Notizen: Neuartige basische Liganden für die homogenkatalytische Methanolcarbonylierung, XXVII [1] / Fluktuierendes Verhalten von Tris(Ether-Phosphan)-Ruthenium(II)-Komplexen / Novel Basic Ligands for the Homogenous Catalytic Carbonylation of Methanol, XXVII. Fluxional Behaviour of Tris(ether-phosphane) Ruthenium(II) Complexes

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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(Ether‐phosphan)eisen(II)1‐Komplexe mit den Koordinationszahlen Vier, Fünf und Sechs

Lindner

Geprägs

Fawzi

et al. 1993

Chem. Ber.

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(Ether‐phosphane)iron(II) Complexes with the Coordination Numbers Four, Five, and Six Photolysis of cis,cis,trans1‐Br2(OC)2 Fe(P∑O)2 (1a, b) [O,PPh2PCH2CH2OCH3 (a), Ph2PCH2C4H7O (b)] results in the formation of the iron(II) complexes Br2Fe(P∼O)2 (2a), [BrFe‐(P∩O)(μ1‐Br)]2 (4b), and [trans1‐Br2Fe(P∩O)(μ1‐CO)]2 (5a) with the coordination numbers four, five, and six, respectively. 2a crystallizes in the triclinic space group P\documentclass{article}\pagestyle{empty}\begin{document}$\bar{1}$\end{document} with Z2 and has two monodentated O,P functions (P∼O: η1‐P1‐coordinated; P∩O:η2‐O,P1‐coordinated). The dimeric complex 4b with two O∩P‐chelated ligands crystallizes in the orthorhombic space group Pbca with Z4. 2a and 4b, which react under CO pressure to give the starting complexes 1a, b, are also accessible from the ether‐phosphanes 3a, b and anhydrous FeBr2.

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Cited by 12 publications

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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, XXXVIII. Synthese, Eigenschaften und fluktuierendes Verhalten von (Ether‐Phosphan)palladium‐Komplexen

(Ether‐phosphan)eisen(II)1‐Komplexe mit den Koordinationszahlen Vier, Fünf und Sechs

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