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First example of a redox stable conducting polymer with a rhodamine backbone.

Here we address a longstanding challenge in the field of optoelectronic materials by evaluating the molecular and solid-state arrangements of heterocyclic oligomers and correlating their crystal structures to their optical properties.

Electropolymerization has become a convenient method for synthesizing and characterizing complex organic copolymers having intrinsic electronic conductivity, including the donor (D)–acceptor (A) class of electronically conducting polymers (ECPs). This review begins with an introduction to the electrosynthesis of common second-generation ECPs. The information obtainable from electroanalytical studies, charge carriers such as polarons (positive and negative) and bipolarons (positive and negative) and doping will be discussed. The evolutionary chain of ECPs is then presented. ECPs comprising electron-rich D and electron-deficient A moieties have been shown to possess intrinsic electronic conductivity and unique optical and electronic properties. They are third generation ECPs and electropolymerization of mixtures of D and A leads to stoichiometrically controlled block copolymers. These D–A type ECPs are discussed on the basis of selected representative materials. Since the discovery of electropolymerization as a powerful tool to synthesize copolymers of conjugated monomers with a pre-determined ratio of D and A repeat units present in the polymer, the field of D–A type ECPs has grown considerably and the literature available since 2004 to 2021 is summarized and tabulated. Electronic and optical properties of the materials determined by computational chemistry are presented. The data obtained from electrochemical and optical methods are compared with those obtained from computational methods and reasons for discrepancies are given. The literature on the concept of electropolymerization extended to synthesizing triblock and many-block copolymers is reviewed. Finally, applications of D–A polymers in optoelectronic devices (organic solar cells and field-effect transistors) and in bio-imaging are explained quoting appropriate examples.

This work provides fascinating insights into NIR fluorophore design and methods to effectively alter the photophysical and morphological properties of the nanoaggregates for bio-imaging purposes.

Shortwave infrared (SWIR)-emitting small molecules are desirable for biological imaging applications. In this study, four novel pentamethine indolizine cyanine dyes were synthesized with N,N-dimethylaniline-based substituents on the indolizine periphery at varied substitution sites. The dyes are studied via computational chemistry and optical spectroscopy both in solution and when encapsulated. Dramatic spectral shifts in the absorption and emission spectrum wavelengths with added donor groups are observed. Significant absorption and emission with an emissive quantum yield as high as 3.6% in the SWIR region is possible through the addition of multiple donor groups per indolizine.

Guided by computational analysis, herein we report the design, synthesis and evaluation of four novel diazine-based histone deacetylase inhibitors (HDACis). The targets of interest (TOI) are analogues of panobinostat, one of the most potent and versatile HDACi reported. By simply replacing the phenyl core of panobinostat with that of a diazine derivative, docking studies against HDAC2 and HDAC8 revealed that the four analogues exhibit inhibition activities comparable to that of panobinostat. Multistep syntheses afforded the visualized targets TOI1, TOI2, TOI3-rev and TOI4 whose biological evaluation confirmed the strength of HDAC8 inhibition with TOI4 displaying the greatest efficacy at varying concentrations. The results of this study lay the foundation for future design strategies toward more potent HDACis for HDAC8 isozymes and further therapeutic applications for neuroblastoma.

Linear-dendritic block copolymers (LDBCs) have emerged as promising materials for drug delivery applications, with their hybrid structure exploiting advantageous properties of both linear and dendritic polymers. LDBCs have promising encapsulation efficiencies that can be used to encapsulate both hydrophobic and hydrophilic dyes for bioimaging, cancer therapeutics, and small biomolecules. Additionally, LDBCS can be readily functionalized with varying terminal groups for more efficient targeted delivery. However, depending on structural composition and surface properties, LDBCs also exhibit high dispersities (

This study represents a successful approach toward employing polycaprolactone-polyamidoamine (PCL-PAMAM) linear dendritic block copolymer (LDBC) nanoparticles as small-molecule carriers in NIR imaging and photothermal therapy. A feasible and robust synthetic strategy was used to synthesize a library of amphiphilic LDBCs with well-controlled hydrophobic-to-hydrophilic weight ratios. Systems with a hydrophobic weight ratio higher than 70% formed nanoparticles in aqueous media, which show hydrodynamic diameters of 51.6 and 96.4 nm. These nanoparticles exhibited loading efficiencies up to 21% for a hydrophobic molecule and 64% for a hydrophilic molecule. Furthermore, successful cellular uptake was observed via trafficking into endosomal and lysosomal compartments with an encapsulated NIR theranostic agent (C3) without inducing cell death. A preliminary photothermal assessment resulted in cell death after treating the cells with encapsulated C3 and exposing them to NIR light. The results of this work confirm the potential of these polymeric materials as promising candidates in theranostic nanomedicine.

