Stepwise reduction of the thiocarbonyl ligand: hydride transfer to CS: thioformyl,thioformaldehyde, methylthiolato,secondary carbene,formyl and iminoformyl complexes of osmium

The complexes OsHX(CS)L(PPh₃)₂ (X  Cl, Br; L  CO and X  Cl; L  CN-p-tolyl), which contain mutually cis hydrido and thiocarbonyl ligands, undergo transfer of the hydrido ligand to CS when treated with CO to give blue complexes containing the thioformyl ligand [OsCHS]. OsCl(CHS)(CO)₂(PPh₃)₂ reacts with borohydride to give the first metal complex of the thioformaldehyde monomer, viz. Os(η²-CH₂S)(CO)₂(PPh₃)₂, which reacts rapidly with HCl to give OsCl(SCH₃)(CO)₂(PPh₃)₂ and then, by a slower reaction, OsCl₂(CO)₂(PPh₃)₂ and CH₃SH. The ligands produced in this stepwise reduction have possible relevance as models for postulated intermediates in the Fischer—Tropsch synthesis. Synthetic routes to formyl [OsCHO], iminoformyl [OsCHNMe] and secondary carbene complexes [OsCHSMe, OsCHNMe₂, OsCHOMe] are also demonstrated.     

The tris(triphenylphosphine)osmium zerovalent complexes Os(CO)2(PPh3)3, .Os(CO)(CNR)(PPh3)3, Os(CO)(CS)(PPh3)3, Os(CS)(cNR)(PPh3)3 and derived compounds

Detailed procedures for the syntheses of Os(CO)₂(PPh₃)₃, Os(CO)(CNR)-(PPh₃)₃ (R = p-tolyl), Os(CO)(CS)(PPh₃)₃ and Os(CS)(CNR)(PPh₃)₃, together with the derived complexes Os(CO)₂(CS)(PPh₃)₂, Os(CO)(CS)(CNR)(PPh₃)₂, Os(η²-C₂H₄)(CO)(CNR)(PPh₃)₂, Os(η²-C₂H₄)(CO)(CS)(PPh₃)₂, Os(η²CS₂)(CO)₂-(PPh₃)₂, Os(η²CS₂)(CO)(CS)(PPh₃)₂, Os(η²-CS₂)(CO)(CNR)(PPh₃)₂, Os(η²PhC₂Ph)(CO)₂(PPh₃)₂ and OsH(C2Ph)(CO)₂(PPh₃)₂ are described.     

Alkoxide attack at carbonyl and hydrosulphide attack at isocyanide in the mixed carbonyl-isocyanide cation [OsCl(CO)2(CNR)(PPh3)2]+. A new synthesis of π-bound isothiocyanate (RNCS) complexes

[OsCl(CO)₂(CNR)(PPh₃)₂]⁺ (R = p-tolyl) reacts with OMe^? to give OsCl(CO₂Me)(CO)(CNR)(PPh₃)₂ but reaction with SH^? produces the π-bound p-tolylisothiocyanate complex, Os(η²-SCNR)(CO)₂(PPh₃)₂, which can be protonated or methylated at N to yield complexes containing bidentate thiocarboxamido-ligands.     

Synthesis of low-valent thiocarbonyl complexes via 1,2-elimination of methylthiol from cis-metal-hydrido-dithiomethylester complexes. Os(cs)(CO)2(PPh3)2 and IrCl(CS)(PPh3)2.

[OS(η²-CS₂Me)(CO)₂(PPH₃)₂]⁺ and [Ir(η²-CS₂Me)Cl(CO)(PPh₃)₂)⁺ react with NaBH₄ giving OsH(CS₂Me)(CO)₂(PPh₃)₂ and IrH(CS₂Me)Cl(CO)(PPh₃)₂ respectively; These compounds contain mutually $\text{cis}$ hydride and η¹-dithiomethylester ligands and upon heating undergo 1,2-elimination of MeSH producing Os(CS)(CO)₂(PPh₃)₂ and IrCl(CS)(PPh₃)₂.     

