Structural properties of a series of photochromic fluorinated indolylfulgides.

Fluorinated indolylfulgides are a class of photochromic organic compounds that meet many of the requirements for use as optical memory media and optical switches. The X-ray crystal structures of a series of five photochromic fluorinated indolylfulgides have been determined, namely (3Z)-3-[1-(1,2-dimethyl-1H-indol-3-yl)-2,2,2-trifluoroethylidene]-4-(1-methylethylidene)dihydrofuran-2,5-dione (trifluoromethylisopropylideneindolylfulgide), C(19)H(16)F(3)NO(3), (I), (3Z)-3-[1-(1,2-dimethyl-1H-indol-3-yl)-2,2,3,3,3-pentafluoropropylidene]-4-(1-methylethylidene)dihydrofuran-2,5-dione (pentafluoroethylisopropylideneindolylfulgide), C(20)H(16)F(5)NO(3), (II), (3Z)-3-[1-(1,2-dimethyl-1H-indol-3-yl)-2,2,3,3,4,4,4-heptafluorobutylidene]-4-(1-methylethylidene)dihydrofuran-2,5-dione (heptafluoropropylisopropylideneindolylfulgide), C(21)H(16)F(7)NO(3), (III), (3Z)-3-[1-(1,2-dimethyl-1H-indol-3-yl)-2,2,2-trifluoroethylidene]-4-(tricyclo[3.3.1.1(3,7)]decylidene)dihydrofuran-2,5-dione (trifluoromethyladamantylideneindolylfulgide), C(26)H(24)F(3)NO(3), (IV), and (3Z)-3-[1-(1,2-dimethyl-1H-indol-3-yl)-2,2,3,3,4,4,4-heptafluorobutylidene]-4-(tricyclo[3.3.1.1(3,7)]decylidene)dihydrofuran-2,5-dione (heptafluoropropyladamantylideneindolylfulgide), C(28)H(24)F(7)NO(3), (V). The photochromic property of fulgides is based on the photochemically allowed electrocyclic ring closure of a hexatriene system to form a cyclohexadiene. For each fulgide examined, the bond lengths within the hexatriene system alternate between short and long, as expected. Comparing the structures of the five fulgides with each other demonstrates no significant difference in bond lengths, bond angles or dihedral angles within the hexatriene systems. The distance between the bond-forming C atoms at each end of the hexatriene system does vary. Correlations of structural properties with optical properties are addressed.

Investigations of the Copper Bromide-2,2'-Dipyridyl System: Hydrothermal Synthesis and Structural Characterization of Molecular Cu(3)Br(4)(C(10)H(8)N(2))(2), One-Dimensional CuBr(2)(C(10)H(8)N(2)), and Two-Dimensional [Cu(2)(OH)(2)(C(10)H(8)N(2))(2)][Cu(4)Br(6)].

The hydrothermal reactions of CuBr(2), CuBr, and 2,2'-dipyridyl have resulted in the synthesis of three new compounds. Cu(3)Br(4)(C(10)H(8)N(2))(2) (1) is a molecular phase; CuBr(2)(C(10)H(8)N(2)) (2) is a one-dimensional chain structure; and [Cu(2)(OH)(2)(C(10)H(8)N(2))(2)][Cu(4)Br(6)] (3) crystallizes in a two-dimensional sheet structure. All three compounds were characterized by single-crystal X-ray diffraction. Crystal data for 1, triclinic, space group P&onemacr; (No. 2) with a = 10.604(2) Å, b = 11.642(2) Å, c = 11.688(2) Å, alpha = 61.965(5) degrees, beta = 68.965(5) degrees, gamma = 69.523(5) degrees, Z = 2; 2, monoclinic, space group C2/c (No. 15) with a = 16.766(4) Å, b = 9.287(2) Å, c = 7.392(2) Å, beta = 110.536(6) degrees, Z = 4; 3, monoclinic, space group P2(1)/n (No. 14) with a = 10.907(3) Å, b = 6.0677(13) Å, c = 21.620(5) Å, beta = 90.542(4) degrees, Z = 4.