Lutz Dahlenburg

Substitution products of [V(CO)6]- and [η5-CpV(CO)4] with di-and tetra-tertiary phosphines

Abstract Complexes of the type cis -[R 4 N][V(CO) 4 Ph 2 P (CH 2 ) n PPh 2 ] (R  Et, n  2, 3, 4; R  n-Bu, n  1, 3) have been prepared by photosubstitution of [R 4 N][V(CO) 6 ]. UV irradiation of [η 5 -CpV(CO) 4 ] in the presence of Ph 2 P(CH 2 ) n PPh 2 results in the formation of cis -[η 5 -CpV(CO) 2 Ph 2 P(CH 2 ) n PPh 2 ] ( n  1, 2, 4) or, in the case of n  3, of a polymeric compound cis -[η 5 -CpV(CO) 2 Ph 2 P(CH 2 ) 3 PPh 2 ] m . Evidence is presented for a relationship between 51 V chemical shifts and the ring size of the chelated structures. Photosubstitution of [Et 4 N][V(CO) 6 ] with the potentially tetradentate Ph 2 P(CH 2 ) 2 PPh(CH 2 ) 2 PPh(CH 2 ) 2 PPh 2 (tetraphos) yields an isomeric mixture of a mono-metallic triligate complex mer -[Et 4 N][V(CO) 3 tetraphos] and the probably polymeric cis -[Et 4 N] 2 n [{V(CO) 4 } 2 tetraphos] n . The structures are discussed on the basis of IR and 31 P NMR spectra.

A novel doubly phenoxo-bridged Cu(II) trimer: synthesis, crystal structure and low-temperature magnetic behaviour

A novel doubly phenoxo-bridged Cu(II) trimeric complex, [trinuclear diperchlorato {2,2′-[1,3-propanediylbis (nitriloethylidyne)]bisphenolato}-tricopper] has been synthesised with a tetradentate Schiff base ligand and characterised by IR, electronic spectra, X-ray structure and variable temperature magnetic moments. The Cu1 centre has square pyramidal geometry where as the Cu2 centre achieves square planar geometry. The dihedral angle between the two planes, Cu1 – O1 – O2 and Cu2 – O1 – O2 is 26.50°.

Chiral chelate phosphanes ☆: XI. Application of cyclopentane-based C2 chiral bis(phosphane) ligands C5H8(PR2)2 to PtSn-catalyzed styrene hydroformylation

Abstract Treatment of [(1,5-C8H12)PtCl(X)] (X=Cl, CH3, CH2CMe3) with C2 chiral cyclopentane-1,2-diyl-bis(phosphanes) C5H8(PR2)2, either as racemic mixtures or as resolved enantiomers, afforded the chelate complexes [C5H8(PR2)2Pt(Cl)(X)] (X=Cl: R=Ph (1), N-pip (2), OPh (3); X=CH3: R=Ph (4), N-pip (5), OPh (6); X=CH2CMe3: R=Ph (7), N-pip (8), OPh (9); ‘N-pip’=N(CH2)5), (+)-[(1R,2R)-C5H8{P(OPh)2}2PtCl2] [(R,R)-3], (−)-[(1S,2S)-C5H8{P(OPh)2}2PtCl2] [(S,S)-3], (−)-[(1R,2R)-C5H8(PPh2)2Pt(Cl)(X)], and (+)-[(1S,2S)-C5H8(PPh2)2Pt(Cl)(X)] (X=CH3: (R,R)-4, (S,S)-4; X=CH2CMe3: (R,R)-7, (S,S)-7). Reacting 4, 6, and 7 with AgO3SCF3 led to triflate derivatives [C5H8(PR2)2Pt(X)(OSO2CF3)] [X=CH3: R=Ph (11), OPh (12); X=CH2CMe3: R=Ph (13)] with covalently bonded OSO2CF3 ligands. The unusual Pt2 complex [μ-Cl{C5H8(PPh2)2PtCH3}2]O3SCF3 (14) containing an unsupported single PtClPt bridge was also isolated. In the presence of SnCl2, complexes 1, 3, 4, 6, 7, and 9 are catalysts for the hydroformylation of styrene forming 2- and 3-phenylpropanal together with ethylbenzene. Except for 1, they also catalyze the consecutive hydrogenation of the primary propanals to alcohols. High regioselectivities towards 2-phenylpropanal (branched-to-normal ratios ≥91:9) were obtained in hydroformylations catalyzed by 3 and 4, for which the influence of varied CO/H2 partial pressures, catalyst-to-substrate ratios and different reaction temperatures and times on the outcome of the catalytic reaction was also studied. When tin-modified complexes (R,R)-3, (S,S)-3, and (S,S)-4 were used as optically active Pt(II) catalysts, an only low stereoselectivity for asymmetric hydroformylation (e.e.

