Basische metalle : XXXVI. Die synthese stabiler hydrido(olefin)rhodium-komplexe und von[C5H5Rh(PMe3)(η3-CH3CHC6H5)]PF6

The complexes C₅H₅Rh(PMe₃)C₂H₃R′ (R′  H, Me, Ph) and C₅H₅Rh(PR₃)C₂H₄(PR₃  PMe₂Ph, PPrⁱ₃) are prepared by reaction of[PMe₃(C₂H₃R/t')RhCl]₂ or [PR₃(C₂H₄)RhCl]₂ and TlC₅H₅, respectively. They react with HBF₄ in ether/propionic anhydride to form the BF₄ salts of the hydrido(olefin)rhodium cations [C₅H₅RhH(C₂H₃R′)PR₃]⁺(R  Me; R′  H, Me and R  Prⁱ; R′  H). From C₅H₅Rh(PMe₃)C₂H₃Ph and CF₃COOH/NH₄PF₆ the η³-benzyl complex [C₅H₅Rh(PMe₃)(η³-CH₃CHC₆H₅)]PF₆ is obtained. The reversibility of the protonation reactions is demonstrated by temperature-dependent NMR spectra and by deuteration experiments. The complexes C₅H₅Rh(PMe₃)C₂H₃R′ (R′  H, Ph) and C₅H₅Rh(PMe₂Ph)C₂H₄ react with CH₃I in ether to give the salts [C₅H₅RhCH₃(C₂H₃R′)PR₃]I which in THF or CH₃NO₂ yield the neutral compounds C₅H₅RhCH₃(PR₃)I.     

Further studies on organonickel compounds: the synthesis of some new alkyl-, acyl- and cyclopentadienyl-derivatives and the crystal structure of trans-[Ni(CH2SiMe3)2(PMe3)2]

The complex [NiCl₂(PMe₃)₂] reacts with one equivalent of mg(CH₂CMe₃)Cl to yield the monoalkyl derivative trans-[Ni(CH₂CMe₃)Cl(PMe₃)₂], which can be carbonylated at room temperature and pressure to afford the acyl [Ni(COCH₂CMe₃)Cl(PMe₃)₂]. Other related alkyl and acyl complexes of composition [Ni(R)(NCS)(PMe₃)₂] (R = CH₂CMe₃, COCH₂CMe₃) and [Ni(R)(η-C₅H₅)L] (L = PMe₃, R = CH₂CMe₃, COCH₂CMe₃; L = PPh₃, R = CH₂CMe₂Ph) have been similarly prepared. Dialkyl derivatives [NiR₂(dmpe)] (R = CH₂SiMe₃, CH₂CMe₂Ph; dmpe = 1,2-bis(dimethylphosphine)ethane, Me₂PCH₂ CH₂PMe₂) have been obtained by phosphine replacement of the labile pyridine and NNN′N′-tetramethylethylenediamine ligands in the corresponding [Ni(CH₂SiMe₃)₂(py)₂] and [Ni(CH₂CMe₂Ph)₂(tmen)] complexes. A single-crystal X-ray determination carried out on the previously reported trimethylphosphine derivative [Ni(CH₂SiMe₃)₂(PMe₃)₂] shows the complex belongs to the orthorhombic space group Pbcn, with a = 14.345(4), b = 12.656(3), c = 12.815(3) Å, Z = 4 and R 0.077 for 535 independent observed reflections. The phosphine ligands occupy mutually trans positions P-Ni-P 146.9(3)° in a distorted square-planar arrangement.     

Basic metals IV. The synthesis of monocyclopentadienylcobalt complexes containing CoZn,CoCu,CoSn and CoHg bonds

The pronounced Lewis basic character of the metal atom in C₅H₅Co(PMe₃)₂ is demonstrated by its reactions with ZnCl₂/PMe₃, [(PMe₃)₂CuCl]₂, SnCl₄, R₃SnCl (R  Me, Ph) and HgCl₂ which lead to stable monocyclopentadienylcobalt complexes containing CoZn, CoCu, CoSn and CoHg bonds.     

