Cationic Palladium η3-Allyl Complexes with Hemilabile P,O-Ligands : Synthesis and Reactivity : Insertion of Ethylene into the Pd-Allyl Function
نویسندگان
چکیده
Cationic palladium allyl complexes [(η3-C3H5)Pd(κ2P∧O)]+SbF6(2[SbF6], P∧O≡ Ph2P(CH2)2C(dO)OEt; 3[SbF6], o-Ph2PC6H4C(dO)OEt; 4[SbF6], Ph2P(CH2)2P(dO)Ph2) have been prepared. In all complexes the oxygen donor can be displaced by other ligands such as carbon monoxide and ethylene. Displacement of an ester donor occurs much more readily than displacement of the phosphine oxide function. Above 0 °C, the resulting ethylene complexes [(η-C3H5)Pd(C2H4)(κ1P∼O)]+ react to give (1,2,5-η3)-pent-1-en-5-yl complexes [(H2CdCH(CH2)3Pd(κ2P∧O)]+. A rate constant of e.g. k(17 °C) ) (2.27 ( 0.11) × 10-4 s-1 was determined for P,O ≡ Ph2P(CH2)2C(O)OEt by 1H NMR spectroscopy. Using 2-4 as catalyst precursors for ethylene dimerization, the allyl moiety is ultimately cleaved from the metal center as 1,4pentadiene.
منابع مشابه
Palladium Catalyzed Alternating Cooligomerization of Ethylene and Carbon Monoxide to Unsaturated Ketones
Wilhelm Keim*. H eiko Maas, Stefan M ecking Institut für Technische Chemie der RW TH A achen, W orringer Weg 1, D-52074 Aachen, G erm any Dedicated to Prof. Dr. Dr. h.c. mult. Günther Wilke on the occasion o f his 70th birthday Z. N aturforsch. 50b, 430-438 (1995); received Septem ber 15, 1994 Cooligom erization, C arbonylation. Palladium , Hemilabile, U nsaturated Ketone Cationic palladium cat...
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