0th and 1st generation organometallic nanostars from ferrocenylamine and ferrocenylaniline /

Abstract

Covalently bonded organometallic oligomers and polymers have been designed to have rigid and thermally and chemically stable organometallic repeating units such as [trans-Mo(phJ>CH2CH2Ph2h(j.t-CN-l,4-C6f4-NC)]. In the first step towards such materials, the chemical and electronic properties of model compounds with only one or a few metal centers will be investigated. Putting electrochemical "sensors" (e.g., ferrocenyl isocyanide or para-isocyanoferrocenylbenzene) at one or more ends of the oligomers, will give information pertaining to the electronic communication via the metal centers. Ferrocenylamine is the essential starting material for the synthesis of ferrocenyl isocyanide. The main drawback for the synthesis of ferrocenylamine is its multistage preparation. It has been found that the conventional methods of electrophilic substitution, which were appropriate for benzene analogues, resulted in the oxidation of the ferrocene to the ferricenium cation. A procedure using ferrocenylphthalimide as the precursor proved to be most successful. Bromo- or iodoferrocene were prepared as a precursor of N-ferrocenylphthalimide; the amine is then liberated using the Gabriel method. The electronic properties of the CN-R function can be altered by the nature of the various alkyl and aryl substituents. Using cyclic voltammetry, the oxidation potentials of the molybdenum or nickel centers having ferrocenylisonitrile ends will be determined depending on other substituents on the molecules. These substituents, in addition to chelating phosphines, include other isonitriles such as p-isocyanotetramethylbenzene, panisole, p-nitrobenzene, p-ferrocenylbenzene, and ferrocene.