Synthesis and polymerization of a four-arm star with pendent cyclopentadienyliron moieties

The synthesis of the title complex was achieved via the reaction of a eta(6)-p-dichlorobenzene-eta(5)- cyclopentadienyliron cation with an organic four-arm core to produce the tetrairon complex. This tetrairon-containing core was subsequently polymerized via nucleophilic aromatic substitution with various dinucelophiles such as 4,4'-thiobenzenethiol, bisphenol-A, 4,4'-(1-phenylethylidene) bisphenol, 4,4'-biphenol, bis(4-hydroxyphenyl) methane, producing five different cross-linked cationic organoiron polymers. Another cross-linked polymer was produced via direct polymerization of the four-arm organic core with the eta(6)-p-dichlorobenzene-eta(5)-cyclopentadienyliron cation. Due to the poor solubility of these cross-linked polymers, solid-state C-13 CPMAS NMR was performed in order to verify that polymerization was successful. Thermogravimetric analysis (TGA) revealed that following the decoordination of the cyclopentadienyliron moieties, the polymers were thermally stable. Differential scanning calorimetry (DSC) showed that the polymers exhibited glass transition temperatures (T-g' s) ranging from 104 to 146 degrees C.