Liquid-crystalline methanofullerodendrimers which display columnar mesomorphism

Liquid-crystalline methanofullerodendrimers were synthesized <i>via</i> the Bingel addition reaction of mesomorphic malonate derivatives and C₆₀. Second- and third-generation poly(benzyl ether) dendrons were selected as liquid-crystalline promoters to induce columnar mesomorphism. Based on a convergent and modular synthetic methodology, symmetrical (two identical dendrons) and non-symmetrical (two different dendrons) dendrimers were prepared, as well as hemidendrimers (only one dendron). The liquid-crystalline properties of the malonates and fullerodendrimers were investigated by polarized optical microscopy, differential scanning calorimetry, and X-ray diffraction. All the malonates give rise to hexagonal columnar phases of <i>p</i>6<i>mm</i> symmetry. As for the fullerodendrimers, the second-generation hemidendrimer shows a rectangular columnar phase of <i>c</i>2<i>mm</i> symmetry, while the other materials give rise to hexagonal columnar phases of <i>p</i>6<i>mm</i> symmetry.