In organometallic chemistry, a flyover complex features two metals bridged by the fragment OC(RC=CR)<sub>2</sub>. Some flyover complexes are symmetrical and some are not.
Common examples are the iron carbonyl derivatives, which are typically air-stable, soluble in nonpolar solvents, and red-orange in color. These diiron complexes arise by the reaction of alkynes with iron carbonyls. Such reactions are known to generate many products, e.g. complexes of cyclopentadienones and para-quinones.
Some ferrole complexes react with tertiary phosphines to give the substituted flyover complex Fe<sub>2</sub>(CO)<sub>5</sub>(PR<sub>3</sub>)(C<sub>4</sub>R<sub>4</sub>CO). They insert alkynes en route to tropones (R<sub>6</sub>C<sub>7</sub>O).