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A Novel Route to Cationic Four‐Coordinate Rhodium(I) Complexes with Rh=C Bonds
Author(s) -
Windmüller Bettina,
Nürnberg Oliver,
Wolf Justin,
Werner Helmut
Publication year - 1999
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/(sici)1099-0682(199904)1999:4<613::aid-ejic613>3.0.co;2-l
Subject(s) - chemistry , acetone , cationic polymerization , rhodium , ligand (biochemistry) , pyridine , medicinal chemistry , ketone , alkyne , stereochemistry , polymer chemistry , organic chemistry , catalysis , biochemistry , receptor
The complex [Rh(acetone) 2 (C 8 H 14 ) 2 ]PF 6 ( 2 ), which is prepared from [RhCl(C 8 H 14 ) 2 ] 2 and AgPF 6 in acetone, reacts with P i Pr 3 to afford the PF 6 salt 3 of the cation [Rh(acetone) 2 (P i Pr 3 ) 2 ] + containing the ketone and phosphane ligands in cis dispositions. Treatment of 3 with MeC≡CPh leads to the displacement of one acetone ligand and the formation of the corresponding π‐alkyne complex 4 . In contrast, from 3 and terminal alkynes such as HC≡CC 6 H 4 –4‐Me or HC≡CCPh 2 OH the cationic vinylidenerhodium(I) compounds 5 and 6 are obtained. The latter, with C=CHCPh 2 OH as the ligand, is rather labile and even at room temperature eliminates water to give the cationic four‐coordinate rhodium allenylidene 7 . The molecular structure of this compound has been determined by X‐ray crystallography. In the presence of pyridine or ammonia, the acetone ligand of 5 and 7 is readily displaced and the substitution products 8 – 10 are formed almost quantitatively. Anions such as acetate or hydroxide also displace the ketone unit of 7 and yield the neutral allenylidenerhodium(I) complexes trans ‐[RhX(=C=C=CPh 2 )(P i Pr 3 ) 2 ] with × = OAc ( 11 ) and OH ( 12 ).