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Carbenerhodium Complexes of the Half‐Sandwich‐Type: Synthesis, Substitution, and Addition Reactions
Author(s) -
Werner Helmut,
Schwab Peter,
Bleuel Elke,
Mahr Norbert,
Windmüller Bettina,
Wolf Justin
Publication year - 2000
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/1521-3765(20001215)6:24<4461::aid-chem4461>3.0.co;2-f
Subject(s) - chemistry , ligand (biochemistry) , medicinal chemistry , adduct , aryl , bond cleavage , substitution reaction , stereochemistry , olefin fiber , catalysis , organic chemistry , biochemistry , alkyl , receptor
A series of carbenerhodium( I ) complexes of the general composition [(η 5 ‐C 5 H 5 )Rh(=CRR′)(L)] ( 2 a – 2 i ) with R=R′=aryl and L=Sb i Pr 3 or PR 3 has been prepared from the square‐planar precursors trans ‐[RhCl(=CRR′)(L) 2 ] and NaC 5 H 5 in excellent yields. Reaction of the triisopropylstibane derivative 2 a , which contains a rather labile Rh−Sb bond, with CO, PMe 3 , and CNR (R=Me, CH 2 Ph, t Bu) leads to the displacement of the Sb i Pr 3 ligand and affords the substitution products [(η 5 ‐C 5 H 5 )Rh(=CPh 2 )(L)] ( 3 – 7 ). In contrast, treatment of the triisopropylphosphane compound 2 c with CO and CN t Bu leads to the cleavage of the Rh=CPh 2 bond and gives besides [(η 5 ‐C 5 H 5 )Rh(P i Pr 3 )(L)] ( 10, 12 ) by metal‐assisted CC coupling diphenylketene Ph 2 C=C=O ( 11 ) or the corresponding imine Ph 2 C=C=N t Bu ( 13 ). While the reaction of 2 a , c with C 2 H 4 yields [(η 5 ‐C 5 H 5 )Rh(C 2 H 4 )(L)] ( 14, 15 ) and the trisubstituted olefin Ph 2 C=CHCH 3 ( 16 ), treatment of 2 a , c with RN 3 leads to the cleavage of both the Rh−E i Pr 3 and Rh=CPh 2 bonds and gives the chelate complexes [(η 5 ‐C 5 H 5 )Rh( κ 2 ‐R N NN N R)] ( 19, 20 ). The substitution products 3 (L=CO) and 4 (L=PMe 3 ) react with an equimolar amount of sulfur or selenium by addition of the chalcogen to the Rh=CPh 2 bond to generate the complexes [(η 5 ‐C 5 H 5 )Rh( κ 2 ‐ECPh 2 )(L)] ( 21 – 24 ) with thio‐ or selenobenzophenone as ligand. Similarly, treatment of 3 with CuCl affords the unusual 1:2 adduct [(η 5 ‐C 5 H 5 )(CO)Rh(μ‐CPh 2 )(CuCl) 2 ] ( 25 ), which reacts with NaC 5 H 5 to form [(η 5 ‐C 5 H 5 )(CO)Rh(μ‐CPh 2 )Cu(η 5 ‐C 5 H 5 )] ( 26 ). The molecular structures of 3 and 22 have been determined by X‐ray crystallography.