Zur reaktion von metallkoordiniertem kohlenmonoxid mit yliden: XIV. Eisenacyl-phosphor-ylide mit elektronenreicher organometallgruppierung

Treatment of [C₅Me₅(CO)₃Fe]BF₄ (I) with the phosphines Me₃P and Et₃P under thermal or photochemical conditions yields the novel iron salts [C₅Me₅-(CO)₂(R₃P)Fe]BF₄ (R = Me (IIa), R = Et (IIb)) and [C₅Me₅(CO)(Me₃P)₂Fe]BF₄ (IIc). The reaction of I and IIa with two mol of the ylide Me₃PCH₂ leads to the formation of the ironacyl-ylides C₅Me₅(CO)(L)FeC(O)CHPMe₃ (L = CO (IVa), Me₃P (IVb)). IVa selectively reacts at the “ylidic” carbon with the electrophilic reagents MeI, MeOSO₂F, Me₃SiOSO₂CF₃ to give the ironacyl-phosphonium salts [C₅Me₅(CO)₂FeC(O)CH(R)PMe₃] X (VaVc), while IVb is partially converted to [C₅Me₅(CO)₂FeC(O)CH₂PMe₃]BF₄ (IIIa) is obtained together with [C₅Me₅-(CO)₂Fe]₂ from I and IVa.     

SYNTHESIS AND NMR CHARACTERIZATION OF P-VINYL SUBSTITUTED PHOSPHAZENE PRECURSORS1

Abstract

The reactions of either PhPCl₂ or PCl₃ with (Me₃Si)₂NLi followed by H₂C[dbnd]CHMgBr were used to prepare the new P-vinyl substituted [bis(trimethylsilyl)amino]phosphines, (Me₃Si)₂NP(R)CH[dbnd]CH₂ [1: R=Ph, 2: CH[dbnd]CH₂, 3: R=Me, and 4: R=N(SiMe₃)₂]. Oxidative bromination of phosphines 3–1 afforded the P-bromo-P-vinyl-N-(trimethylsilyl)phosphoranimines, Me₃SiN[dbnd]P(CH[dbnd]CH₂)(R)Br [5: R=Ph, 6: R=CH[dbnd]CH₂, 7: R=Me], which, upon treatment with CF₃CH₂OH/Et₃N, were subsequently converted to the P-trifluoroethoxy derivatives, Me₃SiN[dbnd]P(CH[dbnd]CH₂)(R)OCH₂CF₃ [8: R=Ph, 9: R=CH[dbnd]CH₂, 10: R=Me]. Compounds 1–10, which are of interest as potential precursors to P-vinyl substituted poly(phosphazenes), were fully characterized by elemental analyses (except for the thermally unstable P-Br derivatives 5–7) and NMR spectroscopy (¹H, ¹³C, and ³¹P) including complete analysis of the vinylic proton splitting patterns via HOM2DJ experiments.     

Dictionary of organometallic compounds : (J. Buckingham,Executive Editor), Chapman and Hall,London, New York,and Toronto, 1984, 3232 pages (in three volumes), £575. ISBN 0-412-24710-0.

[C₅H₅Fe(CO)₂THF]BF₄ reacts with freshly prepared Me₃SbSe₂ to give the stable complex [C₅H₅Fe(CO)₂(Me₃SbSe)]BF₄ and red selenium.     

Dreikern- sowie homo- und heterometall-zweikernkomplexe mit der baueinheit C5Me5Rh. Die kristallstruktur von C5Me5[P(OMe)3[Rh(μ-CO)2RhC5Me5

