Complex Os Cl Research Articles

Substituent Effect on the Reactions of OsCl2(PPh3)3 with o-Ethynylphenyl Carbonyl Compounds

Reactions of OsCl2(PPh3)3 with o-ethynylphenyl-carbonyl compounds o-HC≡CC6H4C(O)R (2, R = H (a) and Et (b)) produced the η3-o-ethynylphenyl-carbonyl complexes OsCl2(PPh3)2{η3-(o-HC≡CC6H4C(O)R)} (3)...

Reactions of Osmium Carbyne Complexes OsCl3(≡CR)(PPh3)2 (R = CH═CPh2, CH2Ar) with Bromine and Hydrogen Peroxide

The reactions of the trichloro carbyne complexes OsCl3(≡CR)(PPh3)2 (R = CH═CPh2, CH2Ar) with bromine and hydrogen peroxide were studied. Unlike monochloro carbyne complexes OsCl(≡CAr)(CO)(PPh3)2, the trichloro complexes OsCl3(≡CR)(PPh3)2 do not undergo oxidation reactions at the metal center or the metal–carbyne bond. Treatment of OsCl3(≡CCH═CPh2)(PPh3)2 with Br2/H2O and H2O2/HCl produced OsBr3(≡CCH═CPh2)(H2O)(PPh3) and OsCl3(≡CCCl═CPh2)(PPh3)2, respectively. Reactions of OsCl3(≡CCH2-C6H4-p-R)(PPh3)2 (R = H, CMe3) with H2O2/HCl or H2O2 gave OsCl3{≡CC(O)-C6H4-p-R}(PPh3)2. Computational studies suggest that the difference in the reactivity of OsCl(≡CAr)(CO)(PPh3)2 and OsCl3(≡CR)(PPh3)2 is mainly of thermodynamic origin.

Synthesis and reactivity of osmium and ruthenium PBP–LXL boryl pincer complexes

The reaction of HB(NCH2PPh2)2C6H4-1,2 with [OsCl(Ph)(CO)(PPh3)2] affords the boryl pincer complex [OsCl(CO)(PPh3){B(NCH2PPh2)2C6H4}]. This complex, and its ruthenium analogue were observed to undergo various reactions involving substitution of the chloride and triphenylphosphine co-ligands to give new complexes [MCl(CO)(CNC6H2Me3){B(NCH2PPh2)2C6H4}] (M=Ru, Os), [MH(CO)(PPh3){B(NCH2PPh2)2C6H4}] (M=Ru, Os) and [Ru(κ2-S,S′-S2CNEt2)(CO){B(NCH2PPh2)2C6H4}]. The ruthenium complex [RuH(CO)(PPh3){B(NCH2PPh2)2C6H4}] was found to react with carbon disulfide and carbon monoxide to give the complexes [Ru(κ2-S,S′-S2CH)(CO){B(NCH2PPh2)2C6H4}] and [RuH(CO)2{B(NCH2PPh2)2C6H4}], respectively, the latter as an apparently interconverting mixture of cis and trans dicarbonyl isomers.

Preparation of Osmium η3-Allenylcarbene Complexes and Their Uses for the Syntheses of Osmabenzyne Complexes

Treatment of OsCl2(PPh3)3 with HC≡CAr (Ar = Ph, p-tolyl) produced the η3-allenylcarbene complexes OsCl2(═CAr-η2-CH═C═CHAr)(PPh3)2. Reactions of the η3-allenylcarbene complexes with gold alkynyls Au(C≡CR)(PPh3) (R = Ph, p-tolyl, TMS, nBu, CH(OEt)2) or copper(I) alkynyls Cu(C≡CR) (R = Ph, TMS) in the presence of HNEt3Cl produced the osmabenzynes Os{≡CC(R)═C(CH2Ar)CH═CAr}Cl2(PPh3)2. Computational studies suggest that the osmabenzynes are formed through electrocyclization of osmium alkynyl-allenylcarbene intermediates followed by protonation with HNEt3Cl.

