Reaction of OsCl(PPh
3)(PCP) with terminal acetylenes HC≡CR (R = Ph, Bu
t, C(OH)Ph
2) produced vinylidene complexes OsCl(=C=CHR)(PPh
3)(PCP). Protonation of OsCl(=C=CHPh)(PPh
3)(PCP) and OsCl(=C=CHC(OH)Ph
2)(PPh
3)(PCP) with HCl gave the carbyne complexes OsCl
2(≡CCH
2Ph)(PCP) and OsCl
2(≡CCH=CPh
2)(PCP), respectively , while using HBF
4 as the acid afforded [OsCl(≡CCH
2Ph)(PPh
3)(PCP)]BF
4 and [OsCl(≡CCH=CPh
2)(PPh
3)(PCP)]BF
4, respectively. Reaction of OsH
3(PPh
3)(PCP) with HC≡CPh gave the coupling product Os(C≡CPh)(=C=CHPh)(PPh
3)(η
3-CHPh=C-2, 6-(PPh
2CH
2)
2C
6H
3).
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Reaction of OsCl(PPh
3)(PCP) with terminal acetylenes HC≡CR (R = Ph, Bu
t, C(OH)Ph
2) produced vinylidene complexes OsCl(=C=CHR)(PPh
3)(PCP). Protonation of OsCl(=C=CHPh)(PPh
3)(PCP) and OsCl(=C=CHC(OH)Ph
2)(PPh
3)(PCP) with HCl gave the carbyne complexes OsCl
2(≡CCH
2Ph)(PCP) and OsCl
2(≡CCH=CPh
2)(PCP), respectively , while using HBF
4 as the acid afforded [OsCl(≡CCH
2Ph)(PPh
3)(PCP)]BF
4 and [OsCl(≡CCH=CPh
2)(PPh
3)(PCP)]BF
4, respectively. Reaction of OsH
3(PPh
3)(PCP) with HC≡CPh gave the coupling product Os(C≡CPh)(=C=CHPh)(PPh
3)(η
3-CHPh=C-2, 6-(PPh
2CH
2)
2C
6H
3).
Treatment of OsCl
2(PPh
3)
3 with HC≡CCMe
3 produced OsCl(=C=CHCMe
3)-(C(C≡CMe
3)=CHCMe
3)(PPh
3)
2 and OsCl
3(≡CCH
2CMe
3)(PPh
3)
2. Reaction of OsCl
2(PPh
3)
3 with HC≡CAr(Ar=Ph, p-tolyl) yielded OsCl
2(=CAr-η
2-CH=C=CHAr)(PPh
3)
2 and OsCl
2(CH=CAr(PPh
3))(=C=CHAr)(PPh
3)
2. The carbyne complexes OsCl
3(≡CCH
2R)( PPh
3)
2(R=CMe
3, Ph, p-tolyl) could be prepared from a one-pot reaction of OsCl
2(PPh
3)
3 with HC≡CR in the presence of HCl, which by deprotonation with Et
3N gave the vinylidene complexes OsCl
2(=C=CHR)(PPh
3)
2. Treatment of OsCl
2(=C=CHPh)(PPh
3)
2 with OsCl
2(PPh
3)
3 produced (PPh
3)
2ClOs(μ-Cl)
3Os(=C=CHPh)(PPh
3)
2. OsCl
2(=C=CHAr)(PPh
3)
2 and OsCl
2(=CAr-η
2-CH=C=CHAr)(PPh
3)
2 are catalytically active for the ROMP of norbornene and norbornadiene.
Reaction of OsCl
2(PPh
3)
3 with HC≡CC(OH)Ph
2 at room temperature produced the carbyne complexes , fac-OsCl
3(≡CCH=CPh
2)(PPh
3)
2 and mer-OsCl
3(≡CCH=CPh
2)(PPh
3)
2 in low yield, which could be alternatively prepared from the reaction in the presence of HCI. (PPh
3)
2ClOs(μ-Cl)
3Os(=C=CH-C(OH)Ph
2)( PPh
3)
2 could be isolated at the early stage in the reaction of OsCl
2( PPh
3)
3 with HC≡CC(OH)Ph
2. When the reaction was carried out in refluxing toluene, mer-OsCl
3(≡CCH=CPh
2)(PPh
3)
2, OsCl
2(CO)(=C=C=CPh
2)( PPh
3)
2 and CH
2=CPh
2 were obtained. Treatment of OsCl
2(PPh
3)
3 with HC≡CC(OH)Ph
2 in the presence of HPPh
3BF
4 produced [OsCl
2(≡CCH =CPh
2)(H
2O)(PPh)
3)
2]BF
4. Reaction of [OsCl
2(≡CCH =CPh
2)(H
2O)(PPh)
3)
2]BF
4 with HC≡CSiMe
3 afforded fac-OsCl
3(≡CCH=CPh
2)(PPh
3)
2 and [OsCl(η
2-C(O)CH
3)(≡CCH=CPh
2)(PPh)
3)
2]BF
4.
