Alkylidenverbrückte diphosphane und dichlalkogenodiphosphorane als liganden in kationischen cyclopentadienyleisencarbonyl-komplexen

Oxidative cleavage of the FeFe bond in [C₅H₅Fe(CO)₂]₂ in the presence of alkylide-bridged diphosphanes LL (LL = (C₆H₅)₂P(CH₂)_n(P(C₆H₅)₂; n = 1–3), (C₆H₅)₂PCH₂As(C₆H₅)₂ and dichalcogenodiphosphoranes (X)LL(X) ((X)LL(X) = (C₆H₅)₂P(X)(CH₂)_n(X)P(C₆H₅)₂; X  O, S, Se; n = 1–3) yields the complexes [C₅H₅Fe(CO)₂L′]BF₄ (L′ = LL, (X)LL(X); X  S, Se) in high yield. the complexes react with Ni(CO)₄ under photochemical conditions to form [C₅H₅Fe(CO)₂(μ-L′)Ni(CO)₃]BF₄ in quantitative yield, and lose a CO group under irradiation (λ_max > 300 nm) to form the chelate compounds [C₅H₅Fe(CO)L′]BF₄, which are isolable for L′  LL (P,As ligand) and (X)LL(X) (X = S, Se). Some substitution reactions with phosphanes are described.     

Cyclopentadienyleisen-komplexe mit P(OR)3-liganden; Synthese und spektroskopische charakterisierung

Reactions of reactive cyclopentadienyliron complexes C₅H₅Fe(CO)₂I, [C₅H₅Fe(CO)₂THF]BF₄, [C₅H₅Fe(CO)((CH₃)₂S)₂]BF₄ and [C₅H₅Fe(p-(CH₃)₂C₆H₄)]PF₆ with P(OR)₃ as ligands (R = CH₃, C₂H₅, i-C₃H₇ and C₆H₅) lead to the formation of the complex compounds C₅H₅Fe(CO)_2?n(P(OR)₃)_nI and [C₅H₅Fe(CO)_3?n(P(OR)₃)_n]X (n = 1, 2 and n = 1–3, X = BF₄, PF₆). Spectroscopic investigations (IR, ¹H, ¹³C and ³¹P NMR) indicate an increase of electron density on the central metal with increasing substitution of CO groups by P(OR)₃ ligands. The stability of the compounds increase in the same way.     

Reactions of metal carbonyl derivatives : XI. Tertiary phosphine,phosphite and stibine and ditertiaryphosphine and arsine derivatives of bis(μ-phenyl- sulphidotricarbonyliron)

The ditertiary phosphines (C₆H₅)₂P(CH₂)_nP(C₆H₅)₂ (n = 1 and 2), cis(C₆H₅)₂PC₂H₂P(C₆H₅)₂ and (C₆H₅)₂PN(C₂H₅)P(C₆H₅₂ and the ditertiary arsines (C₆H₅)₂As(CH₂)_nAs(C₆H₅)2 (_n = 1 and 2) react with [Fe(CO)₃SC₆H₅]₂ to give a wide range of products, the nature of which depends on the reaction conditions and the ligand involved. Examples of the different types of comp isolated include, (i) Fe₂(CO)₅[(C₆H₅)₂PCH₂P(C₆H₅)₂](SC₆H₅)₂, in which the ligand acts as a monodentate, (ii) {[Fe(CO)₂SC₆H₅]₂[(C₆H₅)₂PC₂H₄P(C₆H₅)₂]}₂, in which two [Fe(CO)₂SC₆H₅]₂ moieties are bridged by two diphosphine ligands, (iii) [Fe(CO)₂SC₆H₅]₂[(C₆H₅)₂PN(C₂H₅)P(C₆H₅)₂], in which the ligand bridges the two iron atoms, and (iv) Fe(CO)₃(SC₆H₅)₂Fe(CO)[(C₆H₅)₂PC₂H₂P(C₆H₅)₂], which contains the ligand chelated to a single iron atom. The tertiary phosphines PR₃ (R=C₂H₅ and C₆H₅), phosphites P(OR′)₃(R′ = CH₃, C₂H₅, i-C₃H₇ and C₆H₅) and the stibine Sb(C₆H₅)₃ bring about mono-, bis- or tris-substitution in [Fe(CO)₃SC₆H₅]₂ depending on the reaction conditions and the ligand involved. Whereas in solution [Fe(CO)₂L(SC₆H₅)]₂ [L = PR₃ (R = C₂H₅ and C₆H₅), P(OC₆H₅)₃ and Sb(C₆H₅)₃] exist as a single isomer, [Fe(CO)₂L′(SC₆H₅)]₂ [L′=P(OR′)₃ (R'=CH₃, C₂H₅ and i-C₃H₇)] occur as a mixture of isomers.     