Reactivity study of a hydroxyl coordinated osmium vinyl complex OsCl2(PPh3)2[CH=C(PPh3)CHPh(OH)

We studied the reactivity of an osmium vinyl complex containing a coordinated hydroxyl group OsCl2(PPh3)2[CH=C(PPh3)-CHPh(OH)] (1) toward bidentate ligand 1,4-bis(diphenylphosphino)butane (DPPB), π acid ligand (CO), base (Cs2CO3) and heat. Two osmium vinyl complexes OsCl2(dppb)[CH=C(PPh3)CHPh(OH)] (2) and OsCl2(CO)2(PPh3)[CH=C(PPh3)CHPh(OH)] (3), as well as two relatively rare phosphonium-containing osmafuran complexes Os(η2-OCOO)(PPh3)2[CHC(PPh3)CPhO] (4) and OsCl2(PPh3)2[CHC(PPh3)CPhO] (5), were obtained in high yields from these reactions. All products were characterized by NMR spectroscopy, elemental analysis, and their structures were further confirmed by single crystal X-ray diffraction.

Preparation of Half-Sandwich Stannyl Complexes of Osmium(II)

Trichlorostannyl complexes OsCl(SnCl3)(η6-p-cymene)P (1; P = P(OEt)3 (a), PPh(OEt)2 (b), PPh2OEt (c)) were prepared by allowing the dichloro compounds OsCl2(η6-p-cymene)P to react with an excess of...

Preparation of Half-Sandwich Alkoxycarbene Complexes of Osmium(II)

Alkoxy-alkylcarbene complexes [OsCl{═C(OR′)CH2R′′}(η6-p-cymene)L]BPh4 (1−4) [R′ = Me, Et; R′′ = Ph, p-tolyl, But; L = P(OMe)3, P(OEt)3, PPh(OEt)2, PPh2OEt] were prepared by allowing dichloro compounds OsCl2(η6-p-cymene)L to react with terminal alkyne R′′C≡CH in alcohol. Ethoxy-methylcarbene [OsCl{═C(OEt)CH3}(η6-p-cymene)L]BPh4 (5) was also prepared from reaction with trimethylsilyl acetylene. A reaction path for the formation of compounds 1−5, involving the nucleophilic attack of alcohol on intermediate vinylidene complexes, is discussed. Acetylide derivatives OsCl(C≡CAr)(η6-p-cymene)L (6, 7) [Ar = Ph, p-tolyl; L = P(OMe)3, P(OEt)3, PPh(OEt)2] were prepared by reacting dichloro compounds OsCl2(η6-p-cymene)L with lithium acetylide (Li+[ArC≡C]−) in thf. Protonation reaction with Brønsted acids of 6 and 7 led to vinylidene cations [OsCl{═C═C(H)Ar}(η6-p-cymene)L]+. Complexes OsCl2(η6-p-cymene)L also reacted with both PhC≡CH and (CH3)3SiC≡CH in the presence of H2O to give alkyl-carbonyl derivatives [Os(η1-CH2Ph)(CO)(η6-p-cymene)L]BPh4 (8) and [Os(η1-CH3)(CO)(η6-p-cymene)L]BPh4 (9). The complexes were characterized spectroscopically (IR and 1H, 13C, 31P NMR) and by X-ray crystal structure determinations of [OsCl{═C(OEt)CH2Ph}(η6-p-cymene){PPh(OEt)2}]BPh4 (1c), [OsCl{═C(OEt)CH2Ph}(η6-p-cymene)(PPh2OEt)]BPh4 (1d), and [Os(η1-CH2Ph)(CO)(η6-p-cymene){PPh(OEt)2}]BPh4 (8c).

Synthesis of Coordinated η2-α,β-Unsaturated Ketone Osmacycles from an Osmium-Coordinated Alkyne Alcohol Complex