Arylkomplexe des typs trans-[Ir(Ar)(CO)(PPh3)2]

Abstract The preparation and properties as well as some reactions of a series of arylcarbonylbis(triphenylphosphine)iridium(I) complexes [Ir(Ar)(CO)(PPh 3 ) 2 ] (Ar  C 6 H 5 , C 6 F 5 , 2-C 6 H 4 CH 3 , 3-C 6 H 4 CH 3 , 4-C 6 H 4 CH 3 , 2-C 6 H 4 OCH 3 , 2,6-C 6 H 3 -(OCH 3 ) 2 , 4-C 6 H 4 N(CH 3 ) 2 , 3-C 6 H 4 Cl, 4-C 6 H 4 Cl, 4-C 6 H 4 Cl, 3-C 6 H 4 CF 3 , 4-C 6 H 4 CF 3 ) are described, and the most important IR data as well as the 31 P NMR parameters of these, without exception trans -planar, compounds are given. Some of the complexes react with molecular oxygen to form well defined dioxygen adducts [Ir(Ar)(O 2 )(CO)(PPh 3 ) 2 ] (Ar  C 6 H 5 , 3-C 6 H 4 CH 3 , 4-C 6 H 4 CH 3 ). Complexes with ortho -substituted aryl ligands are not oxygenated. This effect is referred to as a steric shielding of the metal center by the corresponding ortho -substituents. With SO 2 the similar irreversible addition compound [Ir(4-C 6 H 4 CH 3 )-(SO 2 )(CO)(PPh 3 ) 2 ] is obtained. Sulfur dioxide insertion into the IrC bond cannot be observed. The first step of the reaction between [Ir(4-C 6 H 4 CH 3 )(CO)(PPh 3 ) 2 ] and hydrogen chloride involves an oxidative addition of HCl to give [Ir(H)(Cl)(4-C 6 -H 4 CH 3 )(CO)(PPh 3 ) 2 ]. IrC bond cleavage by reductive elimination of toluene from the primary adduct does not occur except at elevated temperature.

Oligophosphan-Liganden: XXXII. Katalytische Dimerisierung von 1-Alkinen zu linearen 1-En-3-inen an cis-Arylhydridoruthenium(II)Chelatkomplexen. Molekülstruktur von (pp3)RuH(C6H4CF3-3) (pp3 P(CH2CH2CH2PMe2)3)☆

Abstract The complexes L4RuH(C6H5) with L4  P(CH2CH2CH2PMe2)3, N(CH2CH2PPh2)3, and MeSi(CH2PMe2)3/PMe3 all serve as catalysts for the dimerization of 1-alkynes, RCCH (R  C6H5, n-C4H9, t-C4H9). The reaction proceeds to yield 1,4-disubstituted 1-en-3-ynes, RCHCHCCR, with varyig E/Z stereoselectivities, presumably via intermediates containing 1-en-3-yn-2-yl ligands, -C(CCR)CHR. The X-ray structure analysis of (pp3)RuH(C6H4CF3-3)(pp3  P(CH2CH2CH2PMe2)3) which is available from (pp3)RuCl2 by reduction with sodium amalgam in C6H5CF3 but not from (pp3)RuH(C6H5) and C6H5CF3 by transmetalation, is also reported.

