A carbon allotrope based on "sp" hybridization containing alternating triple and single bonds (an acetylenic or linear carbon allotrope) has been prepared. Studies of small (8 to 28 carbon atoms) acetylenic carbon model compounds show that such species are quite stable (130 degrees to 140 degrees C) provided that nonreactive terminal groups or end caps (such as tert-butyl or trifluoromethyl) are present to stabilize these molecules against further reactions. In the presence of end capping groups, laser-based synthetic techniques similar to those normally used to generate fullerenes, produce thermally stable acetylenic carbon 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 compounds are not particularly moisture or oxygen sensitive but are moderately light sensitive.

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COMMUNlCATlONSpolymerization of r-maltosyl fluoride with a-amylase as cata-Keywords: a-amylase assay chemoenzymatic syntheses l y~t .~'~] Under these conditions I1 was obtained in 78% yield enzymes . fluorescence . oligosaccharides -(determined by HPLC, 59 YO isolated yield). The epimerization at the 4'-position in the formation of 4 is beneficial for two reasons. Firstly, 7 is accepted by the a-amylase as a donor, but neither 7 nor 11 are acceptors because of the axial 4-OH at the nonreducing end unit. Therefore only one disaccharide is added and 11 is obtained in good yield. Secondly, the nonreducing galactosyl residue at the C-6 position in I1 can be oxidized regiospecifically by the galactose oxidase/catalase system to give aldehyde 12.1'4J In the final step the EDANS group can be introduced by reductive amination, giving 1 in 54% isolated yield ( Table 1 ) .The intramolecular fluorescence quenching in 1 was demonstrated in preliminary experiments at concentrations of 10 p~. When 1 was excited at 290 nm, the EDANS fluorescence emitted at 490 nm was 12 times more intense than that of free EDANS. We also detected a fivefold decrease in the intensity of the indolylethyl emission at 345 nm. At this concentration we can assume that variation of fluorescence intensity due to collisional quenching is negligible. In fact a 2% increase in fluorescence intensity at 490 nm was observed for solutions of free EDANS with indolylethylpentasaccharide 11 when the EDANS concentration was increased from 10 to 20pM.When a 5 p~ solution of 1 was incubated with PPA, the intensity of the fluorescence at 490 nm decreased rapidly. After 6 min the substrate was completely hydrolyzed (Fig. 1). At this stage, a) D. French in Eiochemistry nf Curhohjdrufrs, Serie one, V d . 5 (Ed. W. J.

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