32 No. 1
Coordination Polymers and Metal Organic Frameworks: Terminology and Nomenclature Guidelines
As is often the case, practice precedes theory and synthesis precedes nomenclature and terminology. This is certainly the case in one of the fastest growing fields of contemporary inorganic chemistry: coordination polymers (CPs) and metal organic frameworks (MOFs).1 This is an interdisciplinary research field with origins in coordination and solid-state chemistry that is now also attracting the interest of the chemical industry.2 The porous properties of some of these materials are promising for numerous applications, from gas storage to catalysis.
The diversity in both focus and scientific basis of the researchers involved has lead to numerous terminology suggestions and practices for this class of compounds and of several subgroups within; additionally, a disquieting number of abbreviations are also in use and practices are not consistent among research groups, causing unnecessary conflicts and confusion.
Thus, coordination chemists would normally consider any Lewis base bonded to a metal cation as a coordination compound, whereas some solid-state chemists may want to single out, for example, metal-carboxylates as being different from a valence bond perspective. Some researchers consider the two terms “coordination polymers” and “metal organic frameworks” as equivalent, while others state that MOFs are a porous subgroup. Some view 1D ladder-like coordination polymers as MOFs, whereas others demand that MOFs form three-dimensional networks.
The task group is charged with the delicate task of finding one or more definitions that can gain a broad acceptance within the CP and MOF community, while at the same time not deviating too much from the picture the more general chemical public may have gotten from the many articles this prolific research area has generated in various science news magazines.3 The term MOF is now also found in basic textbooks.4
The task group needs to balance the advantages and drawbacks of basing these definitions on concepts of chemical bonding (coordination, covalent, dative, ionic), on crystal structure information (network formation, dimensionality, and derived properties), and on actual measured physical properties (solubility, porosity as measured by gas sorption isotherms). The task group will evaluate the need to further divide such compounds into subclasses based on properties or structures, and the group may consider the need for topology descriptions of specific networks formed.
Moreover, it has been noted that current IUPAC nomenclature rules for coordination polymers, dating from 1985,5 do not apply to these classes of compounds and need to be amended or extended.
It is expected that the group will deliver clear guidelines to help researchers communicate with each other, minimize terminology controversies among authors, referees, and journal editors; and enable end users in industry, government, and academia to understand and apply research from this new and important field.
- G. Ferey, Chem. Soc. Rev. 2008, 37, 191-214; J.R. Long, O.M. Yaghi, Chem. Soc. Rev., 2009, 38, 1213–1214
- U. Müller, M. Schubert, F. Teich, H. Puetter, K. Schierle-Arndt and J. Pastré, J. Mater. Chem. 2006, 16, 626-636
- For example, New Scientist, February 2004; Chemical & Engineering News, Aug 2008; Chemistry World, 18 October 2009.
- Shriver and Atkins’ Inorganic Chemistry, 5th ed, P. Atkins, N. Overton, J. Rourke, M. Weller, F. Armstrong, Oxford University Press, Oxford, 2009
- L.G. Donaruma, B.P. Block, K.L. Loening, N. Plate, T. Tsuruta, K.C. Buschbeck, W.H. Powell and J. Reedijk, Pure Appl. Chem. 1985, 57, 149–168.
For more information and comments, contact Task Group Chair Lars Öhrström <firstname.lastname@example.org>.
last modified 24 January 2010.
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