Condensation of aromatic and heterocyclic aldehydes with benzenediacetonitriles

Abstract

The values 1437 and 3031 cm.-1 were used twice, for a total of 14 wavenumbers.The first three values in this list (below 600 cm.-1) were taken from Crowder (2), and the remaining values were taken from Moritz (6). The methyl thiocyanate molecule has seven atoms and therefore has 15 fundamental vibrational frequencies. Vapor state infrared frequencies are available for all 15 except for the methyl torsion, for which no experimental value is available, and the symmetric C-S-C stretch, for which the liquid state value is available. However, the methyl torsional frequency is not needed for calculation of the thermodynamic functions because the barrier to internal rotation has been determined from the microwave spectrum. Also, it is unlikely that the vapor state frequency for the C-S-C stretch would differ enough from the liquid state value of 674 cm.-1 to affect the calculated thermodynamic properties appreciably, especially at the lower temperatures.

Self‐Assembled α‐Cyanostilbenes for Advanced Functional Materials

“…In the latter case, an attractive variety of liquid crystalline organizations has been obtained to date. With a focus on classical liquid crystals, nematic[10,12,14d,101] and smectic[10,12,14b,d,101b,g,102] mesophases from typical rod‐like molecules, as well as columnar liquid crystalline organizations with different molecular designs, have been described. Both low molecular weight compounds and macromolecules (homopolymers,[101d,e,102a] homopolymers doped with a CS‐LC,[101o] copolymers, or even H‐bonded supramolecular polymers)[101j,105] have been used with success.…”

“…With a focus on classical liquid crystals, nematic[10,12,14d,101] and smectic[10,12,14b,d,101b,g,102] mesophases from typical rod‐like molecules, as well as columnar liquid crystalline organizations with different molecular designs, have been described. Both low molecular weight compounds and macromolecules (homopolymers,[101d,e,102a] homopolymers doped with a CS‐LC,[101o] copolymers, or even H‐bonded supramolecular polymers)[101j,105] have been used with success. On following common liquid crystal molecular design trends, CS[101f,102b] or DCS[10,12,14b,d,101a,n] structures with a reduced number of terminal flexible chains (alkoxy‐ or alkyl‐tails) as lateral substituents or combined with amino,[102c,106] carboxylic acid, or ester groups have allowed the synthesis of rod‐like molecules that form nematic or smectic phases.…”

“…Both low molecular weight compounds and macromolecules (homopolymers,[101d,e,102a] homopolymers doped with a CS‐LC,[101o] copolymers, or even H‐bonded supramolecular polymers)[101j,105] have been used with success. On following common liquid crystal molecular design trends, CS[101f,102b] or DCS[10,12,14b,d,101a,n] structures with a reduced number of terminal flexible chains (alkoxy‐ or alkyl‐tails) as lateral substituents or combined with amino,[102c,106] carboxylic acid, or ester groups have allowed the synthesis of rod‐like molecules that form nematic or smectic phases. However, it should be noted that CSs with less common molecular structures, such as six‐arm star‐shaped cyclotriphosphazenes,[101k,l] dimers,[101c,g–i,102d] or even carbazole derivatives,[37a] assembled in a similar manner to give calamitic mesophases.…”

“…On following common liquid crystal molecular design trends, CS[101f,102b] or DCS[10,12,14b,d,101a,n] structures with a reduced number of terminal flexible chains (alkoxy‐ or alkyl‐tails) as lateral substituents or combined with amino,[102c,106] carboxylic acid, or ester groups have allowed the synthesis of rod‐like molecules that form nematic or smectic phases. However, it should be noted that CSs with less common molecular structures, such as six‐arm star‐shaped cyclotriphosphazenes,[101k,l] dimers,[101c,g–i,102d] or even carbazole derivatives,[37a] assembled in a similar manner to give calamitic mesophases. On the other hand, more crowded CS[103b] and DCS[103a] structures surrounded by six alkoxy chains or incorporating one or two cyanostilbene moieties as a side chain[103c] on a triphenylene core are able to induce columnar mesophases by filling space.…”

“…Subsequent results on CS‐LCs have opened up new and attractive prospects for interesting applications. For example, different CS‐based liquid crystal materials have been proposed for photonic band‐edge laser devices by using DCS as dyes in a chiral nematic phase[101n] or for light‐emitting liquid crystal displays based on LC matrices doped with CS and DCS. [100d,104,105] Furthermore, nematic liquid crystalline elastomer microactuators[100b] that showed simultaneous thermomechanical deformation and PL emission variations have been described, as liquid crystalline composite polymeric films with directional MCF behavior.…”