Justin Wolf

Basische metalle: LI. Neuartige hydridorhodium(III)- und -iridium(III)-komplexe mit triisopropylphosphan-liganden. Die dihydrido-verbindungen C5H5MH2(PR′3) als metall-basen☆

Abstract The coordinatively unsaturated compound [RhCl(PR′ 3 ) 2 ] (I), which has been isolated as violet crystals, reacts with H 2 to form [RhH 2 Cl(PR′ 3 ) 2 ] (II). The reaction of II with NaC 5 H 5 gives only minor amounts of C 5 H 5 RhH 2 (PR′ 3 ) (IV). This dibydrido complex has been prepared in good yields either from C 5 H 5 Rh(OCOCF 3 ) 2 (PR′ 3 ) (III) and Na[AlH 2 (OC 2 H 4 OMe) 2 ] (Red-al) or from C 5 H 5 RhHCl(PR′ 3 ) (V) and LiAlH 4 . On protonation of IV with CF 3 CO 2 H/NH 4 PF 6 , the PF 6 salt of the dinuclear complex [(C 5 H 5 RhPR′ 3 ) 2 (μ-H 3 ] + (VI) is obtained. In contrast, treatment of the corresponding dihydridoiridium compound C 5 H 5 IrH 2 (PR′ 3 ) (IX) with HBF 4 ·Et 2 O gives the BF 4 salt of the mononuclear iridium(V) cation [C 5 H 5 IrH 3 (PR′ 3 )] + (X). Compound IX is obtained either from [IrH 2 Cl(PR′ 3 )py] (VIII) and NaC 5 H 5 or from C 5 H 5 Ir(OCOCF 3 ) 2 (PR′ 3 ) and Red-al. The reactions of [IrCl(PR′ 3 ) 2 ] with H 2 , HCl and HI give the five-coordinate complexes [IrH 2 Cl(PR′ 3 ) 2 ] (VII), [IrHCl 2 (PR′ 3 ) 2 ] (XI) and [IrHClI(PR′ 3 ) 2 ] (XII), which in the presence of pyridine form the octahedral compounds VIII, [IrHCl 2 (PR′ 3 ) 2 py] (XIII) and [IrHClI(PR′ 3 ) 2 py] (XIV), respectively. Structural proposals for the two isomers of XII and XIV are discussed.

Ruthenium Trichloride, Tricyclohexyl‐ phosphane, 1‐Alkynes, Magnesium, Hydrogen, and Water—Ingredients of an Efficient One‐Pot Synthesis of Ruthenium Catalysts for Olefin Metathesis

An active role is played by MgCl2 during the conversion of the vinylidene precursor 2 into carbenes 3 (R=H, Ph; L=P(C6 H11 )3 ). These complexes can be prepared in a convenient and very efficient one-pot synthesis and have a catalytic activity in metathesis comparable to that of Grubbs compound (Ph instead of CH2 R).

Vinylidene transition-metal complexes: I. Novel rhodium(I) and rhodium(III) complexes containing alkynes, alkynyls, and vinylidenes as ligands.Crystal structure of IC5H5Rh(CCHPh)(PPri3)

Abstract The syntheses of the novel cyclopentadienylphosphinevinylidenerhodium complexes C 5 H 5 Rh(CCHR)(PPr i 3 ) (R = Ph, Me, H) and, for R = Ph, of the isomeric alkynyl hydrido compound C 5 H 5 RhH(C 2 Ph)(PPr i 3 ) are reported. The square-planar complexes trans -[RhCl(RC 2 H)(PPr i 3 ) 2 ] (IIa, IIb), which in solution are in equi-librium with the five-coordinated pyridine to give the octahedral compounds RhHCl(C 2 R)(PRr i 3 ) 2 (py) (VIa, VIb). Treatment of Via, VIb with NaC 5 H 5 gives the vinylidene complexes IVa, IVb in good yield. C 5 H 5 Rh(CCH 2 )(PPr i 3 ) (IVc) is directly obtained from trans -[RhCl(C 2 H 2 )(PPr i 3 ) 2 ] (IIc) and NaC 5 H 5 . Mechanistic studies confirm that the reaction of VIa, VIb with the cyclopentadienide anion primarily gives, by elimination of HCl, the rhodium(I) compounds trans -[Rh(C 2 R)(py)(PPr i 3 ) 2 ] (VIIIa, VIIIb), which react with cyclopentadiene, possibly via trans -[Rh(C 2 R)(η 2 -C 5 H 6 )(PPr i 3 ) 2 ](X) as an intermediate, to give C 5 VIIIa with cyclopentadiene in presence of water gives the complex C 5 H 5 RhH(C 2 Ph)(PPr i 3 ), which isomerizes only slowly to form IVa and, therefore, is not an intermediate in the reaction of VIIIa and C 5 H 6 to give IVa. The crystal structure of IVa has been determined. The RhCC arrangement is almost linear. The RhC distance is significantly shorter than in carbenerhodium complexes, which, in agreement with 13 C NMR data and MO calculations, indicates a high degree of multiple bonding.