C₅Me₅Rh(L)P₂Me₄ (L = CO, C₂H₄) reacts with [C₅Me₅Rh(μ-CO)]₂, to give the trinuclear complexes C₅Me₅(L)Rh(μ-P₂Me₄)RhC₅Me₅(μ-CO)₂RhC₅Me₅ (VI, VII). In the reactions of C₅Me₅Rh(CO)P₂Me₄ with C₅H₅(CO)₂ (M = Rh, Co) and C₅H₄RMn(CO)₃ (R = H, Me), the homo- and hetero-metallic binuclear compounds C₅Me₅(CO)Rh(μ-P₂Me₄)M(CO)C₅H₅ (VIII, IX) and C₅Me₅(CO)Rh(μ-P₂Me₄)Mn(CO)₂C₅H₄R (X, XI) are obtained in almost quantitative yield. The X-ray structure of the complex C₅Me₅[P(OMe)₃]Rh(μ-CO)₂RhC₅Me₅ (III), which is structurally related to VI and VII, has been determined. The molecule contains an unsymmetrical, non-planar Rh₂C₂-skeleton with different Rh-C(O) bond lengths. The Rh-Rh distance is 268.5(1) pm; the planes of the two five-membered rings form an angle of 62.6°.     

Author index

The reduction of ([C₅Me₅(CO)₂Ru]₂ with Na/K alloy provides a suitable way to the potassium ruthenate K[Ru(CO)₂C₅Me₅] (2). 2 reacts readily with HCl, MeI, MeOCH₂Cl, HSiCl₃ and t-BuPCl₂ to give the corresponding complexes C₅Me₅(CO)RuX (X = H, Me, CH₂OMe, Si(H)Cl₂, P(t-Bu)Cl) containing a Main Group element—ruthenium-σ-bond. HCl transforms C₅Me₅(CO)₂RuCH₂OMe into C₅Me₅(CO)₂RuCH₂Cl, which undergoes a complex redox reaction in the presence of 2 or Na[Fe(CO)₂C₅Me₅] .     

On the Reactivity of Disilylphosphido Complexes of Transition Metals Towards Acid Chlorides

Abstract

The first phosphaalkenyl complex Cp(CO)₂Fe-P=C (OSiMe₃)(t-Bu) was generated from Cp(CO)₂FeP(SiMe₃)₂ and t-Bu(CO)Cl. In order to test the validity of this synthetic approach, we varied the ring ligand (Cp, C₅Me₅), the metal (Fe, Ru, Os), the main group element (P, As), and the carbonyl chlorides. The diphosphenyl complexes (C₅Me₅)(CO)₂M-P=P-[2,4,6-t-Bu₃C₆H₂] were obtained from (C₅Me₅)(CO)₂M-P(SiMe₃)₂ and the corresponding phosphonous chloride. These metallated diphosphenes are easily converted to diphospho-ureas by treatment with Fe₂(CO)₉.     

1,2-Diphosphaferrocene als Liganden in Übergangsmetallkomplexen. Röntgenstrukturanalyse von [(η5-1,3-tBu2C5H3){η5-1,2-[Co2(CO)6]-3,4-(Me3SiO)2-5-(Me3Si)P2C3}]

1,2-Diphosphaferrocenes as Ligands in Transition Metal Complexes. X-Ray Structure Analysis of [(η⁵-1,3-tBu₂C₅H₃){η⁵-1,2-[Co₂(CO)₆]-3,4-(Me₃SiO)₂-5-(Me₃Si)P₂C₃}] Reaction of metallo-1,2-diphosphapropene (η⁵-tBuC₅H₄)(CO)₂Fe? P(SiMe₃)? P?C(SiMe₃)₂ with (Z-cyclooctene)Cr(CO)₅ afforded the pentacarbonylchromium adduct of a 1,2-diphosphaferrocene [(η⁵-tBuC₅C₅H₄){η⁵-1-[Cr(CO)₅]-3,4-(Me₃SiO)₂-5-(Me₃Si)P₂C₃}Fe] ( 1 c ). Diphosphaferrocene [(η⁵-tBuC₅H₄){η⁵-3,4-(Me₃SiO)₂-5-(Me₃Si)P₂C₃}Fe] ( 2 c ) was formed when (η⁵-tBuC₅H₄)(CO)₂FeBr was treated with (Me₃Si)₂P? P?C(SiMe₃)₂ in toluene at 60°C. Photolysis of molybdenum- and tungsten hexacarbonyl in the presence of [(η⁵-1,3-tBu₂C₅H₃){η⁵-3,4-(Me₃SiO)₂-5-(Me₃Si)P₂C₃}Fe] ( 2 b ) gave the pentacarbonylmetal adducts 8 (M = Mo) and 9 (M = W), respectively. A corresponding manganese derivative resulted from the photochemical reaction of 2 b and (MeC₅H₄)Mn(CO)₃. Treatment of 2 b with Co₂(CO)₈ yielded trinuclear [(η⁵-1,3-tBu₂C₅H₃){η⁵-1,2-[Co₂(CO)₆]-3,4-(Me₃SiO)₂-5-(Me₃Si)P₂C₃}Fe] ( 11 ). Constitution and configuration of compounds 1 c, 2 c, 8 – 11 were determined by elemental analyses and spectra (IR, ¹H-, ¹³C-, ³¹P-NMR, MS). In addition the molecular structure of 11 was established by single crystal X-ray analysis.     

