D–π–A type conjugated indandione derivatives: ultrafast broadband nonlinear absorption responses and transient dynamics

The ultrafast nonlinear optical response of two 1,3-indandione derivatives (INB3 and INT3) was systematically investigated by the femtosecond Z-scan and pump-probe technique at multiple visible and near infrared wavelengths. Both compounds show strong broadband nonlinear absorption (NLA) and different wavelength-dependent two-photon absorption (TPA) characteristics in the range of 650–1100 nm. The TPA cross section of trithiophene-based compound INT3 was found to be larger than that of triphenylamine-based compound INB3 in the red region (650–800 nm), which is attributed to its longer π-conjugated structure and better molecular planarity. Interestingly, the effective NLA of INB3 was found to be larger than INT3 in the NIR region (800–1100 nm), which is related to the excited state absorption (ESA) induced by TPA. The ultrafast dynamics of both compounds were investigated by femtosecond transient absorption spectroscopy, which revealed a broadband ESA including several relaxation processes. This work extends nonlinear optical research on indandione derivatives, and the results suggest that these derivatives are promising candidates for optical limiting applications.

In the red region (650–800 nm), the nonlinear absorption of trithiophene-based compound INT3 is greater than that of triphenylamine-based compound INB3, while in the NIR region (800–1100 nm), the strength of nonlinear absorption is the opposite.     

Theoretical study of D–A′–π–A/D–π–A′–π–A triphenylamine and quinoline derivatives as sensitizers for dye-sensitized solar cells

We have designed four dyes based on D–A′–π–A/D–π–A′–π–A triphenylamine and quinoline derivatives for dye-sensitized solar cells (DSSCs) and studied their optoelectronic properties as well as the effects of the introduction of alkoxy groups and thiophene group on these properties. The geometries, single point energy, charge population, electrostatic potential (ESP) distribution, dipole moments, frontier molecular orbitals (FMOs) and HOMO–LUMO energy gaps of the dyes were discussed to study the electronic properties of dyes based on density functional theory (DFT). And the absorption spectra, light harvesting efficiency (LHE), hole–electron distribution, charge transfer amount from HOMO to LUMO (Q_CT), D index, H_CT index, S_m index and exciton binding energy (E_coul) were discussed to investigate the optical and charge-transfer properties of dyes by time-dependent density functional theory (TD-DFT). The calculated results show that all the dyes follow the energy level matching principle and have broadened absorption bands at visible region. Besides, the introduction of alkoxy groups into triarylamine donors and thiophene groups into conjugated bridges can obviously improve the stability and optoelectronic properties of dyes. It is shown that the dye D4, which has had alkoxy groups as well as thiophene groups introduced and possesses a D–π–A′–π–A configuration, has the optimal optoelectronic properties and can be used as an ideal dye sensitizer.

We have designed four dyes based on D–A′–π–A/D–π–A′–π–A triphenylamine and quinoline derivatives for DSSCs and studied their optoelectronic properties as well as the effects of the introduction of alkoxy groups and thiophene group on the properties.     

Correction: D–π–A type conjugated indandione derivatives: ultrafast broadband nonlinear absorption responses and transient dynamics

Correction for ‘D–π–A type conjugated indandione derivatives: ultrafast broadband nonlinear absorption responses and transient dynamics’ by Lu Chen et al., RSC Adv., 2022, 12, 8624–8631, DOI: 10.1039/D2RA00349J.

The authors regret that contact details for the corresponding authors were not provided. The corrected contact details for the corresponding authors are provided below.* Corresponding author. E-mail addresses: nc.ude.stsu@ihzgnixuw (Xingzhi Wu), nc.ude.adus@0102yjy (Junyi Yang), nc.ude.tih@gnosly (Yinglin Song).The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.     

