Gary H. Williams

Organocobalt cluster complexes : XII. The arylation and alkylation of methylidynetricobalt nonacarbonyl with organomercury compounds☆

Abstract The reaction of diarylmercurials and arylmercuric halides with methylidynetricobalt nonacarbonyl in benzene or THF at reflux results in formation of benzylidynetricobalt nonacarbonyl complexes, ArCCo3(CO)9, in good yield, especially when the reactions are carried out under an atmosphere of carbon monoxide. The alkylation of HCCo3(CO)9 with dialkylmercurials or alkylmercuric halides proceeds much more slowly and in much lower yields. Similar reactions of (α-haloalkyl)mercurials, (RCHX)2Hg, with HCCo3(CO)9, gives reduced products, RCH2CCo3(CO)9, rather than the expected RCHXCCo3(CO)9. Similar arylation of the apical carbon atom of the CCo3 cluster occurred in the reactions of XCCo3(CO)9 (X = Cl, Br, I) with diphenylmercury, and in reactions of tetraphenyltin and tetraphenyllead with HCCo3(CO)9.

Organocobalt cluster complexes : XIV. The reduction of formyl- and acyl-methylidynetricobalt nonacarbonyl complexes to the respective alkylidyne- and hydroxyalkylidyne-tricobalt nonacarbonyls by triethylsilane

Abstract The action of triethylsilane/trifluoroacetic acid in THF on (OC)9Co3CC(O)R (R = alkyl or aryl) resulted in reduction to the respective (OC)9Co3CCH2R complexes. Reduction of these ketones to the respective alcohol, (OC)9Co3CCH(OH)R, could be affected by treating them with triethylsilane in refluxing benzene and then pouring the reaction product into concentrated sulfuric acid and hydrolyzing the solution thus formed.

Organocobalt cluster complexes: XXII. α,β-Unsaturated methylidynetricobalt nonacarbonyl complexes☆

Abstract The reaction of the appropriate RCCl 3 compound with dicobalt octacarbonyl has been used to prepare CH 2 CHCCo 3 (CO) 9 , CH 2 C(CH 3 )CCo 3 (CO) 9 , Me 3 SiCHCHCCo 3 (CO) 9 and CH 3 C(O)CHCHCCo 3 (CO) 9 . A similar reaction with CH 2 CHCH 2 CCl 3 gave a mixture of CH 2 CHCH 2 CCo 3 (CO) 9 , CH 3 CH CHCCo 3 (CO) 9 and CH 3 CH 2 CH 2 CCo 3 (CO) 9 . Protonation of these α,β-unsaturated methylidynetricobalt nonacarbonyl complexes resulted in formation of the αcluster carbonium ions (e.g., CH 2 =C(CH 3 )CCo 3 (CO) 9 + HPF 6 → (OC) 9 Co 3 CC(CH 3 ) 2 + PF6 6 − ), with desilylation occurring during the protonation of Me 3 SiCH CHCCo 3 (CO) 9 . The CH 3 C(O)Cl/AlCl 3 reagent was used to acetylate the first two listed complexes in the β position, and methoxymercuration of CH 2  CHCCo 3 (CO) 9 with Hg(O 2 CCF 3 ) 2 , followed by anion exchange with NaCl, gave ClHgCH 2 CH(OCH 3 )CCo 3 (CO) 9 .

A carbon-13 NMR spectroscopic study of ferrocenylmethyl carbonium ions

Abstract The 13C NMR spectra of three ferrocenylmethyl carbonium ions and of the alcohols from which they were derived have been obtained. The chemical shifts and coupling constants of the carbonium ions are explicable in terms of a structure that has the positive charge extensively delocalized throughout the entire molecule, with a fulvenelike structure for the substituted cyclopentadienyl ring.

Organocobalt cluster complexes : XVI. Vinyl derivatives of methylidynetricobalt nonacarbonyl: useful precursors to (OC)9 Co3 c-substituted carbonium ions and functionally substituted derivatives☆

Abstract Vinyl-substituted of methylidynetricobalt nonacarbonyl of the type RR′CC(R″)CCo3(CO)9 have been prepared, with vinylic groups CH2 CH, CH2 C(CH)3, Me3SiCHCH and CH3 C(O)CHCH. Reaction of the first two with HPF6 produced the carbonium ions via β-proton addtions to the CC bonds. Acetylium ion addition also could be achieved. Proton addition to the Me3Si compound resulted in desilylation.