Metal catalysed Brooke rearrangement of 3-Halo-1-(trimethylsilyl) propan-2-one (Halo = Cl or Br)

The complexes [IrH(CO)(PPh₃)₃], trans-[IrCI(CO)- (PPh₃)₂], [RhH(PPh₃)₄], [Pd(PPh₃)₄], [Pt(trans-stilbene)(PPh₃)₂] and [Pt(η³-CH₂-COCH₂)-(PPh₃)₂] catalyse the rearrangement of Me₃SiCH₂C(O)CH₂Cl to CH₂?C(OSiMe₃)-CH₂Cl.     

Reactions involving transition metals : XIX. Some reactions of perfluoronorbornadiene with low valent transition metal complexes

Perfluoronorbornadiene reacts with the compounds [M(PPh₃)₄] (M = Pt, Pd) and [IrCl(CO)(PMePh₂)₂] to give the adducts [(C₇F₈)M(PPh₃)₂] and [(C₇F₈)IrCl(CO)(PMePh₂)₂] in which one of the double bonds is coordinated to the metal atom. The platinum complex reacts further with [Pt(PPh₃)₄] to give [(C₇F₈){Pt(PPh₃)₂}₂] having both double bonds coordinated to a Pt atom. The carbonylmetal anions [M^?] react to form the mono-substitution products [(C₇F₇)M] (M = Mn(CO)₅, Re(CO)₅, Ir(CO)₂(PPh₃)₂, Rh(CO)₂(PPh₃)₂), but the use of an excess of [Fe(CO)₂(η-C₅H₆)]^? leads to substitution of one fluorine atom on each of the double bonds. The complex having M = Mn(CO)₅ reacts with [Pt(PPh₃)₄] to afford the derivative [(C₇F₇){Mn(CO)₄(PPh₃)}{Pt(PPh₃)₂}], and the compound where M = Ir(CO)₂(PPh₃)₂ undergoes an oxidative addition reaction with acetyl chloride. Oxidative coupling products have been isolated on UV irradiation of a mixture of perfluoronorbornadiene and [Fe(η⁴-CH₂CRCHCH₂)(CO)₃] (R = H, Me), and under similar conditions the reaction with Fe(CO)₅ affords [(C₇F₈)Fe(CO)₄] in very low yield.     

The interaction of an osmium-carbon triple bond with copper(I), silver(I) and gold(I) to give mixed dimetallocyclopropene species and the structures of Os(AgCl) (CR) Cl(CO) (PPh3)2

The osmium carbyne complex, Os(CR)Cl(CO)(PPh₃)₂, (R  p-tolyl) reacts with Group I halides to form the mixed dimetallocyclopropene species, $\text{Os(Cul)(C}$R)Cl(CO)(PPh₃)₂, $\text{Os(AgCl)(C}$R)Cl(CO)(PPh₃)₂, $\text{Os(AuCl)(C}$R)Cl(CO)(PPh₃)₂, and [$\text{Os[Ag(OClO}{}_3\text{)](C}$R)Cl(CO)(MeCN)(PPh₃)₂] ClO₄ X-ray crystal structure determination of $\text{Os(AgCl)(C}$R)Cl(CO)(PPh₃)₂ confirms the presence of a three-membered ring and the structure can be viewed as the “acetylene-like” interaction of an osmium—carbon triple bond with AgCl. In acid solution AgCl is precipitated and an alkylidene complex results from proton addition to the carbyne ligand.     

