X-ray diffraction, DFT theoretical, and IR polarized spectroscopic studies of the crystal-like E-mesophase of 4′-hexyloxy-isothiocyanatotolane (6OTOLT)

Observation of a reversible isomorphous phase transition and an interplay of "σ-holes" and "π-holes" in Fmoc-Leu-ψ[CH2-NCS]

Fmoc-Leu-ψ[CH2NCS] undergoes a reversible isomorphous phase transition upon cooling. The crystal structure at 100 K displays a short N=C=S···N=C=S intermolecular interaction, which has been characterized based on experimental charge density analysis, as a stabilizing interaction with both σ-holes and π-holes acting cooperatively.

Crystal structure of chlorido(η2-phenyl isothiocyanate-κ2C,S)-mer-tris(trimethylphosphane-κP)iridium(I)

In this distorted octa­hedral iridium complex, the three PMe3 ligands are arranged in a meridional geometry, with the chloride ion cis to all three PMe3 groups and the phenyl iso­thio­cyanate ligand bonded in an η²-fashion through the C and S atoms. The geometric parameters for the metal-complexed PhNCS group are compared with other metal-complexed phenyl iso­thio­cyanates, as well as with examples of uncomplexed aryl iso­thio­cyanates.

The molecule of the title compound, [IrCl(C₇H₅NS)(C₃H₉P)₃], is a distorted octa­hedral iridium complex with three PMe₃ ligands arranged in a meridional geometry, a chloride ion cis to all three PMe₃ groups and the phenyl iso­thio­cyanate ligand bonded in an η²-fashion through the C and S atoms. The C atom is trans to the chloride ion and the S atom is responsible for a significant deviation from an ideal octa­hedral geometry. The geometric parameters for the metal-complexing phenyl isothiocyanate group are compared with other metal-complexed phenyl iso­thio­cyanates, as well as with examples of uncomplexed aryl iso­thio­cyanates.

Study of polymorphism of 4-hexyl-4'-isothiocyanatobiphenyl by complementary methods

The results of adiabatic calorimetry, mid-infrared spectroscopy, X-ray diffraction, and polarized microscopy of 4-hexyl-4'-isothiocyanatobiphenyl are presented. Apart from the well-known isotropic liquid and smectic phases, calorimetric measurements indicate the existence of two stable crystalline phases. Quantitative analysis of infrared bands enabled the determination of phase transitions, observation of crystallization kinetics, and elucidation of the glass transition of the crystal-like smectic E phase. The structural information about the glass of the smectic E obtained from the diffraction studies is complemented by textures recorded by polarized microscopy.

Infrared spectroscopic and X-ray studies of the 4-propyl-4'-isothiocyanatobiphenyl (3TCB)

The results of mid-infrared spectroscopy and X-ray studies of the third member of the 4-n-alkyl-4'-isothiocyanatobiphenyl (nTCB) homologous series are presented. Correspondence between the phase transitions observed by means of the IR spectroscopy and those given by the adiabatic calorimetry was found. The structure of five solid phases was obtained by X-ray measurements. IR spectroscopic and X-ray data give the arguments supporting the identification of the glass of smectic E phase. Assignment of the IR vibrational bands, in the smectic E, in the glass of smectic E, and in one of the crystalline phases, with help of the hybrid B3LYP/6-311++G(d,f) functional calculations is presented.