Transition metal complexes of hexaphenylcarbodiphosphorane

The displacement of tetrahydrofuran (THF) from W(CO)₅(THF) with hexaphenylcarbodiphosphorane yields a compound with a carbon-metal bond (CO)₅W C[P(C₆H₅)₃]₂. The in situ photolysis of tungsten hexacarbonyl and hexaphenylcarbodiphosphorane, however, yields a product (CO)₅W^?CC ⁺P(C₆H₅)₃. Ethylenebis(triphenylphosphine)platinum and hexaphenylcarbodiphosphorane in benzene yield a platinum containing heterocycle [(C₆H₅)₃P]₂$\text{PtC[ P(C}{}_6\text{H}{}_5\text{)}{}_3\text{]P}$-(C₆H₅)₃.     

The stereospecificity at the iron center of the decarbonylation of an ironacetyl complex

The dinuclear complex [(h⁵-1-CH₃-3-C₆H₅C₅H₃)Fe(CO)₂]₂ was synthesized by reaction of Fe₂(CO)9 with 1-methyl-3-phenylcyclopentadiene; it was converted to (h⁵-1-CH₃-3-C₆H₅C₅H₃)Fe(CO)₂CH₃ by reduction with sodium amalgam and addition of CH₃l, and thence to (h⁵-1-CH₃-3-C₆H₅C₅H₃)Fe(CO)[P(C₆H₅)₃] (COCH₃) (I) by reaction with P(C₆H₅)₃. The acetyl I was separated into two diastereomerically related pairs of enantiomers. Ia and Ib, by a combination of column chromatography on alumina and crystallization from benzene/pentane. The photochemical decarbonylation of Ia and Ib in benzene or THF solution was examined by ¹H NMR spectroscopy. This reaction proceeds with high stereospecificity (>84% retention or inversion) at the iron center to yield (h⁵-1-CH₃-3-C₆H₈C₅H₃)Fe(CO)[P(C₆H₅)₃]CH₃(II), enriched in the diastereomerically related pairs of enantiomers, IIa and IIb, respectively. Since IIa and IIb epimerize under the photolytic conditions of decarbonylation, the actual stereospecificity of the conversion of I to II is higher than 84%, and likely 100%. This is supported by the data from kinetic studies of the decarbonylation of I and the epimerization of II, carried out under identical photolytic conditions. The implications of the foregoing results to the mechanism of the decarbonylation are considered. Also described herein is the synthesis of other complexes with two asymmetric centers of the general formula (h⁵-cyclopentadienyl)Fe(CO)(L)(COR) and (h⁵-cyclopentadienyl)Fe(CO)(L)R that contain either an unsymmetrically substituted h⁵-cyclopentadienyl ring or a chiral tertiary phosphine.     

Oxidative addition of some geminal halonitroalkanes to iridium(I) and platinum(0) compounds

Oxidative addition of 1-chloro-1-nitroethane to trans-IrCl(CO)-[P(CH₃)₂C₆H₅]₂ followed by treatment of the initial product with pyridine yields a new iridium(III) complex IrCl(py)[COC(NO₂)CH₃][P(CH₃)₂C₆H₅]₂, whose structure has been confirmed by X-rays crystallography. Two intermediate products have been observed by NMR spectroscopy; their structures have been tentatively assigned. The reaction of the corresponding bromine derivatives yields two isomers of the composition IrBr₂(CO)[CH(NO₂)CH₃][P(CH₃)₂C₆H₅]₂, and these are not affected by pyridine. The reaction of 1-chloro-1-nitroethane with Pt[P(C₆H₅)₃]₄ takes a completely different course in that yields nitrorethane and cis-PtCl₂[P(C₆H₅)₃]₂ as the main products, with no detectable formation of the products of oxidation addition. A brief mechanistic investigation points towards the participation of radicals and radical anions as transient intermediates and a mechanism is proposed which explains most of the experimental results.     

