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Thiophene complexes of the platinum group metals. 2. Preparation and characterization of cationic thiophene complexes of [(cyclooctadiene)Ir][BF[sub 4]] and [(norbornadiene)Rh] [BF[sub 4]] and X-ray crystal structure of [[eta][sup 5]-2,5-dimethylthiophene(cyclooctadiene)Rh][BF[sub 4]]

Journal Article · · Organometallics; (United States)
DOI:https://doi.org/10.1021/om00033a022· OSTI ID:5576807
;  [1]
  1. Univ. of Texas, El Paso, TX (United States)

Cleavage of chloro-bridged rhodium and iridium dimers, [(NBD)RhCl][sub 2] and [(COD)IrCl][sub 2], in methanol leads to the formation of cationic (COD)[sub 2]Ir[sup +] and (NBD)Rh[sup +] monomers, respectively. Reaction of these cationic species with 2-methylthiophene and 2,5-dimethylthiophene results in the formation of complexes in which the thiophene coordinates in an [eta][sup 5] manner. With benzothiophene and dibenzothiophene, complexes bearing a 1:1 metal:ligand stoichiometry are obtained with the ligand coordinating in an [eta][sup 6] fashion using the six carbon atoms of the arene ring. Good yields of these Rh and Ir products are obtained with the exception of those of reactions involving thiophene, where only small amounts of product were obtained. A crystal structure determination of the cationic (cyclooctadiene)rhodium 2,5-dimethylthiophene complex shows that the thiophene ligand binds to the transition metal center in an [eta][sup 5] manner. The S atom is displaced 0.1888 A from the least-squares plane defined by the four carbon ring atoms and displays C-S bond lengths similar to those found in free thiophene. 17 refs., 2 figs., 3 tabs.

OSTI ID:
5576807
Journal Information:
Organometallics; (United States), Journal Name: Organometallics; (United States) Vol. 12:9; ISSN ORGND7; ISSN 0276-7333
Country of Publication:
United States
Language:
English