Structure of anthra[9,1-cd:10,5-d'd']bis[1,2]-diselenole (TSA) and of its partially oxidized, metallic polyiodide TSA I1.2

Abstract

Tetraselenaanthracene' (TSA), C 14H6Se4' M r = 490·04, crystallizes in the monoclinic space group P2 1/n with a = 9·318 (3), b = 4·111 (1), c = 16·035 (4) A,β = 90·43 (2)°, V = 614·3 A3, Z = 2, d c = 2·65 Mg m-3• R = 0·030 for 1039 observed reflections. The planar molecules form stacks along b with an interplanar separation of 3·59 A. The normals to the molecular planes are inclined at 29° to the stacking axis. Short intermolecular Se-Se contacts exist between adjacent stacks, the shortest one being 3·467 (1) A. 'Tetraselenaanthracenium iodide' (TSA I 1.2), C14H6I 1.20Se4' Mr = 642·32, is monoclinic, P2 1/c, with a = 18·644 (12), b = 3·856 (2), c = 19·746(12)A,β= 93.36 (5)0,.V= 1417·1A3, dc = 3·01 Mg m-3• R = 0·118 for 1080 observed reflections.