Organometallic dendrimers based on (tetraphenylcyclobutadiene)cyclopentadienylcobalt modules.
The synthesis and characterization of novel organometallic polyphenylene dendrimers containing 24 or 44 phenyl rings and one cyclobutadiene(cyclopentadienyl)cobalt unit is reported. The dendrimers are made by the convergent CpCo(CO)(2)-mediated dimerization of di- or tetraethynyltolanes followed by a divergent core extension utilizing tetraphenylcyclopentadienone. The obtained dendrimers are air and water stable, soluble materials that show interesting differences in their hydrodynamic properties as evidenced by gel permeation chromatography. Scanning pulse voltammetry in solution shows that the dendrimers are oxidized at potentials ranging from 0.8 to 0.83 V. The more sterically encumbered the dendrimer, the higher its oxidation potential, that is, the more difficult oxidation is.
Department of Chemistry and Biochemistry, The University of South Carolina, Columbia, South Carolina 29208, USA.
Shane M
SM
Waybright
Kanika
K
McAlpine
Matthew
M
Laskoski
Mark D
MD
Smith
Uwe H F
UH
Bunz