(CH3NH3)3Sb2Cl9 single crystals are grown which appear to be isomorphous with Cs3Sb2Cl9 crystals of β‐modification. They are characterized by the space group Pmcn with the lattice constants: a = 0.7920(5), b = 1.3334(11), and c = 1.966(2) nm. In the crystal one can distinguish the poly‐anionic (Sb2Cl9)3‐ stacks directed along the a‐axis with three crystallographically inequivalent CH3NH 3+ cations. The DSC, dielectric, and PMR studies reveal a structural phase transition at 208 K which is related to a freezing of rotational motion of CH3NH 3+ cations.

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Chiral high-performance liquid chromatography separation of two recently synthesized liquid crystalline materials C1 and C2 was studied in the reversed-phase mode. Both materials have an azo-moiety and one chiral center in their molecular structures. They were available in racemic and pure S forms. For the enantiomeric separations, a Chiralpak AY-RH stationary phase based on amylose tris(5-chloro-2-methylphenylcarbamate) coated on 5 μm silica was used. The compounds were analyzed in both of their possible forms, the more thermodynamically stable E form and the labile Z form. The conditions and time scale of the UV-induced E to Z transition were briefly evaluated. Under the optimized conditions, we were able to baseline separate S and R enantiomers of both of the studied materials not only in their E forms, but also in their Z forms. In comparison to the separation in the normal-phase mode, which we have reported recently, the resolution in the reversed-phase mode is significantly better. Interestingly, peak reversal was noticed for the S and R enantiomers when the separation was carried out with E versus Z forms of both compounds.

Phototropic liquid crystals (PtLC) are a new class of materials possessing number of potential applications in photonics devices. However, so far a significant majority of PtLC materials has been realized by the doping a classical liquid crystal with a photochromic dye. The photochemical phase transition in such systems was investigated mainly by the monitoring of the changes in the transmittance. In this study, the photochemical phase transition of single-component phototropic liquid crystals was investigated using a holographic grating recording in combination with a polarized optical microscope. The cis–trans photoisomerization of compounds causes the isotropic-to-nematic (I–N) phase transition and so that the interference pattern can be mapped as a diffraction grating. The process of the grating build up was monitored by the first-order light diffraction, and simultaneously the area of the material exposed to the light was observed directly under a polarized microscope. The combination of the holographic technique with polarized optical microscopy has allowed to propose the mechanism of the I–N phase transition of LC compounds. It assumes three processes responsible for the grating formation. The results have a crucial importance in understanding the mechanism of photochemical phase transition of PtLCs, and thus they can be useful in construction of new optical devices.

Dimerizations of C4 precursors RC≡CC≡CTMS [R = C6H5 (1), p‐CH3C6H5, (2), 4‐n‐C5H11C6H4 (3), C6H9 (4), p‐CH3OC6H4 (5), p‐C6H5COC6H4 (6), p‐NO2C6H4 (7), and p‐NCC6H4 (8)] by Hay coupling with in situ deprotection gave stable octatetraynes R(C≡C)4R (1–8‐C8‐1–8) in 42–80 % yields as light yellow to brown powders. The same tetraynes were next synthesized from the same C4 precursors by an alternative Mori–Hiyama method that typically utilizes trimethylsilyl‐substituted alkynes without prior deprotection. The latter protocol proved useful and gave the expected products but with lower yields of 8–74 %. The resulting tetraynes were characterized by spectroscopic methods and in some cases by X‐ray crystallography. In the cases of 1‐C8‐1 and 3‐C12‐3, close analysis of the crystal data showed high degrees of carbon chain linearity, with % contraction indexes of 0.13 % and 0.19 %, respectively. The chains were more strained in the cases of 6‐C8‐6 (0.34 %) and 3‐C8‐3 (0.68 %). Deeper analysis of packing motifs revealed 3‐C12‐3 to be a very promising candidate for topochemical 1,4‐polymerization.