Designing Supramolecular Liquid-Crystalline Hybrids from Pyrenyl-Containing Dendrimers and Arene Ruthenium Metallacycles

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• 作者：Ana茂s Pitto-Barry ; Nicolas P. E. Barry ; Virginie Russo ; Beno卯t Heinrich ; Bertrand Donnio ; Bruno Therrien ; Robert Deschenaux
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：December 17, 2014
• 年：2014
• 卷：136
• 期：50
• 页码：17616-17625
• 全文大小：678K
• ISSN：1520-5126

文摘

The association of the arene ruthenium metallacycle [Ru₄(p-cymene)₄(bpe)₂(donq)₂][DOS]₄ (bpe = 1,2-bis(4-pyridyl)ethylene, donq = 5,8-dioxydo-1,4-naphtoquinonato, DOS = dodecyl sulfate) with pyrenyl-functionalized poly(arylester) dendrimers bearing cyanobiphenyl end-groups is reported. The supramolecular dendritic systems display mesomorphic properties as revealed by polarized optical microscopy, differential scanning calorimetry and small-angle X-ray scattering measurements. The multicomponent nature of the dendrimers and of the corresponding host鈥揼uest supramolecules (i.e., end-group mesogens, dendritic core, pyrene unit, aliphatic spacers, and metallacycle) leads to the formation of highly segregated mesophases with a complex multilayered structure due to the tendency of the various constitutive building-blocks to separate in different organized zones. The pyrenyl dendrimers exhibit a multilayered smectic A-like phase, thereafter referred to as LamSmA phase to emphasize this unaccustomed morphology. As for the corresponding Ru₄鈥搈etallacycle adducts, they self-organize into a multicontinuous thermotropic cubic phase with the Im3虆m space group symmetry. This represents a unique example of liquid-crystalline behavior observed for such large and complex supramolecular host鈥揼uest assemblies. Models of their supramolecular organizations within both mesophases are proposed.