number of relatively simple organic entities containing at least one characteristic group that also could be treated as parent structures. These entities are known as functional parents.

For example, the preferred IUPAC name of the structure (a) is 2-hydroxybenzoic acid. Why not 2-hydroxybenzenecarboxylic acid? Because (a) is thought of as a derivative of benzoic acid (b). Now (b) contains a characteristic group –COOH and so cannot be called “parent hydride”, while benzene (c), indeed, is a parent hydride of both (a) and (b). However (b) is a functional parent and thus the name “benzoic acid” can be used to construct the substitutive name “2-hydroxybenzoic acid”.

(a)	(b)	(c)

salicylic acid (trivial) 2-hydroxybenzoic acid (substitutive) 2-hydroxybenzenecarboxylic acid (substitutive) benzoic acid (trivial) benzenecarboxylic acid (substitutive) benzene (trivial)

Substitutive names and parent hydrides

Let’s try to name the structure (a).

(a)

CBr4 carbon tetrabromide (compositional) tetrabromidocarbon (additive) tetrabromomethane (substitutive)

We can give it a binary name carbon tetrabromide. We can name it additively tetrabromidocarbon.

Or we can call it in a completely different fashion: tetrabromomethane.

Dealing with dinuclear and polynuclear entities

The additive names are easy to construct for mononuclear entities, that is, when we have to describe an entity with just one central atom. What if we have two?

(a)

[ClO2] OClO• dioxidochlorine(•) μ-chlorido-dioxygen(•)

If we consider the structure (a) a mononuclear entity, [ClO₂], we would call it dioxidochlorine(•). Alternatively, we may think of two oxygen atoms bridged by one chlorine atom, OClO, and call it μ-chlorido-dioxygen(•). Here, a bridging ligand is indicated by the Greek letter μ.

Addi(c)tive names

Let’s have a look at uranium hexafluoride, UF₆. As you remember, in binary-type nomenclature both formulae (e.g. UF₆) and names (e.g. uranium hexafluoride) are divided in two parts, electropositive (or less electronegative) always followed by (more) electronegative. Grammatically, the binary name is a noun phrase consisting of a head noun such as hexafluoride preceded by an attributive noun such as uranium^*.

Neither the compositional name nor formula tell us anything about its structure. For all we know, it could be an ionic compound composed of ions U⁶⁺ and F⁻.

Now let’s say we learn from Wikipedia that this compound consists of discrete molecules which could be represented like this:

(a)

Can we give a name that reflects the structure (a)?