Transition metalcarbon bonds XXXVII. platinum acetylide complexes formed from ethynyl alcohols or ethers

Several new platinum(II) acetylide complexes, trans-{Pt[CCCR₁R₂(OR₃)]₂-L₂} (R₁, R₂  H, Me, Et; CR₁R₂  cyclohexylidene; R₃  H, Me or Ph), trans-[Pt(CCCH₂CH₂OH)₂L₂], trans-[Pt(p-tolylacetylide)₂L₂] and trans-[PtX(p-tolylacetylide)L₂] (L  PMe₂Ph or in one case, AsMe₂Ph) have been prepared. Platinum(II) acetylide complexes with tertiary hydroxyl groups are easily dehydrated by acetic anhydride/pyridine to give platinum-enyne complexes. Analogous compounds with primary hydroxyl groups do not dehydrate but give acetates. ¹H and ¹³C NMR data are given and the shift reagent Eu(fod)₃ was used to analyse the ¹H NMR spectrum of trans-[Pt(CCCH₂CH₂OH)₂(PMe₂Ph)₂].     

Cp2Ti(PMe3(C2H2), eine Ausgangsverbindung für Titanocen-Vinylkomplexe

Cp₂Ti(PMe₃)(C₂H₂) reacts with alcohols ROH (: R  Me, Et, Ph) and water to give new vinyltitanocene complexes.     

Phosphin-stabilisierte carbonylnitrosylvanadium-verbindungen: Darstellung und spektroskopische eigenschaften

Numerous new complexes of the type V(CO)₅_n(NO)L_n, have been prepared either by nitrosylation of [V(CO)₆_nL_n]^?(n  2, 3) with NOX (X  Cl, BF₄) and [Co(NO)₂Br]₂, resp., or by reaction of L with “V(CO)₅NO” generated in situ. The compounds comprise n  1: L  PPh₃, PMe₂H, P(OMe)₃ and Ph₂PCH_2?PPh₂ (dppm); n  2: L₂2  2 PMe₂H, 2 PMe₃, 2 P(OMe)₃, dppm, Ph₂P(CH₂)_2?PPh₂, Ph₂P(CH₂)₃,PPh₂, Me₂P(CH₂)₂PMe₂, Ph₂As(CH₂)₂AsPh₂, o_?C₆H₄(AsMe₂)₂ (diars) and o_?C₆H₄(AsPh₂)PPh₂; n  3: L₃  1.5 diars and CH₃C(CH₂PPh₂)₃. IR (CO and NO stretching region) and ⁵¹V NMR spectra are discussed; for n  2 and 3, the positions of the arsine and phosphine ligands relative to NO are either cis for all the ligand functions (arsines) or cis/trans.     

Redox properties of the carbyne,aminocarbyne and η2-vinyl complexes trans-[ReCl(LH)(dppe)2][BF4] (LH  CCH2But,CCH2Ph,CNH2 or η2-C(CH2Ph)CH2) and of their parent vinylidene,isocyanide and allene compounds

The redox properties of the carbyne-, aminocarbyne- and η²-vinyl-(metallacyclopropene) complexes trans-[ReCl(LH)(dppe)₂][BF₄] (1; LH  CCH₂R (R Bu^t or Ph), CNH₂ and η²-C(CH₂Ph)CH₂; dppe  Ph₂PCH₂CH₂PPh₂), as well as of their parent vinylidene, isocyanide and allene complexes, trans-[ReClL(dppe)₂] (2; L  CCHR, CNH or

, have been studied by cyclic voltammetry and controlled potential electrolysis in aprotic media. The results are interpreted in terms of anodically- or cathodically-induced β-dehydrogenation processes of complexes (1), to give the corresponding compounds (2) (in the oxidized or the neutral form), as well as of a reversible dissociation of the former into the latter, in a basic solvent. The electrochemical P_L ligand parameter has been estimated for all these ligands.     

