Can $\ce{Ph-CH2-Ph}$ be also be named as as (phenyl methyl) benzene instead of diphenyl methane?

I came to this thinking that $\ce{CH2-Ph}$ can be considered as side chain at side chain.

  • 1
    $\begingroup$ You could also call it "benzylbenzene", and although I don't think that would be IUPAC approved, it does seem to be in common use. $\endgroup$
    – Curt F.
    Jul 15, 2015 at 16:05
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    $\begingroup$ @CurtF. According to the pubchem database, this is the preferred IUPAC name. $\endgroup$ Jul 15, 2015 at 16:34
  • $\begingroup$ Whoah, thanks for the correction. I guess I need to bone up on IUPAC rules... $\endgroup$
    – Curt F.
    Jul 15, 2015 at 16:38

1 Answer 1


The current version of Nomenclature of Organic Chemistry – IUPAC Recommendations and Preferred Names 2013 (Blue Book) reads as follows:

P- Systems composed of rings and chains (exclusive of linear phanes)

Two methods are recognized to name systems composed of rings and chains (exclusive of linear phanes).

(1) Within the same class, a ring or ring system has seniority over a chain. When a ring and a chain contain the same senior element, the ring is chosen as parent. Rings and chains are chosen regardless of their degree of hydrogenation. As a consequence, this approach prefers the choice of a ring over a chain in systems composed of cyclic and acyclic hydrocarbons.

(2) The context may favor the ring or the chain, so that, for example, substituents may be treated alike or an unsaturated acyclic structure may be recognized, or the one chosen has the greater number of skeletal atoms in the ring or in the principal chain of the acyclic structure.

(…) For selection of a preferred IUPAC name, see P-52.2.8.


P-52.2.8 Selection between a ring and a chain as parent hydride

Within the same heteroatom class and for the same number of characteristic groups cited as the principal characteristic group, a ring is always selected as the parent hydride to construct a preferred IUPAC name. In general nomenclature, a ring or a chain can be the parent hydride (see P-

Method (1): “1,1'-methylenedibenzene” (preferred IUPAC name; ring preferred to chain)

Method (2): “diphenylmethane” (treats phenyl groups alike as substituents)

(This example is is explicitly mentioned in the Blue Book.)



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