Thermal chemical synthesis of conjugated polymers has often been plagued by low product yields, by-product contamination and high-cost catalysts. Electrochemical synthesis is an alternative strategy that can overcome these failures to obtain highly efficient syntheses. Herein, we present the study of diketopyrrolopyrrole-bisthiophene (DPPT2), diketopyrrolopyrrole-bisfuran (DPPF2) and thienothiadiazole-bisthiophene (TTDT2) for diblock copolymerization with terthiophene (T3) as a π-linker to form tunable narrow band gap polymers. The polymers suspended as thin films have similar redox characteristics to the monomers with potential shifts that prove the identity of the respective polymers. Electrochemical impedance measurements were carried out in the −0.6 V to 1.0 V potential range with an average electron transport resistance (Re) value of 110 Ω irrespective of the applied potential. This confirms the polymers to have higher intrinsic electrical conductivity. The atomic ratios of the synthesized materials were calculated experimentally using energy dispersive X-ray (EDX) analysis, and they confirm the theoretical composition of the polymers. These doped polymers exhibit absorption bands in the visible to SWIR region (800–1800 nm) with optical band gaps from 0.773 to 1.178 eV in both the solid and the solution state.

The study of π-conjugated oligomers has garnered significant interest because of their use in organic optoelectronic devices, such as organic light-emitting diodes or organic field-effect transisto...

Shortwave infrared (SWIR) emission has great potential for deep-tissue in vivo biological imaging with high resolution. In this article, the synthesis and characterization of two new xanthene-based RosIndolizine dyes coded PhRosIndz and tolRosIndz is presented. The dyes are characterized via femtosecond transient absorption spectroscopy as well as steady-state absorption and emission spectroscopies. The emission of these dyes is shown in the SWIR region with peak emission at 1097 nm. TolRosIndz was encapsulated with an amphiphilic linear dendritic block co-polymer (LDBC) coded 10-PhPCL-G3 with high uptake yield. Further, cellular toxicity was examined in vitro using HEK (human embryonic kidney) cells where a >90% cell viability was observed at practical concentrations of the encapsulated dye which indicates low toxicity and reasonable biocompatibility.

Small molecular organic fluorophores have garnered significant interest because of their indispensable use in fluorescence imaging (FI) and optoelectronic devices. Herein, we designed triphenylamine (TPA)-capped donor-acceptor-donor (D-A-D)-based fluorophores having a variation at the heterocyclic donor (D) units, 3,4-ethylenedioxythiophene (EDOT), furan (FURAN), thiophene (THIO), and 1-methyl-1H-pyrrole (MePyr), with isoindigo as the core electron acceptor (A) unit. Synthesis of these fluorophores (II-X-TPA) resulted in four symmetrical dye molecules: II-EDOT-TPA, II-FURAN-TPA, II-THIO-TPA, and II-MePyr-TPA, where TPA functioned as a terminal unit and a secondary electron donor group. Photophysical, electrochemical, and computational analyses were conducted to investigate the effect of heterocyclic donor units on the II-X-TPA derivatives. Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations provided insightful features of structural and electronic properties of each fluorophore and correlated well with experimental observations. Electron density distribution maps, overlapping frontier molecular orbital diagrams, and highest occupied molecular orbital (HOMO) to lowest unoccupied molecular orbital (LUMO) electron transfer indicated intramolecular charge transfer (ICT). Theoretical studies confirmed the experimental HOMO energy trend and demonstrated its crucial importance in understanding each heterocycle's donor ability. Stokes shifts of up to ∼178 nm were observed, whereas absorptions and emissions were shifted deeper into the NIR region, resulting from ICT. Results suggest that this isoindigo fluorophore series has potential as a molecular scaffold for the development of efficient FI agents. The studied fluorophores can be further tuned with different donor fragments to enhance the ICT and facilitate in shifting the optical properties further into the NIR region.