Coordination complexes of acetylenic phosphines and diphosphines : V. Acetylene bridged derivatives of dicobalt octacarbonyl

Reactions of the phosphinoacetylenes RR′PCCR″ (R  R′  Ph, R″  H, CF₃, Ph, Me, t-Bu; R  R′  C₆F₅, R″  Ph, Me; R  Ph, R′  Me, R″  Me) with Co₂(CO)₈ have been studied. Complexes of four types have been characterised: (A)(RR′PC₂R″)CO₂(CO)₆ (R  R′  C₆F₅, R″  Ph, Me; R  R′  Ph, R″  t-Bu), (B) (RR′PC₂R″)₂Co₄(CO)₁₀ (R  R′  Ph, R″  H, CF₃, Ph, Me; R  R′  C₆F₅, R″  Me; R  Ph, R′  Me, R″  Me), (C) (RR′PC₂R″)₂Co₂(CO)₆ (R  R′  Ph, R″  t-Bu), (D) (RR′P(O)C₂R″)Co₂(CO)₆ (R  R′  Ph, R″  t-Bu; R  R′  C₆F₅, R  Ph). The complexes were characterised by microanalysis, IR, NMR and where possible mass spectra. Substitution reactions of the complexes with tertiary phosphites are described. In complexes of type (A) only the alkyne function is utilised whereas the tetranuclear compounds (B) have structures in which both alkyne and phosphorus moieties are coordinated. Compounds of type (C) are simple disubstituted phosphine complexes of Co₂(CO)₈ and those of type (D) are μ-alkyne derivatives of acetylenic phosphine oxides. The mechanism of formation of complexes of type (B) is discussed in the light of IR data.     

The reaction between [Pt(cod)Cl(PMe2Ph)]BF4 and aryltrimethyltin compounds

The complex [Pt(cod)Cl(PMe₂Ph)]BF₄ reacts in dichloromethane with SnArMe₃ compounds having Ar = 2-thienyl, 2-benzol [b]thienyl, or 2-benzo[b]furyl to give air-stable cationic aryl complexes [Pt(cod)Ar(PMe₂Ph)]BF₄. No reaction takes place when Ar  Ph. The cod ligand in the new complexes can be readily replaced by ligands such as PMe₂Ph, dppe, or 4-dimethylaminopyridine. The¹H and³¹P-{¹H} NMR parameters of the various complexes are reported.     

Carbamoyl and alkoxycarbonyl complexes of palladium(II) and platinum(II)

Carbamoyl and alkoxycarbonyl complexes of palladium(II) and platinum(II) of the type M(pnp)(CONHR)Cl (pnp = 2,6-bis(diphenylphosphinomethyl)pyridine; M Pd, R  C₆H₅, p-CH₃C₆H₄, p-CH₃OC₆H₄, C₆H₁₁, t-Bu; M  Pt, R  C₆H₅), Pd(pnp)[CON(Pr)₂]Cl (Pr = propyl), M(pnp)(COOR)Cl (M  Pd, R  C₆H₅, CH₃; M  Pt, R  CH₃), Pd(pnp)(COOCH₃)₂ result from reaction of M(pnp)Cl₂ with carbon monoxide and amines or alkoxides at room temperature and atmospheric pressure.The carbamoyl complexes react with bases to give urethane or diphenylurea depending upon the experimental conditions.     

The formation of alkyne and alkynyl complexes by reaction of 1-alkynes with trans-[M(N2)2(PH2PCH2CH2PPh2)2] (M  Mo OR W) and with [Mo(Ph2PCH2PPh2)3]: X-ray structure of trans-[Mo(CCPh)2(PH2PCH2CH2PPh2)2]

Reaction of RCCH (R  Ph, CO₂Meor CO₂Et) with trans-[M(N₂)₂(dppe)₂] (M  Mo or W; dppe  Ph₂PCH₂CH₂PPh₂) or [Mo(dppm)₃] (dppm  Ph₂PCH₂PPh₂) gives the alkyne complexes [M(RCCH)₂(diphos)₂] (diphos  dppe, M  Mo, R = Ph; dihpos  dppm, M  Mo, R  Ph or CO₂Me) and the alkynyl complexes trans-[M(cCR)₂(dppe)₂], [MH₂(CCR)₂ (dppe)₂] (M  Mo or W. R  Ph, CO₂Me or CO₂Et) and cis-[WH(CCCO₂Me)(dppe)₂]: the X-ray structure of trans-[Mo(CCPh)₂(dppe)₂] is reported.     

