DOI: 10.1002/chem.201102193 Supermolecular Chiral Mesogenic Tripedes Abdelhak Belaissaoui,* [a] Isabel M. Saez, [a] Stephen J. Cowling, [a] Xiangbing Zeng, [b] and John W. Goodby [a] Introduction Mesogens are the building blocks of liquid crystalline meso- phases, which combine fluid mobility and anisotropic order- ing properties in a single material. Typically, low molar mass liquid-crystals are composed of a relatively rigid shape ani- sometric mesogenic core to which one or two terminal flexi- ble spacers, most commonly alkyl chains, are attached (Figure 1). In essence, the nature of the liquid crystal behaviour is dictated primarily by the anisometry of the mesogenic core. For example, rod-like molecules induce the formation of ca- lamitic mesophases while disc-like molecules self-organize to give columnar mesophases. Molecular conformational properties of low molar mass mesogens have limited impact on their corresponding over- all molecular anisometry and consequently have limited in- fluence on their structural phase type. However, conforma- tional isomerism can critically affect the thermodynamic sta- bility of the mesophases. On the other hand, conventional dendritic-like supermo- lecular liquid crystals [1] consist of a number of mesogenic units attached to an inner core via flexible spacers (Figure 2). The associated conformational properties give rise to a number of different molecular anisometric shapes. Hence, the mesophase type of supermolecular liquid crystals strongly depends on the dominant conformational struc- ture(s) in the bulk. In contrast to low molar mass mesogens, there is a strong interdependence between the conforma- tional properties and the phase type of supermolecular liquid crystals. However, the statistical probability of the condensed phase dominant conformer(s) is dictated primari- ly by the space filling efficiency. [2] Thus, the dominant con- formational structure(s) may differ from the minimum energy conformers in the single-molecule state. Overall, the core-shell structure is the key component controlling the three-dimensional orientation of the mesogenic units and consequently the supermolecular conformational properties and their associated packing characteristics. In addition, the self-assembly in mesophases of globular supermolecular liquid crystals can be tuned further by incor- porating specific functional moieties within the central core structural components to add site specific interactions, such as hydrogen bonding or nanosegregation. Carbohydrate-based mesogens represent a large class of liquid crystals that exhibit lyotropic as well as thermotropic phase behaviours. [3, 4] The growing interest in such materials, as a promising source of novel liquid crystalline materials, has arisen as a result of their profound importance in many biological and molecular recognition processes. [3, 5] Yet, there have been very few reports on the synthesis and mesomor- phic properties of supermolecular liquid crystals with carbo- hydrate-based cores and mesogenic units attached at the pe- riphery. [6, 7] Moreover, in nature, hydrogen bonding interactions are considered of crucial importance in inducing aggregation. Abstract: A novel series of chiral liquid crystalline tripedes Glucoside and Mannoside derivatives G n and M n (n = 1–3) have been synthesised. The inner cores consist of methyl a-d-Glu- coside G or methyl a-d-Mannoside M, regioselectively functionalised at the less hindered position C6, with tert-bu- tyldimethylsilyl (TBDMS), hydroxyl or carboxylic acid moieties. The cores, which can acquire several flexible con- formations, are attached to rod-like smectogenic-preferring cyanobiphenyl units, by means of a flexible hexanoyl spacer. These Glyco-Supermolecules exhibit chiral nematic (N*) and smectic A (SmA) phases. The combined effects of core chirality and functional groups on thermal and mesomorphic charac- teristics are discussed. Keywords: carbohydrates · chirality transfer · liquid crystals · mesogens · tripedes [a] Dr. A. Belaissaoui, Dr. I. M. Saez, Dr. S. J. Cowling, Prof. J. W. Goodby Department of Chemistry, University of York Heslington Road, York, YO10 5DD (UK) E-mail : abdel.belaissaoui@york.ac.uk [b] Dr. X. Zeng Department of Materials Science and Engineering The University of Sheffield, Sheffield, S1 3JD (UK) Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/chem.201102193. Figure 1. Typical low molar mass mesogens consisting of a shape-aniso- metric core and one or two flexible end-chains.  2012 Wiley-VCH Verlag GmbH&Co. KGaA, Weinheim Chem. Eur. J. 2012, 18, 2366 – 2373 2366