Recent advancements in material science exploit non-covalent interactions, such as halogen bonding (XB) or π-stacking within solid-state molecular frameworks for application in organic electronic devices. Herein, we focus on these and other non-covalent interactions and the effect that furan and thiophene substituents play on the solid-state properties of co-crystals formed between pentafluoro(iodoethynyl)benzene (F5BAI; XB donor) and a pyridine disubstituted with either furans or thiophenes (PyrFur2 and PyrThio2; XB acceptors). Spectroscopic and thermal analyses of 1 : 1 mixtures provide indirect evidence of XB interactions, whereas X-ray crystallography provides direct evidence that XB and π-stacking are present in both co-crystals. Density functional theory (DFT) computations provide insight into the relative electronic energetics of each pair-wise contact observed in the experimental F5BAI-PyrFur2 and F5BAI-PyrThio2 co-crystals.

Block copolymers comprising benzothiadiazole were successfully electro-copolymerized leading to (BTD-T2)n(BTD-F2)m, where n and m were varied in a perfectly controllable, well-defined manner. The polymers were characterized by cyclic voltammetry, AC-impedance, SEM–EDAX and XPS analyses. They exhibit absorbance and emission in the near infrared (NIR) region. Results support an efficient strategy towards the creation of even more complex materials with innumerable possible applications in optoelectronic.

A quantitative assessment of the substituent, hybridization, and crystal-packing effects on the electronic, structural, and vibrational properties of halogen bonded systems is presented. Through a combined experimental and theoretical approach employing Raman spectroscopy, X-ray crystallography, and density functional theory, a series of solid-state iodobenzene and iodoethynylbenzene derivatives substituted with electron withdrawing groups (-F2, -(CF3)2, -F5, and -(NO2)2) and their complexes with two pyridine-based building blocks are characterized. Structural analysis via X-ray crystallography and density functional theory computations suggests that these 1:1 molecular assemblies are not only driven by halogen bonding, but also by other energetically competitive noncovalent interactions, such as π-stacking. The magnitude of the σ-hole localized around the C–I bond in the isolated halogen bond (XB) donors and the interaction strength in the complexes unambiguously depend on the nature of the substituents ...

Presented are design strategies towards hierarchically assembling a C2-symmetric π-conjugated oligomer (DAD-XB-Boc) based on a donor–acceptor–donor motif through hydrogen bonding (HB), halogen bonding (XB), and π-stacking interactions. Upon co-crystallization with tetrafluoro-1,4-diiodobenzene (TFDIB), single crystal X-ray analysis reveals highly directional XB induced 2D assemblies which further organize via π–π interactions. Crystal photoluminescence (PL) analysis indicates that the co-crystal exhibits a red shift in its PL spectrum with enhanced intensity compared to the mono-crystal. Pyrolytic cleavage and removal of the t-butyloxycarbonyl (Boc) groups of DAD-XB-Boc exposes complementary hydrogen bonding sites; the H-bonding capability of DAD-XB-NH is evident from thermal gravimetric analysis (TGA) and infrared (IR) spectroscopy. Overall, the data show that both halogen and hydrogen bonding can be used together with π-stacking interactions to enhance the solid-state properties of DAD oligomers essential for optoelectronic device applications. Ongoing work seeks to use such supramolecular approaches to control the nanoscale to microscale arrangement of molecules in thin films and increase device efficiency (i.e., charge mobility).

The thienopyrazine (TPz) building block allows for NIR photon absorption in dye-sensitized solar cells (DSCs) when used as a π-bridge. We synthesized and characterized 7 organic sensitizers employing thienopyrazine (TPz) as a π-bridge in a double donor, double acceptor organic dye design. Donor groups are varied based on electron donating strength and sterics at the donor-π bridge bond with the acceptor groups varied as either carboxylic acids or benzoic acids on the π-bridge. This dye design was found to be remarkably tunable with solution absorption onsets ranging from 750 to near 1000 nm. Interestingly, the solution absorption measurements do not accurately approximate the dye absorption on TiO2 films with up to a 250 nm blue-shift of the dye absorption onset on TiO2. This shift in absorption and the effect on electron transfer properties is investigated via computational analysis, time-correlated single photon counting studies, and transient absorption spectroscopy. Structure–performance relationships...