Alkinylphosphinhaltige substitutionsprodukte von chrom- und wolfram-hexacarbonyl

The photochemical preparation of [M(CO)₅(P(CCC₆H₅)_n(C₆H₅)_3-n], cis-[M(CO)₄(PCCC₆H₅)_n(C₆H₅)_3-n] (M = Cr, W; n = 1,2,3) and fac-[Cr(CO)₃(P(CCC₆H₅)(C₆H₅)₃] by the corresponding substitution reactions of the hexacarbonyls is described. The IR and Raman spectra of the complexes in the region of the ν(CO) and ν(CC) vibrations and the ³¹P NMR spectra are discussed.     

The 31P NMR spectra of ArCr(CO)2P(C6H5)3 compounds in neutral and acidic media

The ³¹P NMR spectra of C₆H₅XCr(CO)₂P(C₆H₅)₃ (X = H, CH₃, OCH₃, N(CH₃)₂, COOCH₃) (I), p-C₆H₄X₂Cr(CO)₂P(C₆H₅)₃ (X = COOCH₃)(II) and C₆H₃X₃Cr(CO)₂P(C₆H₅)₃ (X = CH₃) (III) complexes in neutral and acidic media were investigated. The protonation of complexes I and III in trifluoroacetic acid results in the greater upfield shielding of ³¹P{¹H} signal. In this case the complexes I (X = H, CH₃, OCH₃) are completely protonated at the metal, complex I (X = COOCH₃)is partially protonated, while no protonation occurs in the case of complex II.Temperature-dependence of the ³¹P{¹H} NMR spectra was investigated for complexes I (X = H, OCH₃) in a 1/10 mixture of trifluoroacetic acid and toluene and for complexes I (X = COOCH₃) and II in trifluoroacetic acid. The degree of protonation was found to increase with decreasing temperature.     

A mild phase transfer synthesis of the ylid adduct (CO)4FeCH2P(C6H5)3 from iron pentacarbonyl and dichloromethane: Evidence for the transient generation of the tetracarbonyl ferrate anion Fe(CO)42−

The ylid adduct (CO)₄FeCH₂P(C₆H₅)₃ (I) was rapidly produced (along with (CO)₄FeP(C₆H₅)₃) by introducing iron pentacarbonyl into the following phase transfer system under nitrogen: CH₂Cl₂/P(C₆H₅)₃; H₂O/NaOH 1 M, Bu₄N⁺₂, SO₄^2? Production of I goes through the transient generation of the tetracarbonyl ferrate anion Fe(CO)₄^2?, which reacts with the dichloromethane.     

Basische metalle: LII. Synthese von carbenoid- und ylidcobalt(III)-komplexen aus substitutionslabilen cobalt(I)-vorstufen

The cyclopentadienylcobalt(I) compounds C₅H₅Co(PMe₃)P(OR)₃ (R = Me, Et, Prⁱ) and C₅H₅Co(C₂H₄)L (L = PMe₃, P(OMe)₃, CO) are prepared by ligand substitution starting from C₅H₅Co(PMe₃)₂ and C₅H₅Co(C₂H₄)₂. Whereas the reaction of C₅H₅Co(PMe₃)P(OMe)₃ with CH₂Br₂ mainly gives [C₅H₅CoBr(PMe₃)P(OMe)₃]Br, the dihalogenocobalt(III) complexes C₅H₅CoX₂(PMe₃) (X = Br, I) are obtained from C₅H₅Co(CO)PMe₃ and CH₂X₂. Treatment of C₅H₅Co(CO)PMe₃ or C₅H₅Co(C₂H₄)PMe₃ with CH₂ClI at low temperatures produces a mixture of C₅H₅CoCH₂Cl(PMe₃)I and C₅H₅CoCl(PMe₃)I, which can be separated due to their different solubilities. The same reaction in the presence of ligand L gives the carbenoidcobalt(III) compounds [C₅H₅CoCH₂Cl(PMe₃)L]PF₆ in nearly quantitative yields. If NEt₃ is used as the Lewis base, the ylide complexes [C₅H₅Co(CH₂PMe₃)(PMe₃)X]PF₆ (X = Br, I) are obtained. The PF₆ salts of the dications [C₅H₅Co(CH₂PMe₃)(PMe₃)L]²⁺ (L = PMe₃, P(OMe)₃, CNMe) and [C₅H₅Co(CH₂PMe₃)(P(OMe)₃)₂]²⁺ are prepared either from [C₅H₅Co(CH₂PMe₃)(PMe₃)X]⁺ and L, or more directly from C₅H₅Co(CO)PMe₃, CH₂X₂ and PMe₃ or P(OMe)₃, respectively. The synthesis of C₅H₅CoCH₂OMe(PMe₃)I is also described.     