Basische metalle: LVIII. Vinylrhodium-komplexe durch protonierung der alkin-verbindungen C5H5Rh(C2Ph2)PPr3i und C5H5Rh(PhC2H)PPri3. Molekül- und kristallstruktur von C5H5Rh(E-CphCHPh)(PPri3)OCOCF3 und des metallacyclus C5H5(PPri3)RhC6H4CHCPh☆

The square-planar compounds trans-[RhCl(RC2R′)(PPri3)2] (II: R  R′  H; III: R  H, R′  Ph; IV: R  R′  Ph) are prepared from [(C8H14)2RhCl]2, PPri3 and the alkyne via the intermediate [RhCl(PPri3)2]. The reaction of III and IV with NaC5H5 produces the corresponding cyclopentadienyl complexes C5H5Rh(RC2R′)-PPri3 (V, VI). Similarly, starting with [(C8H14)2RhCl]2 the compound C5H5Rh(C2Ph2)PMe3 (IX) is obtained. The reaction of C5H5Rh(C2Ph2)PPri3 (V) with CF3CO2H leads to the formation of the vinyl complex C5H5Rh(E-CPhCHPh)(PPri3)OCOCF3 (XI) which is methanol, in the presence of Bronsted acids, reacts to give the metallaindene derivative C5H5(PPri3)RhC6H4CHCPh (XVIII). The molecular structure of XI and XVIII were determined by X-ray structural analyses. Displacement of the trifluoracetate ligand in XI by NaN3, NaI, CH3MgI and PMe3 produces the compounds C5H5Rh(E-CPhCHPh)(PPri3)X (XII: X  N3; XIII; X  I; XV: X  CH3) and [C5H5Rh(E-CPhCHPh)(PMe3)2]PF6 (XIV) whereas on treatment of XI with hydride donors such as Li[BEt3H] or Red-al the cis-stilbene complex C5H5Rh(Z-CHPhCHPh)PPri3 (XVII) is formed. The reaction of C5H5Rh(PhC2H)PPri3 (VI) with CF3CO2H gives the compound C5H5Rh(CPhCH2)(PPri3)OCOCF3 (XXIV) which reacts with NaI to give the corresponding iodo derivative C5H5Rh(CPhCH2)(PPri3)I (XXV). Using deuterium-labeling experiments, the mechanism of formation of the α-phenylvinyl complexes was investigated. Treatment of the metallacycle XVIII with CF3CO2H yields the compound C5H5Rh(OCOCF3)2(PPri3) (XXIX) which on reaction with excess CH3MgI produces the dimethylrhodium complex C5H5Rh(CH3)2(PPri3) (XXXII). The preparation of C5H5RhCl2(PPri3) (XXX) and C5H5RhI2(PPri3) (XXXI) is also described.

Carbynehydridoruthenium Complexes as Catalysts for the Selective, Ring-Opening Metathesis of Cyclopentene with Methyl Acrylate

The first members of a homologous series of long-chain, multiply unsaturated esters were obtained upon selective ring-opening metathesis of cyclopentene with methyl acrylate [Eq. (a)]. The catalysts are cationic carbynehydridoruthenium complexes (e.g. L=OEt2 ), which were prepared for the first time by protonation of hydridovinylideneruthenium compounds in the presence of L.

Vinyliden-Übergangsmetallkomplexe: III. Zur Reaktivität der Verbindungen C5H5Rh(CCHR)(PPri3) gegenüber Diazomethan, Schwefel, Selen und Tellur. Die Erzeugung nicht-stabiler Chalcogenoketene in der Koordinationssphäre eines Übergangsmetalls

