The synthesis and photochemistry of 1,3-bis-O-(9-anthroyl)-1,3-propanediol is reported. UV irradiation of this compound led to the formation of both intra- and intermolecular photoproducts; unexpectedly, the major product was identified by NMR and X-ray crystallography as a 1,9'-4,10'dianthracene intramolecular cyclomer. The photocyclomer could be prepared in 98% yield and was found to be thermally stable in the dark at room temperature but underwent photochemical reversion to the starting material upon exposure to 285 nm light or via thermal conversion at 80 degrees C. Epoxidation of the cyclomer locked the molecule in its cyclized form, inhibiting both photochemical and thermal ring-opening.

We report the synthesis, mesophase characterization, and ionic conductivity of a new family of liquid crystalline materials based on amphiphilic beta-cyclodextrin (beta-CD) derivatives. These unique derivatives are based on a novel design to have 14 aliphatic chains of varying lengths attached to the secondary face of beta-CD via ester linkages, and 14 O-monomethyl triethylene glycol units grafted onto the primary face via copper(i)-mediated azide-alkyne cycloaddition (CuAAC) with the help of chlorohydrin chemistry. Compared to previously reported analogues, these amphiphilic CDs exhibit a distinct molecular geometry with an expanded hydrophilic domain. Mesophase studies reveal that derivatives bearing longer aliphatic chains (>= C10) self-assemble into thermotropic liquid crystalline phases, predominantly forming smectic A (SmA) mesophases through nanophase segregation of polar and non-polar regions, while one derivative also demonstrates the ability to form a bicontinuous cubic phase that coexists with the lamellar phase. Solid-state nuclear magnetic resonance (NMR) and variable-temperature X-ray diffraction (XRD) studies confirm the presence of long-range molecular order within the SmA phases. Moreover, impedance spectroscopy reveals that these materials exhibit excellent lithium-ion conductivity, achieving a maximum of 4.86 & times; 10-3 S cm-1, suggesting their potential as a group of promising electrolytes based biodegradable scaffolds. This work underscores the potential of applying innovative molecular designs to enhance the performance of organic electrolytes.

We report the synthesis and dielectric characterization of a zwitterionic compound based on two common ionic liquid moieties. This compound can be blended with poly(methyl methacrylate) (PMMA) to form thin films. At high zwitterion concentrations, elevated temperatures, and low frequencies, the films exhibit behavior typical of electrochemical double layers, despite the absence of free ions. Capacitance values are in the range of 10 mu F cm-2 and do not depend on film thickness. At low temperatures, the films behave as linear dielectric materials with a dielectric constant of approximately 7. The transition between these two regimes is governed by a phase transition corresponding to the melting temperature of the zwitterion, as observed through differential scanning calorimetry (DSC) and polarized optical microscopy (POM). X-ray diffraction (XRD) analysis suggests that at low temperatures and high concentrations, zwitterions adopt a lamellar structure characterized by strong antiparallel interactions between lamellae, which inhibit a strong paraelectric response. As the temperature increases, the compounds no longer exhibit phase separation and can adopt a parallel configuration, resulting in high capacitance paraelectric behavior. Overall, the zwitterionic compound reported here shows promising behavior that can be well-understood from its thermophysical and morphological properties.

Two cholesterol-based liquid crystalline materials were synthesized by incorporating perfluorinated acyl chains of different lengths with the help of epichlorohydrin and copper(I)-mediated azide-alkyne 2+3 dipolar cycloaddition chemistries. These materials were characterized by differential scanning calorimetry, cross-polarized optical microscopy and powder X-ray diffraction. The compound with the longer perfluorinated chain exhibited a smectic A (SmA) phase as confirmed by XRD and POM, while the shorter-chain derivative exhibited diffraction peaks suggestive of both simple SmA* ordering as well as lamellar solid phase exhibiting multilayer ordering.

