Controlling Intermolecular Interactions between Metallomesogens: Side-Chain Effects in Discotic Copper, Palladium, and Vanadyl Bis(.beta.-Diketonates)

Abstract

A systematic study of the liquid-crystalline properties of 30 metal bis (/3-diketonate) complexes (M = Cu, VO, Pd) that exhibit discotic mesophases is reported. This study has determined that the ability of the metal center to influence the mesophase stability depends upon the density of side chains. In the 10-side-chain complexes series 3, all of the materials were found to be liquid crystalline. In this series the M = VO analogues were found to have lower melting and clearing points than those with M = Cu and M = Pd. For the 12side-chain series 4 the opposite is true, and the M = VO materials have substantially higher clearing points. The differences between series 3 and 4 arise from the enhanced core-core interactions that accompany the increased side-chain density. The side-chain-induced organization assists the expression of the metal center's character in determining the stability and nature of the mesophase. The fact that the transition temperatures of the M = Cu and M = Pd compounds differ more in series 4 than in series 3 is also a manifestation of this greater organization. The influence of the metal centers is discussed in the context of intermolecular dative associations and for some phases of the M = VO materials these interactions produce polymeric (-V=0-V=0-)" structures.

Investigation on the Synthesis and Photocatalytic Property of Uranyl Complexes of the β-Diketonates Biscatecholamide Ligand

“…The resonance signals of the methylene protons of the major species isomers showed four peaks at 5.18 (dd, J = 23.8, 12.1 Hz, 2H, -CH 2 -), 4.78 (d, J = 11.9 Hz, 2H, -CH 2 -), 4.00 (t, J = 12.0 Hz, 2H, -CH 2 -), and 3.63 (d, J = 14.2 Hz, 2H, -CH 2 -). And the active methylene of -diketonates shows [20,[28][29][30]. It confirmed that oxygen atom of -diketonate did not bind to uranyl ion, also indicated by the FTIR spectra analysis.…”

“…[7,[20][21][22], which confirmed that oxygen atoms of carbonyl group of -diketonate did not bind to uranyl ion. The bands at 1640-1643 cm…”

Diskotische Flüssigkristalle: Von der maßgeschneiderten Synthese zur Kunststoffelektronik

“…Im Fall dendritischer Texturen entstehen häufig "Blumen"-Muster. [25] Darüber hinaus sind die relativ seltenen Sphärulit-(Abbildung 8 c) und Fingerprint-Texturen [26] bekannt. Diese Fingerprint-Texturen weisen keine Analogie zu denen cholesterischer Mesophasen auf, wo die äquidistanten Streifen die Periodizität der durch Chiralität induzierten helicalen Struktur widerspiegeln.…”

Discotic liquid crystals of transition metal complexes, 54: Rapid microwave-assisted synthesis and homeotropic alignment of phthalocyanine-based liquid crystals

“…There have been a very few example exhibiting more than three Col h mesophases in one compound. However, Swager and his co-workers also reported that the long chain-substituted b-diketonato copper(II) complexes exhibited four different Col hd mesophases [24]. We reported another example of the phthalocyanine-based liquid crystals showing plural Col h mesophases in one compound [25].…”