One-pot synthesis of 4′-alkyl-4-cyanobiaryls on the basis of the terephthalonitrile dianion and neutral aromatic nitrile cross-coupling

• Roman Yu. Peshkov,
• Elena V. Panteleeva,
• Wang Chunyan,
• Evgeny V. Tretyakov and
• Vitalij D. Shteingarts

Beilstein J. Org. Chem. 2016, 12, 1577–1584, doi:10.3762/bjoc.12.153

• an alkyl halide. Earlier, we used butyl bromide for anion 3 trapping and obtained 4-butyl-4'-cyanobiphenyl (5aa) in 56% yield (Table 1, entry 1) [23]. In order to expand the scope of the synthetic utilization of the cross-coupling reaction under investigation, as well as to work out a short and

• obtained for 5-bromopent-1-ene (6b). Reactions with ω-substituted alkyl bromides 6d and 6e provided lower product yields, which depended on the nature of the alkylating reagent. In the reaction with dibromopentane 6c we found no disubstitution product – the corresponding 1,5-bis(4-cyanobiphenyl-4-yl

• ), as well as 4'-methyl-2-cyanobiphenyl (2h). In addition, two new neutral carbonitriles – 2,6-difluorobenzonitrile (2g) and 1-cyanonaphthalene (2i) – were tested as cross-coupling participants and found to react with dianion 12−. Alkylation of intermediate anions 3b–i in all these reactions was

A new family of four-ring bent-core nematic liquid crystals with highly polar transverse and end groups

• Kalpana Upadhyaya,
• Venkatesh Gude,
• Golam Mohiuddin and
• Rao V. S. Nandiraju

Beilstein J. Org. Chem. 2013, 9, 26–35, doi:10.3762/bjoc.9.4

• -core mesogens; cyanobiphenyl; dipole moment; liquid crystals; nematic phase; polarity; Introduction Following the discovery of chiral and polar properties of mesomorphic bent-core compounds [1][2][3][4][5][6] the area of design, synthesis and properties of banana or bent-shaped liquid crystals (LC

• molecular architectures [31][32][33][34][35][36][37][38][39]. Furthermore, the introduction of a polar cyanobiphenyl moiety in bent-core systems exhibiting mesomorphism is rare [22]. Design of the molecule The recent experimental support in favour of a biaxial nematic phase that is exhibited by bent-core

• azobenzene or salicylideneimine or phenylbenzoate unit in one of the arms of the bent molecule by a polar cyanobiphenyl moiety lends stiffness to the molecule with a strong dipole moment in the lateral direction. The realization of such a molecular architecture leads to a reduction in rotational disorder as

Liquid-crystalline heterodimesogens and ABA-heterotrimesogens comprising a bent 3,5-diphenyl-1,2,4-oxadiazole central unit

• Govindaswamy Shanker,
• Marko Prehm and
• Carsten Tschierske

Beilstein J. Org. Chem. 2012, 8, 472–485, doi:10.3762/bjoc.8.54

• terminally connected ABA-heterotrimesogens and heterodimesogens, composed of a bent 3,5-diphenyl-1,2,4-oxadiazole central unit and one or two rod-shaped 4-cyanobiphenyl cores or one 2-phenyl-1,3,4-thiadiazole core, connected by flexible spacers, have been synthesized, and their mesomorphic behavior was

• the 3,5-diphenyl-1,2,4-oxadiazole unit with one cyanobiphenyl core leads to the removal of tilted smectic and cybotactic nematic phases (SmC, NcybC), which are replaced by the nontilted CybA phases and nematic phases composed of SmA-type clusters (NcybA). The orthogonal cybotactic nematic phases of

• mesogenic units through flexible spacers are reported (Scheme 1). The trimesogens CB-Ox-CB/n combine the 3,5-diphenyl-1,2,4-oxadiazole unit with two nematogenic cyanobiphenyl (CB) units (Scheme 2), in the dimesogens CB-Ox/n only one CB unit is incorporated, and in compounds Thia-Ox/n a 3-heptyl-5-phenyl

Perhydroazulene-based liquid-crystalline materials with smectic phases

• Zakir Hussain,
• Henning Hopf and
• S. Holger Eichhorn

Beilstein J. Org. Chem. 2012, 8, 403–410, doi:10.3762/bjoc.8.44

• with the chemical structures of both compounds. In the case of 8b, the presence of only one aromatic ring with a short alky chain at the ester side could result in a lower melting range, while the presence of cyanobiphenyl in the case of 10b could cause its higher melting behavior. Conclusion We have