Reaction of OsCl
2( PPh
3)
3 with HC≡SiMe
3 produced OsCl
3(≡CCH
3)(PPh
3)
2, OsCl(=C=CHSiMe
3)(C(C≡CSiMe
3)=CHSiMe
3)( PPh
3)
2, Os(=C=CHSiMe
3)(C≡C-SiMe
3)(C(C≡CSiMe
3)=CHSiMe
3)(PPh
3)
2 and osmabenzyne Os(≡C-C(SiMe
3)=C(CH
3)C(SiMe
3)=CH)Cl
2(PPh
3)
2. Protonation of the osmabenzyne with HBF
4, under variation of reaction conditions, produced the cationic osmabenzyne [Os(≡CC(SiMe
3)=C(CH
3)C(SiMe
3)=CH)Cl(H
2O)(PPh
3)
2]BF
4, or the desilylated cationic osmabenzyne [Os(≡CCH=C(CH
3)CH=CH)Cl(H
2O)(PPh
3)
2]BF
4 and the neutral desilylated osmabenzyne Os(≡CCH=C(CH
3)CH=CH)Cl
2(PPh
3)
2, respectively. The desilylated osmabenzynes underwent H-D exchange with CF
3SO
3D to give 3,5-deuteriated derivatives. Os(≡CC(SiMe
3)=C(CH
3)C(SiMe
3)=CH)-Cl
2(PPh
3)
2 underwent substitution reaction with PCy
3 to give Os(≡CC(SiMe
3)=C(CH
3)C(SiMe
3)=CH)Cl
2(PCy
3)
2. Os(≡CC(SiMe
3)=C(CH
3)-C(SiMe
3)=CH)Cl
2(PPh
3)
2 could be alternatively prepared from the reaction of OsH
3Cl(PPh
3)
3 with HC≡CSiMe
3 in the presence of Et
3NHCl. Reactions of OsH
3Cl(PPh
3)
3 with HC≡CAr produced the corresponding osmabenzynes Os(≡CC(Ar)=C(CH
2Ar)CH=C(Ar))Cl
2(PPh
3)
2(Ar = Ph, p-tolyl).
Reaction of HC≡CSiMe
3 with OsCl
2(=CPh-η
2-CH=C=CHPh)(PPh
3)
2 gave the η
6-fulvene complex OsCl
2(η
6-C
5H
2(SiMe
3)(Ph)CHPh)(PPh
3). Treatment of OsCl
2(=CPh-η
2-CH=C=CHPh)(PPh
3)
2 with styrene produced [(PPh
3)
2ClOs(μ-Cl)
3Os(H
2O)(PPh
3)
2] and the cyclic CH
2CH(Ph)C(Ph)=CHC=CHPh. Reaction of OsCl(PPh
3)(PCP) with HC≡CPh in benzene for 4 days led to the monomeric complex [OsCl(fac-PCP)(η
5-2,3-diphenyl-CpCH
2Ph)]Cl and dimeric complexes, including dicationic rac-[OsCl(fac-PCP)(η
5-2,3-diphenyl-CpCHPh-)]
2Cl
2, and neutral dimers rac-[Os(fac-PCP)(η
5-2,3-diphenyl-CpCHPh-)]
2 and meso-[Os(fac-PCP)(η
5-2,3-diphenyl-CpCHPh-)]
2.
Treatment of OsH
3Cl(PPh
3)
3 with HC≡CSiMe
3 produced OsCl(=C=CHSiMe
3)(C(C≡CSiMe
3)=CHSiMe
3)(PPh
3)
2 and a small amount of Os( =C=CHSiMe
3)(C≡CSiMe
3)(C(C≡CSiMe
3)=CHSiMe
3)(PPh
3)
2 and osmabenzyne Os(≡CC(SiMe
3)=C(CH
3)C(SiMe
3)=CH)Cl
2(PPh
3)
2. Reaction of OsH
3Cl(PPh
3)
3 with HC≡CCMe
3 produced OsCl(=C=CHCMe
3)(C(C≡CCMe
3)=CHCMe
3)(PPh
3)
2 exclusively, whereas reaction of OsH
3Cl(PPh
3)
3 with HC≡CBu
n yielded OsCl(=C=CHBu
n)(CBu
n=CH-CH=CBu
n)(PPh
3)
2.
Reaction of PhC≡CCH
3 with OsH
3Cl(PPh
3)
3 produced the unusual complex OsCl(C(CH
3)=CHPh)(η
2-CH
2=C=CHPh)(PPh
3)
2 containing a β-agostic vinyl ligand and an η
2-phenylallene ligand. Reaction of PhC≡CCH
2CH
3 with OsHCl(PPh
3)
3 gave OsCl{η
6-(Ph)CHC(CH
2CH
3)C(Ph)C(C
6H
4-PPh
2)CH(CH
3)}(PPh
3) containing a chelating η
1:η
5-phosphinopentadienyl ligand. Protonation of OsCl(C(CH
3)=CHPh)-(η
2-CH
2=C=CHPh)(PPh
3)
2 with HCl produced OsCl
3(≡CCH
2Ph)(PPh
3)
2 and CH
2=C(CH
3)CH
2Ph, which can be rationalized as a result of the metathesis of the coordinated allene ligand with the carbene ligand formed by protonation.
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