We report the synthesis and mesomorphic studies of a family of amphiphilic β-cyclodextrin derivatives that are polyesterified at the secondary face with either 14 lauroyl or 14 stearoyl chains (apolar), and 7 tri- or tetra-ethylene glycols (polar) at the primary face. The end of each tri- and tetra-ethylene glycol chain is further modified with different terminal functionalities in term of their dipole moment (O-methyl vs O-acetyl vs O-2-cyanoethyl). This has generated several subgroups of amphiphilic β-cyclodextrin derivatives with a systematic change of their relative volumes of the hydrophobic and hydrophilic regions. Our studies showed that all these derivatives self-assemble into thermotropic liquid crystals, with the majority forming hexagonal column mesophases while three compounds form a bicontinuous cubic phase. We rationalized the mesomorphic behaviour of these compounds in term of the relative total van der Waals fractional volumes occupied by the hydrophilic and hydrophobic chains. Upon added with LiTFSI, the formed bicontinuous cubic phase (as a pure compound) was found to transition to form the more stable smectic A mesophase (composite), and both solid NMR studies and impedance spectroscopy revealed that these novel amphiphilic β-cyclodextrin-based liquid crystalline materials have the potential to be used as efficient electrolytes for lithium conduction.

A group of new zwitterion based ionic liquid crystals (ILCs) have been synthesized. Depending on the counter anion (mesylate or hydrogen sulfate) the phase behavior of the resulting ILCs is quite different. Mesylate based ILCs show complex phase behavior with multiple phases depending on the alkyl chain length. In contrast, hydrogen sulfate based systems always exhibit Colr phases irrespective of the alkyl chain length. The latter show much larger ILC mesophase windows and are thermally stable up to ca. 200 degrees C. All ILCs show reasonable ionic conductivities of up to 10-4 S cm-1 at elevated temperatures, making these ILCs candidates for intermediate temperature ionic conductors.

Blue/green to red/purple [PcMnL 2 ]SbF 6 complexes (L = THF, pyridine, DMAP, Ph 3 PO, N -methylimidazole, MeCN) with increased solubility in organic solvents illustrate facile tuning of visible colours via axial-ligand exchange for PcMn( iii ) materials.

Although discotic dimers commonly feature bulky ether substituents adjacent to the linking group, the impact of these chains on self-assembly remains unclear. A series of dibenzo[a,c]phenazine dimers with alkoxy groups ortho to the linker were prepared and their solution conformational dynamics and liquid crystalline properties examined. The presence of a methoxy substitutent adjacent to the bridging group increased the phase stability, whereas longer chains dramatically decreased clearing temperatures. NMR solution studies indicated that adjacent groups increased the preference of dimers to adopt unfolded conformers. DFT models indicated that the unfolded structures were nonplanar and hence less compatible with columnar ordering, leading to a destabilization of the mesophases. Although discotic dimers commonly feature bulky ether substituents adjacent to the linking group, the impact of these chains on self-assembly remains unclear.

This study explores the liquid crystalline properties of novel amphiphilic β-cyclodextrin derivatives functionalized with seven oligoethylene glycol chains at the primary face, terminated with either an O-methyl or an O-cyanoethyl group, and fourteen hydrophobic aliphatic chains (elaidic or oleic acids) at the secondary face. These derivatives were designed to study the impact of chain conformation and terminal group polarity on their mesomorphic behavior. Thermal, microscopic, and X-ray diffraction studies revealed that the elaidic derivatives form columnar hexagonal mesophases, with the O-cyanoethyl derivative undergoing a slow, temperature-dependent transition to a bicontinuous cubic phase. The oleic derivatives, although less stable, also exhibit columnar hexagonal phases, but clear differences were observed in the clearing temperatures between these two groups of molecules, and they are also different from analogous derivatives containing no alkene functionalities. This work provides direct insights into the structure–mesomorphic property relationships of amphiphilic cyclodextrins in terms of the geometry and conformation flexibility of the hydrophobic regions, as well as the functional group attached to the end of the polar region.