Synthesis and mesomorphic properties of calamitic malonates and cyanoacetates tethered to 4-cyanobiphenyls

• Katharina C. Kress,
• Martin Kaller,
• Kirill V. Axenov,
• Stefan Tussetschläger and
• Sabine Laschat

Beilstein J. Org. Chem. 2012, 8, 371–378, doi:10.3762/bjoc.8.40

• described in the literature [33][34]. Therefore, we decided to explore the synthesis and mesomorphic properties of malonates and cyanoacetates 5 tethered to calamitic 4-cyanobiphenyl units (Scheme 2). Results and Discussion The syntheses of malonate and cyanoacetate derivatives 11, 13 are shown in Scheme 3

• liquid-crystalline phase, but melted without decomposition into isotropic liquids. It was observed that the melting points increased with an increase of the spacer length between 4-cyanobiphenyl and ester groups. Thus, melting points were recorded at 49.1 °C/63.4 °C for the series of 11a/11b and at 89.0

• patterns of 11a: (A) crystalline phase at 50 °C, (B) isotropic phase at 25 °C, and (C) nematic phase at 15 °C. Diketonato metallomesogens and diketones with mesomorphic properties. Malonates and cyanoacetates tethered to calamitic 4-cyanobiphenyl units. Synthesis of malonate and cyanoacetates tethered to 4

Liquid-crystalline nanoparticles: Hybrid design and mesophase structures

• Gareth L. Nealon,
• Romain Greget,
• Cristina Dominguez,
• Zsuzsanna T. Nagy,
• Daniel Guillon,
• Jean-Louis Gallani and
• Bertrand Donnio

Beilstein J. Org. Chem. 2012, 8, 349–370, doi:10.3762/bjoc.8.39

• acicular particles. The mesophase behaviour was lost for hybrids prepared with 1 and NPs with lower aspect ratios and a deliberately prepared polydisperse sample, and furthermore, none of the hybrids prepared with the cyanobiphenyl based amine 2 exhibited any mesophases. In an extension of this work

• arrangement of the NP cores, but this work was important in stimulating further research in the field by a variety of groups. Subsequently, a similar procedure was reported in which Au NPs of diameter 2.7 ± 0.5 nm were directly synthesised in the presence of a cyanobiphenyl group appended with an alkylthiol

• observed mesophase behaviour of hybrid pseudospherical NPs. Another detailed investigation into the disposition of the ligands about mesogenic Au NPs was reported based on hybrid particles prepared in a two-step process by using a wider suite of mesogenic cyanobiphenyl based thiols [62]. Gold NPs of ~2.4

The interplay of configuration and conformation in helical perylenequinones: Insights from chirality induction in liquid crystals and calculations

• Elisa Frezza,
• Silvia Pieraccini,
• Stefania Mazzini,
• Alberta Ferrarini and
• Gian Piero Spada

Beilstein J. Org. Chem. 2012, 8, 155–163, doi:10.3762/bjoc.8.16

• (Merck) nematic solvent E7 (nematic–isotropic transition temperature TNI ~ 330 K) is composed of a eutectic mixture of cyanobiphenyl and terphenyl compounds [30]. DFT calculations Atomic coordinates and energy of the conformers of 1 and 2 were obtained by geometry optimization in vacuum, by using DFT at

Improved syntheses of high hole mobility phthalocyanines: A case of steric assistance in the cyclo-oligomerisation of phthalonitriles

• Daniel J. Tate,
• Rémi Anémian,
• Richard J. Bushby,
• Suwat Nanan,
• Stuart L. Warriner and
• and Benjamin J. Whitaker

Beilstein J. Org. Chem. 2012, 8, 120–128, doi:10.3762/bjoc.8.14

• shown that in the cyanobiphenyl and cyanoterphenyl series the differences are substantial with the N/I transition temperatures being lower in the isoalkyl series by between 8 and 50 °C (on the basis of comparing chains of equal maximum length): An effect reasonably attributed to the greater lateral

Chiral amplification in a cyanobiphenyl nematic liquid crystal doped with helicene-like derivatives

• Alberta Ferrarini,
• Silvia Pieraccini,
• Stefano Masiero and
• Gian Piero Spada

Beilstein J. Org. Chem. 2009, 5, No. 50, doi:10.3762/bjoc.5.50