The reduction of hydrated ruthenium(III) chloride with zinc in the presence of cyclooctadiene: Molecular structure of Ru(C8H10)(C8H12) and isolation and x-ray structural characterization of Ru2Cl4(C8H12)2, RuH(C8H11)(C6H6) and Ru3Cl3(OCH3)(C8H12)3

Abstract The preparation of Ru(C8H10)(C8H12) (1) by reduction of hydrated ruthenium trichloride with zinc in the presence of cyclooctadiene occasionally results in mixtures from which the addition compound Ru2Cl4(C8H12)2·RuH(C8H11)(C6H6)·0.5C6H6(2·3·0.5C6H6) and the trinuclear complex Ru3Cl3(OCH3)(C8H12)3 (4) could be isolated. Complexes 1–4 were characterized by X-ray crystallography. Relevant crystallographic data are: 1: orthorhombic Pna21, a = 2159.7(9), b = 878.9(4), c = 692.4(4) pm, Z = 4, R = 0.029, Rw = 0.030 (2281 data). 2·3·0.5C6H6: triclinic P 1 , a = 773.8(2), b = 1316.9(2), c = 1766.9(6) pm, α = 72.40(2), β = 79.70(3), γ = 74.78(2)°, Z = 2, R = 0.051, Rw = 0.061 (9564 data). 4: orthorhombic Pna21, a = 1784.6(4), b = 939.5(1), c = 3076.3(7) pm, Z = 8, R = 0.070, Rw = 0.075 (2805 data).

Funktionelle Phosphane ☆: Part XI. Optisch reine β-Aminophosphane und β-Aminophosphinite für die komplexkatalysierte Reduktion organischer Carbonylverbindungen. Molekülstrukturen von [(1R,2R)-Ph2PCH(Ph)CH(Me)NH2Me]Cl, (1R,2S)-Ph2PCH(Ph)CH(Me)NHSO2Me und [{(1R,2R)-Ph2PCH(Ph)CH(Me)NHMe-κN,κP}Rh(η4-1,5-C8H12)]BF4

The preparation of optically active β-aminophosphane ligands, (−)-(1 R ,2 S )-Ph 2 PCH(Ph)CH(Me)NH 2 ( 5 ), (+)-(1 S ,2 S )-Ph 2 PCH(Ph)CH(Me)NH 2 ( 6 ), (−)-(1 R ,2 R )-Ph 2 PCH(Ph)CH(Me)NHMe ( 7 ), and (1 R ,2 S )-Ph 2 PCH(Ph)CH(Me)NHSO 2 Me ( 8 ), as well as of related β-aminophosphinites, (+)-(1 R ,2 S )-Ph 2 POCH(Ph)CH(Me)NH 2 ( 9 ), (−)-(1 R ,2 R )-Ph 2 POCH(Ph)CH(Me)NHMe ( 10 ), (+)-(1 S ,2 S )-Ph 2 POCH(Ph)CH(Me)NHMe ( 11 ), and (−)-(1 R ,2 S )-Ph 2 POCH(Ph)CH(Me)NHMe ( 12 ), from commercially available ephedrine, norephedrine, and pseudoephedrine enantiomers is reported. Ligands 6 and 7 react with [M(η 4 -1,5-C 8 H 12 ) 2 ]BF 4 (M=Rh, Ir) to afford the P , N chelate complexes [{(1 S ,2 S )-Ph 2 PCH(Ph)CH(Me)NH 2 -κ N ,κ P }Ir(η 4 -1,5-C 8 H 12 )]BF 4 ( 13 ), [{(1 R ,2 R )-Ph 2 PCH(Ph)CH(Me)NHMe-κ N ,κ P }Rh(η 4 -1,5-C 8 H 12 )]BF 4 ( 14 ), and [{(1 R ,2 R )-Ph 2 PCH(Ph)CH(Me)NHMe-κ N ,κ P }Ir(η 4 -1,5-C 8 H 12 )]BF 4 ( 15 ), of which 14 and 15 exist as mixtures of three sterically locked ring conformers. The molecular structures of the prevailing λ ( R C , R C, S N ) form of rhodium complex 14 , of β-aminophosphane 8 and of the hydrochloride of ligand 7 were determined by single-crystal X-ray diffraction. In the presence of added triethylamine, iridium complex 15 catalyzes the enantioselective hydrogenation of acetophenone, giving (−)-( S )-1-phenylethanol in modest enantiomeric excess (40%).