Improving optoelectronic and charge transport properties of D–π–D type diketopyrrolopyrrole-pyrene derivatives as multifunctional materials for organic solar cell applications

A series of novel diketopyrrolopyrrole-pyrene-based molecules were designed for small molecule based organic solar cell (SMOSC) applications. Their electronic and charge transfer properties were investigated by applying the PBE0/6-31G(d,p) method. The absorption spectra were simulated using the TD-PBE0/6-31G(d,p) method. The results showed that the frontier molecular orbital (FMO) energy levels, reorganization energy, the energetic driving force, and absorption spectra can be tuned by the introduction of different aromatic heterocyclic groups to the side of diketopyrrolopyrrole fragments'' backbones. Additionally, the designed molecules possess suitable FMOs to match those of typical acceptors PC₆₁BM and PC₇₁BM. Meanwhile, the designed molecules can act as good ambipolar charge transport materials in SMOSC applications. Meanwhile, the electron and hole reorganization energies of the designed molecules are smaller than those of the typical electron and hole transport materials, respectively. Moreover, the differences between electron and hole reorganization energies do not exceed 0.046 eV. Our results suggest that the designed molecules can act as promising candidates for donor and ambipolar charge transport materials in SMOSC applications.

A series of novel diketopyrrolopyrrole-pyrene-based molecules have been designed as donor materials with suitable FMOs to match those of typical acceptors PC₆₁BM and PC₇₁BM and ambipolar charge transport materials in SMOSCs applications.     

Photophysical properties and fluorosolvatochromism of D–π–A thiophene based derivatives

Solvation-dependent photophysical properties of two push–pull thiophene-based compounds with donor–π–acceptor (D–π–A) structures were investigated using absorption, fluorescence emission and time resolved spectroscopy, and supported by different solvation models. Intramolecular charge transfer characteristics of the structurally similar 2-fluoro-4-(5-(4-methoxyphenyl)thiophen-2-yl)benzonitrile (MOT) and 4-(5-(4-(dimethylamino)phenyl)thiophen-2-yl)-2-fluorobenzonitrile (DMAT) were investigated. Significant enhancement of intramolecular charge transfer strength has been observed through molecular structure modification of the electron donating group from a methoxy to dimethylamine group. Ground state absorption spectra show a small red shift of about 10 nm and 18 nm while the fluorescence emission spectra show a large red shift of about 66 nm and 162 nm on changing from the nonpolar cyclohexane to the aprotic polar DMSO for MOT and DMAT, respectively. Dipole moment change from the ground state to the charge transfer excited state is calculated to be 6.6 D in MOT and 9.0 D in DMAT. The fluorescence quantum yield, fluorescence lifetime and the derived radiative and non-radiative rate constants were found to be better correlated to the emission energy rather than any of the solvent properties. Three multi-parametric relationships were used in the interpretation of the specific versus non-specific solute–solvent interactions, namely, Kamlet–Taft, Catalán and Laurence et al. models. The findings of these approaches are used to extract useful information about different aspects of solvent effects on the photophysical properties of the two studied compounds. Kamlet–Taft solvatochromic model indicates that non-specific interactions are dominant in controlling the photophysical properties. Catalán''s solvent dipolarity/polarizability parameter is found to play a significant role in solvatochromic behaviour which is also designated by the Laurence model.

Solvation-dependent photophysical properties of two push–pull thiophene-based compounds with donor–π–acceptor (D–π–A) structures were investigated using absorption, fluorescence emission and time resolved spectroscopy, and supported by different solvation models.     

First principles study of electronic and nonlinear optical properties of A–D–π–A and D–A–D–π–A configured compounds containing novel quinoline–carbazole derivatives