Ferrio-Dimethylphosphanes

Abstract

Stable metallo-dimethylphosphanes are available via the deprotonation of the PH-functional cationic iron complexes (C₅R₅) (L)₂(HMe₂P)Fel⁺ (R = H, Me; L = CO, HMe₂P, Me₃P) (1a-d). While [Cp(a)₂(HMe₂P)Fe]⁺ (1a) yields the dinucle-ar ferrio-phosphane 2a, the analogoues reaction of Ib-d leads to the monomeric derivatives 2b-d as a consequence of the electron releasing character of C₅Me₅ unit or the phosphane ligands respectively. The mechanism for the formation of 2a involves the intermediate formation of the metallo-phosphane “Cp(CO)₂Fe-PMe₂”.     

Synthesis and crystal structures of cyclodiazastannoxides fused cyclopentadienyl M-Sn (M = Mo, W) bonded organometallic heterocycle

The condensation reaction of CH₃COC₅H₄M(CO)₃SnCl₃ (M = Mo or W) with PyCONHNH₂ (Py = 2,3,4-pyridyl or 2-pyridylmethyl) in mild conditions yields cyclodiazastannoxides fused cyclopentadienyl M-Sn bonded organometallic heterocycle {μ-[C₅H₄(CH₃)CN-NC(O)PyH]M(CO)₃SnCl₃}. The similar reaction of CH₃COC₅H₄M(CO)₃SnCl₃ with ArCONHNH₂ (Ar = 2-furanyl) gives complexes μ-[C₅H₄(CH₃)CN-NC(O)Ar]M(CO)₃SnCl₂(H₂O), in which the water molecule can be replaced by other N-donor ligands, such as pyridine or 4,4-bipyridine. Arene-bridged organometallic heterocyclic complexes μ-{[C₅H₄(CH₃)CN-NC(O)]₂C₆H₄}{M(CO)₃SnCl₂(Solvent)}₂ have also been prepared by the reaction of CH₃COC₅H₄M(CO)₃SnCl₃ with terephthaloyl hydrazine. In these new organometallic heterocyclic complexes, it seems that the tin atom prefers to be six-coordinate through absorbing the chloridion or solvent molecules.     

SILYL- AND GERMYL-DIAZADIPHOSPHETIDINES

Abstract

Reaction of the 1,3,2,4-diazadiphosphetidine, trans-[C₆H₅N(H)P(S)NC₆H₅]₂ with LiR (R = Me, n-Bu) followed by treatment of the resulting dianions with Me₃SiCl and Me₃GeBr produced trans-[C₆H₅N(R)P(S)NC₆H₅]₂(R = Me₃Si, 2; Me₃Ge, 3). Substitution occurs without cis-trans isomerization or significant cleavage of the 1,3,2,4-diazadiphosphetidine ring. 2 and 3 have been characterized by spectral (¹H and ³¹P NMR, IR, and MS) and elemental analytical data. Analogous reactions involving Me₃SnCl yield mixtures containing [C₆H₅N(SnMe₃)P(S)NC₆H₅]₂ which could not be isolated or completely characterized.     

