Related Experiment Video
Updated: Jun 19, 2026

Experimental Approaches for the Synthesis of Low-Valent Metal-Organic Frameworks from Multitopic Phosphine Linkers
Published on: May 12, 2023
Orientational order of fluorinated mesogens containing the 1,3,2-dioxaborinane ring: a multidisciplinary approach
S Borsacchi1, L Calucci, J Czub
1Dipartimento di Chimica e Chimica Industriale, Universita di Pisa, via Risorgimento 35, 56126 Pisa, Italy.
Abstract:
Orientational order properties of two fluorinated liquid crystals containing the 1,3,2-dioxaborinane ring have been investigated by means of optical, dielectric, and (13)C and (19)F NMR spectroscopies. The optical birefringence and dielectric anisotropy values determined in the mesomorphic phases were analyzed in terms of well-established theoretical models to obtain the order parameters relative to the principal axis of the polarizability tensor and molecular dipole moment, respectively. A large set of data, including (13)C and (19)F chemical shift anisotropies and (13)C-(19)F and (1)H-(19)F couplings relative to nuclei on the aromatic rings, was acquired in the NMR experiments and analyzed to determine local order parameters (principal order parameter and biaxiality) for different rigid fragments of the mesogen aromatic core using advanced DFT methods for the calculation of geometrical parameters and chemical shift tensors. A critical analysis of the dependence of the order parameters on the data set employed and on the theoretical assumptions and approximations has also been performed. The orientational order parameters obtained using the different techniques are compared and discussed in relation to the reference frame associated with the anisotropic properties monitored.
More Related Videos
10:10Application of Elemental Lanthanides in the Selective C-F Activation of Trifluoromethylated Benzofulvenes Providing Access to Various Difluoroalkenes
Published on: July 28, 2018
06:44From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding
Published on: March 24, 2018
Related Concept Videos
Electrophilic Aromatic Substitution: Fluorination and Iodination of Benzene
ortho–para-Directing Activators: –CH3, –OH, –⁠NH2, –OCH3
Regioselectivity and Stereochemistry of Hydroboration
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn stereochemistry.
Halogenation of Alkenes
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.
Hydroboration-Oxidation of Alkenes
ortho–para-Directing Deactivators: Halogens