Materials with nonlinear optical (NLO) properties have significant applications in different fields, including nuclear science, biophysics, medicine, chemical dynamics, solid physics, materials science and surface interface applications. Quinoline and carbazole, owing to their electron-deficient and electron-rich character respectively, play a role in charge transfer applications in optoelectronics. Therefore, an attempt has been made herein to explore quinoline–carbazole based novel materials with highly nonlinear optical properties. Structural tailoring has been made at the donor and acceptor units of two recently synthesized quinoline–carbazole molecules (Q1, Q2) and acceptor–donor–π–acceptor (A–D–π–A) and donor–acceptor–donor–π–acceptor (D–A–D–π–A) type novel molecules Q1D1–Q1D3 and Q2D2–Q2D3 have been quantum chemically designed, respectively. Density functional theory (DFT) and time-dependent density functional theory (TDDFT) computations are performed to process the impact of acceptor and donor units on photophysical, electronic and NLO properties of selected molecules. The λ_max values (321 and 319 nm) for Q1 and Q2 in DSMO were in good agreement with the experimental values (326 and 323 nm). The largest shift in absorption maximum is displayed by Q1D2 (436 nm). The designed compounds (Q1D3–Q2D3) express absorption spectra with an increased border and with a reduced band gap compared to the parent compounds (Q1 and Q2). Natural bond orbital (NBO) investigations showed that the extended hyper conjugation and strong intramolecular interaction play significant roles in stabilising these systems. All molecules expressed significant NLO responses. A large value of β_tot was elevated in Q1D2 (23 885.90 a.u.). This theoretical framework reveals the NLO response properties of novel quinoline–carbazole derivatives that can be significant for their use in advanced applications.

Materials with nonlinear optical properties have significant applications in nuclear science, biophysics, medicine, chemical dynamics, solid physics & materials science. We show how π bridges, donors & acceptors can be reconfigured to improve optical properties.     

Ruthenium carboranyl complexes with 2,2′-bipyridine derivatives for potential bimodal therapy application

Ruthenium complexes of carboranyl ligands offer the possibility of dual action (chemo + radiotherapy) that might result in significant clinical benefits. In that frame, we describe herein the development of ruthenium–carboranyl complexes bearing bipyridyl derivatives with the general formula [3-CO-3,3-{κ²-4,4′-R₂-2,2′-bipy}-closo-3,1,2-RuC₂B₉H₁₁] (R = CH₃, RuCB1 or R = CH₂OH, RuCB2). Both compounds crystallized in the monoclinic system, showing the expected three-legged piano stool structure. The ruthenacarboranes are stable in cell culture media and were tested against two cell lines that have shown favorable clinical responses with BNCT, namely melanoma (A375) and glioblastoma (U87). RuCB1 shows no cytotoxic activity up to 100 μM while RuCB2 showed moderate activity for both cell lines. Cell distribution assays showed that RuCB2 presents high boron internalization that is proportional to the concentration used indicating that RuCB2 presents features to be further studied as a potential anticancer bimodal agent (chemo + radiotherapy).

The substituents at the bipyridine lead to different cell uptake and stability.     

Antioxidant and anti-aging potential of a peptide formulation (Gal2–Pep) conjugated with gallic acid

Skin is highly vulnerable to premature aging due to external stress, therefore, in this study, a peptide formulation, (galloyl)₂–KTPPTTP (Gal₂–Pep) was synthesized by combining TPPTTP peptide, and gallic acid (GA). All peptides were synthesized on 2-chlorotrityl chloride resin using solid-phase peptide synthesis (SPPS), and analyzed on an electrospray ionization (ESI)/quadrupole-time-of-flight (Q-TOF) tandem mass spectroscopy (MS) system. Initially, Gal₂–Pep showed no toxicity below the concentration 100 μM with cell survival rate of 88% for keratinocytes and fibroblasts. The reactive oxygen species (ROS) scavenging activity of Gal₂–Pep was more stable compared to GA alone; and after four weeks at room temperature, its ROS scavenging activity remained higher than 50%. Moreover, the peptide formulation, Gal₂–Pep also exhibited elastase inhibitory effect in CCD-1064Sk fibroblast cells. Based on the results of RT-qPCR, it was proved in this study that Gal₂–Pep increased the expression of PGC-1α to prevent oxidative stress, and validated its potential as an anti-aging agent through increasing the expression of type I collagen and by decreasing the expression of matrix metalloproteinase-1 (MMP1). The findings obtained reinforce the suggestion that the peptide formulation synthesized in this study could be used as a natural antioxidant and anti-aging agent for its cosmetic applications.

Skin is highly vulnerable to premature aging due to external stress, therefore, in this study, a peptide formulation, (galloyl)₂–KTPPTTP (Gal₂–Pep) was synthesized by combining TPPTTP peptide, and gallic acid (GA).     

