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The ruthenium and iron dicarbonyl complexes Ru(MeP(CH 2 CH 2 PMe 2 ) 2 )(CO) 2 ( 1 ), Ru(MeP(CH 2 CH 2 CH 2 PMe 2 ) 2 )(CO) 2 ( 2 ) and Fe(MeP(CH 2 CH 2 CH 2 PMe 2 ) 2 )(CO) 2 ( 3 ) bearing strong donor tridentate phosphine ligands were prepared and fully characterised. The structures of the complexes have been established by X-ray diffraction studies. Oxidative addition of MeI to 1 – 3 proceeds instantaneously at room temperature and affords the corresponding octahedral cationic complexes fac , cis -[RuMe(MeP(CH 2 CH 2 PMe 2 ) 2 )(CO) 2 ]I ( 5a ) and mer , cis -[RuMe(MeP(CH 2 CH 2 PMe 2 ) 2 )(CO) 2 ]I ( 5b ), mer , trans -[MMe(MeP(CH 2 CH 2 CH 2 PMe 2 ) 2 )(CO) 2 ]I ( 6a (M=Ru); 7a (M=Fe)) and mer , cis -[MMe(MeP(CH 2 CH 2 CH 2 PMe 2 ) 2 )(CO) 2 ]I ( 6b (M=Ru); 7b (M=Fe)), respectively. The triphosphine preferentially adopts a facial arrangement in the case of the ethylene bridged tridentate ligand ( 5a ) and a meridional arrangement in the case of the trimethylene bridged ligand ( 6a – 7b ). mer , cis -[RuMe(MeP(CH 2 CH 2 CH 2 PMe 2 ) 2 )(CO) 2 ]I ( 6a ) undergoes CO insertion to the acetyl complex mer , trans -[Ru(COMe)(MeP(CH 2 CH 2 CH 2 PMe 2 ) 2 )(CO) 2 ]I ( 8 ). Attempts to produce a ketene complex from the deprotonation of 8 were not successful. The acetyl protons in 8 show very low acidity and no reaction occurred when the complex was reacted with bases such as DBU, BEMP (2-tert-Butylimino-2-diethylamino-1,3-dimethyl-perhydro-1,3,2-diazaphosphorine) or LDA. |
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