The study on the reactivity of an osmium-coordinated alkyne alcohol complex OsCl2(CH═C(PPh3)CH(OH)-η2-C≡CH)(PPh3)2 (1) has been carried out. Treatment of 1 with acetic acid, ethylene diamine, 2,2′-bipyridine, trimethylphospine, or tributylphosphine led to the formation of several coordinated η2-α,β-unsaturated ketone osmacycles, including OsCl2(CH═C(PPh3)C(O)-η2-CH═CH2)(PPh3)2 (3), [OsCl(CH═C(PPh3)C(O)-η2-CH═CH2)(PPh3)(H2NCH2CH2NH2)]Cl (4), [OsCl(CH═C(PPh3)C(O)-η2-CH═CH2)(PPh3)(2,2′-bipy)]Cl (5), OsCl2(CH═C(PPh3)C(O)-η2-CH═CH2)(PMe3)2 (6), [OsCl(CH═C(PPh3)C(O)-η2-CH═CH2)(PMe3)3]Cl (8), and OsCl2(CH═C(PPh3)C(O)-η2-CH═CH2)(PBu3)2 (9). Similar chemistry was also observed starting from OsBr2(CH═C(PPh3)CH(OH)-η2-C≡CH)(PPh3)2 (10), which afforded OsBr2(CH═C(PPh3)C(O)-η2-CH═CH2)(PPh3)2 (11) on treatment with acetic acid. All these cyclic α,β-unsaturated ketone complexes are air-stable in the solid state, and most of them are also stable in solution except for OsCl2(CH═C(PPh3)C(O)-η2-CH═CH2)(PMe3)2 (6) and [OsCl(CH═C(PPh3)C(O)-η2-CH═CH2)(PMe3)3]Cl (8). Complex 8 can isomerize to the osmaphenol [OsCl(CHC(PPh3)C(OH)CHCH)(PMe3)3]Cl (12) as the major product in dry chloroform, but transforms into the osmafuran [Os(CO)(CHC(PPh3)C(CH3)O)(PMe3)3]Cl2 (13) in wet chloroform, while complex 6 is stable in dry solvent, but can convert to the osmafuran [OsCl(CO)(CHC(PPh3)C(CH3)O)(PMe3)2]Cl (14). The remarkable thermostability and chemical stability of the coordinated α,β-unsaturated ketone osmacycles have been studied preliminarily with 3 as a representative example. The coordinated α,β-unsaturated ketone metallacyclic framework of 3 is stable in different ligand environments. For example, treatment of 3 with carbon monoxide led only to ligand substitution to produce OsCl2(CH═C(PPh3)C(O)-η2-CH═CH2)(CO)(PPh3) (15).

NH-Tautomerization of 2-Substituted Pyridines and Quinolines on Osmium and Ruthenium: Determining Factors and Mechanism

Complexes MH2Cl2(PiPr3)2 (M = Os (1), Ru (1a)) promote the NH-tautomerization of 2-methylpyridine and stabilize the resulting NH-tautomer to afford the dihydrogen derivatives MCl2(η2-H2){κ-C-[HNC5H3Me]}(PiPr3)2 (M = Os (2), Ru (3)), containing the heterocycle coordinated by the Cα atom. In dichloromethane under reflux, complex 3 loses the coordinated hydrogen molecule to give the five-coordinate derivative RuCl2{κ-C-[HNC5H3Me]}(PiPr3)2 (4). In contrast to 2-methylpyridine, the reactions of 1 and 1a with pyridine lead to MCl2{κ-N-[NC5H5]}3(PiPr3) (M = Os (5), Ru (5a)), containing the heterocycle coordinated by the lone pair of the nitrogen. DFT calculations using PMe3 as a model of PiPr3 show that the formation of 2 and the related quinoline complex OsCl2(η2-H2){κ-C-[HNC9H6]}(PiPr3)2 (6) involves an intermolecular osmium to nitrogen hydrogen migration, the subsequent Cα−H bond activation of the protonated heterocycle, and the dihydride−dihydrogen tautomerization of the resulting dihydride. The structures of 2 and 5 have been determined by X-ray diffraction analysis.

Formation of Four Conjugated Osmacyclic Species in a One-Pot Reaction

Treatment of HC≡CCH(OH)CH═CH2 with OsCl2(PPh3)3 in THF produced the η2-allyl alcohol osmacycle OsCl2(PPh3)2(CH═C(PPh3)CH(OH)CH═CH2) (2) with poor solubility and low stability, which underwent a ligand substitution reaction with PMe3 to give the more stable analogue [OsCl(PMe3)3(CH═C(PPh3)CH(OH)CH═CH2)]Cl (3). Heating the suspension of 2 in CH2Cl2 led to the formation of four interesting conjugated osmacycles in one pot, including the osmabenzene OsCl2(PPh3)2(CHC(PPh3)CHCHCH) (4), the cyclic osmium η2-allene complex OsCl2(PPh3)2(CH═C(PPh3)CH═C═CH2) (5), the osmafuran OsCl2(PPh3)2(CHC(PPh3)C(CH2CH3)O) (6), and the α,β-unsaturated ketone complex OsCl2(PPh3)2(CH═C(PPh3)C(O)C═CH2) (7). All of the four products could also be produced in higher yield under appropriate conditions.

