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Reactivity of Molybdenum and Rhenium Hydroxo‐Carbonyl Complexes toward Organic Electrophiles
Author(s) -
Cuesta Luciano,
Gerbino Darío C.,
Hevia Eva,
Morales Dolores,
Navarro Clemente M. Elena,
Pérez Julio,
Riera Lucía,
Riera Víctor,
Miguel Daniel,
del Río Ignacio,
GarcíaGranda Santiago
Publication year - 2004
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/chem.200305577
Subject(s) - chemistry , electrophile , medicinal chemistry , adduct , rhenium , reactivity (psychology) , phenylisocyanate , molybdenum , stereochemistry , inorganic chemistry , organic chemistry , catalysis , medicine , alternative medicine , pathology
The hydroxo compounds [Re(OH)(CO) 3 (NN)] (NN=bipy, 2 a ; Me 2 bipy, 2 b ) were prepared in a biphasic H 2 O/CH 2 Cl 2 medium by reaction of [Re(OTf)(CO) 3 (NN)] with KOH. In contrast, when anhydrous CH 2 Cl 2 was used, the binuclear hydroxo‐bridged compound [{Re(CO) 3 (bipy)} 2 (μ‐OH)]OTf ( 3 ‐OTf) was obtained. Compound [Re(OH)(CO) 3 (Me 2 bipy)] ( 2 b ) reacted with phenyl acetate or vinyl acetate to afford [Re(OAc)(CO) 3 (Me 2 bipy)] ( 4 ) and phenol or acetaldehyde, respectively. The reactions of [Mo(OH)(η 3 ‐C 3 H 4 Me‐2)(CO) 2 (phen)] ( 1 ), 2 a , and 2 b toward several unsaturated organic electrophiles were studied. The reaction of 1 with ( p ‐tolyl)isocyanate afforded an adduct of N , N ′‐di( p ‐tolyl)urea and the carbonato‐bridged compound [{Mo(η 3 ‐C 3 H 4 Me‐2)(CO) 2 (phen)} 2 (μ‐η 1 (O),η 1 (O)‐CO 3 )] ( 5 ). In contrast, the reaction of 2 a with phenylisocyanate afforded [Re(OC(O)NHPh)(CO) 3 (bipy)] ( 6 ); this results from formal PhNCO insertion into the OH bond. On the other hand, compounds [Mo[SC(O)NH( p ‐tolyl)](η 3 ‐C 3 H 4 Me‐2)(CO) 2 (phen)] ( 7 ), [Re[SC(O)NH( p ‐tolyl)](CO) 3 (Me 2 bipy)] ( 8 a ), and [Re[SC(O)NHEt](CO) 3 (Me 2 bipy)] ( 8 b ) were obtained by reaction of 1 or 2 b with the corresponding alkyl or aryl isothiocyanates. In those cases, RNCS was inserted into the MO bond. The reactions of 1, 2 a , and 2 b with dimethylacetylenedicarboxylate (DMAD) gave the complexes [Mo[C(OH)C(CO 2 Me)C(CO 2 Me)O](η 3 ‐C 3 H 4 Me‐2)(CO)(phen)] ( 9 ) and [Re[C(OH)C(CO 2 Me)C(CO 2 Me)O](CO) 2 (NN)] (NN=bipy, 10 a ; Me 2 bipy, 10 b ). The molecules of these compounds contain five‐membered metallacycles that are the result of coupling between the hydroxo ligand, DMAD, and one of the CO ligands. The new compounds were characterized by a combination of IR and NMR spectroscopy, and for [{Re(CO) 3 (bipy)} 2 (μ‐OH)]BF 4 ( 3 ‐BF 4 ), 4 , 5 , 6 , 7 , 8 b , 9 , and 10 b , also by means of single‐crystal X‐ray diffraction.