Molecular Design of Conjugated Small Molecule Nanoparticles for Synergistically Enhanced PTT/PDT

Simultaneous photothermal therapy(PTT)and photodynamic therapy(PDT)is beneficial for enhanced cancer therapy due to the synergistic effect.Conventional materials developed for synergistic PTT/PDT are generally multicomponent agents that need complicated preparation procedures and be activated by multiple laser sources.The emerging monocomponent diketopyrrolopyrrole(DPP)-based conjugated small molecular agents enable dual PTT/PDT under a single laser irradiation,but suffer from low singlet oxygen quantum yield,which severely restricts the therapeutic efficacy.Herein,we report acceptor-oriented molecular design of a donor-acceptor-donor(D-A-D)conjugated small molecule(IID-ThTPA)-based phototheranostic agent,with isoindigo(IID)as selective acceptor and triphenylamine(TPA)as donor.The strong D-A strength and narrow singlet-triplet energy gap endow IID-ThTPA nanoparticles(IID-ThTPA NPs)high mass extinction coefficient(18.2 L g^-1 cm^-1),competitive photothermal conversion efficiency(35.4%),and a dramatically enhanced singlet oxygen quantum yield(84.0%)comparing with previously reported monocomponent PTT/PDT agents.Such a high PTT/PDT performance of IID-ThTPA NPs achieved superior tumor cooperative eradicating capability in vitro and in vivo.

Small molecule conjugates with selective estrogen receptor β agonism promote anti-aging benefits in metabolism and skin recovery

Estrogen is imperative to mammalian reproductivity,metabolism,and aging.However,the hormone activating estrogen receptor(ERs)αcan cause major safety concerns due to the enrichment of ERαin female tissues and certain malignancies.In contrast,ERβis more broadly expressed in metabolic tissues and the skin.Thus,it is desirable to generate selective ERβagonist conjugates for maximizing the therapeutic effects of ERs while minimizing the risks of ERαactivation.Here,we report the design and production of small molecule conjugates containing selective non-steroid ERβagonists Gtx878 or genistein.Treatment of aged mice with our synthesized conjugates improved aging-associated declines in insulin sensitivity,visceral adipose integrity,skeletal muscle function,and skin health,with validation in vitro.We further uncovered the benefits of ERβconjugates in the skin using two inducible skin injury mouse models,showing increased skin basal cell proliferation,epidermal thickness,and wound healing.Therefore,our ERβ-selective agonist conjugates offer novel therapeutic potential to improve aging-associated conditions and aid in rejuvenating skin health.

Simulation of Inelastic Electron Tunnelling Spectroscopy on Different Contact Structures in 4,4＇-Biphenyldithiol Molecular Junctions

A first-principles computational method is developed to study the inelastic electron tunnelling spectroscopy （IETS） of 4,4＇-biphenyldithiol molecular junction with three different contact structures between the molecule and electrodes in the nonresonant regime. The obtained distinct IETS can be used to resolve the geometrical structure of the molecular junction. The computational results demonstrate that the IETS has certain selection rule for vibrational modes, where the longitudinal modes with the same direction as the tunnelling current have greatest contribution to the IETS. The thermal effect on the IETS is also displayed.

Synthesis and Physical Properties of Benzopyridazine-Based Conjugated Molecules

A series of novel organic conjugated molecules （5a--5d） comprising 2,3-benzopyridiazine as electron-with- drawing core and thiophene derivatives as electron-donating arms have been synthesized successfully in good yields. The ultraviolet-visible （UV-Vis） absorption spectra and fluorescence spectra of 5a--5d revealed that the optical properties are strongly influenced by the interactions between nitrogen and sulfur atoms in the conjugated backbone, as well as the position of the alkyl chains in the thiophene rings. The experimental results and theoretical calculation data clearly indicated that the band gap and the energy levels of LUMO and HOMO could be fine-tuned by the po- sition of alkyl chains in the thiophene rings. Thus, the structure-property correlation of this class of conjugated molecules can be well established.

