Liquid-crystalline coordination polymers based on tetra(alkoxybenzoato)dirhodium(II) complexes axially linked by tetrazine, phenazine and 4,4′-bipyridine

Abstract

The reaction of dirhodium tetrakis(3,4,5-trialkoxy)benzoates Rh 2 (B3OCn) 4 (n = 10, 14, and 18) with three different dinitrogenated axial ligands (L ax ), namely tetrazine (tz), phenazine (phz), and 4,4′-bipyridine (bpy), gave rise to three homologous series of mesogenic coordination polymers, [Rh 2 (B3OCn) 4 ]L ax . All of them exhibited thermotropic columnar mesophases that were of the hexagonal type for tz and phz and rectangular for bpy. The lighter n = 10 homologs of the three series are liquid crystals (LC) at room temperature. Their mesomorphic properties have been compared with those of the previously studied L ax = pyrazine series. Models for the supramolecular organization of the three polymeric series in their Col LC phases are proposed on the basis of their structural parameters, as measured by XRD and SAXS. The differences are interpreted in terms of different coordination features of the axial ligands.

Very intense polarized emission in self-assembled room temperature metallomesogens based on Zn(ii) coordination complexes: an experimental and computational study

“…In the last decade, the fine tuning of the molecular structure (nature of the metallic center, nature and functionalities of ligands, the presence of non-innocent counterions for ionic derivatives, etc.) to offer the right intermolecular interactions permitted a substantial decrease of the transition temperatures, obtaining low-temperature or even roomtemperature MMs based on linearly coordinated Cu(I) 7 or Au(I) 7b,8 and Ag(I), 9 planar Au(III), 10 Pt(II) and Pd(II) 11 or Ni(II), Zn(II), and Cu(II) 12 and even for bulkier coordination geometries like tetrahedral or trigonal bipyramidal Zn(II), 13 Ag(I), 14 Cu(I), 15 octahedral Ir(III), 16 Ru(II) 17 or Rh(II) 18 metal centres.…”

Mesomorphic properties of linear and branched new triphenylene‐based poly(ester‐ether)s

“…Accessibility drove our choice to the last technique. Nevertheless, as commercial devices require a large quantity of compounds (above 50 g), we used a home‐made extruder device, previously built‐up in our group in order to work with metallomesogens, which requires few compound quantities (approximately 100 mg). As P(est‐eth)C11 and its branched derivatives showed liquid crystal phases at room temperature, extrusion was performed without any thermal treatment.…”

“…Oriented samples of the studied polymers were obtained using a homemade micro‐extruder device . The extruder consists of two stainless steel cylindrical pieces and a bronze pit (Fig.…”

Mesogenic Coordination Polymers Based on Ru2(II,II)‐Paddle‐Wheel Units Exhibit High Electrical Conductivity

“…For doing that, experiments were performed on material fibers, extruded under different conditions from their CLC phase. Our previous experience with this kind of CP indicated that, in order to warrant a CLC phase when using L ax ligands -which act as "connectors" from an electronic viewpoint but as "spacers" from a structural viewpoint-the use of bulky equatorial carboxylates (R eq CO 2 ) is mandatory [20,22,[32][33][34] We thus decided to use 3,4,5-tri(alkoxy)benzoates (noted hereafter B3OCn, n being the length of each alkoxy chain) as R eq CO 2 À , thus targeting CP of the Ru 2 (B3OCn) 4 tz type. We report herein the synthesis and characterization of both such Ru 2 (B3OCn) 4 building blocks and their Ru 2 (B3OCn) 4 tz coordination polymers, as well as the study of their liquidcrystalline properties, their orientation as extruded fibers, and the resulting electrical conductivity.…”