Preparation of new (η5-C5H4CH3)Mn(NO)(PPh3) and (η7-C7H7)Mo(CO)-(PPh3) complexes

The complex (η⁵-C₅H₄CH₃)Mn(NO)(PPh₃)I has been prepared by the reaction of NaI with [(η⁵-C₅H₄CH₃)Mn(NO)(CO)(PPh₃)]⁺ and also by the reaction of [(η⁵-C₅H₄CH₃)Mn(NO)(CO)₂]⁺ with NaI followed by PPh₃. This iodide compound reacts with NaCN to yield (η⁵-C₅H₄CH₃)Mn(NO)(PPh₃)CN which is ethylated by [(C₂H₅)₃O]BF₄ to yield [(η⁵-C₅H₄CH₃)Mn(NO)(PPh₃)(CNC₂H₅)]⁺. Both [(η⁵-C₅H₄CH₃)Mn(NO)(CO)₂]⁺ and [(η⁵-C₅H₄CH₃)Mn(NO)(PPh₃)(CO)]⁺ react with NaCN to yield [(η⁵-C₅H₄CH₃)Mn(NO)(CN)₂]^?. This anion reacts with Ph₃SnCl to yield cis-(η⁵-C₅H₄CH₃)Mn(NO)(CN)₂SnPh₃ and with [(C₂-H₅)₃O]BF₄ to yield [(η⁵-C₅H₄CH₃)Mn(NO)(CNC₂H₅)₂]⁺. The reaction of (η⁵-C₅-H₄CH₃)Mn(NO)(PPh₃)I with AgBF₄ in acetonitrile yields [(η⁵-C₅H₄CH₃)Mn-(NO)(PPh₃)(NCCH₃)]⁺. The complex (η⁵-C₅H₄CH₃)Mn(NO)(CO)I, produced in the reaction of [(η⁵-C₅H₄CH₃)Mn(NO)(CO)₂]⁺ with NaI, is not stable and decomposes to the dimeric complex (η⁵-C₅H₄CH₃)₂Mn₂(NO)₃I for which a reasonable structure is proposed. Similar dimers can be prepared from the other halide salts. The reaction of (η⁷-C₇H₇)Mo(CO)(PPh₃)I with NaCN yields (η⁷-C₇-H₇)Mo(CO)(PPh₃)CN which is ethylated by [(C₂H₅)₃O]BF₄ to yield [(η⁷-C₇H₇)-Mo(CO)(PPh₃)(CNC₂H₅)]⁺. The interaction of this molybdenum halide complex with AgBF₄ in acetonitrile and pyridine yields [(η⁷-C₇H₇)Mo(CO)(PPh₃)-(NCCH₃)]⁺ and [(η⁷-C₇H₇)Mo(CO)(PPh₃)(NC₅H₅)]⁺, respectively. Both (η⁵-C₅-H₄CH₃)Mn(NO)(PPh₃)I and (η⁷-C₇H₇)Mo(CO)(PPh₃)I are oxidized by NOPF₆ to the respective 17-electron cations in acetonitrile at ?78°C but revert to the neutral halide complex at room temperature. This result is supported by electrochemical data.     

Dihapto-acyl derivatives of ruthenium(II). Preparation and structure of Ru[η2-C(O)CH3] I(CO)(PPh3)2 and Ru[η2-C(O)p-tolyl]I(C0) (PPh3) 2

Reaction between Ru(CO)₂(PPh₃)₃ and MeHgI yields Ru[η²-C(O)CH₃]I(CO)(PPh₃)₂ which in solution exists mainly as RuCH₃I(CO)₂(PPh₃)₂ and crystal structure determination of Ru[η²-C(O)CH₃]I(CO)(PPh₃)₂ and previously described Ru[η²-C(O)p-tolyl]I(CO) (PPh₃)₂ confirms that in the solid state both molecules contain dihapto-acyl ligands.     

Interconversion of Metallabenzenes and Cyclic η2‐Allene‐Coordinated Complexes

Treatment of the osmabenzene [Os{CHC(PPh₃)CHC(PPh₃)CH} Cl₂(PPh₃)₂]Cl ( 1 ) with excess 8‐hydroxyquinoline produces monosubstituted osmabenzene [Os{CH C(PPh₃) CHC(PPh₃)CH}(C₉H₆NO)Cl(PPh₃)]Cl ( 2 ) or disubstituted osmabenzene [Os{CHC(PPh₃)CHC(PPh₃)CH} (C₉H₆NO)₂]Cl ( 3 ) under different reaction conditions. Osmabenzene 2 evolves into cyclic η²‐allene‐coordinated complex [Os{CH?C(PPh₃)CH=(η²‐C?CH₂)}(C₉H₆NO)(PPh₃)₂]Cl ( 4 ) in the presence of excess PPh₃ and NaOH, presumably involving a P? C bond cleavage of the metallacycle. Reaction of 4 with excess 8‐hydroxyquinoline under air affords the S_NAr product [(C₉H₆NO)Os{CHC(PPh₃)CHCHC} (C₉H₆NO)(PPh₃)]Cl ( 5 ). Complex 4 is fairly reactive to a nucleophile in the presence of acid, which could react with water to give carbonyl complex [Os{CH?C(PPh₃)CH?CH₂}(C₉H₆NO) (CO)(PPh₃)₂]Cl ( 6 ). Complex 4 also reacts with PPh₃ in the presence of acid and results in a transformation to [Os {CHC(PPh₃)CHCHC}(C₉H₆NO)Cl (PPh₃)₂]Cl ( 7 ) and [Os{CH?C(PPh₃) CH=(η²‐C?CH(PPh₃))}(C₉H₆NO) Cl(PPh₃)]Cl ( 8 ). Further investigation shows that the ratio of 7 and 8 is highly dependent on the amount of the acid in the reaction.     

