SYNTHESIS OF LINEAR ACETYLENIC CARBON - THE SP CARBON ALLOTROPE

A carbon allotrope based on ''sp'' hybridization containing alternatin g triple and single bonds (an acetylenic or linear carbon allotrope) h as been prepared. Studies of small (8 to 28 carbon atoms) acetylenic c arbon model compounds show that such species are quite stable (130 deg rees to 140 degrees C) provided that nonreactive terminal groups or en d caps (such as tert-butyl or trifluoromethyl) are present to stabiliz e these molecules against further reactions. In the presence of end ca pping groups, laser-based synthetic techniques similar to those normal ly used to generate fullerenes, produce thermally stable acetylenic ca rbon species capped with trifluoromethyl or nitrile groups with chain lengths in excess of 300 carbon atoms. Under these conditions, only a negligible quantity of fullerenes is produced. Acetylenic carbon compo unds are not particularly moisture or oxygen sensitive but are moderat ely light sensitive.