Olefin uptake as tool for linking platinum(II) and iridium(III) in heterobinuclear complexes: Synthesis and characterization of [PtI2(Me2phen){(C5Me4CH2CH2CHCH2)Ir(Me)(CO)(Ph)}]

The ability of [PtX₂(Me₂phen)] (Me₂phen = 2,9-dimethyl-1,10-phenanthroline, X = Cl, Br, I) to act as olefin scavengers, easily giving stable trigonal bipyramidal five-coordinated platinum species [PtX₂(Me₂phen)(η²-olefin)], has been checked toward [(C₅Me₄CH₂CH₂CHCH₂)Ir(Me)(CO)(Ph)], a cyclopentadienyl complex containing an olefinic function introduced by ring methyl activation in the pentamethylcyclopentadienyl iridium(III) complex [(C₅Me₅)Ir(Me)(CO)(Ph)]. The reaction of [PtI₂(Me₂phen)] with [(C₅Me₄CH₂CH₂CHCH₂)Ir(Me)(CO)(Ph)] results in the formation of the heterometallic binuclear complex [PtI₂(Me₂phen){(C₅Me₄CH₂CH₂CHCH₂)Ir(Me)(CO)(Ph)}] which is stable and has been completely characterized by elemental analysis, ¹H, ¹³C, and ¹⁹⁵Pt NMR spectroscopy.     

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.     

A PETERSON OLEFINATION REACTION USING SILYL-SUBSTITUTED SULFONAMIDE CARBANIONS. SYNTHESIS OF VINYLIC SULFONAMIDES

Abstract

α-Trimethylsilyl-substituted sulfonamides RCH(SiMe₃)SO₂N(CH₃)₂ (3), (R[dbnd]H, CH₃ and C₆H₅) are synthetized in almost quantitative yields. Their lithium derivatives 4 undergo a smooth Peterson olefination reaction with nonenolisable carbonyl compounds to give good to excellent yields of vinylsulfonamides 6. With R[dbnd]H, the reaction is highly E-stereoselective. Moderate stereoselectivity is obtained in the cases of R[dbnd]CH₃ and R[dbnd]C₆H₅.     

Synthesis,characterization, and electrochemistry of monophosphine‐containing diiron propane‐1,2‐dithiolate complexes related to the active site of [FeFe]‐hydrogenases

Five monophosphine‐substituted diiron propane‐1,2‐dithiolate complexes as the active site models of [FeFe]‐hydrogenases have been synthesized and characterized. Reactions of complex [Fe₂(CO)₆{μ‐SCH₂CH(CH₃)S}] ( 1 ) with a monophosphine ligand tris(4‐methylphenyl)phosphine, diphenyl‐2‐pyridylphosphine, tris(4‐chlorophenyl)phosphine, triphenylphosphine, or tris(4‐fluorophenyl)phosphine in the presence of the oxidative agent Me₃NO·2H₂O gave the monophosphine‐substituted diiron complexes [Fe₂(CO)₅(L){μ‐SCH₂CH(CH₃)S}] [L = P(4‐C₆H₄CH₃)₃, 2 ; Ph₂P(2‐C₅H₄N), 3 ; P(4‐C₆H₄Cl)₃, 4 ; PPh₃, 5 ; P(4‐C₆H₄F)₃, 6 ] in 81%–94% yields. Complexes 2 – 6 have been characterized by elemental analysis, spectroscopy, and X‐ray crystallography. In addition, electrochemical studies revealed that these complexes can catalyze the reduction of protons to H₂ in the presence of HOAc.     

ORGANOBISMUTH HOMOCYCLES (RBi)n AND HETEROCYCLES (RBiS)2

The homocycles (RBi)_n (n = 3–5) react with MeC₅ H₄Mn(CO)₂(thf) (thf = tetrahydrofuran) or Fe₂(CO)₉ to give Bi₂[Mn(CO)₂MeC₅ H₄]₃ (1) or Bi₂Fe₃(CO)₉ (3). Reaction of R₄Bi₂ (R = Me₃SiCH₂) with Fe₂(CO)₉ in toluene gives R₂Bi₂Fe₂(CO)₈ (4) and R₄Bi₂Fe(CO)₄ (5). The heterocycles (RBiS)₂(R = 2-(Me₂NCH₂)C₆ H₄ (6), 2, 6-(Me₂NCH₂)₂ C₆ H₄ (7) are formed by reaction of the corresponding dihalides RBiCl₂ with Na₂S. The reaction of (RBiS)₂(R = 2-(Me₂NCH₂)C₆ H₄) with W(CO)₅(thf) leads to (RBiS)₂[W(CO)₅]₂ (8).     

