1205685-23-9Relevant academic research and scientific papers
A simple chemical tuning of the effective concentration: Selection of single-, double-, and triple-stranded binuclear lanthanide helicates
Terazzi, Emmanuel,Guenee, Laure,Bocquet, Bernard,Lemonnier, Jean-Francois,Favera, Natalia Dalla,Piguet, Claude
supporting information; experimental part, p. 12719 - 12732 (2010/06/14)
The replacement of terminal 2-benzimidazol-6-carboxypyridine (two internal rotational degrees of freedom) with 2-benzimidazol-8-hydroxyquinoline (one internal rotational degree of freedom) into segmental bis-tridentate ligands in going from L2 and [L32H]2- to [L12D-2H]2- does not significantly affect the structures of the resulting binuclear lanthanide triplestranded helical complexes [Ln2(L2)3]6+, [Ln2(L3-2H)3], and [Ln2(L12b-2H)3] (palindromic helices, intermetallic contact distance 9 A, helical pitch 1.4 nm per turn). However, their thermodynamic assemblies are completely different in solution, as evidenced by the spectacular decrease of the effective concentrations by two orders of magnitude for [L12b-2H] 2-. This key parameter in the [Ln2(L12b-2H)n] (n = 2, 3) complexes is further abruptly modulated along the lanthanide series (Ln = La to Lu), which provides an unprecedented tool for 1) tuning the number of ligand strands in the final helicates, 2) selectively coordinating lanthanides in the various complexes, and 3) controlling the ratio of lanthanide-containing polymers over discrete assemblies.