A novel zwitterion composed of an imidazolium tethered to an anionic sulfonyl(trifluoromethane sulfonyl)imide group was prepared as an alternative dielectric material to traditional ionic liquids. The zwitterion not only melted below 100 degrees C but also proved to be nonhygroscopic. High-capacitance organic dielectric materials were obtained by blending this compound with poly(methyl methacrylate) over a range of concentrations and thicknesses. Above a specific temperature and concentration, films exhibit a capacitance nearly equivalent to that of an electrostatic double layer, approximately 10 mu F/cm(2), regardless of their thickness. Grazing-incidence wide-angle X-ray scattering experiments suggest that the zwitterions adopt a lamellar ordering at their surface above a critical concentration. The observed ordering is correlated with a 1000-fold increase in capacitance. The behavior suggests that the zwitterions exhibit strong electrostatic correlations throughout the film bulk, pointing the way toward a novel class of organic dielectric materials.

Amphiphilic supramolecular materials based on biodegradable cyclodextrins (CDs) have been known to self-assemble into different types of thermotropic liquid crystals, including smectic and hexagonal columnar mesophases. Previous studies on amphiphilic CDs bearing 14 aliphatic chains at the secondary face and 7 oligoethylene glycol (OEG) chains at the primary face showed that the stability of the mesophase can be rationally tuned through implementation of terminal functional groups to the OEG chains. Here, we report the syntheses of first examples of crown ether-functionalized amphiphilic cyclodextrins that unexpectedly form thermotropic bicontinuous cubic phases. This constitutes the first reported examples of cyclodextrins forming such phases, which are potentially capable of 3D ion transport. Lithium composites were made to assess lithium conduction in the material. XRD revealed the added lithium salt destabilizes the cubic phase in favour of the smectic phase. Solid-state NMR studies showed that these materials conduct lithium ions with a very low activation energy.

Two diastereomeric dibenzo[a,c]phenazine 1,2-cyclohexyl bridged diesters were prepared and their phase properties examined. While the trans dimer exhibited a broad columnar liquid crystal phase, the cis dimer was amorphous at all temperatures studied. This difference was attributed to the conformational dynamics of the two systems. NMR and DFT studies indicate that both dimers adopt folded and unfolded conformers in solution. While their folded geometries were similar, the trans dimer adopts an extended, largely planar structure, whereas the cis dimer is limited to non-planar unfolded structures and likely disrupts columnar ordering. Geometric constraints imposed by the cylcic linker were also important for columnar stability, with the trans dimer clearing 40 °C lower than the corresponding acyclic 2R,3R-butyl linked dimer, likely because the cyclohexyl group hinders π-π stacking in the unfolded conformation of the former.

The addition of ether functional groups to a metallophthalocyanine ring is known to significantly decrease the oxidation potentials of the ring. In this light, the impact of the branching of alkyl-ether groups on the electronic properties was investigated via the synthesis of non-peripheral ([Formula: see text]-substituted n-butyl (1), iso-butyl (2) and sec-butyl (3) 1,4,8,11,15,18,22,25-octabutoxyphthalocyanines, in conjunction with Co and Cu metal centers. From 1 to 3 the first and second ring-based oxidation potentials were decreased by 70 mV and 110 mV respectively both for Cu and Co-containing complexes; the UV-visible Q-band maxima only changed by 4-8 nm, consistent with the destabilization of both the HOMO and LUMO, as confirmed by TD-DFT calculations. The reversibility of both redox couples was improved via branching (3) for the Co complexes. All six complexes were structurally characterized, with varying levels and types of ring distortions. All molecules show 1-D supramolecular stacking, but for n-butoxy 1Co an intermolecular Co-O interaction aligns the molecular stacks, while for sec-butoxy 3Co only [Formula: see text]-[Formula: see text] stacking of the Pc-ring was present. Both 3Co and 3Cu were ring-oxidized at lower potentials than 1Co and 1Cu, and the increased steric bulk from the branched ether chains prevented the overlap of their N 8 C 8 inner rings.

A series of discotic dimers were synthesized in an attempt to obtain nematic discotic liquid crystal phases. Although initial target compounds were nonmesogenic, the incorporation of bulky groups adjacent to the ester bridge, in conjunction with peripheral chains of mixed length, were used to promote the formation of an enantiotropic nematic phase.

Polyesterified amphiphilic β-cyclodextrin derivatives bearing functionalized tetraethylene glycols showed excellent abilities to self-assemble into stable hexagonal columnar mesophases with 1D ion conducting channels.

