Preparation of multinuclear Ruthenium Vinylidene Complexes and Their Deprotonation Reactions

• Main Authors: Chung-Wei Liu, 劉中偉
• Other Authors: 林英智
• Format: Others
• Language: en_US
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/17152775044433618155

碩士 === 國立臺灣大學 === 化學研究所 === 94 === Treatment of [Ru]-Cl, [Ru] = CpRu(PEt3)2, with phenylacetylene in the presence of KPF6 in methanol affords [Ru]=C=C(H)Ph+ (2) and then deprotonation of 2 by MeONa yields complex [Ru]-C≡C-Ph (3) isolated as yellow solid in high yield. Reactions of 3 with various organic halides in the presence of KPF6 yield corresponding air stable cationic vinylidene complexes [Ru]=C=C(Ph)CH2R+ (4a, R = CH=CH2; 4b, R = CN; 4c, R = C≡CH; 4d, R = CO2Me; 4e, C≡C(SiMe3); 4f, R = Ph; 4g, R = COOEt), respectively, all in high yield. Deprotonation of mononuclear cationic vinylidene complexes of ruthenium [Ru]=C=C(Ph)CH2R (4a, R = CH=CH2, 4b, R = CN, 4f, R = Ph) yields corresponding cyclopropenyl complexes [Ru]-C=C(Ph)CHR (5a, R = CH=CH2, 5b, R = CN, 5f, R = Ph) in high yield. The neutral ruthenium furyl complexes [Ru]-C=C(Ph)CH=C(O)OR, (6d, R = Me; 6g, R = Et) are also prepared by deprotonation of corresponding ruthenium vinylidene complexes containing an ester group at Cγ. Reaction of the terminal alkynyl group of 4c with [Ru’]-Cl in the presence of KPF6 affords the bisvinylidene complexes [Ru]=C=C(Ph)CH2C(H)=C=[Ru’], (7w, [Ru’] = CpR (PEt3)2; 7x, [Ru’] = CpRu(PPh3)2) which deprotonated to give the alkynyl,vinylidene complexes [Ru]=C=C(Ph)CH2C≡C-[Ru’], (8w, [Ru’] = CpRu(PEt3)2; 8x, [Ru’] = CpRu(PPh3)2 in the presence of base. Alkylation of complex 8w with various primary alkyl halide affords the corresponding cationic ruthenium bisvinylidene complexes[Ru]=C=C(Ph)CH2C(CH2R)=C=[Ru’], ([Ru’] = CpRu(PEt3)2; 9w, R = CH=CH2; 10w, R = CN; 11w, R = C≡CH; 12w, R = CO2Me; 13w, R = COOEt; 14w, R = Ph; 15w, R = C≡C(SiMe3)). Complexes 9x, 10x, 11x, 12x, 13x, 15x are also successfully obtained by the same synthetic strategy. Deprotonation of the dinuclear dicationic vinylidene complex {[Ru]=C=C(Ph)CH2C(CH2CN)=C=[Ru’]}2+ (10w) by n-Bu4NOH is also followed by a cyclization process, however, yielding the distinctive stable complex 16w containing a five-membered carbocyclic ring ligand which is fully characterized by 2D-NMR analysis and single crystal X-ray diffraction analysis. Deprotonation of {[Ru]=C=C(Ph)CH2C(CH2COOEt)=C=[Ru’]}2+ (13w) similarly gave the stable product 17w containing a bridging ligand also with the same five-membered carbocyclic ring. Interestingly, analogous dinuclear complex 16x with bistriphenylphosphine ligand on one metal, which is prepared in a similar manner from {[Ru]=C=C(Ph)CH2C(CH2CN)=C=[Ru’]}2+ (10x), however, is unstable undergoing isomerization to give the dinuclear complex 18x containing cyclopropenyl ligand. The reaction of 11w with [Ru”]-Cl, [Ru”] = CpRu(PEt3 2, gives the trinuclear trisvinylidene complex 21 which undergoes deprotonation to give the trinuclear bisvinylidene acetylide complex 22 characterized by spectroscopic method. Treatment of complex 1 with 1,1 diphenyl-2-propyn-1-ol yields the cationic ruthenium allenylidene complex [Ru]=C=C=C(Ph)2+, (30, [Ru] = CpRu(PEt3)2), in high yield which reacts with Grignard reagent RCH2MgBr in THF affords the neutral ruthenium acetylide complexes [Ru]-C≡C-C(Ph)2CH2R, (31a, R = CH=CH2; 31b, R = C≡CH). Complexes 30 undergo protonation reactions giving the corresponding vunylidene complexes [Ru]=C=C(H)-C(Ph)2CH2R+, (32a, R = CH=CH2; 32b, R = C≡CH). Unfortunately, no transformation of complexes 32 in solution is observed indicating the reactivity of complexes 32a and 32b is different from that reported previously. A number of cationic ruthenium isocyanide complexes [Ru]-CNCH2R+, ([Ru] = CpRu(PEt3)2; 41a, R = Ph; 41b, R = C≡CH) are prepared by alkylation of Ru cyano complex 40 with corresponding alkyl halide. Treatment of complex 41a with base in acetone cause the formation of ruthenium oxazolinyl complex Cp(PEt3)2RuCNCH(Ph)C(Me)2O (43). Complex 41a also reacts with benzaldehyde in CH2Cl2 to afford another ruthenium oxazolinyl complex Cp(PEt3)2RuCNCH(Ph)C(Ph)HO (44).