Structural Study on Columnar Mesophases Consisting of H-Bonded Supramolecules

Abstract

The use of complementary 2,4,6-triarylamino-1,3,5-triazines and benzoic acids has allowed the preparation of a variety of disklike supramolecules with different substitution patterns around an H-bonded aromatic core. Most of the complexes obtained show columnar mesomorphism promoted by an efficient columnar packing of the aromatic cores surrounded by a minimum of six peripheral tails. The steric requeriments for the appearance of mesomorphic behavior in these supramolecular complexes have been established by X-ray diffraction studies and density calculations based on the parameters of the liquid crystalline organization.

Room‐Temperature Columnar Mesophases in Triazine–Gold Thiolate Metal–Organic Supramolecular Aggregates

“…Thus, they do not show the ν(OH) absorptions of the metalloacid phosphine gold thiolate precursors, and the ν(CO) band of the carboxylic acid appears clearly shifted from their positions in the parent complexes (Table 1; Supporting Information, Figure S1). Changes in the ν(NH) region are also observed upon formation of the aggregate, as reported for triazine–carboxylic acid aggregates 3b. Consequently, the presence of unreacted materials can be excluded, even when assignment of the ν(OH), ν(NH), and ν(CO) frequencies for the triazine–metalloacid supramolecular complexes is precluded by the low intensity and large width, for ν(OH) and ν(NH) absorptions, or by overlapping of the ν(CO) absorptions with the ν(CN) triazine bands in the region 1660–1560 cm −1 .…”

Complementary Hydrogen Bonding Between a Clicked C3‐Symmetric Triazole Derivative and Carboxylic Acids for Columnar Liquid‐Crystalline Assemblies

“…The C = O stretching vibration in TBA appears at 1685 cm À1 (Figure 2 a), which indicates dimeric H-bonding. [12] Conversely, the carbonyl band in HBC-1 shifted to 1703 cm À1 , which is lower than that (1733 cm À1 ) of the free carboxylic acid. [12] This result suggests that the carbonyl group still interacts with a different H-bonding donor, presumably CH a of the triazole in TTB.…”

“…[12] Conversely, the carbonyl band in HBC-1 shifted to 1703 cm À1 , which is lower than that (1733 cm À1 ) of the free carboxylic acid. [12] This result suggests that the carbonyl group still interacts with a different H-bonding donor, presumably CH a of the triazole in TTB. Furthermore, the shift to the lower frequency of 1703 cm À1 may confirm that the carbonyl groups form hydrogen bonds with CH a , which is a weaker H-bonding donor than the OH group from the carboxylic acid.…”

“…[2] TBA was prepared by sequential alkylation and hydrolysis reactions as described elsewhere. [12] The obtained TTBs and TBA were characterized by 1 H and 13 C NMR spectroscopy, elemental analysis, and gel permeation chromatography (GPC). All of the experimental data fit well with the designed molecular structure (see the Supporting Information).…”

A Star‐shaped Oligo(phenylenevinylene) Liquid Crystal Host with an Anthracene Guest—A Double Nanosegregating Supermesogen

“…Only a few examples are known, in which empty space has been claimed in the LC state, for example based on shape‐persistent macrocycles or on peptide‐functionalized minidendrons . A family of liquid crystals based on melamine is known to provide space for one incoming guest molecule . Swallow‐tailed mesogens were reported to accommodate electron‐deficient guests generating filled LC phases and the discotic CPI system furnishes a pocket, in which the liquid crystalline triphenylene perfectly fits .…”