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Department of Physics

Staff profile

Publication details for Professor Stewart Clark

Smith, C.E., Smith, P.S., Thomas, R.L., Robins, E.G., Collings, J.C., Dai, C.Y., Scott, A.J., Borwick, S., Batsanov, A.S., Watt, S.W., Clark, S.J., Viney, C., Howard, J.A.K., Clegg, W. & Marder, T.B. (2004). Arene-perfluoroarene interactions in crystal engineering: structural preferences in polyfluorinated tolans. Journal of Materials Chemistry 14(3): 413-420.

Author(s) from Durham

Abstract

The compounds 4-ROC6F4C[triple bond, length as m-dash]CPh (4) where R = Me (a), Et (b), Prn (c), Pri (d), Bun (e), n-C5H11 (f), PhCH2 (g), PhCH2CH2 (h), 4-MeC6H4 (i), 4-EtC6H4 (j) and menthyl (k), have been prepared by reaction of C6F5C[triple bond, length as m-dash]CPh (3) with ROH in the presence of KOH, and characterised by NMR (1H, 13C, 19F) and mass spectroscopy. The single-crystal structures of PhC[triple bond, length as m-dash]CPh·C6F5C[triple bond, length as m-dash]CC6F5 (1∶2), 3 and 4a,c,d,f,g,i have been determined by X-ray diffraction at 120–160 K, and that of 3 also calculated by an ab initio pseudo-potential DFT method. The tolan moiety is nearly planar in each molecule except 4a, which has a Ph/C6F5 dihedral angle of 25.8°. The R group adopts an out-of-plane orientation except in 4f, where the n-pentyl chain is nearly coplanar with the C6F5 group at the cost of severe distortion of the C(ar)–C(ar)–O angles (which differ by 13.5°). The structures of 1∶2, 3 (pseudo-isomorphous with 1∶2), 4a, 4g (disordered) and 4i contain stacks of alternating arene and perfluoroarene moieties; 4c and 4d form discrete centrosymmetric dimers with arene/perfluoroarene overlap, while 4f forms infinite stacks without such overlap. Differential thermal analysis and transmitted polarised light microscopy revealed no liquid-crystalline behaviour of 3 and 4.

Notes

ISI:000188492100023