Exploratory organometal-sulfur chemistry; syntheses and unusual properties of rhenium CH2SR,CHSRR′, and CHSR]+ complexes

The methylidene complex [(η-C₅H₅)Re(NO)(PPh₃)(CH₂)]⁺PF₆^?(I) yields kinetically labile sulfonium salts when treated with CH₃SCH₃, CH₃SCH₂C₆H₅, and (η-C₅H₅)Re(NO)(PPh₃)(CH₂SCH₃) (V);the binuclear adduct formed in the latter case, [(η-C₅H₅)Re(NO)(PPh₃)CH₂]₂S⁺CH₃ (VI), is substantially more stable than the others and undergoes hydride transfer disproportionation to [(η-C₅H₅)Re(NO)(PPh₃)(CHSCH₃)]⁺PF₆^?(VII) and (η-C₅H₅)Re(NO)(PPh₃)(CH₃) (VIII) when heated.     

Neue 1,1′-Ferrocendichalkogenato-Komplexe des Rutheniums und Osmiums

New 1,1′-Ferrocene Dichalcogenato Complexes of Ruthenium and Osmium Both trinuclear 1,1′-ferrocene dichalcogenato complexes(¹) such as fc(E[ML_n])₂ ( 1a—c ) (with [ML_n] = Ru(CO)₂Cp*; E = S, Se, Te) and dinuclear [3]ferrocenophane derivatives of the type fcE₂[ML_n] (with [ML_n] = Ru(CO)(η⁶-C₆Me₆) ( 2a, b ), Ru(NO)Cp* ( 3a, b ) (E = S, Se) or Os(NO)Cp* ( 4a—c ) (E = S, Se, Te)) were synthesized and characterized by their IR-, ¹H- and ¹³C NMR spectra as well as their mass spectra. The molecular structure of fcS₂[Os(NO)Cp*] ( 4a ) was determined by an X-Ray structure analysis; the long Fe…?Os distance of 431.1(1)pm excludes any direct bonding interactions.     

Hydride-phosphoniodithiocarboxylate/ phosphonium-betaine isomerism in Cy3PCS2 complexes of ruthenium

Reaction of Cy₃PCS₂ (Cy = cyclohexyl) with the hydrido complexes [RuClH(CA)(PPh₃)₃] (A  O, S), [RuH(CO)(NCMe)₂(PPh₃)₂]⁺, and [RuH(OClO₃)(CO)(CN^tBu)(PPh₃)₂] leads to the complex cations [RuH(CA)(PPh₃)₂(η²-S₂CPCy₃)]⁺, [Ru(η²-S₂CHPCy₃)(CO) (PPh₃)₂]⁺, [RuH(η¹-S₂CPCy₃)(CO)(CN^tBu)(PPh₃)₂]⁺. The σ-vinyl complex [Ru(CHCHC₆H₄Me-4)Cl(CO)(PPh₃)₂] reacts with Cy₃PCS₂ to give the cationic complex [Ru(CHCHC₆H₄Me-4) (CO)(PPh₃)₂(η²-S₂CPCy₃)]⁺, but this complex is not formed by hydroruthenation of HCCC₆H₄Me-4 by [RuH(CO)(PPh₃)₂(η²-S₂CPCy₃)]⁺. The inter-relationships between the above complexes are discussed.     

