Studies On The Properties And Applications Of Cyclometallated Ferrocenylimines

In this thesis, the properties and applications of cyclometallated ferrocenylimines were studied in the following two aspects.I Applications of cyclopalladated ferrocenylimines as catalysts in a wide range of useful and well-known C-C coupling processes such as Suzuki, Heck reactions and dimerization of arylmercuric chlorides.The Suzuki reaction1 Initially, we performed a brief solvent / base optimization for the cross-coupling of bromobenzene with phenylboronic acid and the best results were obtained at 140℃ with potassium phosphate in DMF (Scheme 1).Scheme 12 Under the optimized conditions, the catalytic activities of catalyst 1 towards different aryl halides and arylboronic acids were studied (Scheme 2). The results showed that cyclopalladated ferrocenylimine 1 could catalyze the coupling of a wide range of aryl halides and arylboronic acids efficiently under mild conditions without protection of inert gases. Upon completion of the reaction, good to excellent yields and higher turnover numbers were obtained whatever substituent effect the arylhalides or arylboronic acids behave. The highest turnover numbers obtained for arylbromides and arylchlorides were 9.99 × 104 and 9.06 ×104, respectively.ArX:a. C6H5Br g. 4-CH3OC6H4Brb. 4-NO2C6H4Br h. 4-NO2C6H4Clc. 4-CF3C6H4Br i. 3-NO2C6H4Cld. 4-CNC6H4Br j. 3-CF3C6H4Cle. 4-CH3COC6H4Br k. 4-CH3COC6H4Clf. 4-ClC6H4Br 1. 2,4-(NO2)2C6H3ClAr' = C6H5j2-CH3C6H4)3-CH3C6H4,4-CH3C6H4,Scheme 23 Cyclopalladated ferrocenylimines 1~6 were applied to the Suzuki reaction of jp-BrC6H4COCH3 withjp-CH3C6H4B(OH)2 (Scheme 3). All of them could catalyze the coupling efficiently and the yields were not significantly influenced by whatever substituent the N-phenyl ring and the imino carbon bearing. The mechanism was proposed.Fig. 1 Proposed mechanism for Suzuki reaction catalyzed by cyclopalladated ferrocenyliminesThe dimerization of arylmercuric chlorides4 The catalytic activities of cyclopalladated ferrocenylimines 1, 7 and 8 towards dimerization of arylmercuric chlorides were studied (Scheme 4). The results showed that dimerization of arylmercuric chlorides could proceed using a catalytic amount of cyclopalladated ferrocenylimines 1 or 7 under mild conditions, affording a variety of biaryls in moderate to excellent yields. Even ortho-substituted phenylmercuric chlorides and a-naphthylmercuric chloride, which could not be catalytically dimerized by rhodium salt, are applicable to this reaction. The best results were obtained with 0.025 (molar fraction) 1 in the presence of 2.0 equiv. of LiClinHMPA at 80℃.The Heck reaction in neat water5 Cyclopalladated ferrocenylimine 7 was applied to the Heck reaction in neat water. Some commercial surfactants, including the commonly used quaternary ammonium salts, have been proved well to excellent in promoting the reaction. Similar to Heck reactions in organic solvents, EtsN and NaOAc were proved to be the best bases in neat water among the various bases examined (Scheme 5).Scheme 56 The Heck reactions of aryliodides, arylbromides with different olefms in neat water were studied. It was found that catalyst 7 could catalyze the Heck reactions of a wide range of substrate with the characteristics of high efficiency and convenience of operation, which make it an excellent kind of practical catalyst for Heck coupling reaction in neat water.X= I,R = H,CH3,C1)R' = CO2Bu , CO2Me, CO2Et, CONH2 , PhX = Br , R = NO2, CN R' = CO2EtScheme 67 The emulsions were characterized to be O / W type by the use of dyeing method. Fig. 2 shows the microphotograph of triton X-100 with rhodium B. The optimized amount of the emulsifying agents was determined via surface tension ^ concentration curve (Fig. 3).Fig.2 Microphotograph of triton X-100 with Rhodium BFig.3 Surface Tension Concentration of Tween60(%)11II Transmetallation reaction of optically active cyclometallated ferrocenylimines with metallic mercury, tin...