Unpredicted photocatalytic activity of clinoptilolite–mordenite natural zeolite

Zeolites are not often used directly as photocatalysts. Their framework and nanocavities have served as support or hosts for photoactive materials or traces of transition metals functioning as photoactive sites for catalysing decomposition and oxidation reactions in the gas phase. Research in this area has been limited to a few synthetic zeolites and in this context, efforts are directed to the preparation of new zeolite-based photocatalysts, when in nature there is an abundance of materials with properties yet to be discovered. We report the application of a natural clinoptilolite–mordenite zeolite as an efficient self-photocatalytic material for the decomposition of caffeine in aqueous solution. Adsorption experiments, combined with textural, crystallographic, and spectroscopic characterization were performed comparatively for the natural zeolite, a synthetic homologue, and the iron-exchanged zeolite. The neat zeolite containing 1.2 wt% of endogenous iron exhibited 99% decomposition of caffeine after 4 h irradiation and a faster reaction rate, followed by the synthetic sample. In contrast, the iron-loaded sample was the less effective zeolite because of pore blocking. Caffeine adsorption occurred on the outer zeolite surface and the photoproducts were hydroxylated pyrimidine rings and linear amide derivatives.

Clinoptilolite + mordenite are self-photocatalytic in the decomposition of caffeine under UV-irradiation because endogenous iron originates photoinduced species and intermediates are confined in zeolite nanopores.     

Strategies for the application of metal–organic frameworks in catalytic reactions

Efficient catalysts play crucial roles in various organic reactions and polymerization. Metal–organic frameworks (MOFs) have the merits of ultrahigh porosity, large surface area, dispersed polymetallic sites and modifiable linkers, which make them promising candidates for catalyzation. This review primarily summarizes the recent research progress on diverse strategies for tailoring MOFs that are endowed with excellent catalytic behavior. These strategies include utilizing MOFs as nanosized reaction channels, metal nodes decorated as catalytic active sites and the modification of ligands or linkers. All these make them highly attractive to various applications, especially in catalyzing organic reactions or polymerizations and they have proven to be effective catalysts for a wide variety of reactions. MOFs are still an evolving field with tremendous prospects; therefore, through the research and development of more modification and regulation strategies, MOFs will realize their wider practical application in the future.

Metal–organic frameworks (MOFs) are promising candidates for catalyzation. This review primarily summarized the recent research progress in diverse strategies for tailoring MOFs which are endowed with more excellent catalytic behavior.     

Design,synthesis and fungicidal activity of isothiazole–thiazole derivatives

3,4-Dichloroisothiazoles can induce systemic acquired resistance (SAR) to enhance plant resistance against a subsequent pathogen attack, and oxathiapiprolin exhibits excellent anti-fungal activity against oomycetes targeting at the oxysterol-binding protein. To discover novel chemicals with systemic acquired resistance and fungicidal activity, 21 novel isothiazole–thiazole derivatives were designed, synthesized and characterized according to the active compound derivatization method. Compound 6u, with EC₅₀ values of 0.046 mg L⁻¹ and 0.20 mg L⁻¹ against Pseudoperonospora cubensis (Berk. et Curt.) Rostov and Phytophthora infestans in vivo, might act at the same target as oxysterol binding protein (PcORP1) of oxathiapiprolin; this result was validated by cross-resistance and molecular docking studies. The expression of the systemic acquired resistance gene pr1 was significantly up-regulated after treating with compound 6u for 24 h (43-fold) and 48 h (122-fold). These results can help the development of isothiazole–thiazole-based novel fungicides.

Compound 6u exhibits ultrahigh fungicidal activity by acting at its potent target PcORP1 and induces systemic acquired resistance by activating the salicylic acid pathway.     

