Metalloles are metallacycle derivatives of cyclopentadiene in which the carbon atom at position 5, the saturated carbon, is replaced by a heteroatom. In contrast to its parent compound, the numbering of the metallole starts at the heteroatom. Some of these compounds are described as organometallic compounds, but in the list below quite a number of metalloids are present too.[1] Many metalloles are fluorescent. Polymeric derivatives of pyrrole and thiophene are of interest in molecular electronics.
Metalloles, which can also be viewed as structural analogs of pyrrole, include:
Calculated geometry and inversion barrier energy E for some C4H4MH metalloles[2]
^Tracy, Henry J.; Mullin, Jerome L.; Klooster, Wim T.; Martin, James A.; Haug, Judith; Wallace, Scott; Rudloe, Isaac; Watts, Kimberly (2005). "Enhanced Photoluminescence from Group 14 Metalloles in Aggregated and Solid Solutions". Inorganic Chemistry. 44 (6): 2003–2011. doi:10.1021/ic049034o. PMID15762727.
^Pelzer, Silke; Wichmann, Karin; Wesendrup, Ralf; Schwerdtfeger, Peter (2002). "Trends in Inversion Barriers IV. The Group 15 Analogous of Pyrrole". The Journal of Physical Chemistry A. 106 (26): 6387. Bibcode:2002JPCA..106.6387P. doi:10.1021/jp0203494.
^Dettlaf G, Weiss E (1976). "Kristallstruktur, 1H-NMR- und Massenspektrum von Tricarbonylferracyclopentadien-tricarbonyleisen, C4H4Fe2(CO)6" [Crystal Structure, Proton NMR and Mass Spectrum of Tricarbonylferracyclopentadienetricarbonyliron, C4H4Fe2(CO)6]. J. Organomet. Chem. 108: 213–23. doi:10.1016/S0022-328X(00)82143-9.