The structures of diisopropyl 9,9'-bifluorenylidene-1,1'-dicarboxylate and 9,9'-bifluorenylidene

Crystal and molecular structures of overcrowded halogenated compounds. IX. Stereochemistry of molecules containing the perchlorofluorenyl and perchlorofluorenylidene moieties and of their hydrogen analogues

“…10); steric distortion of the fluorenylidene moieties was ascribed to interactions between hydrogens attached to C(1), C(16) and C(10), C(25). Similar geometrical results were reported for diisopropyl 9,9'-bifluorenylidene-l,l'-dicarboxylate (Bailey & Hull, 1978). phenanthren-4-ylidene has a shape similar to that of bifluorenylidene but with a twist angle (about the ethylenic bond) of 31 ° (Stezowski, Hildenbrand, Suissa & Agranat, 1989).…”

“…The third group contains the compounds 9,9'-bifluorenylidene [in two polymorphic forms and as 2:1 complexes with pyrene and perylene (Lee & Nyburg, 1985)], diisopropyl-9,9'-bifluorenylidene-1,1'-dicarboxylate (Bailey & Hull, 1978) and hexadecachloro-9,9'-bifluorenylidene [for synthesis see * Tables 1, 2 ,4,5,7 and 8,and Fig. 7 Ballester et al, 1985)] as its 2:1 complex with tetrachloroethylene (Molins & Miravitlles, 1990).…”

Refinement of the α-modification of 9,9'-bifluorenylidene, C26H16, and structure analyses of the β-modification, the 2:1 pyrene complex, 2(C26H16).C16H10, and the 2:1 perylene complex, 2(C26H16).C20H12

“…Nyburg (1954), using Fenimore's phased data, calculated electron density sections in the neighborhood of C atoms 1 and 8 and concluded that the molecule was doubly bent, C(A 1), C(A8) being on one side of the mean molecular plane, C(B1), C(B8) on the other. This has since been shown by Bailey & Hull, (1978) The structure analysis of B & H was based on visually estimated photographic data and thus, not surprisingly, was of limited accuracy. We report here structure analyses of fl-BFL, 2/1 BFL complexes with pyrene and with perylene and a refinement of ct-BFL based on diffractometer intensity data.…”

Selenium- and tellurium-bridged heteromerous overcrowded bistricyclic aromatic enes with central six-member and seven-member rings

“…The principal mode of deviation from planarity is dependent on the sizes of the central rings and on the bridges X, Y (bond lengths C-X and C-Y, distances C 4a ÁÁÁC 10a ) [10,11]. A variety of conformations have been revealed in the homomerous bistricyclic enes [5], including twisted (t) bifluorenylidene (2) [12,13], anti-folded (af) dixanthylene (3) [14,15], anti-folded (af) bianthrone (4) [1,[16][17][18][19], and anti-folded (af) and syn-folded (sf) 5,5 0 -bi-(5H-dibenzo[a,d]cyclohepten-5-ylidene) (5) [20]. A major attraction of BAEs is attributed to their thermochromic, photochromic, electrochromic, and piezochromic behavior and to their rich dynamic stereochemistry [5].…”