Synthetic and structural Studies on Organomolybdenum-Bismuth Halide Complexes

The reactions between either BiBr₂Ph and Na/K[Mo(CO)₃(η? C₅H₅)], [BiPh{Mo(CO)₃(η? C₅H₅)}₂] and BiBr₂Ph, or BiBr₃ and BiPh₃ and [Bi{Mo(CO)₃(η? C₅H₅)}₃] afford the complex [BiBrPh{Mo(CO)₃(η? C₅H₅)}] 1 which has been characterised by X-ray crystallography. Complex 1 comprises a bismuth centre bonded to a bromine atom, a phenyl group and a Mo(CO)₃(η? C₅H₅) fragment together with a longer secondary intermolecular interaction between a bromine from an adjacent molecule which results in a one-dimensional polymeric structure. Addition of a source of bromide anion to 1 affords the anionic complex [BiBr₂Ph{Mo(CO)₃(η? C₅H₅)}]^? 3 ^? although prolonged reaction results in the complex [BiBr₂{Mo(CO)₃(η? C₅H₅)}₂]^? 5 ^? which was characterised by X-ray crystallography as its [Ph₄P]⁺ salt. Complex 5 ^? comprises a mononuclear bismuth centre bonded to two bromine atoms and two Mo(CO)₃(η? C₅H₅) fragments in a geometry which lies between equatorially vacant trigonal bipyramidal and tetrahedral. The complex [PPN]₂[Bi₂Cl₆{Mo(CO)₃(η? C₅H₅)}₂] 8 has also been synthesised and characterised by X-ray crystallography. A dimeric dianion is observed which can be viewed as two edge-shared square-based pyramids with chlorine atoms in the basal planes and Mo(CO)₃(η? C₅H₅) fragments in the apical positions on opposite sides of the Bi₂Cl₆ plane.     

Triosmium compounds containing the oxametallacycle [Os(CO)3{C(R)CHC(O)CHC(H)C5H4FeC5H5}] moiety. Synthesis and electrochemical studies

The compounds [Os₃(CO)₁₀{μ,η³-(SCH₂CH₂SCCHC(O)CHCH(C₅H₄)Fe (C₅H₅)}] (2), [Os₃(CO)₉{μ,η³-(SCH₂CH₂SCCHC(O)CHCH(C₅H₄)Fe(C₅H₅)}] (3) and [Os₃(CO)₈{μ₃,η²-{CCHC(O)CHCH(C₅H₄)Fe(C₅H₅)}(SCH₂CH₂S)}] (4) have been obtained by rupture of S-C bonds in the ketene dithioacetal [C₅H₅FeC₅H₄CHCHC(O)CHC(SCH₂CH₂S)], in their reaction with the activated cluster [Os₃(CO)₁₀(NCMe)₂]. The presence of an oxametallacycle in these derivatives has been confirmed by an X-ray diffraction analysis. The electrochemical study has indicated the ability of these compounds to modify the electrode surfaces.     

