Othmar Stelzer

Phosphines with 2-imidazolium and para-phenyl-2-imidazolium moieties - synthesis and application in two-phase catalysis

Abstract Deprotonation of 1-n-butyl-3-methyl-imidazolium chloride or hexafluorophosphate with n-butyl lithium and subsequent reaction of the intermediate 2,3-dihydro-imidazol-2-ylidene with diphenylchlorophosphine affords the 2-imidazolium phosphines 3a or 3b. The phosphine 4 with a para-phenylene spacer between the imidazolyl moiety and the phosphorus atom has been obtained by Kosugi–Stille coupling between 2-tri-n-butyl-stannyl-1-methylimidazole and 4-fluoroiodobenzene followed by nucleophilic substitution of fluorine with PPh2K. The X-ray structure of 4 (space group P 1 ) has been determined. Selective N-protonation or N-quaternization of 4 affords the corresponding imidazolium phosphines 5a–5c. The ligands 3b and 5c have been tested in the biphasic Rh-catalyzed hydroformylation of 1-octene employing the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate as catalyst solvent.

1-Vinylimidazole – a versatile building block for the synthesis of cationic phosphines useful in ionic liquid biphasic catalysis

Abstract Base catalyzed addition of 1-vinylimidazole to primary and secondary phosphines affords tertiary phosphines with terminal 1-imidazolyl substituents C3H3N2 in high yields. The X-ray structure of the oxide Ph2P(O)–(CH2)2–1-C3H3N2 has been determined (space group P 1 ). By selective N-protonation and protected group N-quaternization novel cationic phosphines, e.g. 2a, 2b, 9 and 10, with peripheral 1-imidazolium groups are obtained. These are interesting ligands for catalytic reactions in biphasic systems containing ionic liquids as polar phase and may be employed in hydroformylation of long-chain olefins like 1-octene.

Reaktionen koordinierter liganden : X. Reaktivität zweikerniger eisencarbonylkomplexe mit sekundären phosphidobrüken μ-rph

Abstract The reaction between pentacarbonyliron(0) and phenylphosphane affords, depending on the conditions applied, the complexes (CO) 4 FePhPh 2 (I), (CO) 6 − Fe 2 (PhPH)2 (II) or [(CO) 3 Fe] 3 (PhP) 2 (III) in high yields and purity. Compound I reacts with (η-C 5 H 5 )Fe(CO)2Br in the presence of NEt 2 H to give the phosphido complex (CO) 4 Feue5f8PhPHue5f8Fe(CO) 2 (η-C 5 H 5 ) (IV). Deprotonation of II with MeLi yields the lithio-phosphido complexes (CO) 6 Fe 2 (PhPH)(PhPLi) (IIb) or (CO) 6 Fe 2 (PhPLi) 2 (IIa). By reaction of the PhPH groups in II with halophosphanes PhPCl 2 , PhPIue5f8PPhI and Ph 2 PCl the novel phosphido complexes (CO) 6 Fe 2 (PhP) n ( n ue5fb 3, 4) (VII, VIII), (CO) 6 Fe 2 (PhPPPh 2 ) 2 (V), and [(CO) 6 Fe 2 (PhPH)(PhP)] 2 PPh (IX) are accessible. With formaldehyde, compound II yields the hydroxymethyl-substituted derivative (CO) 6 Fe 2 (PhPCH 2 OH) 2 (X). The stereochemistry of the complexes is discussed on the basis of their 31 P NMR spectra.

Organometallphosphin-substituierteübergangsmetallkomplexe XI. Organometallphosphincyclopentadienyldicarbonyl- und -methylcyclopentadienyldicarbonyl-mangan-komplexe

Summary The reaction of π-cyclopentadienylmanganese tricarbonyl or π-methylcyclopentadienylmanganese tricarbonyl with tri(tert-butyl)phosphine, tris(trimethylsilyl)-, tris(trimethylgermyl)-, and tris(trimethylstannyl)phosphine results in the elimination of one CO-ligand and the formation of corresponding (organometalphosphine)cyclopentadienylmanganese dicarbonyl and (organometalphosphine)methylcyclopentadienylmanganese dicarbonyl complexes. The IR, UV, 1 H NMR and 31 P NMR spectra are reported and discussed.