Polysulfone (PSU) –based Proton Exchange Membranes (PEMs) were synthesized from different pre-sulfonated monomers and evaluated for use in a vanadium redox flow battery (VRFB). Two types of sulfonated monomers, containing either an allyl sulfonate or styrene sulfonate group, were synthesized by a Mizoroki-Heck reaction from a 4,4′-difluorodiphenyl sulfone derivative. These monomers were polymerized with 4,4′-(hexafluoroisopropylidene)diphenol to give partially fluorinated PSUs with controlled placement and content of sulfuric acid moieties. PEMs were then fabricated by solution casting and characterized against the membranes made from traditional backbone sulfonated PSU. The new PEMs revealed desirable physical properties and performance in a VRFB cell competitive with the Nafion membrane. Furthermore, each PEM with a different acid side-chain structure exhibited varying properties and performance depending on its acid content, providing a path to optimization.

The effects of intermolecular interactions by a series of haloaromatic halogen bond donors on the normal modes and chemical shifts of the acceptor pyrimidine are investigated by Raman and NMR spectroscopies and electronic structure computations. Halogen bond interactions with pyrimidine's nitrogen atoms shift normal modes to higher energy and shift 1H and 13C NMR peaks upfield in adjacent nuclei. This perturbation of vibrational normal modes is reminiscent of the effects of hydrogen bonded networks of water, methanol, or silver on pyrimidine. The unexpected observation of vibrational red shifts and downfield 13C NMR shifts in some complexes suggests that other intermolecular forces such as pi-interactions are competing with halogen bonding. Natural bond orbital analyses indicate a wide range of charge transfer from pyrimidine to different haloaromatic donors is possible and computed halogen bond binding energies can be larger than a typical hydrogen bond. These results emphasize the importance in strategic selection of substituents and electron withdrawing groups in developing supramolecular structures based on halogen bonding.

Histone deacetylases (HDAC) are being targeted for a number of diseases such as cancer, inflammatory disease, and neurological disorders. Within this family of 18 isozymes, HDAC4 is a prime target for glioma, one of the most aggressive brain tumors reported. Thus, the development of HDAC4 inhibitors could present a novel therapeutic route for glioma. In this work, molecular docking studies on cyclopropane hydroxamic acid derivatives identified five novel molecular interactions to the HDAC4 receptor that could be harnessed to enhance inhibitor binding. Thus, design guidelines for the optimization of potent HDAC4 inhibitors were developed which can be utilized to further the development of HDAC4 inhibitors. Using the developed guidelines, eleven novel cyclopropane hydroxamic acid derivatives were designed that outcompeted all original cyclopropane hydroxamic acids HDAC4 inhibitors studied in silico. The results of this work will be an asset to paving the way for further design and optimization of novel potent HDAC4 inhibitors for gliomas.

Among recent advances toward efficient semiconducting materials, rational design guidelines have emerged focusing on the synergy between various intermolecular interactions to improve the solid-state order of π-conjugated molecules in organic electronic devices. Herein, we focus our attention on halogen bonding (XB) interactions and the crucial role of electron withdrawing substituents (e.g., nitro and fluoro) toward influencing solid-state properties via secondary interactions. Employing iodoethynyl benzene derivatives (F2BAI and (NO2)2BAI) and thiophene/furan-based building blocks equipped with pyridyl groups as self-assembling domains (PyrTF and PyrT2), co-crystals driven by XB and π-stacking interactions were formed and studied. Spectroscopic and thermal analysis of 1:1 mixtures provide initial evidence of co-crystallization. X-ray crystallography affords the inherent solid-state packing motifs within each assembly. Computational studies support experimental observations, revealing the dominant intera...

Histone Deacetylases (HDACs) are an important family of 18 isozymes, which are being pursued as drug targets for many types of disorders. HDAC2 and HDAC8 are two of the isozymes, which have been identified as drug targets for the design of anti-cancer, neurodegenerative, immunological, and anti-parasitic agents. Design of potent HDAC2 and HDAC8 inhibitors will be useful for the therapeutic advances in many disorders. This work was undertaken to develop potent HDAC2 and HDAC8 inhibitors. A docking study was performed comparing panobinostat derivatives in both HDAC2 and HDAC8. Six of our derivatives showed stronger binding to HDAC2 than panobinostat, and two of our derivatives showed stronger binding to HDAC8 than panobinostat. We evaluated the molecular features, which improved potency of our inhibitors over panobinostat and also identified another molecular consideration, which could be used to enhance histone deacetylase inhibitor (HDACi) selectivity towards either the HDAC2 or HDAC8 isozymes. The results of this work can be used to assist future design of more potent and selective HDACi for HDAC2 and HDAC8.

