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Tetracyanoethylene (TCNE): The Characteristic Geometries and Vibrational Absorptions of Its Numerous Structures
Author(s) -
Miller Joel S.
Publication year - 2006
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.200503277
Subject(s) - tetracyanoethylene , valency , delocalized electron , chemistry , crystallography , valence (chemistry) , computational chemistry , stereochemistry , photochemistry , organic chemistry , philosophy , linguistics
Abstract Tetracyanoethylene (TCNE) undergoes numerous reactions and is reported to exist in many structural motifs. Identification of these forms and motifs can be challenging. Nonetheless, the number of $\tilde \nu $ CN absorptions and their frequencies provide insight with respect to the specific forms and charge on the TCNE fragment. Particularly informative is the average of the fundamental $\tilde \nu $ CN bands, as well as the length of the central CC bond. This Review discusses the assignment of structure and formal charge for TCNE‐containing compounds. Scrutiny of previous assignments reveals some discrepancies which are discussed, and provides a basis for further study of TCNE structure–function relationships. Several multimetal complexes with bridging [TCNE] z units exhibit mixed valency and extensive delocalization. The scarcity of suitable model compounds, especially those with M d π–π*backbonding to the CN groups, have thwarted the detailed description of these valence ambiguous compounds; thus, new well‐characterized polynuclear compounds are needed.