Synthesis and mesomorphic properties of liquid crystals containing a perfluorinated segment via different linkers

Abstract

et al.. Synthesis and mesomorphic properties of liquid crystals containing a perfluorinated segment via different Abstract This study presents the synthesis and mesomorphic properties of a series of biphenyl benzoate liquid crystals carrying a perfluorinated segment, via three uncommon flexible linkers. In particular, a (E)-2-propenyloxy linker was used which was issued from an elegant regioselective dehydrohalogenation reaction. The remarkable microsegregation effect of the perfluorinated segment, led to the formation of highly stable untilted lamellar mesophases, including a specific SmE pseudo-B mesophase. For all mesophases, the molecular packing corresponds to a monolayer arrangement of the mesogenic parts and a partial intercalation of the perfluorinated chains. -heptadecafluoronon-2-enyl)oxy}-(1,1'biphenyl)-4-yl benzoate (4b). Yield: 83%: 1 H NMR( CDCl 3 ) δ 8.25 (d, 2H, J = 7.2 Hz), 7.5-7.7 (m, 7H), 7.25 (d, 2H, J = 8.7 Hz), 7.0 (d, 2H, J = 8.7 Hz), 6.66 (dtt, 1H, 3 J trans = 15.6 Hz, 4 J H-F = 2.1 Hz, CH=CH-CH 2 O, E enantiomer), 6.15 (dt, 1H, 3 J trans = 15.6 Hz, 3 J H-F = 12.6 Hz, CF 2 -CH=CH-, E enantiomer), 4.75 (m, 2H, -CH 2 O-). 13 C NMR (CDCl 3 ) δ(ppm) 165.2 (C=O), 157.4, 150.0, 138.4, 137.2 (t, 3

Fluorophobic Effect Promoting Lamellar Self‐Assembly of Donor Acceptor Dyes

“…Extrapolated layer spacings d ( T cl ) indicated a smectic A phase consisting of semibilayer aggregates (SmA d ) due to L mol < d ( T cl )<2 L mol . This packing model was also reported for other smectic liquid crystals with a terminal perfluorinated carbon chain segment . In Figure , a proposed model of the SmA d phase with interdigitating perfluorinated chain segments is shown.…”

Engineering On‐Surface Spin Crossover: Spin‐State Switching in a Self‐Assembled Film of Vacuum‐Sublimable Functional Molecule

“…Beyond the information directly extracted from the XRD patterns, the common lamellar structure of bulk sample and film can be scrutinized using a geometrical analysis . To do so, the geometrical features of the [Fe(H 2 B(pz) 2 ) 2 (C 12 ‐bpy)] complex have been modeled by extracting the density and crystallographic data of the constituent molecular entities, the [Fe(H 2 B(pz) 2 ) 2 (bpy)] SCO head and the dodecyl carboxylate tail, and compared with the molecular area A mol of the layer sequence, defined as the ratio of molecular volume V mol to lamellar thickness d . The volume contribution of the SCO head V head was found to range between 620 and 660 Å 3 , on the basis of the single crystal structure of the parent [Fe(H 2 B(pz) 2 ) 2 (bpy)] SCO complex without the dodecyl carboxylate tail and of reference partial volume data.…”

N-Cyanoimine as an electron-withdrawing functional group for organic semiconductors: example of dihydroindacenodithiophene positional isomers

“…2×18.5 Å 2 for two crystallized chains 79 and that a compact intercalated monolayer of chains is effectively formed in this case, whereas this threshold is not reached for the meta isomer meta-IDT(=NCN) 2 (A mol = 34.90 Å 2 ; σ c = 26-27 Å 2 ) and chains accordingly arrange in strongly tilted double-layers (Table 1). 80 Table 1 Structural parameters of the triclinic structures adopted by meta-and para-IDT(NCN) 2 in the single crystal state at -123°C, in the crude powder at 20°C and in the mesophase at 190°C, whereas indexation of the room temperature pattern of paraisomer failed, presumably due to coexistence of several modifications: a, b, c, α, β, γ, V, Z and ρ are the parameters, volume, number of molecules per cell and density of the triclinic lattices; d 001 and Z L are the cell periodicity along the sequence of molecular layers and the number of involved layers; A and Z A are the area of the sublattice formed by the lateral arrangement of molecules and the number of involved molecules. Indexation of the room temperature S/WAXS patterns performed in the crystalline powder state of meta-IDT(=NCN) 2 demonstrated the m a n u s c r i t p t same triclinic structure as in the single-crystal state, with only slight deviations of the lattice parameters due to thermal expansion (Table 1).…”