A novel metal–organic framework of Ba–hemin with enhanced cascade activity for sensitive glucose detection

Early glucose detection is important in both healthy people and diabetic patients. Glucose biosensing based on glucose oxidase (GOX) is a common method. However, native proteins are mostly membrane impermeable and are prone to degradation in complex sample environments. Herein, we report a facile one-step biomineralization method by simply mixing aqueous solutions of hemin and barium nitrate with glucose oxidase (GOX) to form Ba–hemin@GOX composites. Glucose (Glu) is introduced through self-driven sampling to trigger the GOX-catalysed production of hydrogen peroxide, which could help the subsequent 3,3′,5,5′-tetramethylbenzidine (TMB) oxidation reaction catalysed by Ba–hemin to yield the blue-coloured product. The sensor exhibited a detection limit as low as 3.08 μM. The operability and accuracy of the Ba–hemin@GOX biosensor were confirmed by the quantitative determination of glucose in real samples, such as tap water, serum and drinks. Moreover, the Ba–hemin@GOX-based colorimetric biosensor showed good selectivity, storage stability and recoverability. The experimental results reveal that a GOX activity of more than 90% was still maintained even after being incubated at 60 °C for 30 minutes, and Ba–hemin@GOX could be reused for glucose detection at least six times. Even after 30 days of storage, the relative activity was still more than 90%. Overall, the developed Ba–hemin@GOX biosensor provides a valuable and general platform for applications in colorimetric biosensing and medical diagnostics.

The Ba–hemin@GOX composite is used for sensitive glucose detection.     

Characterization and simulation study of organic solar cells based on donor–acceptor (D–π–A) molecular materials

In this study, the analysis of microelectronic and photonic structure in a one dimension program [AMPS-1D] has been successfully used to study organic solar cells. The program was used to optimize the performance of organic solar cells based on (carbazole-methylthiophene), benzothiadiazole and thiophene [(Cbz-Mth)-B-T]2 as electron donors, and [6,6]-phenyl-C₆₁-butyric acid methyl ester (PCBM) as an electron acceptor. The optoelectronic properties of these dyes were investigated by using the Density Functional Theory DFT/B3LYP/6-31G(d,p) method. We studied the influence of the variation of the thickness of the active layer, the temperature, and the density of the effective states of the electrons and the holes in the conduction and valence bands respectively on the performance of the solar cells based on [(Cbz-Mth)-BT]2–PCBM as a photoactive material, sandwiched between a transparent indium tin oxide (ITO) and an aluminum (Al) electrode. The addition of other thiophene units in the copolymer or the deposition of a layer of PEDOT between the anode (ITO) and the active layer, improves the performances of the cell, especially resulting in a remarkable increase in the value of the power conversion efficiency (PCE).

The solar cell ITO/PEDOT/[(Cbz-Mth)-B-DT]2-A:PCBM/Al under study and the results obtained, including a power conversion efficiency of 11%. The impact of several parameters on the performance has been studied to obtain the optimal device architecture.     

New organic dye-sensitized solar cells based on the D–A–π–A structure for efficient DSSCs: DFT/TD-DFT investigations

Global energy consumption has increased due to population growth and economic development. Solar energy is one of the most important renewable energy sources for human consumption. In this research, four novel organic dyes (D2–D5) of the D–A–π–A structure based on triphenylamine (TPA) were studied theoretically using DFT and TD-DFT techniques for future usage as dye-sensitized solar cells (DSSCs). The effects of modifying the π-spacer of the reference molecule D1 on the structural, electronic, photovoltaic, and optical characteristics of the D2–D5 dyes were studied in detail. D2–D5 exhibited band gaps (E_gap) in the range from 1.89 to 2.10 eV with λ_abs in the range of 508 to 563 nm. The results obtained show that modifying the π-spacer of the dye D1 increased its hole injection and reinforced the intramolecular charge-transfer (ICT) impact, which resulted in a red-shifted ICT absorption with a greater molar extinction coefficient. The theoretically calculated open-circuit voltage (V_oc) values ranged from 0.69 to 1.06 eV, while the light-harvesting efficiency (LHE) values varied from 0.95 to 0.99. Indeed, this theoretical research could guide chemists to synthesize effective dyes for DSSCs.

Global energy consumption has increased due to population growth and economic development.     