Nucleophilic Aromatic Addition Reactions of the Metallabenzenes and Metallapyridinium: Attacking Aromatic Metallacycles with Bis(diphenylphosphino)methane to Form Metallacyclohexadienes and Cyclic η2‐Allene‐Coordinated Complexes

The reactions of phosphonium‐substituted metallabenzenes and metallapyridinium with bis(diphenylphosphino)methane (DPPM) were investigated. Treatment of [Os{CHC(PPh₃)CHC(PPh₃)CH}Cl₂(PPh₃)₂]Cl with DPPM produced osmabenzenes [Os{CHC(PPh₃)CHC(PPh₃)CH}Cl₂{(PPh₂)CH₂(PPh₂)}]Cl ( 2 ), [Os{CHC(PPh₃)CHC(PPh₃)CH}Cl{(PPh₂)CH₂(PPh₂)}₂]Cl₂ ( 3 ), and cyclic osmium η²‐allene complex [Os{CH?C(PPh₃)CH?(η²‐C?CH)}Cl₂{(PPh₂)CH₂(PPh₂)}₂]Cl ( 4 ). When the analogue complex of osmabenzene 1 , ruthenabenzene [Ru{CHC(PPh₃)CHC(PPh₃)CH}Cl₂(PPh₃)₂]Cl, was used, the reaction produced ruthenacyclohexadiene [Ru{CH?C(PPh₃)CH?C(PPh₃)CH}Cl{(PPh₂)CH₂(PPh₂)}₂]Cl₂ ( 6 ), which could be viewed as a Jackson–Meisenheimer complex. Complex 6 is unstable in solution and can easily be convert to the cyclic ruthenium η²‐allene complexes [Ru{CH?C(PPh₃)CH?(η²‐C?CH)}Cl{(PPh₂)CH₂(PPh₂)}₂]Cl₂ ( 7 ) and [Ru{CH?C(PPh₃)CH?(η²‐C?CH)}Cl₂{(PPh₂)CH₂(PPh₂)}₂]Cl ( 8 ). The key intermediates of the reactions have been isolated and fully characterized, further supporting the proposed mechanism for the reactions. Similar reactions also occurred in phosphonium‐substituted metallapyridinium [OsCl₂{NHC(CH₃)C(Ph)C(PPh₃)CH}(PPh₃)₂]BF₄ to give the cyclic osmium η²‐allene‐imine complex [OsCl₂{NH?C(CH₃)C(Ph)?(η²‐C?CH)}{(PPh₂)CH₂(PPh₂)}(PPh₃)]BF₄ ( 11 ).     

Cyclopentadienyl-ruthenium and -osmium chemistry: XXIV. Some complexes containing the olefinic tertiary phosphine 2-CH2CHC6H4PPh2 (sp): X-ray structures of one isomer of OsBr(sp)(η-C5H5), and of Ru(η3-S2CCHMeC6H4PPh2-2)(η-C5H5), containing an η3-dithiocarboxylato group

Reactions between MX(PPh₃)₂(η-C₅H₅) (M = Ru, X = Cl; M = Os, X = Br) and 2-CH₂CHC₆H₄PPh₂ afford $\text{MX(η}{}^2\text{-CH}{}_2\text{CHC}{}_6\text{H}{}_4\text{P}$Ph₂)(η-C₅H₅); the Os complex is obtained in two isomeric forms. The X-ray structure of the major isomer shows the CC double bond (OsC, 2.214, 2.195 Å; CC, 1.57 Å) is almost coplanar with the OsBr vector, with the terminal C cis to Br; the minor isomer is assumed to have the alternative, more sterically congested conformation, with the β-C cis to Br. The chlororuthenium complex reacts with NaOMe/MeOH to give the corresponding hydrido complex, which also exists as two isomers in solution; reaction of this complex with CS₂ gives the expected dithio acid derivative $\text{Ru(S}{}_2\text{CCHMeC}{}_6\text{H}{}_4\text{P}$Ph₂)(η-C₅H₅), together with small amounts of a complex assumed to be $\text{Ru[S}{}_2\text{C(CH}{}_2\text{)}{}_2\text{C}{}_6\text{H}{}_4\text{P}$Ph₂](η-C₅H₅). The X-ray structure of the major product reveals an unusual η³-S₂C mode of coordination of the dithio acid fragment (RuS, 2.418, 2.426(1) Å; RuC 2.175(4) Å). Crystals of OsBr(η²-CH₂CHC₆H₄P)Ph₂)( η-C₅H₅) are monoclinic, space group P2₁/n, with a 12.696(2), b 21.719(6), c 15.929(3) Å, β 79.77(2)°, Z = 8; 2867 data (I > 2.5σ(I)) were refined to R = 0.040, R_w = 0.044. Crystals of $\text{Ru(η}{}^3\text{-S}{}_2\text{CCHMeC}{}_6\text{H}{}_4\text{P}$Ph₂)(η-C₅H₅) are orthorhombic, space group Pbca, with a 8.921(2), b 15.982(9), c 32.216(5) Å, Z = 8; 1685 data (I > 2.5σ(I)) were refined to R = 0.027, R_w = 0.030.     

