535931-02-3Relevant academic research and scientific papers
Molecular control of macroscopic cubic, columnar, and lamellar organizations in luminescent lanthanide-containing thermotropic liquid crystals
Terazzi, Emmanuel,Torelli, Stephane,Bernardinelli, Gerald,Rivera, Jean-Pierre,Benech, Jean-Marc,Bourgogne, Cyril,Donnio, Bertrand,Guillon, Daniel,Imbert, Daniel,Buenzli, Jean-Claude G.,Pinto, Andre,Jeannerat, Damien,Piguet, Claude
, p. 888 - 903 (2007/10/03)
The connection of lipophilic gallic acid derivatives at the 5,5′- or 6,6′-positions of the rigid 2,6-bis(1-ethyl-benzimidazol-2-yl)pyridine core provides two pro-mesogenic tridentate ligands L10 and L12, whose molecular shapes, anisometries, and directional intermolecular π-stacking can be tuned. X-ray diffraction data in the crystalline state, combined with solution 1H NMR measurements, show that complexation with trivalent lanthanides, Ln(III), produces the neutral hemi-disklike complexes [Ln(Li)(NO3)3] (i = 10, 12), which dimerize to give the rodlike bimetallic complexes [Ln2(Li)2(NO 3)6] at lower temperature. The relevant thermodynamic parameters for the latter process depend on the nature of the ligand, the size of the metal ion, and the strength of the intermolecular interactions involved in the condensed phase. These three-dimensional models obtained for the complexes in the crystals and in solution are eventually confronted with small-angle XRD profiles recorded in the intermediate thermotropic liquid crystalline phase, in which the rigidity of the packed polyaromatic cores is maintained, while the alkyl chains are molten. According to the specific geometries and nuclearities of the molecular complexes, three types of mesophases (lamellar, columnar, and cubic) can be induced, which provides a direct correlation between the microscopic arrangements and the macroscopic ordering in lanthanide-containing metallomesogens.
Metallomesogens with extended bent tridentate receptors: Columnar and cubic mesomorphism tuned by the size of the lanthanide metal ions
Terazzi, Emmanuel,Benech, Jean-Marc,Rivera, Jeann-Pierre,Bernardinelli, Gerald,Donnio, Bertrand,Guillon, Daniel,Piguet, Claude
, p. 769 - 772 (2007/10/03)
The increase of the curvature of the interface between the rigid mesogenic core and the aliphatic chains in the hexacatenar tridentate ligand L3 was investigated. It was found that the increase in the curvature overcomes the considerable expansion brought
