90858-61-0Relevant academic research and scientific papers
Preparation of homo- and heterobimetallic μ-η2-(C,C)-ketene complexes, FpCH2COMLn, and transformation of the bridging ketene ligand into various C2 functional groups
Akita, Munetaka,Kondoh, Atsuo,Kawahara, Takashi,Takagi, Takenobu,Moro-oka, Yoshihiko
, p. 366 - 374 (2008/10/08)
Eight examples of homo- and heterobimetallic μ-ketene complexes, FpCH2COMLn [3-7: Fp = (η5-C5H5)Fe(CO)2; M = Fe, Mo, Ni, Mn, Co; L = Cp, CO, PR3], are prepared by acylation of an iron-substituted acetyl chloride with various transition-metal anions. IR studies reveal the significant contribution of a π-complex Fp+[CH2=C(O-)Fp] (10) in addition to an oxycarbene structure FpCH2C(O-)=Fp+ (11) which is well-established for mononuclear acyl complexes. As a typical example, FpCH2COFp (3a) is subjected to chemical transformations relevant to catalytic CO hydrogenation. While 3a is not susceptible to carbonylation to lead to a μ-malonyl complex, decarbonylation results in quantitative liberation of ketene molecule or ligand substitution instead of formation of a μ-methylene complex. Reduction of 3a by LiAlH4 affords C3 products as major components. Reaction of 3a with electrophiles takes place at the acyl oxygen atom to give cationic binuclear oxycarbene complexes FpCH2C(OR)=Fp+TfO- (TfO = CF3SO3) (18-20) which exhibit bimodal reactivities toward both nucleophiles and electrophiles. Hard nucleophiles attack the most electrophilic carbene center, soft nucleophiles attack the alkyl side Fp group, and electrophilic reaction takes place at the methylene terminus.
CONVERSION OF A DIIRON μ-KETENE COMPLEX, FpCH2COFp (Fp=(η5-C5H5)Fe(CO)2), INTO BINUCLEAR CATIONIC OXYCARBENE COMPLEXES AND THEIR BIMODAL REACTIVITIES.
Akita, Munetaka,Kondoh, Atsuo,Kawahara, Takashi,Moro-oka, Yoshihiko
, p. C43 - C46 (2007/10/02)
Reactions of a bimetallic μ-ketene complex, FpCH2COFp, with electrophiles take place at the acyl oxygen atom to give cationic binuclear oxycarbene complexes.Bifunctionality of their cationic enol ether structure permits subsequent transformation both with nucleophiles and electrophiles.
Reactions of aziridine, oxirane, and thiirane with carbonyl and thiocarbonyl ligands in complexes of iron, manganese, and ruthenium: Syntheses of cyclic carbene compounds
Singh, Mono M.,Angelici, Robert J.
, p. 2691 - 2698 (2008/10/08)
The 3-membered heterocycles aziridine (HNCH2CH2) and oxirane (OCH2CH2) react with one CO group in each of the cationic carbonyl complexes Cp(OC)3Fe+, Cp(OC)3Ru+, Cp(OC)2(ON)Mn+, and Cp(OC)2(Ph3P)Fe+ in the presence of a halide ion at 25°C or below to form the corresponding 5-membered cyclic amino oxy M=COCH2CH2NH+ and dioxy M=COCH2CH2O+carbene complexes (M = Cp(OC)2Fe, Cp(OC)2Ru, Cp(OC)(ON)Mn, Cp(OC)(Ph3P)Fe). Aziridine and thiirane (SCH2CH2) also react with the CS ligand in the mixed carbonyl thiocarbonyl complex Cp(OC)2(CS)Fe+ to give the corresponding aminothiocarbene (M=CSCH2CH2NH) and dithiocarbene (M=CSCH2CH2S) products. In the reactions M-C≡Z+ + YCH2CH2 →X- M=CZCH2CH2Y+ (Z = O, Y = NH and O; Z = S, Y = NH and S), the role of the halide ion X- as a catalyst has been demonstrated. Prolonged reactions of oxirane with Cp(OC)2LM+ (M = Fe, L = CO; M = Mn, L = NO) in the presence of Br ion generate bis(dioxycarbene) derivatives CpLM(COCH2CH2O)2+. Mechanisms for these reactions have been proposed. Reactions of Cp(OC)2LM+ (M = Fe, L = CO; M = Mn, L = NO) with [BrCH2CH2CH2NH3]Br and the bases azetidine (HNCH2CH2CH2) or oxirane and Br- yield 6-membered aminooxycarbene compounds Cp(OC)LM(COCH2CH2CH2NH)+. The basic behavior of oxiranes R-CHCH2O in the presence of a halide catalyst is demonstrated by the isolation of the 5-membered dioxycarbene compound Cp(CO)2Fe(COCH2CH2O)+ from the reaction of RCHCH2O with Cp(OC)3Fe+ in BrCH2CH2OH. IR and 1H and 13C NMR spectra of the compounds are discussed.