For organic photovoltaic (OPV) cells based on the bulk heterojunction (BHJ) structure, it remains challenging to rationally control the degree of phase separation and percolation within blends of donors and acceptors to secure optimal charge separation and transport. Reported is a bottom-up, supramolecular approach to BHJ OPVs wherein tailored hydrogen bonding (H-bonding) interactions between π-conjugated electron donor molecules encourage formation of vertically aligned donor π-stacks while simultaneously suppressing lateral aggregation; the programmed arrangement facilitates fine mixing with fullerene acceptors and efficient charge transport. The approach is illustrated using conventional linear or branched quaterthiophene donor chromophores outfitted with terminal functional groups that are either capable or incapable of self-complementary H-bonding. When applied to OPVs, the H-bond capable donors yield a twofold enhancement in power conversion efficiency relative to the comparator systems, with a maximum external quantum efficiency of 64%. H-bond promoted assembly results in redshifted absorption (in neat films and donor:C 60 blends) and enhanced charge collection efficiency despite disparate donor chromophore structure. Both features positively impact photocurrent and fill factor in OPV devices. Film structural characterization by atomic force microscopy, transmission electron microscopy, and grazing incidence wide angle X-ray scattering reveals a synergistic interplay of lateral H-bonding interactions and verticalmore » π-stacking for directing the favorable morphology of the BHJ.« less

We previously reported that a branched quaterthiophene donor chromophore functionalized with a phthalhydrazide hydrogen bonding (H-bonding) unit (MeBQPH) gives twofold more efficient bulk heterojunction organic solar cells (with C60 acceptors) compared to a nearly identical donor incapable of H-bonding (MeBQPME). Here, scanning tunneling microscopy (STM) studies confirm the formation of MeBQPH trimer rosettes on Au(1 1 1) through phthalhydrazide H-bonding interactions that are sufficiently strong to compete with adsorbate/substrate interactions. The MeBQPME comparator molecule void of hydrogen bonding functionality does not similarly assemble on the metal surface. Complementary density functional theory (DFT) calculations facilitate a structural understanding of the MeBQPH donor assemblies and their strong stabilization through formation of six hydrogen bonds. STM studies also reveal the templated growth of C60 on ordered MeBQPH monolayers with C60 molecules preferentially occupying the threefold interstitial sites of the MeBQPH monolayer. This work supports the idea that H-bonding interactions can be used to control the morphology of organic donor–acceptor blends to potentially create efficient and stable bulk heterojunction photovoltaic devices.

Although recognized as a significant force in crystal engineering, halogen bonding (XB) has been scarcely investigated in “bottom-up” approaches towards organic electronics. We report, herein, the use of a thiophene-based building block, pyridyl-thiophene (Pyr-T), to achieve an assembly driven by XB and π–π stacking interactions with iodopentafluorobenzene (IPFB). Spectroscopic and thermal analysis of the co-crystal provide indirect evidence of the assembly. The combined effects of XB and π–π stacking are confirmed experimentally via X-ray crystallography. Density functional theory (DFT) computations support experimental observations. The results of the study speak to the use of halogen bond driven self-assembly in organic electronic device application.

A series of near-infrared (NIR) organic emissive materials were synthesized and the photophysical properties analyzed. The donor-acceptor-donor materials were designed with thienopyrazine and thienothiadiazole acceptor groups with thiophene-, furan-, and triphenylamine-based donor groups. The absorption and emission spectra were found to be widely tunable on the basis of the donor and acceptor groups selected. Computational analysis confirms these materials undergo an intramolecular charge-transfer event upon photoexcitation. Large Stokes shifts of ∼150 nm were observed and rationalized by computational analysis of geometry changes in the excited state. Fluorescence studies on the dye series reveal maximum peak emission wavelengths near 900 nm and a quantum yield exceeding 16% for 4,6-bis(2-thienyl)thieno[3,4-c][1,2,5]thiadiazole. Additionally, several dyes were found to have reasonable quantum yields within this NIR region (1%), with emission wavelengths reaching 1000 nm at the emission curve onset. Photostability studies were conducted on these materials in an ambient oxygen environment, revealing excellent stability in the presence of oxygen from all the dyes studied relative to a benchmark cyanine dye (ICG) during photoexcitation with exceptional photostability from the 4,6-bis(5'-dodecyl-[2,2'-bithiophene]-5-yl)thieno[3,4-c][1,2,5]thiadiazole derivative.

