Studies On Design Synthesis And Electrochemical Property Of New Ferrocenyl Indenyl Metllocene Ligands

The indene C₉H₈ compound is a cyclopentadienyl benzo compound,which can form a six electron coordinated isoelectronic species with a cyclopentadienyl group.At the same time,the benzene ring from indene can also be coordinated to metal to form a half sandwich complex or a sandwich metllocene.Therefore,indenyl has many coordination forms and it is an important ligand for establishing metal complex and metllocene.Since the advent of ferrocene in 1951,more and more attentions have been attracted to the research of the ferrocene derivatives,because of its unique sandwich structure and redox property.Ferrocenyl indenyl derivatives combine the advantages of ferrocenyl and indenyl group.Therefore,new metllocenes will be designed and synthesized according to the advantages of ferrocenyl and indenyl group,and it is expected that new metllocenes have a more attractive application prospect on the photoelectric performance.On the basis of the previous works of our group,in this dissertation,a series of new ferrocenyl indenyl derivatives were designed and synthesized,and their electrochemical properties were studied.Our works lay the material foundation for further design and synthesis of metal complexes and metllocene with photoelectric function.The main works in the dissertation are as follows:I.Preparation of reactive raw materials1. According tothe literature method,the ferrocenyl lithium and tetramethyl ethylenediamine complex as an intermediate product was obtained by stirring overnight at room temperature using ferrocene and n-butyl lithium as reaction materials,N,N,N,N-tetramethyl ethylenediamine as protective agent.The reaction flask was cooled to-78?,then iodine was add into the reaction flask which was naturally rised to room temperature.The reaction solution continue to react for 2h,and the product 1,1'-diiodineferrocene and by-product 1,1''-diiodinediferrocene were obtained.2.According to the literature method,using trimethylsilylacetylene and2-bromoindene as reaction materials,bis?triphenylphosphine?palladium?II?dichloride and cuprous iodide as catalyst and triethylamine as solvent,the coupling product trimethylsilylacetylene indene was synthesized by refluxing reaction solution for 8h at50?.2-Acetylenyl indene was obtained by the hydrolysis of trimethylsilylacetylene indene at room temperature using anhydrous potassium carbonate as alkaline additive and methanol as solvent.II.Design and synthesis of new ferrocenyl indenyl metllocene ligands1. Using sonogashira coupling reaction,1,1'-diiodineferrocene and 2-acetylene indene as reaction materials,and bis?triphenylphosphine?palladium?II?dichloride and copper acetate monohydrate as catalyst,and diisopropylamine as solvent,new ferrocenyl indenylmetlloceneligandsI-C₅H₄Fe C₅H₄-C?C-Ind?1?and Ind-C?C-C₅H₄Fe C₅H₄-C?C-Ind?2?were synthesized by refluxing reaction solution for 4h at 86?.2.Under the same reaction conditions,using sonogashira coupling reaction,1,1''-diiodinediferrocene and 2-acetylene indene as reaction materials,new ferrocenyl indenylmetlloceneligandsI-C₅H₄Fe C₅H₄-C₅H₄Fe C₅H₄-C?C-Ind?3?and Ind-C?C-C₅H₄Fe C₅H₄-C₅H₄Fe C₅H₄-C?C-Ind?4?were synthesized.3.Using sonogashira coupling reaction,1,1'-diiodineferrocene and ethynylferrocene as reaction materials,and bis?triphenylphosphine?palladium?II?dichloride and copper acetate monohydrate as catalyst,and diisopropylamine as solvent,new ferrocenyl indenyl metllocene ligand Fc-C?C-C₅H₄Fe C₅H₄-C?C-Ind?5?was synthesized by refluxing reaction solution for 4h at 86?.4.Under the same reaction conditions,using sonogashira coupling reaction,1,1''-diiodinediferrocene and ethynylferrocene as reaction materials,new ferrocenyl indenyl metllocene ligands HC?C-C₅H₄Fe C₅H₄-C₅H₄Fe C₅H₄-C?C-Ind?6?and Fc-C?C-C₅H₄Fe C₅H₄-C₅H₄Fe C₅H₄-C?C-Ind?7?andself-couplingproduct Fc-C?C-C?C-Fc were synthesized.III.An attempt to prepare indenyl iron metlloceneThe material 1,1'-diiodineferrocene?0.5 mmol?and solvent tetrahydrofuran?10 m L?were added into the reaction flask at room temperature,then the reaction solution was cooling to-80?.The n-butyllithium?0.5 mmol?was added into the reaction flask which was stirred for 15min at-80?,then naturally raised to room temperature for 5h.Anhydrous ferric chloride?0.25 mmol?was sequentially added to the reaction flask at room temperature and the reaction solution was stirred at room temperature for 16 h.Unexpectedly,indenyl iron metllocene had not been synthesized,but a new metllocene ligand Fc-C?C-?3-C₄H₉?Ind?8?and a known compound Fc-C?C-Ind were separated.IV.The electrochemical properties of new compounds 1-8The electrochemical properties of eight new ferrocenyl indenyl metllocene ligands 1-8were studied by cyclic voltammetry?CV?method.The results show the oxidation potential of the single ferrocenyl indenyl derivatives 1,2 and 8 with the symmetric and asymmetric conjugated substituent is increased,which means their oxidation is more difficult.Compared with diferrocene,the electron communication between two ferrocenyl units of the diferrocene derivatives 3,4 is basicly not affected by their substituent groups.The electron communication between two ferrocenyl units of compound 6 with asymmetric conjugated ethynyl and indenyl ethynyl substituents is obviously weakened.The electron communication between two ferrocenyl groups bridged by ethynyl unit in the substituted ferrocenyl indenyl derivatives 5 is also weakened by the effect of distance between two metals.The electron communication?E₂₁?V?between two ferrocenyl groups bridged by ethynyl unit in tri-ferrocenyl indenyl derivatives 7 is less than that?E₃₂?V?between diferrocenyl units.