ISSN:
0009-2940
Keywords:
(Borole)dicarbonylcobalt anions, methylation, protonation
;
(Boracyclopentenyl)dicarbonyl(phosphane)cobalt complexes, hydride abstraction
;
(Borole)dicarbonyl(phosphane)cobalt cation, hydride addition
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Derivatives of Borole, XIX[1]. - (Borole)dicarbonylcobaltate Ions: Synthesis, Structure, and Reactivity[3]Reduction of the dinuclear (borole)carbonylcobalt complexes [(3,4-R2C4H2BPh)Co(CO)2]2 (3a: R = H, b: R = Me) with Na/Hg in THF at -30°C affords the anions [(3,4-R2C4H2BPh)-Co(CO)2]- (2a,b-) which can be isolated as [Na([15]crown-5)]+ salts. The structural data of PPh4 · 2a indicate a strong Co - C(CO) interaction and relatively weak cobalt-to-boron bonding. Methylation of the anions 2a,b- gives labile metal alkyl complexes (3,4-R2C4H2BPh)Co(CO)2Me while protonation and subsequent addition of phosphanes afford boracyclopentenyl complexes as e.g. (C4H5BPh)Co(CO)2(PMe3) (5a). The latter reacts with Ph3CBF4 to give the salt [(C4H4BPh)Co(CO)2-(PMe3)]BF4 (6 · BF4). At -80CC cation 6+ undergoes hydride addition at the carbonyl carbon to give the formyl species (C4H4BPh)Co(CO)(CHO)(PMe3) (7) which transforms to the hydride (C4H4BPh)CoH(CO)(PMe3) (8). At room temperature the same reaction produces 5a. Deuteration studies show that the oxidative formation of 6+ from 5a and the formation of 5a by addition of hydride to 6+ are nonstereospecific processes.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19921251104
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