Metallole

Metalloles are 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 and are used in organic light-emitting diodes (OLEDs) and other applications. Metalloles, which can also be viewed as structural analogs of pyrrole, include:

Calculated geometry and inversion barrier energy E for some C₄H₄MH metalloles^[2]

Name	M	d(M-C), Å	d(M-H), Å	α(C-M-C), °	E, kJ/mol
Pyrrole	N	1.37	1.01	110	0
Phosphole	P	1.81	1.425	90.5	67
Arsole	As	1.94	1.53	86	125
Stibole	Sb	2.14	1.725	80.5	160
Bismole	Bi	2.24	1.82	78	220

• Arsole, a moderately-aromatic arsenic analog
• Bismole, a bismuth analog
• Borole, a boron analog
• Furan (oxole), an oxygen analog
• Gallole, a gallium analog
• Germole, a germanium analog
• Phosphole, a phosphorus analog
• Plumbole, a lead analog
• Pyrrole (azole), a nitrogen analog
• Selenophene, a selenium analog
• Silole, a silicon analog
• Stannole, a tin analog
• Stibole, an antimony analog
• Tellurophene, a tellurium analog
• Thiophene, a sulfur analog
• Titanacyclopentadiene, a titanium analog
• Zirconacyclopentadiene, a zirconium analog

References

1. 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. PMID 15762727.
2. 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: 6387. doi:10.1021/jp0203494.