Synthesis,Characterization And Electrochemical Behavior Of 1,1'-Ferrocene-Based Molecular Wires

As silicon-based semiconductors reach the limit of size,traditional electronic devices are faced with enormous challenges.The development of molecular-level molecular electronic devices has become a hot topic of research.One of aim is to assemble molecular materials with specific functions into sub-conductors.Molecular wires are the key to molecular circuits who can transfer energy and information through electron transfer.They are bridges between information exchange between molecular devices and the outside.Among them,the metal organic molecular wires consist of an electroactive transition metal complex and an organic conjugated bridge ligand,which modify,assemble,and trim the metal organic molecules,and can change the metal ligand's peripheral ligands and metal oxidation states to be fine.Regulates the nature of electrons in molecular wires.Ferrocene structure is easily modified,has good thermal stability,has reversible redox activity,and can undergo reversible single-electron oxidation processes in most common solvents.Therefore,it is widely used in molecular electronics research.In this paper,ferrocene radicals are used as bridging ligands.Hetero-nuclear bimetallic and trimetallic organic molecular wires with transition metal ruthenium as the active site of terminal metals and ferrocenes with pyridyl as terminal anchoring groups are mainly synthesized.Electroactive molecular wires have systematically examined the effect of ferrocene as a bridging ligand on the electronic transmission of molecular wires.The specific research contents are as follows:1.In order to study the influence of end group hydrazine ligand units on the electron transport of ferrocene as a bridging ligand for metal-organic molecules,the second chapter mainly designed and synthesized the monosubstituted hydrazine ligands of 1,1'-site ferrocene(a heteronuclear bimetallic organic molecular wire)and a 1,1'-disubstituted fluorene complex(trinuclear metal organic molecular wire)and confirmed by NMR(1H?13C?31P)and X-ray single crystal diffraction,The electrochemical properties were characterized by using electrochemical techniques(CV and SWV)and spectroscopic techniques(ultraviolet-visible spectroscopy,in-situ UV-Vis-NIR-IR and chemical oxidation infrared spectroscopy).The results show that:(1)There is a distinct continuous three-step electron-lost-electron oxidation process of the biguanide compounds in the cyclic voltammograms,which indicates that there exists electronic communication between the two metal centers at the two ends through the bridged ferrocene groups;(2)After ferrocene is oxidized and one electron is lost,most of the charge is localized on ferrocene,and the minority segregation domain is on the entire molecular wire.The double fluorene complex has better conjugate than single fluorene.2.In order to deeply compare the difference in the conjugated bridge hybrid orbital and the effect of the ferrocene embedded in the active metal center ferrocene on the conductance of pure organic molecules,the third chapter has designed and synthesized 1,1'-ferrocene derivatives that uses pyridine as an end group anchor group.1,1'-ferrocene and pyridine pass through a carbon-carbon triple bond(sp hybrid),a double bond(sp2 hybrid),a single bond(sp3 hybrid)connected molecular leads,and a pyridine having no ferrocene group.Base non-electroactive molecular wires connected directly through carbon-carbon triple bonds,double bonds,and single bonds.All the final products were confirmed by 1H NMR,13C NMR and MS.The electrochemical behaviors and surface electrochemical behaviors of ferrocene pyridine molecular wires were studied using CV technology and self-assembled monolayer membrane technology.The STM-BJ technology was used to construct the single Molecular conductance measures the conductance of different compounds.The results show that:(1)The difference in the hybrid orbits of the conjugated bridge will affect the charge transfer;(2)The insertion of ferrocene groups in the molecule can enhance the single molecule conductance of the molecular line.