Cyclometalation of 2-Vinylpyridine with MCl2(PPh3)3and MHCl(PPh3)3(M = Ru, Os)

Treatment of RuCl2(PPh3)3 in benzene at room temperature with 2-vinylpyridine produces the vinylpyridine complex RuCl2(2-CH2CHC5H4N)(PPh3)2. In the presence of Cs2CO3, RuCl2(PPh3)3 reacts with 2-vinylpyridine at room temperature to give the cyclometalated complex RuCl(CHCHC5H4N)(CH2CHC5H4N)(PPh3), which is also produced from the reaction of RuHCl(PPh3)3 with 2-vinylpyridine. OsCl2(PPh3)3 reacts with 2-vinylpyridine/Cs2CO3 at room temperature to give the analogous cyclometalated complex OsCl(CHCHC5H4N)(CH2CHC5H4N)(PPh3). In the presence of NaBF4, the reaction produces [Os(CHCHC5H4N)(CH2CHC5H4N)(PPh3)2]BF4. The dihydrogen complex Os(H2)Cl(CHCHC5H4N)(PPh3)2 is produced from the reaction of OsHCl(PPh3)3 with 2-vinylpyridine. The mechanism of the cyclometalation reactions has been investigated by computational chemistry.

Osmium(II) and Osmium(IV) Complexes with Phosphane–Ethers, –Esters, and –Amines as Mono‐ and Bidentate Ligands

AbstractThe six‐coordinate dihydridoosmium(IV) complex [OsH2Cl2(PiPr3)2] (1) reacted with the hemilabile chelating phosphanes iPr2PCH2CH2OMe and iPr2PCH2CO2R (R = Me, Et) at room temperature to give the substitution products [OsH2Cl2(iPr2PCH2CH2OMe)2] (2) and [OsH2Cl2{κ2(P,O)‐iPr2PCH2C(=O)OR}{κ(P)‐iPr2PCH2CO2R}] (3, 4) in good to excellent yields. Treatment of 1 with iPr2PCH2CH2NMe2 led to the displacement of only one PiPr3 ligand and gave [OsH2Cl2(PiPr3)(iPr2PCH2CH2NMe2)] (5). The reaction of 1 with iPr2PCH2CH2OMe and iPr2PCH2CO2R (R = Me, Et) at elevated temperature afforded the osmium(II) complexes [OsCl2{κ2(P,O)‐iPr2PCH2CH2OMe}2] (6) and [OsCl2{κ2(P,O)‐iPr2PCH2C(=O)OR}2] (7, 8), which were also obtained on heating the osmium(IV) precursor 3 or the labile 1:1 adducts of 3 and 4 with ethene in benzene under reflux. The dihydrido compounds 2 and 3 reacted with CO at room temperature to give initially the octahedral all‐cis‐configured complexes [OsCl2(CO)2{κ(P)‐iPr2PCH2CH2OMe}2] (11a) and [OsCl2(CO)2{κ(P)‐iPr2PCH2CO2Me}2] (12a), which rearrange to the more stable cis,cis,trans isomers 11b and 12b in benzene under reflux. The all‐trans isomer 11c and themonocarbonyl complexes trans,trans‐[OsCl2(CO){κ2(P,O)‐iPr2PCH2C(=O)OR}{κ(P)‐iPr2PCH2CO2R}] (13, 14) were prepared by passing CO through a solution of 6–8 in benzene or toluene/dichloromethane at room temperature. While the osmium(IV) compounds 3, 4 as well as the osmium(II) complexes 7, 8 reacted with CNtBu to give the neutral complexes cis,cis,trans‐[OsCl2(CNtBu)2{κ(P)‐iPr2PCH2CO2R}2] (15, 16), treatment of 5 with CNtBu afforded the ionic product [OsHCl(CNtBu)2(PiPr3)(iPr2PCH2CH2NHMe2)]Cl (17). The reaction of 7 with Ph2CN2 did not lead to the formation of a (carbene)osmium(II) compound but gave the dinitrogen complex trans,trans‐[OsCl2(N2){κ2(P,O)‐iPr2PCH2C(=O)OMe}(κ(P)‐iPr2PCH2CO2Me)] (18) instead. The structurally related vinylidene complexes trans,trans‐[OsCl2(=C=CHPh){κ2(P,O)‐iPr2PCH2CH2OMe}{κ(P)‐iPr2PCH2CH2OMe}] (19a) andtrans,trans‐[OsCl2(=C=CHPh){κ2(P,O)‐iPr2PCH2C(=O)OR}{κ(P)‐iPr2PCH2CO2R}] (20, 21) were prepared from 6–8 and PhC≡CH as starting materials. The cis,cis‐configuredcompound [OsCl2(=C=CHPh)(PiPr3){κ2(P,N)‐iPr2PCH2CH2NMe2}] (22) was obtained analogously from 5 and phenylacetylene. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

