7107. Pentacene

Nomenclature

CAS number: 135-48-8
Benzo[b]naphthacene; 2,3,6,7-dibenzoanthracene; lin-naphthoanthracene.
C22H14; mol wt 278.35.
C 94.93%, H 5.07%.

Description and references

Synthesis from m-xylene or from 4-benzyl-1,3-dimethylbenzene and benzoyl chloride in presence of aluminum chloride or from terephthalyl chloride and o-tolylmagnesium bromide: Clar, John, Ber. 62, 940 (1929); 63, 2967 (1930); 64, 981 (1931). Synthesis by reduction of 6,13-pentacenequinone: Bruckner et al., Tetrahedron Lett. 1960, no. 1, 5; Bruckner, Tomasz, Acta Chim. Acad. Sci. Hung. 28(4), 405 (1961). Structure: Campbell et al., Acta Crystallogr. 14, 705 (1961).

Chemical structure

Properties

Deep blue needles with violet luster from hot nitrobenzene. Sublimes in CO2 stream under reduced pressure at ≈300° (Clar, John, loc. cit.). In presence of air dec >300°. Practically insol in water; sparingly sol in organic solvents. Note: Anthracene (3 linear rings) is colorless; naphthacene (4 linear rings) is orange; pentacene (5 linear rings) is blue; hexacene (6 linear rings) is green.