Alkyl- und arylverbindungen des vaska'schen typs : IV. cis,trans-Isomerie von iridium-komplexen mit 2,6-dialkylsubstituierten arylliganden

ortho-Substituted aryliridium(I) complexes of the type [Ir(R_nC₆H_5-n)(CO)L₂] (R_nC₆H_5-n = 2-EtC₆H₄; 2,6-Et₂C₆H₃; L = PPh₃ PMePh₂) have been prepared from [IrCl(CO)L₂] and the corresponding aryllithiums. With the exception of trans-[Ir(2-EtC₆H₄)(CO)(PPh₃)₂] these compounds show cis, trans isomerism. After separation, the isomers have been studied by NMR (¹H, ³¹P), IR, and UV-VIS spectroscopy. ab]Durch Umsetzung von [IrCl(CO)L₂] (L = PPh₃, PMePh₂) mit den entsprechenden Lithiumarylen wurden ortho-substituierte Aryliridium(I)-Komplexe des Typs [Ir(R_n C₆H_5-n)(CO)L₂] (R_nC₆H_5?n = 2-EtC₆H₄; 2,6-Et₂C₆H₃; 2-Et-6-MeC₆H₃) dargestellt. Mit Ausnahme von trans-[Ir(2-EtC₆H₄)(CO)(PPh₃)₂] zeigen diese Verbindungen die Erscheinung der cis,trans-Isomerie. Die Isomere wurden getrennt und mit Hilfe NMR- (¹H, ³¹P), IR- und UV/VIS-spektroskopischer Methoden untersucht.     

Photochemistry of methyl- and n1-benzyl-n5-cyclopentadienyltricarbonyltungstein(II)

Irradiation of solutions of n⁵-C₅H₅W(CO)₃R (R  CH₃n1-CH₂C₆H₅) in cyclohexane at ca. 310490 nm leads to the formation of [n⁵-C₅H₅W(CO)₃]₂ and methane and of n⁵-C₅H₅W₅(CO)₂(n³-CH₂C₆H₅) and some [n⁵-C₅H₅W(CO)₃]₂, respectively. When the irradiation is carried out in the presence of excess P(C₆H₅)₃, the photoproducts are n⁵-C₅H₅W(CO)₂[P(C₆H₅)₃]CH₃ (R  CH₃) and n⁵-C₅H₅W(CO)₂(n₃-CH₂C₆H₅) and trace [n⁵-C₅H₅W(CO)₃]₂ (R  n¹-CH₂C₆H₅). Photolysis of the n⁵-C₅H₅W(CO)₃R in the presence of benzyl chloride affords n⁵-C₅H₅W(CO)₃Cl (R  CH₃) and both n⁵-C₅H₅W(CO)₂(n³-CH₂C₂H₅) and n⁵-C₅H₅W(CO)₃Cl (R  n¹-CH₂C₆H₅), the relative amounts of the latter products depending on the quantity of added C₆H₅CH₂Cl. Irradiation of n⁵-C₅H₅W(CO)₃-CH₃ in the presence of both P(C₆h₅)₃ and C₆H₅CH₂Cl affords n⁵-C₅H₅W(CO)₂-[P(C₆H₅)₃]CH₃, but no n⁵-C₅H₅W(CO)₃Cl. It is proposed that the primary photo-reaction in these transformations is dissociation of a CO group from n⁵-C₅H₅W-(CO)₃R to generate n⁵-C₅H₅W(CO)₂R, which can either combine with L to form a stable 18 electron complex, n⁵-C₅H₅W(CO)₂(L)R (L  CO, P(C₅H₅)₃; LR  n³-CH₂C₆H₅), or lose the group R in a competing, apparently slower step. This proposal receives support from the observation that, light intensifies being equal, n⁵-C₅H₅W(CO)₃CH₃ undergoes a considerably faster photoconversion to [n⁵-C₅H₅W(CO)₃]₂ under argon than under carbon monoxide.     

