Synthesis and Characterization of Dimetallic Vinylidene Complexes
Date Issued
2007
Date
2007
Author(s)
Yeh, Cheng-Wei
DOI
en-US
Abstract
Ferrocenyl ferrocenyl-substituted allenylidene complexes [(η5-C5H5)(L)2Ru=C=C=C (Ph)(Fc)][PF6] (L = PPh3, 1a; 1/2 dppe, 1b) was prepared by treatment of a methanol solution of (η5-C5H5)(L)2RuCl (L = PPh3, 1/2 dppe) with the propargylic alcohol 1-ferrocenyl-1-phenylprop-2-yn-1-ol in the presence of NH4PF6. Reaction of 1a-b with Grignard reagent RMgBr or MeLi in THF yielded the neutral acetylide complexes 2a-3d (η5-C5H5)(L)2Ru-C≡CCPh(Fc)R (Fc = (η5-C5H4)Fe(η5-C5H5), L = PPh3, R = CH2CH=CH2, 2a; R = CH2C≡CH, 2b; R = CH2C(CH3)=CH2, 2c; L = 1/2 dppe, R = CH2CH=CH2, 3a; R = CH2C≡CH, 3b; R = CH2C(CH3)=CH2, 3c; R = Me, 3d). Complexes 2a-3d undergo protonation reactions affording the corresponding vinylidene complexes 4a-5d [(η5-C5H5)(L)2Ru=C=CHCPh(Fc)R]+ (L = PPh3 ,R = CH2CH=CH2, 4a; R = CH2C≡CH, 4b; R = CH2C(CH3)=CH2, 4c; L = 1/2 dppe, R = CH2CH=CH2, 4a; R = CH2C≡CH, 4b; R = CH2C(CH3)=CH2, 4c; R = Me, 4d). The cationic complex 4a in methanol solution for 12h followed by subsequent addition of NaOMe to give the new neutral acetylide complex (η5-C5H5)(PPh3)2Ru-C≡C-CH2C (Ph)([Fc])CH=CH2 (6). This transformation was proposed that a metathesis process of the terminal vinyl group with the C=C of the vinylidene group as mechanism. The presence of a gem-ferrocenylphenylmethylene moiety at the vinylidene ligand with the appropriate terminal vinyl or alkynyl group along with the correct steric environment implements such a specific reactivity in the ruthenium vinylidene complexes. The bisvinylidene complex [Ru]=C=C(Ph)CH2CH=C=[Ru]2+ (8) ([Ru] = (η5-C5H5) (dppe)Ru) can be obtained from the reaction of {[Ru]=C=CPhCH2C≡CH}+ with [Ru]Cl in the presence of NH4PF6 and methanol. Deprotonation of the bisvinylidene complex 8 formed the alkylnyl vinylidene complex [Ru]=C=C(Ph)CH2C≡C-[Ru]+ (9), which was alkylated by primary alkyl halide to give the ruthenium bisvinylidene complex [Ru]=C=C(Ph)CH2C(CH2R)=C=[Ru]2+ (R = CN, 10a; R = COOMe, 10b; R = C≡CH, 10c). Deprotonation of 10a by NaOMe is followed by a cyclization process yielding the stable complex 11, containing a three-membered carbocyclic ring ligand, which is characterized by NMR spectroscopy. No deprotonation reactions of 10c was observed under various basic conditions. Deprotonation reaction of the cationic isocyanide complexes of molybdenum {[Mo]-C≡NCH2C6F5}Br ([Mo] = (η7-C7H7)(dppe)Mo), with NaOMe in the presence of acetone leads to the synthesis of oxazolinyl complexes 13. This reaction proceeds via an azirinyl intermediate detected by NMR spectra followed by insertion of a carbonyl group into the C-C single bond of the three-membered ring. Regiochemistry of the C-C bond formation is different from that in the photolytically induced insertion of carbonyl compound to organic azirine. Methyl substituted isocyanide complex 14 containing a stereogenic carbon center was obtained by treatment of iodomethane with oxazolinyl complex 13. Complex 14 are determined by X-ray diffraction studies.
Subjects
亞乙烯基
二茂鐵
釕金
屬
雙核金
去質子化反應
Ferrocenyl
Vinylidene
Ruthenium
Bimetallic
Deprotonation
Type
thesis
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