Metallole

Metalloles are derivatives of cyclopentadiene in which the carbon atom at position 5, the saturated carbon, is replaced by an 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. 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

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