Synthese und spektroskopische charakterisierung von cyclopentadienyleisen-komplexen mit PN-liganden des typs (C6H5)3−nP(NR2)n (n = 0−3; R = CH3, C2H5

The complex cations [C₅H₅Fe(CO)₂L]BF₄ (L = (C₆H₅)_3−nP(NR₂)_n; n = 0−3 R = CH₃, C₂H₅) have been obtained from the reaction of [C₅H₅Fe(CO)₂THF]BF₄ (I) with L. The reaction of I with E(NR₂)₃ (E = As, Sb; R= CH₃) is also described. Spectroscopic investigations (IR, ¹H, ¹³C and ³¹P NMR) indicate an increase in electron density on the iron center through increase of the number of P-bound NR₂ groups.     

Optisch aktive übergangsmetall-komplexe : VIII. (+)- und (−)-C5H5Fe(CO)[CN-CH(CH3)(C6H5]J

The interaction of C₅H₅Fe(CO)₂I with (+)-α-methylbenzyl isocyanide yields the diastereoisomeric pair (+)- and (−)-C₅H₅Fe(CO)[CN-CH(CH₃)- (C₆H₅)]I. The two diastereoisomers can be separated on the basis of their different solubilities by repeated precipitation from methylene chloride/pentane. Excluding light the complexes are configurationally stable in the solid state as well as in solution. In daylight, however, the optical rotations decrease rapidly (photoracemisation). The ORD and CD spectra (+)- and (−)-C₅H₅Fe(CO)[CN-CH(CH₃)(C₆H₅)]I show pronounced Cotton effects.     

Stoichiometric vs Catalytic MeLi Reaction with the Mixture of (ẽ5‐C5H5)Fe(CO)2l and P(OR)3: Nucleophilic Methylation vs Arbuzov‐Like Dealkylation

The reaction of stoichiometric MeLi with the 1:1 mixture of (?⁵‐C₅H₅)Fe(CO)₂I/P(OR)₃ (R = Me, Et, and Ph) at ?78°C changes the bonding mode between metal and ring from (?⁵‐C₅H₅) to (?⁴‐exo‐MeC₅H₅) and the oxidation state of metal from Fe(II) to Fe(O), the novel complexes (?⁴‐exo‐MeC₅H₅)Fe(CO)₂P(C)R)₃ being obtained in 45‐57% yields. The reaction of trace MeLi with the 1:1 mixture of (?⁵‐C₅H₅)Fe(CO)₂I/P(OMe)₃ at ?78°C results in 70% yield of the phosphonate complex (?⁵‐C₅H₅)Fe(CO)₂P(O)(OMe)₂ which is an Arbuzov‐like dealkylation product from the cationic intermediate [(?⁵‐C₅H₅)Fe(CO)₂P(OMe)₃⁺] and the iodide. The amines could assist the Arbuzov‐like dealkylation of [(?⁵‐C₅H₅)Fe(CO)₂P(OMe)₃⁺] [PF₆^?] where iron‐carbamoyl intermediates are likely involved in the case of primary amines.     

Über verschiedene Reaktionen der CO-verbrückten Komplexe [Mo(CO)3bipy]2 und [Mo(CO)3phen]2 (bipy = 2,2′-Bipyridyl,phen = 1,10-Phenanthrolin)

The interaction of [Mo(CO)₃bipy]₂ with various monodentate ligands L (L = NH₃, pyr, P(C₆H₅)₃, P(C₆H₅)Cl₂, CN^?, SO₂) yields, according to the reaction equation in ?Inhaltsübersicht”?, mixed tricarbonyl compounds Mo(CO)₃bipyL by cleavage of the CO bridges of the dimeric starting carbonyl. Oxidation of [Mo(CO)₃D]₂ (D = bipy, phen) by means of iodine, partly in the presence of free bipy or phen, leads to the covalent and ionic, respectively, compound types [Mo^II(CO)₃DI₂]₂, [Mo^I(CO)₂DI]₂, [Mo^II(CO)₂D₂I]I and [Mo^II(CO)₂D₂I]I₃.     