Ethinyl- und Butadiinylkomplexe des Eisens und Rutheniums mitterminalen Hauptgruppenelement-Substituenten, Cp* Fe(Ph2PCH(X)CH2PPh2) C ≡ CY (X = H, PPh2; Y = H, PPh2, P(+)Ph2Me) und Ru(Ph2PCH2PPh2)2(X) C ≡ CC ≡ CSiMe3 (X = Cl, C ≡ CC ≡ CSiMe3)

Abstract Treatment of Cp * Fe(dppe)C ≡ CH (dppe = Ph2PCH2CH2PPh2), 1, with an equimolar quantity of t-BuLi or with 2.5 equivalents of MeLi, followed by addition of ClPPh2, yielded Cp * Fe(dppe)C ≡ CPPh2, 2. With excess t- or n-BuLi, the ethylene bridge of the dppe ligand in 1 was also metallated, and further reaction with ClPPh2 resulted in Cp * Fe(tppe)C ≡ CPPh2 (tppe = Ph2PCH(PPh2)CH2PPh2), 3. Quaternization of 3 by Mel smoothly produced the phosphoniumethynyl derivative [Cp * Fe(tppe)C ≡ CPPh2me]I, 4. Reactions of cis-Ru(dppm)2Cl2 (dppm = Ph2PCH2PPh2) with LiC ≡ CC ≡ CSiMe3, in situ generated from Me3SiC ≡ CC ≡ CSiMe3 and MeLi/LiBr in THF, gave cis-Ru(dppm)2(C ≡ CC ≡ CSiMe3)2, 5, trans-Ru(dppm)2(C ≡ CC ≡ CSiMe3)2, 6, and trans-Ru(dppm)2(Cl)C ≡ CC ≡ CSiMe3, 7, depending on the solvent (ether or THF) and the molar ratios of the reactants. According to an X-ray structure analysis, the ethynyl ligand of 1 is structurally characterized by d(Fe-C), 1.876(13) and d(C ≡ C), 1.206(15) A, the value of the angle Fe-C≡C being 176.3(11)°.

The Chemistry of New Nitrosyltungsten Complexes with Pyridyl-Functionalized Phosphane Ligands