Stabilization of NH Tautomers of Quinolines by Osmium and Ruthenium

Complexes OsH2Cl2(PiPr3)2 and RuH2Cl2(PiPr3)2 promote the tautomerization of quinoline and 8-methylquinoline to NH tautomers, which lie about 44 kcal.mol-1 above the usual CH tautomers. The NH tautomers are stabilized by coordination to the metal center and by means of a Cl...HN interaction. As a consequence, the six-coordinate elongated dihydrogen complexes OsCl2{kappa-C2-(HNC9H5R)}(eta2-H2)(PiPr3)2, the five-coordinate derivatives RuCl2{kappa-C2-(HNC9H5R)}(PiPr3)2, and the six-coordinate dihydrogen compounds RuCl2{kappa-C2-(HNC9H5R)}(eta2-H2)(PiPr3)2 (R = H, Me) have been isolated and characterized.

Structure and Dynamics of a Compressed Dihydride Complex of Osmium

The complex OsCl(NH=C(Ph)C 6 H 4 )(PiPr 3 ) 2 (H 2 ) (1) has been characterized by Esteruelas and coworkers (Organometallics 1998, 17, 4065-4076) as an elongated dihydrogen complex based on relaxation time measurements and observation of J H-D = 6.3 Hz in 1-d 1 . Variable-temperature NMR studies were reported in which the single hydride resonance observed at ambient temperature decoalesced into two signals at low temperature (193 K), which was attributed to hindered rotation of the bound H 2 ligand. Reinvestigation of the low-temperature NMR spectra of 1 reveals a more complex situation. Examination of the 1 H and 31 P NMR spectra of 1 and 1-d 1 at lower temperatures than previously studied demonstrates that quantum mechanical exchange coupling is observed between the metal-bonded hydrogen atoms. This coupling is quenched in 1-d 1 . Hindered rotation around Os-P bonds in 1 also contributes to the observed NMR spectra.

Insertion Reactions of Allenes Giving Vinyl Complexes

Treatment of OsHCl(PPh3)3 with allenes CH2CCHR at room temperature in benzene produced the vinyl complexes OsCl(C(CH3)CHR)(CH2CCHR)(PPh3)2, instead of η3-allyl complexes as normally observed. DFT calculations show that the formation of the vinyl complex is favored kinetically.

Dioxygen oxidation of a carbonyl ligand to form a chelating peroxycarbonyl ligand: synthesis, structure, and reactions of Cl(NO)(PPh 3) 2

Reaction between the carbonyl, nitrosyl complex, OsCl(CO)(NO)(PPh 3) 2 ( 1) and dioxygen results in combination of CO and O 2, forming a chelating peroxycarbonyl ligand in the yellow complex, ▪Cl(NO)(PPh 3) 2 ( 2). Confirmation of the unique peroxycarbonyl ligand arrangement in 2 is provided by crystal structure determination. When 2 is heated, as a suspension in heptane under reflux, there is a rearrangement to the regular chelating carbonate ligand in the orange complex, ▪Cl(NO)(PPh 3) 2 ( 3). The structure of 3 has also been determined by X-ray crystallography. Compound 2 also undergoes the following reactions: with water, releasing CO 2 and forming Os(OH) 2Cl(NO)(PPh 3) 2 ( 4); with HCl releasing CO 2 and forming Os(OH)Cl 2(NO)(PPh 3) 2 ( 5); and with excess triphenylphosphine releasing CO 2 and triphenylphosphine oxide forming OsCl(NO)(PPh 3) 3 ( 6).

Synthesis, Spectra and Electrochemistry of Isomeric DichloroBis-[1-Alkyl-2-(Naphthyl-(α/β)-Azo)Imidazole]Osmium(II): Single Crystal X-Ray Structure of Blue-Violet DichloroBis-[1-Ethyl-2-(Naphthyl-α-Azo) Imidazole]Osmium(II)

1-Alkyl-2-(naphthyl-(α/β)-azo)imidazoles (α/β-NaiR; R = Me, Et and CH2Ph) react with (NH4)2[OsCl6] and complexes OsCl2(NaiR)2 are isolated in two isomeric forms: blue-violet (3, 4) and red-violet (5, 6). The ligand is a bidentate N (N(imidazole)), N' (N(azo)) donor type. With reference to the pairs of Cl, Cl; N, N and N', N' atoms the blue-violet and red-violet isomers are assigned to cis-trans-cis (ctc) and cis-cis-cis (ccc) configurations respectively. IR spectra of the complexes show two v(Os-Cl) bands and support the cis-OsCl2 configuration. 1H NMR spectra also support the ctc and ccc-configuration. The structure of the blue-violet complex OsCl2(α-NaiEt)2 has been determined by X-ray crystallography and the ctc configuration has been confirmed. The structure shows an unusually long N=N bond length, 1.331(4) Å, which is elongated by 0.07 Å compared to the free ligand value.