Tripeldecker-komplexe: III. Komplexierungsreaktionen von 1-phenyl-4,5-dihydroborepin unter gerüstumlagerung. Synthese und struktur von tripeldecker-komplexen des mangans und des eisens mit 2-ethyl-1-phenylborol als brückenligand

The thermal reaction of 1-phenyl-4,5-dihydroborepin (I) with Mn₂(CO)₁₀ produces the triple-decked complex (OC)₃Mn(μ-L)Mn(CO)₃ (III) where L is 2-ethyl-1-phenylborole. The analogous system I/[(C₅H₅)Fe(CO)₂]₂ inter alia yields the triple-decked sandwich complex (C₅H₅)Fe(μ-L)Fe(C₅H₅) (VI) and the borabenzene derivative (C₅H₅)Fe(2-CH₃C₅H₄BC₆H₅) (VIII). The structures of the 30-electron compounds III and VI have been determined by X-ray analyses.     

Reactions of metal carbonyl derivatives : XIII. Reaction of bis[μ-(tert-butylsulphido)tricarbonyl-iron] with tertiary and ditertiary phosphines and phosphites

The ligands L  P(C₂H₅)₃, P(C₆H₅)₃, P(OCH₃)₃ and P(OC₆H₅)₃ react with [Fe(CO)₃(S-t-C₄H₉)]₂ to give mono-substituted Fe₂(CO)₅L(S-t-C₄H₉)₂ or bis-substituted [Fe(CO)₂L(S-t-C₄H₉)]₂ depending on the reaction conditions. With the exception of [Fe(CO)₂P(C₂H₅)₃(S-t-C₄H₉)]₂, the latter derivatives occur both in solution and in the solid state as a single isomer in which the ligands L are bonded trans to the metal-metal bond. Whereas an asymmetrically bis-substituted product, Fe(CO)₃(S-t-C₄H₉)₂Fe(CO)L' is formed in the reaction of [Fe(CO)₃(S-t-C₄H₉)]₂ with L' &2.dbnd; cis-(C₆H₅)₂PC₂H₂P(C₆H₅)₂, symmetrically bis-substituted derivatives [Fe(CO)₂(S-t-C₄H₉)]₂L', in which the ligand bridges the two iron atoms are produced in the corresponding reactions involving L'  (C₆H₅)₂P(CH_2nP(C₆H₅)₂ (n  1 and 2). The NMR spectrum of [Fe(CO)₂P(OCH₃)₃(S-t-C₄H₉)]₂, as well as those of the complexes [Fe(CO)₂P(OCH₃)₃SR]₂ (R  CH₃ and i-C₃H₇) which have also been synthesised in this study, is interpreted in terms of a virtual coupling effect.     

Photoinduced synthesis of the mixed metal “manganese rhenium cubane” [Mn3Re(CO)12(SC6H5)4]

The photoinduced synthesis and spectroscopic properties of the new mixed metal compound [Mn₃Re(CO)₁₂(SC₆H₅)₄] by UV irradiation of a mixture of Mn₂(CO)₁₀, Re₂(CO)₁₀ with S₂(C₆H₅)₂ is described. No mixed sulphur/selenium compounds [M₄(CO)₁₂S_nSe_4?n(C₆H₅)₄] (M = Mn or Re, n = 1–3) could be obtained by analogous photoreactions.     

Electrochemical substitution of a carbonyl group by a phosphorus ligand in arenechromium tricarbonyl complexes

Electrochemical oxidation of (η-1,3,5-Me₃C₆H₃)Cr(CO)₃ in the presence of P(OEt)₃ with subsequent electrochemical reduction results in the formation of a (η-1,3,5-Me₃C₆H₃)Cr(CO)₂[P(OEt)₃] and (η-1,3,5-Me₃C₆H₃)Cr(CO)[P(OEt)₃]₂ mixture. Under similar conditions (η⁶-arene)Cr(CO)₃, where arene = 3,5-Me₂C₆H₃(CH₂)₂OPR₂ (R = OEt,OPh,F), yields the corresponding arenephosphite chelate complexes.