Project Details Nomenclature for metallacycles containing transition metals

Project No.:
2013-030-1-800
Start Date:
01 July 2013
End Date:
Division Name:
Chemical Nomenclature and Structure Representation
Division No.:
800

Objective

To develop nomenclature recommendations for ring compounds containing elements of Groups 3-12 directly coordinated to carbon atoms or other Group 14 atoms (‘metallacycles’).

Rationale:
Transition metal metallacycles are receiving increasing attention as catalysts and/or possible intermediates in organometallic catalysis. Thus, there is a steady increase of publications on such compounds, and growing interest in areas of applied chemistry, including the chemical industry. These organometallic complexes lie in the area that is not explicitly covered by the nomenclature rules for inorganic or organic compounds. Hence, there is a need to develop IUPAC recommendations for the nomenclature of this class of compounds.

Description

Exploratory work on the nomenclature of metallacycles of the transition elements was undertaken under the auspices of the old Inorganic Nomenclature Commission in 2001 by Herb Kaesz, Jim Casey, Henri Favre and Yohsuke Yamamoto, with subsequent input by Ebbe Nordlander. Their ideas will be reviewed and taken as a starting point for providing nomenclature recommendations for ring compounds containing elements of Groups 3-12 directly coordinated to carbon atoms (or perhaps Group 14 atoms in general). Such transition metal metallacycles are today receiving increasing attention as catalysts and/or possible intermediates in organometallic catalysis.

After establishing appropriate definitions and outlining which kinds of compounds should or should not be named as metallacycles, naming procedures (e.g. selection of parent ring systems, determination of locants, etc.) will be developed and illustrated with relevant examples. Consideration will be given to naming cationic and anionic metallacyclic species, and the differences in naming metallacyclic compounds of the transition elements compared to main group elements will be highlighted and explored.

Critical evaluation of the proposals by all stakeholders over the time period of the project should result in recommendations that will be adopted by the user community, as well as contribute to the ongoing development of the nomenclature of organometallic compounds.

Progress

Jan 2014 – Project announcement published in Chem. Int. Jan-Feb 2014, p. 18; DOI: 10.1515/ci.2014.36.1.18.

Nov 2017 update – Good progress has been made and a substantial document now exists in the form of a draft “Recommendation” for publication in PAC. At the meeting in August 2016, it was realized that further progress to finalize this document would be contingent on resolution of several difficulties preventing finalization of the “kappa document” (Preferred names for inorganic compounds, project 2006-038-1-800 (Hartshorn)), the outcome of which also impinges on, and will enable completion of, several other current projects in the Division (Boron hydride nomenclature, project 2012-045-1-800 (Beckett); Blue Book revision and extension, project 2015-052-1-800 (Hellwich); Inorganic and coordination polymers, project 2011-035-1-800 (Jones)). To this end, a new project, Alignment of principles for specifying ligands and substituent groups across various areas of nomenclature, project 2017-033-1-800 (Hellwich) was recently initiated and will provide for a meeting to tackle these issues.

Page last updates 9 Nov 2017