Reported is a systematic molecular structure–property relationship study to evaluate the consequences of dedicated H-bonding interactions between molecular electron donors on molecular assembly, absorption, charge collection, and performance in small-molecule bulk heterojunction organic photovoltaic devices. Three families of branched quaterthiophene donor chromophores have been synthesized with members that share nearly identical electronic and optical properties in the molecularly dispersed state but are either capable or incapable of self-association by hydrogen bonding (H-bonding). Phthalhydrazide-functionalized quaterthiophenes are H-bond “active” and show signatures of H-bond promoted assembly in solution (by 1H NMR) and in both neat and blended (with C60) films (by IR). Compared to control compounds with H-bonding “turned off”, the H-bonded derivatives show red-shifted thin film absorption (neat and as blends with C60), different colors as bulk solids, and increased decomposition and melt temperatures. Photovoltaic devices made from blends of H-bonded donor molecules with C60 as the electron acceptor show improved charge collection length and external quantum efficiency resulting in a more than two-fold enhancement in power conversion efficiency relative to non-H-bonding controls, from 0.49% to 1.04%. We anticipate this approach could be generalized to include other donor chromophores with lower optical gap to harvest more longer-wavelength photons and achieve higher power conversion efficiencies.

The photochromism and guest binding of spiro-naphtho-oxazine dimer (SNOD) based materials were investigated. The specifically angled, conjugated dimer, SNOD, was covalently connected to α-methoxy-ω-amino-poly(ethylene glycol) (PEG) and studied under UV irradiation. Results showed the specific effects of the polymer chain on their photochromic properties and relaxation kinetics. These new materials exhibited repeatable photo-switchability and little kinetics dependency on solvent polarity. The nanoscale micelles were prepared by self-assembly of amphiphilic SNOD–PEG conjugates in aqueous medium. A palladium catalyst as a guest agent was encapsulated in the micelle core, which reduced the thermal closing rate of the merocyanine isomer of the spirooxazine dimer. SNOD was also conjugated onto solid polymer beads and investigated for the binding affinity with dyes and catalysts. The stable binding affinity towards the palladium catalyst indicated potential applications for selective recognition, extraction, and controlled release.

Specifically angled, conjugated spiroindolinonaphthooxazine dimers (SNOD) have been synthesized. The photochromic reactions of two types of SNOD were studied under continuous UV irradiation in solvents of different polarity. Comparison of these results with the single unit provides the examination of the specific effect of substituents on their photochromic properties and relaxation kinetics. The photomerocyanine isomers showed positive solvatochromism, supporting the premise for a less polar quinoidal structure. The thermal closing rate at 25 °C ranged from 0.2 to 1.6 s−1 depending on the compound and solvent. Photochromism of these new compounds showed little dependency on solvent polarity and stable cyclability.

Benzotriazole-mediated routes to peptidomimetics and peptide conjugates have been discussed in detail. The Katritzky group developed a benzotriazole methodology toward the activation of carbonyl groups of amino acids and modified analogs, which allowed the synthesis of cyclic peptides, azapeptides, azidopeptides, aminoxypeptides, oxyazapeptides, depsipeptides, and isopeptides. High-yielding reactions of N-, O-, S-, and C-acylated nucleophiles with activated aminoacyl or peptidoyl benzotriazole derivatives have also been reported. Benzotriazole methodology enabled the efficient incorporation of bioactive moieties into peptides, peptidomimetics, amino acids, and other carbonyl-containing compounds. Predominant number of reported products retained chiral purity. Some of the products displayed promising biological activities such as anticancer and antibacterial activity along with the improved stability under physiological conditions.

Reported is characterization of the self-assembly of π-conjugated oligomers, molecules studied recently in photovoltaic devices, using variable temperature diffusion ordered spectroscopy (VT-DOSY). Iterative fitting of diffusion coefficient versus temperature data to a modified Stokes–Einstein equation, molecular modelling, and comparison to non-assembling model compounds, has allowed estimation of assembly size, shape, and molecularity.

A uniquely angled spirooxazine dimer was synthesized as a smart photoswitch for sensing and delivery applications; the dimer showed reversible binding and release ability towards a palladium catalyst.