Abstract The compounds C 5 H 5 Rh(CCHR)(PPr i 3 ) (I–III) react with diazomethane in presence of CuSO 4 to give the corresponding allene complexes C 5 H 5 Rh(η 2 -CH 2 CCHR)(PPr i 3 ) (IV–VI) at 0°C. The 1 H and 13 C NMR data show that the allene ligand is coordinated to the metal via the unsubstituted CC double bond, and that the substituents L n Rh and R of the un-coordinated double bond are cis to each other. Protonation of V (R  CH 3 ) with HBF 4 /NH 4 PF 6 produces the methylallyl complex [C 5 H 5 Rh(transoid, anti -η 3 -CH 2 CHCHCH 3 )(PPr i 3 )]PF 6 (VII), whereas treatment of V with CF 3 CO 2 H and NaI gives the dimethylvinylrhodium compound C 5 H 5 Rh( Z -CCH 3 CHCH 3 )(PPr i 3 )I (IX). Reaction of the starting materials I–III with sulfur, selenium and tellurium leads to the deeply colored, remarkably stable, solid chalcogenoketen complexes C 5 H 5 Rh(η 2 -ECCHR)(PPr i 3 ) (X–XVIII) in good to excellent yields. The molecular structure of X (E  S; R  H) and XIII (E  Se; R  H) has been determined by X-ray diffraction studies. The results confirm that the chalcogenoketenes are linked via the EC double bond to the metal. Methylation of the compounds X, XIII and XVI (E  S, Se, Te; R  H) by CF 3 SO 3 CH 3 /NH 4 PF 6 leads to electrophilic addition of the methyl group to chalcogen atom to give the ionic complexes [C 5 H 5 Rh(η 2 -E(CH 3 )CCH 2 )-(PPr i 3 )]PF 6 (XIX–XXI).

Einkern- und Heterometall-Zweikernkomplexe mit Thio-, Seleno- und Telluroaldehyden als Liganden: Synthese, Struktur, Protonierungs- und Methylierungsreaktionen

Abstract Thio-, seleno- and telluro-formaldehyde rhodium complexes of the general formula C5H5Rh(η2-CH2E)(PR5) (4–11) and C5Me5Rh(η2-CH2E)(L) (14–17 have been prepared from C5H5RhCH2I(PR3)I or C5Me5RhCH2I(L)I (L  CO, P(OMe)3) and NaEH (E  S, Se, Te). In contrast, the reaction of C5Me5RhCHBr2-(CO)Br with NaSeH gives the triply-bridged complex [(C5Me5Rh)2(μ-Br)2(μ-Se)] (19) instead of the bromo-substituted derivative C5Me5Rh(η2-CHBrSe)(CO). Methylation of C5H5Rh(η2-CH2E)(PR3) (E  S, Se) and C5Me5Rh(η2-CH2Se)(CO) affords the mononuclear compounds [C5H5Rh(η2-CH2ECH3)PR3)]PF6 (20–22) and [C5Me5Rh(η2-CH2SECH3)(CO)]PF6 (23), whereas protonation of C5H5Rh(η2-CH2E)(PR3) (E  S, Se) gives the dinuclear products [C5H5(PR3)Rh(μ-ECH3)]2X2 (X  PF6, BF4) (24–26). The CH3E-bridged complexes [C5H5(PMe3)Rh(μ-η1,η2-CH2E)MLn] (MLn  Cr(CO)5, W(CO)5, Mn(CO)2C5H5, Mn(CO)2C5H4Me) (27–31) and [C5Me5(CO)Rh(μ-η1,η2-CH2Se)MLn] (MLn  Cr(CO)5, Mo(CO)5, W(CO)5) (32–34) have been obtained from C5H5Rh(η2-CH2E)(PMe3) or C3Me3Rh(η2-CH2Se)(CO) and the 16-electron fragment [MLn], prepared in situ by irradiation of MLn(CO). Catalytic hydrogenation of the thio- and seleno-ketene compounds C5H5Rh(η2-ECCH2)(PPri3) with RhCl(PPh3)3 as the catalyst leads to the formation of the thio- and seleno-acetaldehyde rhodium complexes C5H5Rh(η2-CH3CHE)(PPri3) (37, 38) in ca. 40% yield. The molecular structure of 38 (E  Se) has been determined by X-ray diffraction studies.