The coordination chemistry of pyridylphosphanes, such as 2-(6-tert-butylpyridyl)diphenylphosphane (Ph2P-tert-Bupy) (6) and 2-(6-tert-butylpyridyl)dimethylphosphane (Me2P-tert-Bupy) (7) towards a number of nitrosyltungsten complexes is reported. Displacement of the loosely coordinated MeCN from [W(CH3CN)3(CO)2(NO)][BF4] led to the following cationic compounds incorporating mono- and bidentate coordinated phosphane ligands: cis,cis-[W(CO)2(NO)(Ph2PR)(η2-Ph2PR)][BF4], [R = 2-pyridyl (9a), 2-picolyl (11)], cis,cis-[W(CO)(NO)(η2-Ph2Ppy)2][BF4] (20), trans,trans-[W(CO)(NO)(η2-Ph2Ppy)2][BPh4] (21), fac-[W(CO)2(NO)(Me2Ppy)3][BF4] (16), fac-[W(CO)2(NO)(Me2P-tert-Bupy)3][BF4] (18), cis,cis-[W(CO)2(NO)(Me2Ppy)(η2-Me2Ppy)][BF4] (22), and cis,cis-[W(CO)2(CH3CN)(NO)(Me2P-tert-Bupy)2][BF4] (23a). The cationic complex cis,mer-[W(CO)3(NO)(Ph2P-tert-Bupy)2][PF6] (14) has been prepared by nitrosylation of cis/trans-W(CO)4(Ph2P-tert-Bupy)2 (13). Reactions of 9a, 11, 14, 16, and 18 with hydride transfer reagents afforded trans,trans-HW(CO)2(NO)(Ph2Ppy)2 (10), trans,trans-HW(CO)2(NO)(Ph2Ppic)2 (12), trans,trans-HW(CO)2(NO)(Ph2-tBupy)2 (15), cis/trans-HW(CO)2(NO)(Me2Ppy)2 (17), and cis/trans-HW(CO)2(NO)(Me2P-tert-Bupy)2 (19), respectively. Reactivity experiments with acetic acid, hydroiodic acid, carbon dioxide, and acetylenedicarboxylic acid were performed, and were found to afford trans-W(CO)(NO)(Ph2Ppy)2(η2-CH3CO2) (24), trans,trans-IW(CO)2(NO)(Ph2Ppy)2 (25), trans-W(HCO2)(CO)2(NO)(Ph2Ppy)2 (26), and trans-W{η2-(Z)-C(CO2Me)=CH[C(O)OMe]}(CO)(NO)(Ph2Ppic)2 (27), respectively. The influence of the pyridyl substituent in 10 was probed by a comparative H/D exchange experiment in which 10 and the analogous complex HW(CO)2(NO)(PPh3)2 were treated with MeOD. The deuterated complex trans,trans-WD(CO)2(NO)(Ph2Ppy)2 (28) could be isolated. The structures of 9a, 11, 14, and 20 have been determined by single-crystal X-ray diffraction analysis.

Metallorganische verbindungen des iridiums und rhodiums: XXVI. CH-metallierung und hydridbildung im system Ir2Cl2(C8H14)4/PR3(PR3 = P(CH2CMe3)3, t-BuP(CH2CMe3)2, t-Bu2PCH2CMe3; i-Pr3P

Abstract Treatment of Ir2Cl2(C8H14)4 with the phosphines t-Bu3−nP(CH2CMe3)n (n = 3,2,1) in hot toluene followed by crystallization of the products from C7H8/ EtOH mixtures gave the cyclometallated hydrides (C8H14)2Ir-μ-Cl2 IrH[CH 2 CMe 2 CH 2 P (CH2CMe3)2][P(CH2 (I) [t-BuP(CH2CMe3)2]2H2Ir-μ-Cl2 IrH[CH 2 CMe 2 CH 2 P But(CH2CMe3)][t-BuP(CH2CMe3)2] (II), and [(t-Bu2 PCH 2 CMe 2 CH 2 )HI rCl]2 (III). The dihydrides IrH2Cl[t-BuP(CH2CMe3)2]2 (IIa) and IrH2Cl(t-Bu2PCH2CMe3)2 (IIIa) were also isolated; these species were, however, more conveniently obtained by bubbling hydrogen through the solution of Ir2Cl2 (C8H14)4 and the respective phosphine in toluene. i-Pr3 reacted with the olefiniridium(I) precursor in C7H8/EtOH to yield the carbonyl complexes (i-Pr3P)2H2Ir-μ-Cl2Ir(CO)(PPri3)2 (IV) and IrCl(CO)(PPi3)2 (IVa), no cyclometallated product being detected. The stereochemistries of the complexes were deduced from IR, 1H, 31P, and 13C NMR data. The crystal structures of IIIa and IVa were also determined.