Übergangsmetall-Fulven-Komplexe: XXXI. Die Reaktivität des [η5-(C5H4CHO)M(CO)3]−-Anions (M  Mo,W) gegenüber Carbonsäurechloriden

The reactivity of the (η⁵-formylcyclopentadienyl)M(CO)₃ anions (M  Mo, W) towards acyl chlorides has been studied. Acetyl chloride reacts with the anions to give two different types of substituted cyclopentadienyl complexes: [M(Cl)(η⁵-C₅H₄CH₂OC(O)CH₃)(CO)₃] and [M(η¹-CH₃CO)(η⁵-CH₃CO)(η⁵-C₅H₄CH₂OC(O)CH₃)(CO)₃]. The reaction of the anions with benzoyl chloride only yields the chloro complexes [M(Cl)(η⁵-C₅H₄CH₂OC(O)C₆H₅)(CO)₃]. The molecular structure of [W(Cl)(η⁵-C₅H₄CH₂OC(O)CH₃)(CO)₃] has been determined by X-ray diffraction studies.     

Synthesis and reactions of isocyanate and carbamoyl complexes of rhenium

Re(CO)₂(NO)(PPh₃)₂ reacts with aroyl azides RCON₃ (R = C₆H₅, p-CH₃C₆H₄) in benzene to form isocyanate complexes of formula Re(CO)(NO)-(PPh₃)₂(RCONCO) (I). When the reaction is carried out in protic solvents such as ethanol, carbamoyl derivatives of formula Re(NCO)(NO)(PPh₃)₂-(CONHCOR) (II) are obtained, which give Re(NCO)(NO)(PPh₃)₂(CO)(NHCOR) when dissolved in chloroform, a terminal carbonyl ligand being formed from the carbamoyl group.I can be transformed into II by reaction with gaseous HCl, via [Re(CO)-(NO)(PPh₃)₂ {C(OH)=NCOR}]⁺Cl^- followed by anion exchange with NaN₃. II reacts with mineral acids HX (X = Cl, BF₄) to give amide derivatives of formula [Re(NCO)(NO)(PPh₃)₂(CO)(NH₂COR)]⁺ X^- which when X = Cl can be easily transformed into Re(NCO)(NO)(PPh₃)₂(CO)Cl, the amide ligand being removed. Both the protonation reactions of I and II are reversible. IR and ¹H NMR data of the new compounds and the mechanisms of formation of I and II are reported and discussed.     

Cyanomethyl cyclopentadienyl complexes of cobalt

The reactions of the complexes CpCo(CO)L (Cp = cyclopentadienyl, L = CO, PPh₃) with ClCH₂CN have been investigated. Chloroacetonitrile reacts with CpCo(CO)PPh₃ to give the cationic complex [CpCo(CH₂CN)(CNCH₂Cl)PPh₃]⁺, which has been isolated and characterized. Compounds of the type [CpCo(CH₂CN)(bipy)]⁺ BPh₄^? and CpCo(CH₂CN)PPh₃CN have been obtained by substitution reactions.     

Synthesis,characterization, and reactivity of the neutral metal formyl (η5-C5Me5)(CO)2(PPh3)MoCHO. A new route to monocationic secondary alkoxycarbene complexes [(η5-C5Me5)(CO)2(PPh3)Mo(CHOE)]+ X− (E = H,Me)

(η⁵-C₅Me₅)(CO)₂(PPh₃)MoCHO (2) one of the few isolated neutral metal formyls, reacts with the electrophilic reagents (CF₃COOH and CH₃SO₃F without disproportionation to give the secondary carbene complexes [(η⁵-C₅Me₅)(CO)₂(PPh₃)Mo(CHOE)]⁺ X⁻ (E = H, X = CF₃COO (4); E = Me, X = PF₆ (5)).