New Solution Method of Pi-Orbital Axis Vector and Its Applications in Fullerenes and Carbon Nanotubes

A new solution method to perform the pi-orbital axis vector analysis was developed in this paper. The model of circular cone was built and the solution equations of the pyramidalization angle were obtained based on the model and the space analytic geometry. Our method merely requires the atomic coordinates of the conjugated central atom and the three attached atoms. Moreover, systematic calculations on the pyramidalization angles of fullerenes and carbon nanotubes were performed using the method we developed. The relationship of pyramidalization angle and the stability for the carbon cages and tubes was also discussed.

Design and Synthesis of Acceptor-Donor-Acceptor Type Non-Fullerene Acceptors Using Oxindole-Based Bridge for Polymer Solar Cells Applications

Two acceptor-donor-acceptor(A-D-A)type non-fullerene acceptors(namely WH1 and WH7)containing the oxindole-based bridge are designed and synthesized for polymer solar cells(PSCs)applications.The bridge unit is introduced through a precursor(6-bromo-1-octylindoline-2,3-dione)that contains both bromine and carbonyl and provides the feasibility of the Pd-catalyzed cross-coupling reaction and the Knoevenagel condensation,respectively.This facile synthetic approach exhibits the potential to gain high performance non-fullerene acceptors through extendingπ-conjugated backbone with strong light-absorbing building blocks.The synthesis and properties of WH1 and WH7 are demonstrated with different endcap units,then PSCs are fabricated using PBDB-T:WH1 and PBDB-T:WH7 as the active layers,and attain an average power conversion efficiency(PCE)of 2.58%and 6.24%,respectively.Further device physics studies afford the deep insight of structure variation influence on the device performance.This work provides a facile non-fullerene acceptor design strategy and shows how structure variations impact the PSC performance.

Fusing Thienoisoindigo to the Conjugated Ribbons with Strong Absorption in the Second Near-Infrared Window

Organic dyes with strong absorption in the second near-infrared(NIR-II)window(1000-1700 nm)have multiple applications.However,the design and synthesis of stable NIR-II absorbing organic dyes are very challenging and constantly defy our synthetic ability.In this work,we have successfully synthesized a series of soluble and stable fused thienoisoindigo(nThIID)ribbons.The absorption maximum(λ_(max))of the ribbons increases from 644 nm of 1ThIID to 1252 nm of 6ThIID.Importantly,nThIIDs with n≥4 all display strong absorption in the NIR-II window with molar extinction coefficients(ε_(max))greater than 105 L mol^(−1)cm^(−1)atλmax.These molecules are promising photothermal conversion dyes with photothermal conversion efficiencies of ca.60%under 1064 nm laser irradiation.

Synthesis and evaluation of peptide-fentanyl analogue conjugates as dualμ/δ-opioid receptor agonists for the treatment of pain

Novel peptide-fentanyl analogue conjugates were synthesized by the covalent coupling of carfentanyl derivatives to the C-terminus or N-terminus of the conformationally constrained dermorphin tetrapeptide BVD03 via a chemical linker.The carfentanyl-related analogues displayed distinct binding and functional activities atμ/δopioid receptors(MOR/DOR)and antinociceptive effects when conjugated to the peptide.The most potent compound,SW-LJ-11,displayed mixed MOR/DOR agonist properties in the low nanomolar range and significant analgesic efficacy in vivo in four classic mouse models of pain.Interestingly,SW-LJ-11 did not exhibit any physical dependence or respiratory depression,in contrast to an equipotent analgesic dose of morphine or BVD03,indicating that the use of opioid peptide-fentanyl analogue conjugates as dual MOR/DOR agonists may be a promising strategy for obtaining safer opioids.

Emission and Energy Transfer Characteristics of Coumarin 6 Molecules Doped in Opal Polymer Photonic Crystal

The emission of coumarin 6（C-6） doped in opal polymethylmethacrylate（PMMA） photonic crystal（PC） was effectively manipulated. Meanwhile the energy transfer（ET） of C-6 in PCs, which are infiltrated with sulforho- damine B（S-B）, was influenced by the concentration of energy acceptor in solution, the size of PMMA micro- sphere（SM） and the photonic stop band（PSB）. The results should be beneficial to people to further understand the potential application of PCs in optoelectronic fields.

