orthonym.rules.heterone_ligands

Note

Internal API. Names and behaviour may change between releases.

The heteroatom ligand of a P/As heterone: -O-P=O -> methoxyphosphanone.

mononuclear_hydrides.name_heterone names a hub X=O (X = P, As,…) whose other ligands are hydrocarbyl or halogen organyls (ethylphosphanone, phenylphosphanone). A ligand bonded to the hub through O, S or N (CH3-O-P=O) was not an organyl, so the producer declined the whole molecule and the molecule fell to a substitutive name built on the prefix ‘oxophosphanyl’. That prefix is for a heterone in the presence of a more senior group; here the heterone is the principal group.

Governing text (the Blue Book, quoted with its section heading):

• “HETERONES” (:25977): “Compounds containing the -PO, -PO2, -AsO or -AsO2 are called heterones (see,. In the presence of a more senior characteristic group they are described by the compound prefixes oxophosphanyl, dioxo-lambda5-phosphanyl, oxoarsanyl, and dioxo-lambda5-arsanyl.” The class is -PO and -AsO in one sentence.

• example (:25985): [(2-methylpropyl)amino]arsanone (PIN) – an arsanone whose only ligand is the heteroatom group ‘amino’ substituted by an alkyl, cited as a prefix of the heterone and not as a suffix of an amine. N-(2-methylpropyl)-1-oxoarsanamine is listed beside it without the (PIN) label.

• “Acyclic heterones” (:29390): the suffix ‘one’ “leads to preferred IUPAC names” (“Method (1)”,:29396).

*, under “ POLYFUNCTIONAL KETONES, PSEUDOKETONES AND HETERONES” (:29585):

“Ketones, pseudoketones and heterones, and their chalcogen analogues in the order =O > =S > =Se > =Te, are senior to hydroxy compounds and their chalcogen analogues, amines, and imines in the seniority order of classes.” An alkoxy, alkylsulfanyl or amino ligand therefore never outranks the heterone, and a ligand that holds any other group is not built here.

• / (:27633,:27649): ‘methoxy’, ‘phenoxy’, ‘(propan-2-yl)oxy’ and ‘methylsulfanyl’ are the preferred prefixes of the O-R and S-R groups; (:7272) cites the one ligand of a mononuclear hub with enclosing marks when it is a compound prefix.

The step from the arsanone amino example (:25985) to -O-P=O is by ANALOGY: the Blue Book prints no phosphanone with an alkoxy ligand. The class, -PO and -AsO), the suffix rule and the seniority are the same for P and As, and for O and N ligands. Nor does the book make -O-P=O an acid group of its own: “Names of mononuclear noncarbon oxoacids” (:35409, the list at:35431) holds phosphinic, phosphinous, phosphonic, phosphonous, phosphoric and phosphorous acid and no HO-P=O, and metaphosphorous acid, [HPO2]n = (-P(OH)O-)n, is polymeric and “only for general nomenclature” (:36677). The hub is admitted only at bonding number 3 with one ligand, the shape of phenylphosphanone (:28291). The label of the name is decided by that analogy: see the lane report.

What is built (fail closed in every other case): P or As hub, one terminal =O (or the =S, =Se, =Te analogue that name_heterone already builds for organyl ligands: ethylphosphanethione, :29585 “and their chalcogen analogues in the order =O > =S > =Se > =Te”), ONE single-bonded ligand (no hydrogen on the hub), the ligand an acyclic neutral O, S or N atom whose organyl part holds only carbon and halogen atoms. A ligand holding any other group (hydroxy, a carbonyl, an ester, a nitro…) needs a seniority comparison against the heterone and is left to the other producers.

The route is not offered while a fragment is being named for a prefix (in_fragment_recursion): the recursive substituent namer turns the name of the H-capped fragment into a prefix by suffix surgery, and a heterone has no ‘-yl’ form (its prefix is ‘oxophosphanyl’,.

orthonym.rules.heterone_ligands.hetero_ligand_prefix(mol, hub_idx, link_idx)

The prefix name of the one ligand link_idx of the heterone hub hub_idx (P or As, one terminal =O/=S/=Se/=Te, bonding number 3), for CH3-O-P=O ‘methoxy’, C6H5-O-P=O ‘phenoxy’, (CH3)2CH-CH2-NH-As=O ‘(2-methylpropyl)amino’; None when the ligand is not in the class above. Pure: no mol mutation.