Routes to Higher Nuclearity Mixed-Metal Carbonyl Clusters Using the [Rh(η<Superscript>5</Superscript>-C<Subscript>5</Subscript>Me<Subscript>5</Subscript>)(NCMe)<Subscript>3</Subscript>]<Superscript>2+</Superscript> Dication as a Building Block

Reaction of the [Rh(η⁵-C₅Me₅)(NCMe)₃]²⁺ (1) dication with the hexaosmium [Os₆(CO)₁₇]²⁻ (2) dianion leads to the initial formation of [Os₆(CO)₁₇Rh(η⁵-C₅Me₅)] (3). This cluster readily adds CO to form [Os₆(CO)₁₈Rh(η⁵-C₅Me₅)] (4) which has been characterised crystallographically. 3 also adds dihydrogen to give [Os₆H₂(CO)₁₇Rh(η⁵-C₅Me₅)] (5) and undergoes a substitution reaction with PPh₃ to form [Os₆(CO)₁₆(PPh₃)Rh(η⁵-C₅Me₅)] (6). With the [Ru₆(CO)₁₈]²⁻ (7) dianion, [Rh(η⁵-C₅Me₅)(NCMe)₃]²⁺ (1) reacts to form three mixed-metal clusters [Ru₅(CO)₁₅Rh(η⁵-C₅Me₅)] (8), [Ru₆(CO)₁₈Rh(η⁵-C₅Me₅)] (9) and [Ru₆(CO)₁₈Rh₂(η⁵-C₅Me₅)₂] (10). The clusters have been characterised spectroscopically and the structures of 8 and 10 have been confirmed crystallographically. The cluster 8 undergoes a substitution reaction with P(OMe)₃ to form the disubstituted product [Ru₅(CO)₁₃(P(OMe)₃)₂Rh((η⁵-C₅Me₅)] (11) which has also been characterised crystallographically.     

Übergangsmetall-substituierte phosphane,arsane und stibane: XLI. Stabilisierung von metallo-dichlorphosphanen durch die tricarbonyl(pentamethylcyclopentadienyl)-molybdän- oder -wolfram-einheit

Metallation of PCl₃ with Na[M(CO)₃C₅Me₅] (M  Mo, W) (1a, 1b) yields the metallodichlorophosphanes C₅Me₅(CO)₃MPCl₂ (2a, 2b), which show a remarkable thermal stability due to metal—phosphorus bond strengthening by the electron-donating C₅Me₅ group. Treatment of 2a with Me₃P leads to the formation of C₅Me₅(CO)₂(Me₃P)MoCl (4) via CO/Me₃P-exchange at 2a and subsequent elemination of “PCl”. The high Lewis basicity of 2a, 2b, which has to be referred to the high electron donor capacity of the transition metal unit is proved by the spontaneous reaction with elemental sulfur or BH₃ · THF to give the mtallodichlorophosphine sulfide C₅Me₅(CO)₃MPCl₂(S) (5a, 5b) or the borane adducts C₅Me₅(CO)₃MPCl₂BH₃ (6a, 6b), respectively. The new metal-phosphorus compounds are characterized by IR and NMR spectroscopy.     

Propionyl complexes of ruthenium derived from the reaction of ethylene with RuHCl(CO)2(PPh3)2

RuHCl(CO)₂(PPh₃)₂ reacts with ethylene under mild conditions (25 psi, 80°C) to yield a propionyl derivative RuCl(C[O]C₂H₅)(CO)(PPh₃)₂ which is believed to be coordinatively unsaturated. Unlike the acetyl analogue, RuCl[C[O]C₂H₅(CO)-(PPh₃)₂ does not isomerize to RuCl(C₂H₅)(CO)₂(PPh₃)₂ in solution. Under one atmosphere of carbon monoxide, RuCl(C[O]C₂H₅(CO)(PPh₃)₂ exists in equilibrium with two species believed to be RuCl(C[O]C₂H₅)(CO)₂(PPh₃)₂ and [Ru(C[O]C₂H₅)(CO)₃(PPh₃)₂]Cl. RuCl(C[O]C₂H₅)(CO)(PPh₃)₂ reacts with CO/ AgClO₄ to give mer-[Ru(C[O]C₂H₅)(CO)₃(PPh₃)₂]ClO₄, p-tolylisocyanide (RNC) and NaClO₄ to give cis-[Ru(C[O]C₂H₅)(CO)(CNR)₂(PPh₃)₂ClO₄, and hydrochloric acid to yield the hydroxycarbene complex, RuCl₂(CO)(C[OH]C₂H₅)(PPh₃)₂.