Cyclometalated Osmium Complexes Containing a Tridentate PCP Ligand

Reactions between [Et4N]2OsCl6 and 1,3-(CH2PBut2)2C6H4 afforded the 16-e chloride complexes OsCl(CO)(PCP) (1) and OsH2Cl(PCP) (2) (PCP = [2,6-(CH2PBut2)2C6H3]-) in methanol/isoamyl alcohol and 2-propanol, respectively. The iodide OsH2I(PCP) (3) was obtained from 2 in methyl iodide. Treatment of 1 and 2 with [BH4]- gave the hydride and dihydrogen compounds OsH(CO)(PCP) (4), OsH(H2)(CO)(PCP) (5), and OsH3(H2)(PCP) (6), while formation of the dihydrogen complexes Os(H2)2Cl(PCP) (7a) and OsH2(H2)Cl(PCP) (7b) was observed by NMR in solution of 2 under H2. The structures of 1, 2, and 3 were determined by X-ray crystallography.

A comprehensive view of M–H addition across the RCCH bond: frustration culminating in ultimate union

The reaction of MHCl(CO)L2 (L = PiPr3; M = Ru or Os) with more than a dozen terminal alkynes RCCH has been studied at variable temperatures and for a variety of R groups representing a wide range of steric and electronic effects. This sometimes reveals (for the slower osmium examples) formation of an η2-alkyne adduct, then the vinylidene OsHCl(CCHR)(CO)L2 and finally the η1-vinyl complex OsCl(CHCHR)(CO)L2. The rate of formation of the vinyl complex decreases with R according to the series primary > tertiary > secondary and electron-withdrawing > electron-donating. Deuterium labeling of OsHCl(CO)L2 at either Os or the alkyne sp carbons shows that isotope exchange between these two sites can be competitive with vinylidene and vinyl product formation, and thus can confuse some attempts to trace the fate of the hydride. When this complication is absent, conventional syn addition of Os–D to HCCR is established, to give Os(E-CHCDR). The rate of conversion to the vinyl product is not suppressed by added free PiPr3 . Taken together, these results are consistent with a mechanism of vinyl complex formation involving neither the adduct with H trans to RCCH, nor the vinylidene, but rather with direct alkyne attack cis to the hydride, which is also consistent with the considerable steric influence on the rate of vinyl formation. DFT (B3PW91) calculations show that the vinyl complex is the thermodynamically most stable product and thus is always the final observed product. The calculations also show that the “direct” addition of the alkyne occurs ia approach of the alkyne cis to M–H inside the H–M–Cl quadrant. This direct route is in fact calculated to be a multistep process with an alkyne intermediate that is not in a deep well and thus cannot be observed experimentally. Calculations also agree with the fact that the vinylidene and the vinyl complexes are obtained through two independent routes.

Vinylidene and Carbyne Complexes Derived from the Reactions of OsCl(PPh3)(PCP) (PCP = 2,6-(PPh2CH2)2C6H3) with Terminal Acetylenes

Treatment of OsCl2(PPh3)3 with 1,3-(PPh2CH2)2C6H4 led to the formation of the coordinatively unsaturated complex OsCl(PPh3)(PCP) (PCP = 2,6-(PPh2CH2)2C6H3). Reactions of OsCl(PPh3)(PCP) with RC⋮CH (R = Ph, t-Bu, C(OH)Ph2) gave OsCl(CCHR)(PPh3)(PCP). Treatment of OsCl(CCHPh)(PPh3)(PCP) and OsCl(CCHC(OH)Ph2)(PPh3)(PCP) with HCl produced the carbyne complexes OsCl2(⋮CCH2Ph)(PCP) and OsCl2(⋮CCHCPh2)(PCP), respectively. The solid-state structures of OsCl(PPh3)(PCP) and OsCl(CCHPh)(PPh3)(PCP) have been determined by X-ray diffraction.