Dipole moments of halogen derivatives of ortho- and meta-carboranes

Four Decades of Organic Chemistry of closo-Boranes: A Synthetic Toolbox for Constructing Liquid Crystal Materials. A Review

“…154 ) results in the almost exclusive formation of the 1,7-isomers, although a small amount of [1,12- Other elements bonded to boron. Although B-chloro and B-fluoro derivatives are too unreactive to be useful intermediates in Pd-catalyzed coupling reactions, they can be used to modify the molecular dipole moments 155,156 and break the symmetry introducing axial chirality.…”

Practical Synthesis of 1,12-Difunctionalized o-Carborane for the Investigation of Polar Liquid Crystals

“…In spite of focus on p-carborane, it can be argued that the remaining two isomeric and essentially isosteric carboranes have additional properties that are of particular interest for certain molecular and functional designs. Thus, unlike A, o-and m-carboranes have moderate ground-state dipole moments of 4.45 and 2.76 D (benzene), respectively, 15 which are oriented about 30°of the 1,12 axis in B and nearly parallel to the 2,9 axis in C (Figure 1).…”

“…In spite of focus on p -carborane, it can be argued that the remaining two isomeric and essentially isosteric carboranes have additional properties that are of particular interest for certain molecular and functional designs. Thus, unlike A , o - and m -carboranes have moderate ground-state dipole moments of 4.45 and 2.76 D (benzene), respectively, which are oriented about 30° of the 1,12 axis in B and nearly parallel to the 2,9 axis in C (Figure ). In addition, the carbon atoms in the 2,9-disubtituted m -carborane ( IC ) are enantiotopic, which raises the possibility of coupling of the electric dipole with molecular chirality, a feature important for some applications including ferroelectric liquid crystals .…”