Effect of fluorine substituents on benzothiadiazole-based D–π–A′–π–A photosensitizers for dye-sensitized solar cells

Two D–π–A′–π–A organic dyes with triazatruxene (TAT) as the electron donor, thiophene as the π-spacer, benzoic acid as the anchor group, and benzothiadiazole (BT) or difluorobenzo[c][1,2,5]thiadiazole (DFBT) as the additional acceptor, namely LS101 and LS102, respectively, were applied to dye-sensitized solar cells (DSSCs). As fluorine substituents are usually strong electron-withdrawing groups, introducing two fluorine atoms into BT was expected to strengthen the electron-withdrawing ability of the auxiliary acceptor, resulting in DSSCs with a broader light capture region and further improved power conversion efficiency (PCE). Fluorine is the smallest electron-withdrawing group with an induction effect, but can also act as an electron-donating group owing to its conjugation effect. When the conjugation effect is dominant, the electron-withdrawing ability of additional acceptor DFBT decreases instead. Accordingly, the band gap of LS102 was broadened and the UV-vis absorption spectrum was blue-shifted. In the end, DSSCs based on LS101 achieved a champion PCE of 10.2% (J_sc = 15.1 mA cm⁻², V_oc = 966 mV, FF = 70.1%) while that based on LS102 gave a PCE of only 8.6% (J_sc = 13.4 mA cm⁻², V_oc = 934 mV, FF = 69.1%) under standard AM 1.5G solar irradiation (100 mW cm⁻²) with Co²⁺/Co³⁺ as the electrolyte.

The results and interpretations can clearly explain the reasons for the poor photovoltaic performance of DFBT in DSSCs.     

Nanochannel-based heterometallic {ZnIIHoIII}–organic framework with high catalytic activity for the chemical fixation of CO2

The exquisite combination of Zn^II and Ho^III generated the highly robust [ZnHo(CO₂)₆(OH₂)]-based heterometallic framework of {[ZnHo(TDP)(H₂O)]·5H₂O·3DMF}_n (NUC-30, H₆TDP = 2,4,6-tri(2′,4′-dicarboxyphenyl)pyridine), which featured outstanding physicochemical properties, including honeycomb nanochannels, high porosity, large specific surface area, the coexistence of highly open Lewis acid–base sites, good thermal and chemical stability, and resistance to most organic solvents. Due to its extremely unsaturated metal tetra-coordinated Zn(ii) ions, hepta-coordinated Ho(iii) and high faveolate void volume (61.3%), the conversion rate of styrene oxide and CO₂ into cyclic carbonates in the presence of 2 mol% activated NUC-30 and 5 mol% n-Bu₄NBr reached 99% under the mild conditions of 1.0 MPa and 60 °C. Furthermore, the luminescence sensing experiments proved that NUC-30 could be used as a fast, sensitive and highly efficiency sensor for the detection of Fe³⁺ in aqueous solution. Therefore, these results prove that nanoporous MOFs assembled from pyridine-containing polycarboxylate ligands have wide applications, such as catalysis and as luminescent materials.

The robust, double-walled, honeycomb material {[ZnHo(TDP)(H₂O)]·2DMF·4H₂O}_n exhibits an excellent catalytic performance in the chemical fixation of CO₂ and the efficient detection of Fe(iii) ions in aqueous solution.     

Synthesis of cyclic α-pinane carbonate – a potential monomer for bio-based polymers

This work reports the first known synthesis of α-pinane carbonate from an α-pinene derivative. Pinane carbonate is potentially useful as a monomer for poly(pinane carbonate), which would be a sustainable bio-based polymer. α-Pinene is a major waste product from the pulp and paper industries and the most naturally abundant monoterpene in turpentine oil. α-Pinene is routinely converted to pinene oxide and pinanediol, but no study has yet demonstrated the conversion of pinanediol into α-pinane carbonate. Here, α-pinane carbonate was synthesised via carboxylation of α-pinanediol with dimethyl carbonate under base catalysis using triazabicyclodecene guanidine (TBD). 81.1 ± 2.8% α-pinane carbonate yield was achieved at 98.7% purity. The produced α-pinane carbonate was a white crystalline solid with a melting point of 86 °C. It was characterised using FTIR, NMR, GCMS and a quadrupole time-of-flight (QTOF) mass spectrometer. The FTIR exhibited a C O peak at 1794 cm⁻¹ confirming the presence of a cyclic carbonate. GCMS showed that the α-pinane carbonate fragments with loss of CO₂, forming pinene epoxide. Base hydrolysis of the α-pinane carbonate using NaOH/ethanol/water regenerated the pinanediol with formations of Na₂CO₃.

