Neuartige basische Liganden für die homogenkatalytische Methanolcarbonylierung, XXIV [1]. Rhodium-Komplexe mit (Ether-Phosphan)-Liganden unterschiedlicher Basizität und ihr Einfluß bei der Methylwanderung / Novel Basic Ligands for the Homogenous Catalytic Methanol Carbonylation, XXIV [1]. Rhodium Complexes with (Ether-Phosphane) Ligands of Different Basicity and their Influence on the Methyl Migration

Novel Basic Ligands for the Homogeneous Catalytic Carbonylation of Methanol, XXVIl). -Dynamic and Reactive Behaviour of (Ether-Phosphane)Ruthenium(II) Complexes in Dependence on the 0-Basicity Reaction of the ether-phosphane ligand Ph2PCH2C4H702 (3a) irradiation cis&, trans-6a is retransformed at 40°C into 4a via with C12Ru(PPh3), (2) results in the formation of the bis(che1ate) all-trans-?a and 5a. The latter and the corresponding comcomplex tran~-Cl~Ru(P"O)~ (4a). (P -0 = ql-P-coordinated; plexes 5b, e, containing THF and CH,0CH3 as ether substit-P"0 = q2-0,P-coordinated). With CO both Ru-0 bonds are uents, show fluxional behaviour. The coalescence temperacleaved to give all-tran~-Cl~Ru(CO)~(P-O), (?a). At 35°C 7a is tures (10, 80, and 55"C, resp.) and the estimated AG * values transformed into the rnonocarbonyl ruthenium complex trans-(52, 65, and 59 kJ/mol, resp.) of the exchange process indicate Cl,(PnO)(P-O)RuCO (5a) with elimination of one CO mole-the weakest Ru-0 contact in 5a compared to 5b, c. The lower cule. On heating all-trans-?a to 110°C in toluene the thermo-basicity of the dioxanyl function is also responsible for the dynamically more stable complex cis-C12(OC)2Ru(frans-different reaction behaviour of 4a, 5a, and ?a compared to the P N O )~ (6a) is obtained. All reaction steps are reversible. Upon corresponding complexes with the ligands 3b, c.

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Neuartige basische Liganden für die homogenkatalytische Methanolcarbonylierung, XXXVIII. Synthese, Eigenschaften und fluktuierendes Verhalten von (Ether‐Phosphan)palladium‐Komplexen

Lindner¹,

Speidel²,

Fawzi³

et al. 1990

Chem. Ber.

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Novel Basic Ligands for the Homogeneous Catalytic Carbonylation of Methanol, XXVIII''. -Synthesis, Properties and Fluxional Behavior of (Ether-Ph0sphine)palladium Complexes Cl,Pd(COD) (1) (COD = 1,5-cyclooctadiene) reacts with 1 equiv. of the (ether-phosphine) ligand PhzP-D (2a-c) [D = CH;!C4H70 (a), CH2C4H702 (b), CH2CH20CH3 (c)] to give the dimeric complexes [p-ClPdCl(Ph,P-D)], (3a-c) (P-D = ql-P-coordinated). According to the field-desorption mass spectra which show only one peak for the monomeric moieties C1-Pd(Ph2P-D), 3a-c have a very weak Pd2C12 bridge. trans-Cl,Pd(Ph,P-D), (4a-c) is obtained either from 3a-c and 2a --c by cleaving the PdzClz bridge or from 1 and 2 equiv. of the ligands 2a-c. 4c crystallizes in the monoclinic space group P2,/c with Z = 2. AgC104 selectively abstracts one Cl0 ligand from 4a-c which results in the formation of the cationic complexes [trans-(PhzPnD)(PhzP-D)PdCl]@ (5a-c) (PnD = q'-D,P-coordinated) containing one chelated and one ql-Pbonded (ether-phosphine) ligand. 5a-c show fluxional behavior which is demonstrated by temperature-dependent 31P{ 'H}-NMR investigations. The coalescence points have been determined and are at 253 pa), 303 (5b), and 283 K (54. The activation enthalpies AG' are estimated at 48, 58, and 54 kJ/mol. The abstraction of the second Cl0 ligand from 5a -c succeeds only in the presence of AgSbFs yielding the dicationic bis(che1ate) complexes [trans-(Ph,PnD),Pd]2Q (6ac). The latter are also obtained from 4a-c and AgSbF6. The hydrogenating properties of 3a-c and 4a-c toward 1-hexyne are investigated in comparison with trans-Cl,Pd(Ph,P-CHZCH2CH3)Z.Bei der in homogener Phase durchgefiihrten, Cobalt-katalysierten Hydrocarbonylierung von Methanol zu Acetaldehyd enveisen sich Ether-Phosphane fur eine Erhohung des Methanol-Umsatzes und die Produktselektivitat als au-Derordentlich vorteiIhaft z), Im Gegensatz zum Phosphor-Atom, das den festen Kontakt zum katalytisch aktiven Metallzentrum herstellt, bildet das Sauerstoff-Atom nur schwache und deshalb leicht zu offnende Metallkontakte aus. Die

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Abstract: M ethanol Carbonylation, Ether-Phosphanes, Rhodium C om plexes [ (C 0 D ) R h (C l)(P '~0 )] (3) is obtained from [i/-C lR h(C O D )]2 (1) and the (ether-phosphane) ligand P '-O (2) [P'-O = Ph2PCH

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The Transition Metal Coordination Chemistry of Hemilabile Ligands

The Transition Metal Coordination Chemistry of Hemilabile Ligands

Neuartige basische Liganden für die homogenkatalytische Methanolcarbonylierung, XXVI. Dynamisches und reaktives Verhalten von (Ether‐Phosphan)ruthenium(II)‐Komplexen in Abhängigkeit von der O‐Basizität

Neuartige basische Liganden für die homogenkatalytische Methanolcarbonylierung, XXXVIII. Synthese, Eigenschaften und fluktuierendes Verhalten von (Ether‐Phosphan)palladium‐Komplexen

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