Synthesis and Characterization of Dirhenadehydro[12]annulenes

The 12‐membered‐ring metallacycles [mer‐Re{≡CCH=C(R)C≡C?}Cl(PMe₂Ph)₃)]₂ (R=CMe₃, 1‐adamantyl), which are organometallic analogues of antiaromatic octadehydro[12]annulene, are prepared by heating the methyl carbyne complexes mer‐Re{≡CCH=C(R)C≡CH}(CH₃)Cl(PMe₂Ph)₃. An intermolecular σ‐bond metathesis between the Re?CH₃ bond and the acetylenic C?H bond is proposed for their formation.     

Reactions of benzoyl(carbonyl)transition metal complexes with LiNMe2: on the feasibility of a reaction route to α-keto amide through an acyl(carbamoyl)cobalt intermediate

CO-coordinated benzoyltransition metal complexes, PhCOCo(CO)₃L (L  PPh₃, PCy₃, and PMe₃), PhCOMn(CO)₅, have been prepared and their reactions with LiNMe₂ examined. The reactions give α-keto amide (PhCO-CONMe₂) after treating the systems with Br₂ or organic halides.     

Reactions involving hydrogen transfer from triosmium clusters to an activated nitrile

The reactions of H₂Os₃(CO)₁₀, Ia and H₂Os₃(CO)₉PMe₂Ph, Ib with CF₃CN have been investigated. Both la and Ib react with CF₃CN to give the products HOs₃[μ-η₂-(CF₃)CNH](CO)₉Land HOs₃[μ-η¹-NC(H)CF3](CO)₉L, IIa, IIIa, L = CO; IIb and IIIb, L = PMe₂Ph. IIb and IIIb have been characterized crystallographically. In each, one nitrile molecule was added to the cluster and one hydride ligand was transferred to the nitrile ligand, but in IIb the hydride was transferred to the nitrogen atom to form a CF₃CNH ligand which bridges an edge of the cluster while in IIIb the hydride was transferred to the carbon atom to form a CF₃(H)CN ligand which also bridges an edge of the cluster. On the basis of spectroscopic measurements IIa and IIIa are believed to have analogous structures. An isotope scrambling experiment established that the formation of Ilia occurs by an intramolecular process. IIa was decarbonylated to yield the compound HOs₃[μ₃-η₂-(CF₃)CNH](CO)₉, which is believed to contain a triply-bridging iminyl ligand. Ilia reacts with PMe₂Ph to give two mono-substitution products, one of which is IIIb.     

Transition metal complexes of azo compounds : VI. Cycloaddition of alkynes to the complexed cis-azo group. Stepwise cyclodimerisation of diphenylacetylene to tetraphenylcyclobutadiene tricarbonyliron

The μ-(cis-azo) complexes LFe₂(CO)₆ (L  4-phenyl-3,3-bis(methoxycarbonyl)-1-pyrazoline, 4-isopropyl-3,3-bis(methoxycarbonyl)-1-pyrazoline, 2,3-diazanorbornene, and benzo[c]cinnoline) each contain an activated NN bond which reacts thermally and/or photochemically with the alkynes RC₂R (R  H, CH₃, Ph, COOCH₃) by insertion into the FeN bond to give the novel cycloaduct L(RC₂R)Fe₂(CO)₆. The pyrazoline and diazanorbornene complexes are transformed smoothly into the 1,2,3-diazaferrole derivatives L(RC₂R)Fe(CO)₄. These compounds react with a further molecule of the alkyne to give the “double-addition” products L(RC₂R)₂COFe(CO)₂, which can be converted into the cyclobutadiene derivative π-(RC₂R)₂Fe)CO)₃ if R  Ph; this complex can be synthesized very conveniently in yields of 70% by reaction of diphenylacetylene and the pyrazoline compound LFe₂(CO)₆ at 150°C. It is shown that the cyclodimerisation of the alkyne occurs stepwise.     

Reactions of nitrilium triflate salts with trans-[IrCl(CO)(PPh3)2

Low yields of the ionic carbene complexes [Ir(RCNHMe)Cl(CO)(PPh₃)₂-(O₃SCF₃)]O₃SCF₃]O₃SCF₃ (R  Ph or PhCH₂) have been isolated from the reactions of trans-[IrCl(CO)(PPh₃)₂] with the nitrilium triflate salts, [RCNMe]O₃SCF₃. The major products from these, and the similar reactions of the nitrilium salts where R  Me or Bu^t, are amorphous, yellow complexes [Ir(RCNHMe)Cl(CO)(PPh₃)₂O₃SCF₃.     