Mehrkernige phenylphosphine, phenylarsine, (phenylphosphino)arsine und (phenylarsino)phosphine☆

Bis(trimethylstannyl)phenylphosphine or tris(trimethylstannyl)phosphine react with diphenylchlorophosphine or -arsine splitting off trimethyltin chloride and forming bis(diphenylphosphino)phenylphosphine, tris(diphenylphosphino)phosphine, bis(diphenylarsino)phenylphosphine and tris(diphenylarsino)phosphine, respectively. In the same manner (trimethylstannyl)diphenylarsine, bis(trimethylstannyl)phenylarsine and tris(trimethylstannyl)arsine with diphenylchlorophosphine or -arsine form the new compounds (diphenylphosphino)diphenylarsine, bis(diphenylphosphino)phenylarsine, tris(diphenylphosphino)arsine, bis(diphenylarsino)phenylarsine and tris(diphenylarsino)arsine, respectively. The IR and Raman spectra of the new compounds are recorded and assigned.

Cationic phosphine ligands with phenylguanidinium modified xanthene moieties—a successful concept for highly regioselective, biphasic hydroformylation of oct-1-ene in hexafluorophosphate ionic liquids

New guanidinium-modified diphosphine ligands with a xanthene nbackbone show high overall activity and high regioselectivity in the nbiphasic hydroformylation of oct-1-ene using hexafluorophosphate ionic nliquids.

Organometallphosphin-substituierte übergangsmetallkomplexe V. Synthese, eigenschaften und komplechemisches verhalten von (trimethylstannyl)di-tert-butylphosphin☆

Abstract (Trimethylstannyl)dimethylamine reacts with di-tert-butylphosphine under formation of (trimethylstannyl)di-tert-butylphosphine, which forms with nickel tetracarbonyl, iron pentacarbonyl and molybdenum hexacarbonyl, under cleavage of one molecule of carbon monoxide, the complexes [(trimethylstannyl)di-tert-butylphosphine]tricarbonylnickel, -tetracarbonyliron and -pentacarbonylmolybdenum, respectively. the IR, 1 H and 31 P NMR spectra are reported and assigned.

Darstellung von triorganyl-und dialkylaminosubstituierten Fluorphosphoniumsalzen / Preparation of Triorgano-and Dialkylamino-substituted Fluorophosphonium Salts

Abstract Fluorophosphonium bromides are easily accessible by ligand exchange reactions between bromophosphonium bromides and difluorophosphoranes. The reaction between fluorophosphoranes of different Lewis acidity is investigated. Fluorophosphonium-organo-fluorophosphates are formed in some cases by transfer of fluoride ion. Alkylamino-substituted fluorophosphonium bromides may be obtained by Br/F-exchange in bromo-phosphonium bromides with sodium fluoride. The products are characterized by means of 1 H, 19 F, and 31 P NMR spectroscopy.

Bonding studies of compounds of boron and the Group 3–5 elements. Part XIII. He(I) photoelectron spectra of phosphines RnPX3–n(R = Me or But; X = H, Cl, or F; n= 1–3), (Me2N)nPCl3–n(n= 1–3), and (R2N)PF2(R = Me or Et)

The He(I) photoelectron spectra of the title compounds have been measured. An empirical assignment of most of the bands is proposed and the effects of various substituents on the phosphorus lone-pair ionisation potentials are assessed. Correlations are made with various other parameters relating to phosphine basicity, and it is concluded that the phosphorus lone-pair i.p. provides a reasonable measure of relative basicity or σ-donor ability within related series of compounds.

Reaktionen koordinierter Liganden, VI [1] Substituenteneinflüsse bei der Bildung von Tri- und Tetraphosphinen in der Koordinationssphäre von Übergangsmetallen / Reactions of Coordinated Ligands, VI [1]. Influence of Substituents on the Formation of Tri- and Tetraphosphines in the Coordination Sphere of Transition Metals

Abstract The lithiumphosphido complex cis-Mo(CO)4(Me2PLi)2 reacts with dichlorophosphines RPCl2(R = Ph, But) to give coordination compounds of tetraphosphines Me2P-PR-PR-PMe2, whereas the complex of the triphosphine cis-Mo(CO)4 (Ph2P-PMe-PPh2) is obtained starting with the lithiumphosphido complex cis-Mo(CO)4(Ph2PLi)2. Phenyldilithiumphosphine and the chlorophosphine complexes cis-Mo(CO)4(R2PCl)2 (R = Me, Ph) give in low yield cis-Mo(CO)4(R2P-PPh-PPh-PR2) and cis-Mo(CO)4(R2P-PPh-PR2). The mechanisms of these reactions are discussed. The {31P}1H- and {1H}31P-NMR spectra are analysed and correlated with the structures of these complexes.