Tethering of two shape mismatched donors and acceptor leads to an unusual mesogen design.

A series of zinc (1,4,8,11,15,18,22,25-octabutoxy)phthalocyanine (2) complexes that spontaneously form 5-coordinate complexes with anionic axial ligands neutralized with side-pocket cations, of the form Cation-PcZnX (X=Cl, OAc; Cation=H+ or Li+), was synthesized and structurally characterized. The side-pocket protonation of the axial-chloride species pushed the emission maximum from 760 nm (for axial ligand-free 2) to 826 nm, well into the NIR region. A 1D-coordinated chain bridged by lithium and chloride atoms was isolated and structurally characterized, representing the first side-pocket metalated PcM species. This preferential formation of axially substituted [PcZnX](-) "ate" complexes and their sequestration of both protons and lithium cations, opens a new series of materials with unique structural and electronic properties. Furthermore, their ability to both absorb and emit in the NIR region makes them desirable for numerous applications.

Although discotic liquid crystal dimers have been widely targeted as organic semiconductors and as LC-glass formers, the role of conformational dynamics on the self-assembly of these flexible mesogens remains poorly understood. In an effort to probe this effect, we investigated the impact of linker stereochemistry on the phase behavior of discotic liquid crystalline dimers. Diastereomeric dibenzo[a,c]phenazine diesters were prepared from (2R,3R)- and meso-2,3-butanediol. While both dimers form columnar phases, the meso-isomer had a clearing temperature (Tc) that was 31 °C higher than that of its chiral diastereomer. Conformational analysis via DFT calculations, 1H-NMR, and DOSY experiments indicated that both compounds adopt predominantly extended conformations but that the meso-dimer shows a stronger preference to unfold in solution. To probe how conformation alters phase stability, we prepared derivatives in which catechol and hydroquinone act as rigid linkers that lock the dimers in a folded or an extended conformation, respectively. The diester of hydroquinone possessed a Tc that was nearly 100 °C higher than the catechol derivative, consistent with a model where extended conformations stabilize the LC phase. Extended dimers also exhibited higher transition enthalpies at the Tc, an indication that their columnar phases are more ordered than folded structures.

Although the impact of individual functional groups on the self-assembly of columnar liquid crystal phases has been widely studied, the effect of varying multiple substituents has received much less attention. Herein, we report a series of dibenzo[a,c]phenazines containing an alcohol or ether adjacent to an electron-withdrawing ester or acid. With one exception, these difunctional mesogens form columnar phases. The phase behavior appeared to be dominated by the electron-withdrawing substituent; transition temperatures were similar to derivatives with these groups in isolation. In most instances, the addition of an electron-donating group ortho to an ester or acid suppressed the melting temperature and elevated the clearing temperature, leading to broader liquid crystal thermal ranges. This effect was more pronounced for derivatives functionalized with longer chain hexyloxy groups. These results suggest a potential strategy for controlling the phase ranges of columnar liquid crystals and achieving room temperature mesophases.

Liquid crystalline self-assembly offers the potential to create highly ordered, uniformly aligned, and defect-free thin-film organic semiconductors. Analogues of one of the more promising classes of liquid crystal semiconductors, 5,5"-dialkyl-α-terthiophenes, were prepared in order to investigate the effects of replacing the central thiophene with either an oxadiazole or a thiadiazole ring. The phase behaviour was examined by differential scanning calorimetry, polarized optical microscopy, and variable temperature x-ray diffraction. While the oxadiazole derivative was not liquid crystalline, thiadiazole derivatives formed smectic C and soft crystal lamellar phases, and maintained lamellar order down to room temperature. Variation of the terminal alkyl chains also influenced the observed phase sequence. Single crystal structures revealed the face-to-face orientation of molecules within the layers in the solid-state, a packing motif that is rationalized based on the shape and dipole of the thiadiazole ring, as corroborated by density functional theory (DFT) calculations. The solution opto-electronic properties of the systems were characterized by absorption and emission spectroscopy, cyclic voltammetry, and time-dependent density functional theory (TD-DFT).