Hierarchical Control of Internal Superstructure, Diameter, and Stability of Supramolecular and Macromolecular Columns Generated from Tapered Monodendritic Building Blocks

Abstract

The synthesis of the first generation AB 3 monodendrons 3,4,5-tris[6-alkyloxy-2-methylnaphthyloxy]benzoic acid (with decyl, dodecyl, tetradecyl, and hexadecyl alkyl groups), 3,4,5-tris[4-(4′dodecyloxyphenyl)benzyloxy]benzoic acid, their ω-hydroxy(tetraethylene glycol) esters, and the corresponding methacrylates and poly(methacrylate)s is described. All monodendrons and the corresponding polymers self-assemble into supramolecular columns that self-organize in a columnar hexagonal (Φh) thermotropic liquid crystalline (LC) phase. The characterization of their Φh phase by a combination of differential scanning calorimetry (DSC), thermal optical polarized microscopy, and X-ray diffraction experiments demonstrated an intracolumnar microsegregated model for these supramolecular structures. The role and the contribution of the aliphatic, aromatic, oligooxyethylenic, and polymethacrylate fragments to the formation and the control of the external diameter, the internal structure, and the stability of these supramolecular columns and of the Φ h phase were quantitatively evaluated and demonstrated that the contribution of the aromatic component dominates over that of the other structural components both in the control of column diameter and in thermodynamic stability of the resulted Φh phase. Scheme 2. Synthesis of 3,4,5-tris-[n-alkyloxy]benzoic Acid Derivatives, 8-n-Nf (n ) 10, 12, 14, 16) and 8-12-Bp

Transformation of a Spherical Supramolecular Dendrimer into a Pyramidal Columnar Supramolecular Dendrimer Mediated by the Fluorophobic Effect

“…[2a, 6,12,13] The electron density computed from the XRD data is consistent with both the pyramidic and nonhelical pine-tree models for the packing of the dendritic molecule (3,4,5) 2 12F8G2-CO 2 CH 3 in the columnar LC phase.…”

Liquid crystalline photoactive hyperbranched and linear benzylidene polyester with terminal epoxy and pendant hydroxyl groups

“…7 Limited availability of AB n monomers increases the use of readily available A 2 þ B 3 monomers for the synthesis of HBP. 8,[9][10][11] After preliminary work by Kim 12 on hyperbranched liquid crystalline polymers, (HBLCPs), synthesized by the AB n approach, the revolutionary work in this field was carried out by Percec et al, [13][14][15][16][17][18] Shibaev et al, 19 and others [20][21][22][23] have reported on photo-addressable dendritic polymers (PADLCPs) containing both mesogenic and photochromic groups. PADLCPs have shown enhanced physicochemical properties and photo and thermally induced physical changes as compared with linear polymers.…”

Exploring and Expanding the Structural Diversity of Self‐Assembling Dendrons through Combinations of AB, Constitutional Isomeric AB2, and AB3 Biphenyl‐4‐Methyl Ether Building Blocks

“…These three new building blocks, together with 4-[4'-(ndodecan-1-yloxy)phenyl]benzyl chloride (11), prepared as previously reported, [26] were employed in the synthesis of seven libraries of dendrons. The synthesis of the dendrons was accomplished by using the convergent strategy [2] developed in our laboratory for the synthesis of dendritic benzyl ethers.…”

“…The synthesis of (4'-(n-dodecane-1-yloxy)biphenyl-4-methyl chloride (17) was performed as reported previously. [26] Pyridinium hydrochloride was prepared by the dropwise addition of HCl to pyridine until pH 4-5 was reached, followed by evaporation of water.…”