Helena Isla

Basque Center for Macromolecular Design and Engineering · Polymat

A novel enantiopure bis-helicenic 2,2'-bipyridine system was prepared using a Negishi coupling. Thanks to the bipyridine unit, the coordination with ZnII and protonation processes were studied revealing efficient tuning of photophysical (UV/Visible and emission) and chiroptical properties (electronic circular dichroism and circularly polarized emis...

The molecular conformation of a bis-helicenic terpyridine system is strongly modified upon binding to Zn(ii) ion, a process that is accompanied by large changes in the optical and chiroptical properties. This system affords a new type of helicene-based chiroptical switching.

Helicenes are mols. with ortho-fused arom. rings that adopt an inherently chiral helical shape. This helical topol. combined with the extended π-conjugated system provides them with excellent chiroptical and photophys. properties. These properties and peculiarities make helicenes important candidates for the conception of new chiroptical switches....

Supramolecular polymers based on dispersion forces typically show lower molecular weights (MW) than those based on hydrogen bonding or metal–ligand coordination. We present the synthesis and self-assembling properties of a monomer featuring two complementary units, a C60 derivative and an exTTF-based macrocycle, that interact mainly through π–π, ch...

Supramolecular polymers based on dispersion forces typically show lower molecular weights (MW) than those based on hydrogen bonding or metal–ligand coordination. We present the synthesis and self-assembling properties of a monomer featuring two complementary units, a C60 derivative and an exTTF-based macrocycle, that interact mainly through π–π, ch...

Including a preorganized macrocyclic host … … in a self-recognizing monomer and using fullerenes as guests leads to supramolecular polymers with a very high degree of polymerization. E. M. PØrez, N. Martín, and H. Isla show in their Communication on page 5629 ff. that molecular weights above 150 kDa were determined in solution, whereas up to 90 kDa...

The supramolecular modification of planar graphene with the geometrically mismatched, curved 9,10-di(1,3-dithiole-2-ylidene)-9,10-dihydroanthracene (exTTF) molecule is demonstrated. The exTTF-graphene interaction is governed by π-π and CH-π interactions, with a negligible contribution from charge transfer. We amplified these weak forces through mul...

We describe the synthesis, electronic, optical and photophysical properties of a family of three electron-donor bowl-shaped organic molecules that absorb light in the whole range of the visible spectrum (up to 800 nm in one case), and associate C60 in solution with binding constants in the range of 104–102 M−1 as measured from both UV-vis and fluor...

A macrocyclic exTTF host for fullerenes offers control over the electronic coupling between an electron donor and an acceptor, and stabilizes the charge separated state lifetimes into the range of 500 ps.

We report the synthesis and C60 binding abilities of gold nanoparticles capped with π-extended tetrathiafulvalene (exTTFAuNPs). The exTTFAuNPs show a strong tendency to aggregate both in solution and in the solid state through multiple weak exTTF-exTTF interactions. A thorough collection of experiments demonstrates that upon addition of C60, stable...

Exploiting the shape and electronic complementarity of C(60) and C(70) with π-extended derivatives of tetrathiafulvalene (exTTF), we have very recently reported a macrocyclic receptor featuring two exTTF recognizing units which forms 1:1 complexes with C(60) with log K(a) = 6.5 ± 0.5 in chlorobenzene at 298 K. This represents one of the highest bin...

A receptor for fullerenes featuring three exTTF units linked to a CTV scaffold is described. The exTTF-CTV host forms remarkably stable complexes with both C(60) (log K(a) = 5.3 +/- 0.2) and C(70) (log K(a) = 6.3 +/- 0.6). Light-induced ESR spectra demonstrate that intracomplex PET processes take place in solution.

An exTTF-based macrocyclic receptor that associates C(60) with a binding constant >10(6) M(-1) in chlorobenzene at room temperature is described. This represents an improvement of 3 orders of magnitude with respect to the previous examples of exTTF-based receptors and one of the highest binding constants toward C(60) reported to date.