Synthesis of α-pinane carbonate from an α-pinene derivative.     

The pioneering role of metal–organic framework-5 in ever-growing contemporary applications – a review

MOF-5 with a Zn(ii) cluster and terephthalic acid is a distinctive porous material among the metal–organic frameworks (MOFs), with unique physical, chemical and mechanical properties. MOF-5 based composites possess ample applications in modern chemistry. Huge surface area, suitable pore dimensions and scope of tunability make MOF-5 noteworthy in advanced materials. The extensive features of MOF-5 provided an opportunity for researchers to explore atomic/molecular scale materials. Various MOF-5 based composites have been designed with revamped properties appropriate to the application by altering and fabricating MOF-5 in situ or using a post-synthetic approach. Surface modification via the dispersion and impregnation of active substances into the pores of MOF-5 enhances its applicability. The boundless topologies and morphologies of MOF-5 combined with other chemical entities has provided opportunities in various fields, including catalysis, gas storage and sensors. The present review illuminates the leading role of MOF-5 and its composites in contemporary applications based on the current literature in heterogeneous catalysis, H₂ and CO₂ storage and sensors.

MOF-5 with a Zn(ii) cluster and terephthalic acid is a distinctive porous material among the metal–organic frameworks (MOFs), with unique physical, chemical and mechanical properties.     

Facile synthesis of novel dithioacetal–naphthalene derivatives as potential activators for plant resistance induction

In this paper, a series of novel dithioacetal–naphthalenes were designed and synthesized for plant immunity. Their antiviral activities were evaluated against tobacco mosaic virus (TMV) and cucumber mosaic virus (CMV). The results indicated that most compounds exhibited better activity against CMV than against TMV. These dithioacetal derivatives also displayed good bacterial activity against rice bacterial leaf blight. Among them, compound S16 exhibited relatively good anti-CMV, anti-TMV, and antibacterial activity. Structure–activity relationships indicated that introducing the naphthalene moiety enhanced their activities for plant resistance induction. Therefore, the basic motif of compound S16 could be the most promising candidate for further structural optimization to develop a potential activator for plant resistance induction.

In this paper, a series of novel dithioacetal–naphthalenes were designed and synthesized for plant immunity.     

Platinum free thermally curable siloxanes for optoelectronic application – synthesis and properties

Polysiloxanes for applications in the area of optical devices are usually based on two-component platinum catalysed cross-linked materials. Here we report the synthesis and properties of a novel one-component siloxane that can be thermally cured showing similar tailorable properties like commercially available encapsulation systems without using a noble metal catalyst. The pre-curing material is formed by an acid catalysed condensation reaction of trialkoxysilanes (TAS), dialkoxysilanes (DAS) and alkoxy-terminated polysiloxanes. NMR analysis of the formed polymeric compounds reveal that the materials are partially cross-linked gels. The obtained compounds can be thermally cured and consolidated at temperatures between 160 and 200 °C. Depending on the composition a tuneable hardness in between 50–90 Shore A, refractive indices of 1.494–1.505, as well as high temperature stabilities up to 443 °C were obtained. The high thermal- and photostability, the high transparency, as well as the tailorable refractive index makes these materials to ideal systems for optoelectronic applications. Investigations under increased temperatures and high-density illumination reveal that the material can withstand conditions, which are typical for high-performance light emitting diodes (LED).

One component thermally curable polysiloxanes with tailorable properties were developed and investigated for their use as LED encapsulation materials.