Synthesis and Molecular Structure of Six‐Coordinate Dichlorodihydridoruthenium(IV) and Five‐Coordinate Vinylideneruthenium(II) Complexes

The dichlorodihydridoruthenium(IV) compound [RuH2Cl2(PiPr3)2] (4) was prepared from [RuCl2(C8H12)]n (3), PiPr3, and H2 in 2-butanol via the chlorohydridoruthenium(II) derivative [RuHCl(H2)(PiPr3)2] (5) as an intermediate. The synthesis of 5 was achieved under similar conditions from 3, PiPr3, H2, and 2-butanol in the presence of NEt3. Compound 4, which was characterized by X-ray crystal structure analysis, reacts with excess phenylacetylene to give the phenylvinylidene complex [RuCl2(=C=CHPh)(PiPr3)2] (7) and with propargylic alcohols or derivatives thereof to afford the vinylcarbene complexes [RuCl2(=CHCH=CR2)(PiPr3)2] (9, 10), respectively. From 5 and terminal alkynes RC≡CH the chlorohydridovinylidene compounds [RuHCl(=C=CHR)(PiPr3)2] (11, 12) were obtained. The phenylvinylidene complex [RuCl2(=C=CHPh)(PCy3)2] (15) was prepared from phenylacetylene and either [RuH2Cl2(PCy3)2] (14) or one of the carbene deriva-tives [RuCl2(=CHR)(PCy3)2] (16, 17) as starting materials. The X-ray crystal structure analysis of 15 confirms a distorted square-pyramidal geometry with the vinylidene ligand in the apical position. The interconversion of 4 to 5 and of the tricyclohexylphosphane counterparts 14 to 13 was achieved by hydrogen transfer from 2-propanol in the presence of PR3. The reverse reaction occurs upon treatment of 5 or 13 with the corresponding phosphonium salt [HPR3]Cl or HCl, respectively.

Synthese der ersten quadratisch-planaren Vinyliden-Komplexe des Vaska-Typs. Kristall- und Molekülstruktur von trans-[RhCl(=C=CHMe)(PPri3)2] / Synthesis of the First Square-planar Vinylidene Complexes of the Vaska Type. Crystal and Molecular Structure of trans-[RhCl(=C=CHMe)(PPri3)2]

Square-planar vinylidene rhodium complexes trans-[RhCl( = C=CHR)(PPri3)2] (X-XII) are prepared either by isomerization of trans-[RhCl(RC≡CH)(PPri3)2] in hexane at 50 °C or by elimination of pyridine from RhHCl(C≡CR)(py)(PPri3)2 in benzene at room temperature. The Xray structural analysis of XI (R = CH3) reveals that the CI-Rh=C=C fragment is almost linear, and that the planes formed by these atoms and C3 (carbon atom of the CH3 substituent) and by these atoms and P1 , P2 are perpendicular to each other. The Rh = C bond length is surprisingly short (177.5(6) pm) and supports the assumption that vinylidenes like CO are strong π-acceptor ligands.

Vinyl and carbene ruthenium(II) complexes from hydridoruthenium(II) precursors

The reactions of the hydrido compounds [RuHCl(CO)(L)2][L = PiPr3 (1), PCy3 (2)] with HC(triple bond)CR (R = H, Ph, tBu) afforded by insertion of the alkyne into the Ru-H bond the corresponding vinyl complexes [RuCl(CHCHR)(CO)(L)2], 3-8, which upon protonation with HBF4 gave the cationic five-coordinated ruthenium carbenes [RuCl(CHCH2R)(CO)(L)2]BF4, 9-14. Subsequent reactions of the carbene complexes with PR3(R = Me, iPr) and CH3CN led either to deprotonation and re-generation of the vinyl compounds or to cleavage of the ruthenium-carbene bond and the formation of the six-coordinated complexes [RuCl(CO)(CH3CN)2(PiPr3)2]BF4, 17, and [RuH(CO)(CH3CN)2(PiPr3)2]X, 18a,b. The acetato derivative [RuH(2-O2CCH3)(CO)(PCy3)2], 19, also reacted with acetylene and phenylacetylene by insertion to yield the related vinyl complexes [Ru(CHCHR)(kappa2-O2CCH3)(CO)(PCy3)2], 20, 21, of which that with R = H was protonated with HBF4 to yield the corresponding cationic ruthenium carbene 22. With [RuHCl(H2)(PCy3)2], 25, as the starting material, the five-coordinated chloro(hydrido)ruthenium(II) compounds [RuHCl(PCy3)(dppf)], 26(dppf = [Fe(eta5-C5H4PPh2)2]), [RuHCl[Sb(CH2Ph)3](PCy3)2], 27, and [RuHCl(CH3CN)(PCy3)2], 30, were prepared. The reactions of 27 with HCCR (R = H, Ph) gave the hydrido(vinylidene) complexes [RuHCl(CCHR)(PCy3)2], 28 and 29, whereas treatment of 30 with HC(triple bond)CPh afforded the vinyl compound [RuCl(CHCHPh)(CH3CN)(PCy3)2], 31. The molecular structures of 11(R = tBu, L = PiPr3) and 26 were determined crystallographically.