Kekulé-based Valence Bond Model. I. The Ground-state Properties of Conjugated π-Systems

The Kekulé-based valence bond (VB) method, in which the VB model is solved using covalent Kekulé structures as basis functions, is justified in the present work. This method is demonstrated to provide satisfactory descriptions for resonance energies and bond lengths of benzenoid hydrocarbons, being in good agreement with SCF-MO and experimental results. In addition, an alternative way of discussing characters of localized substructures within a polycyclic benzenoid system is suggested based upon such simplified VB calculations. Finally, the symmetries of VB ground states for nonalternant conjugated systems are also illustrated to be obtainable through these calculations, presenting very useful information for understanding the chemical behaviors of some nonalternant conjugated molecules.

Recent advances in perovskite/organic integrated solar cells

The integrated perovskite/organic solar cell(IPOSC) is widely concerned as an effective approach to broaden the spectrum of perovskite solar cell(PerSC) by utilizing near-infrared light of lower bandgap organic semiconductor. Compared to tandem solar cells, the IPOSCs eliminate the preparation of the intermediate layer and simplify the manufacturing process, but retain the advantages of wide light harvesting. Meanwhile, the IPOSCs can maintain the open-circuit voltage as high as PerSCs. This review summarizes the recent developments of perovskite materials and low-bandgap organic conjugated materials applied in solar cells. Then, the working mechanism of IPOSCs and the recent developments of IPOSCs based on low-bandgap donor and acceptor materials are highlighted. Besides, the study of charge dynamic in IPOSC is summarized. Finally, the potential of IPOSCs and approach to improve device performance are also envisaged.

Modulating the Helicity of Sugar-Substituted Perylene Diimide Self-assemblies by Solvent Polarilities

Modulating the helicity of self-assemblies of conjugated molecules is important for their application in chiral electronics.In this communication,solvent effect has been investigated on how to modulate the helicity of supramolecular assemblies of sugar-substituted perylenediimide(PTCDI-BAG)by using UV-Vis,circular dichroism spectroscopy and transmission electron microscopy.Left-handed helical nanowires are obtained in the mixed solvent system of both N,N-dimethylformamide/ethanol(DMF/ethanol)and N,N-dimethylacetamide/ethanol(DMAC/ethanol).As changing the solvents into dimethyl sulfoxide/ethanol(DMSO/ethanol),ethylene glycol/ethanol(EG/ethanol),or N-methyl-2-pyrrolidone/ethanol(NMP/ethanol),only right-handed heical nanowires are observed.The chirality of supramolecular structures can be tuned by the controlling of the polarity of the solvents.A theoretical calculation is carried out to explain the chiral optical inversion phenomena of PTCDI-BAG aggregates in different solvents,which reveals that reversed CD spectra is due to the difference of clockwise and anticlockwise rotation of the dimer.

Recent progress in organic mechanoluminescent materials

Mechanoluminescence（ML） refers to the light emission from various organic and inorganic materials upon mechanical stimulus. As a new class of smart materials, mechanoluminescent materials are widely applicable for fluorescence switches, mechanosensors, security papers, optoelectronic devices and data storage etc. In the past few years, systematic investigations have been carried out, resulting in the production of a variety of mechanoluminescent materials. In this review, recent progress in pure organic mechanoluminescent materials is summarized, including mechanofluorescent and triboluminescent effects from conjugated small molecules.

Acceptor-Donor-Acceptor Type Small Molecular Low Band Gap Organic Semiconductors Containing 2-Dicyanomethylen- 3-cya n o-4, 5, 5-t rim ethyl-d i hyd rofu ran

Acceptor-donor-acceptor type compounds WI--W3 were designed and synthesized. These compounds had the same donor moiety of 2,6-di（tbiophen-2-yl）dithieno[3,2-b：2＇,3＇-d]thiophene and different acceptor groups of 2-dicyanomethylen-3-cyano-4,5,5-trimethyl-2,5-dihydrofuran （TCF）, dicyanovinyl （DCV） and 3-ethyl-2-thioxothia- zolidin-4-one. Experimental results showed all compounds had high thermal stability and strong absorption in the visible light region. Among them, compound Wl with TCF as acceptor group displayed the lowest LUMO energy level of-3.74 eV and the smallest HOMO-LUMO band gap of 1.74 eV, suggesting the potential applications of TCF unit in low band gap organic semiconductors.