Alkoxycarbene complexes of nickel(II)

Alkynylnickel complexes trans-C₆Cl₅Ni(PPhMe₂)₂CCR (IIIa, R  H; IIIb, R  Me; IIIc, R  Et; IIId, R  CH₂OH; IIIe, R  CH₂CH₂OH; IIIf, R  Ph; IIIg, R  C₆H₄OMe-p) have been prepared from trans-[C₆Cl₅Ni-(PPhMe₂)₂L]ClO₄ and monosubstituted acetylenes in the presence of triethylamine, and their reactions with alcohols in the presence of perchloric acid were studied. Complexes IIIa and IIIe afforded alkoxycarbene complexes trans-[C₆Cl₅Ni-(PPhMe₂)₂{C(OR′)Me}]ClO₄ (IVa, R′  Me; IVb, R′  Et; IVc, R′  n-Pr) or trans-C₆Cl₅Ni(PPhMe₂)₂{$\text{C(CH}{}_2\text{)}{}_3\text{O}$}]ClO₄(IVd), respectively, but IIIb either decomposed or afforded trans-C₆Cl₅Ni(PPhMe₂)₂CHC(OMe)Me, depending on the amount of acid used. Treatment of IVaIVd with amines resulted in deprotonation to give α-alkoxyvinyl complexes, trans-C₆Cl₅Ni(PPhMe₂)₂C(OR′)CH₂ (VIaVIc) or trans-C₆Cl₅Ni(PPhMe₂)₂$\text{CCHCH}{}_2\text{CH}{}_2\text{O}$ (VId), the reaction being reversible. A ¹H NMR study indicated: (i) that the carbene methyl and the vinyl protons IV or VI are D-exchangeable by MeOD without catalyst; (ii) that the basicity of VIa is comparable to those of amines; (iii) that the carbene complexes IVaIVc have two isomers due to hindered rotation about the C(carbene)O bond in solution, IVb existing in the Z-form in the solid state; (iv) that the rotationalbarriers (°G^≠) about the C(carbene)O bond in IVb and the NiC-(carbene) bond in IVd are 20 (or more) and 11.7 kcal/mol, respectively. These results are explained in term of double bond character of the carbene carbon and its surrounding atoms.     

Methyl- and phenyl-bis(tertiary phosphine) N-bonded carboxamido complexes of platinum(II)

Methyl- or phenylN-carboxamido-complexes of platinum(II) Pt(NHCOR')RL₂ (L = PEt₃, R = Me, R′ = Me, CH = CH₂; L = PEt₃, R = Ph, R′ = Me; L = PMe₂Ph, R = Ph, R′ = Me, Ph; L = PMePh₂, R = Ph, R′ =₃, R = Ph, R′ = Me) have been prepared by the reaction of KOH with cationic nitrile complexes [PtR(NCR′)L₂]BF₄. Thermally unstable hydrido-N-carboxamido-complexes could be detected spectroscopically. IR and NMR (¹H, ³¹P) spectra of some of the complexes indicate the existence of a solvent- and temperature-dependent equilibrium between syn-and anti-isomers arising from restricted rotation about the NC bond of the carboxamido-group. The anti-isomer is favoured by nonpolar solvents and by increasing bulk of L. In the complex [PtH(NCCH CH₂)(PEt₃)₂]BF₄, IR and NMR spectra show acrlonitrile to be bound through nitrogen, not through the olefinic CC bond.     

Alkyl complexes of palladium(II) with trimethylphosphine and 1,2-bis-(dimethylphosphino)ethane ligands

A number of neutral, mononuclear dialkylpalladium(II) tertiary phosphine complexes of geneal formula cis or trans-PdR₂(PMe₃)₂ and cis-PdR₂ (dmpe) [dmpe = 1,2-bis(dimethylphosphino)ethane], R = Me, CH₂Ph, CH₂CMe₂Ph, CH₂SiMe₃ have been obtained by interaction of magnesium reagents with palladium(II) acetate or trans-Pd(O₂CMe)₂(PMe₃)₂.