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Acetic acid-based thioxanthone ( TXCH2 COOH) was synthesized and characterized and used as a photoinitiator for free radical photopolymerization of methyl methacrylate ( MMA) in the absence and presence of a tertiary amine ( MDEA) in different solvents. Different absorption properties were observed depending on the solvent. Fluorescence and phosphorescence experiments were also carried out successfully. The fluorescence quantum yield was found to be 0.09 and the phosphorescence lifetime was calculated as 138 ms at 77 K. The photoinitiator undergoes efficient intersystem crossing into the triplet state and the lowest triplet state possesses π- π* configuration. Laser flash photolysis experiments show that transient absorption of TXCH2 COOH is similar to the parent thioxanthone and the triplet lifetime was calculated as 2.3 μs at 630 nm. [ABSTRACT FROM AUTHOR]

Anthracene was used to form an inclusion complex with methylated-β-cyclodextrin (Me-β-CD) in water. In aqueous Me-β-CD solution, typical fluorescence emission of anthracene was observed. Benesi–Hildebrand's method was used to obtain the stoichiometry of the anthracene–Me-β-CD complex. The Stern–Volmer quenching constants,Ksv, and fluorescence quantum yields were calculated according to changes in the fluorescence emission intensity of anthracene–Me-β-CD inclusion complexes by adding various amounts of Pb2+and Cd2+salts in water. TheKsvvalues and fluorescence quantum yields indicate that Pb2+salts quench the anthracene–Me-β-CD inclusion complexes more efficiently than Cd2+salts. [ABSTRACT FROM AUTHOR]

Free radical photopolymerization of methyl methacrylate (MMA) initiated by 2-mercaptothioxanthone (TX-SH), thioxanthone-thioacetic acid (TXSCH2COOH), and thioxanthone-carboxymethoxy acetic acid (TXOCH2COOH) as so called one-component initiators was performed with and without an external magnetic field (MF). These initiators contain light-absorbing and electron/hydrogen-donating fragments in one molecule and do not require an additional hydrogen donor, and initiate the polymerization of MMA in the air. Polymerization experiments were performed in solutions with 3 different optical densities at λ365 nm, where the photoinitiator absorbs. It was observed that application of MF leads to both larger conversion and higher molecular weight of the prepared PMMA, other conditions being equal. The effect of MF on the photopolymerization of MMA is discussed. [ABSTRACT FROM AUTHOR]

Metal‐organic frameworks (MOFs) are porous materials with numerous chemical and structural possibilities. Due to their ease of modification, well‐organized structure, and diverse guest molecule chemistry, MOFs are ideal platforms for uncovering improved functional material design characteristics. Quantitative analysis of glucose is crucial, especially in some food products, for quality control as well as evaluation of the glucose levels helps diagnose and treat diabetes. Recent glucose sensing devices have relied heavily on MOFs and other nanomaterials to enable user‐friendly and safe non‐invasive sensing methods. Nevertheless, the conventional synthesis methods involve multi‐day reactions, cooling, and depressurization processes. This study demonstrates the unprecedented high‐power laser‐induced rapid synthesis (LIRS) of Ni‐based MOF nanospheres with interconnected nano‐rods and noncentrosymmetric primitive triclinic crystalline structure, highlighting their multifunctional usage in sensing and gas sorption applications. Ab initio simulations show excellent agreement with the experimental physical and gas sorption properties. Furthermore, the Ni‐MOF‐based biosensor accurately measures glucose real‐life beverage samples, yielding promising glucose detection biosensor results with a low limit of the detection (LOD) of 13.96 µM and high sensitivity of 120.606 µA mM−1 cm−2. [ABSTRACT FROM AUTHOR]

• Kinetic and thermodynamic properties of photoinitiators are investigated with DFT. • Natural transitions orbitals of thioxanthone acetic acid derivatives are generated. • Spin densities & Fukui functions are correlated with free energies of activation. • A fast and predictive approach to determine the initiation efficiency is proposed. In this study, One-Component Type II thioxanthone acetic acid based photoinitiators, as well as the conventional Type II photoinitiator with phenyl acetic acid based co-initiators, have been investigated in terms of their photophysical, kinetic and thermodynamic properties by a series of Density Functional Theory (DFT) calculations. Experimental UV–Vis spectra have been compared with computationally generated UV–Vis spectra via Time-Dependent DFT (TD-DFT) and by taking into consideration the vibrational and dynamic effects (Wigner). Natural transition orbitals have been generated for thioxanthone acetic acid derivatives to understand the physical nature of electronic transitions. Furthermore, kinetic and thermodynamic parameters of radical attack to the monomer of thioxanthone acetic acid based radicals and phenyl acetic acid based co-initiator radicals have been investigated. Comparison of the thermodynamic parameters of the initiating radicals has shown that initiation is more favorable with exocyclic radicals in both cases. Exocyclic radicals of the thioxanthone acetic acid derivatives and phenyl acetic acid derivates have been found to have comparable activation energies for their attack to methyl methacrylate. Furthermore, the spin densities and the radical Fukui functions of the attacking radicals have been nicely correlated with the activation barriers. In this way, a fast and predictive approach for the determination of radical reactivity in photopolymerization reactions has been proposed; this enables the evaluation of the initiation efficiency of the photoinitiators prior to synthesis. [ABSTRACT FROM AUTHOR]

In this study, we designed a platform based on a laser-driven approach for fast, efficient, and controllable MOF synthesis. The laser irradiation method was performed for the first time to synthesize Zn-based MOFs in record production time (approximately one hour) compared to all known MOF production methods with comparable morphology. In addition to well-known structural properties, we revealed that the obtained ZnMOFs have a novel optical response, including photoluminescence behavior in the visible range with nanosecond relaxation time, which is also supported by first-principles calculations. Additionally, photocatalytic degradation of methylene blue with ZnMOF was achieved, degrading the 10 ppm methylene blue (MB) solution 83% during 1 min of irradiation time. The application of laser technology can inspire the development of a novel and competent platform for a fast MOF fabrication process and extend the possible applications of MOFs to miniaturized optoelectronic and photonic devices. [ABSTRACT FROM AUTHOR]

Thioxanthone and its derivatives are the most remarkable molecules due to their vast variety of application such as radiation curing that is, until using them as a therapeutic drug. Therefore, in this study it was intended to use 2-Thioxanthone acetic acid with and without NaCl in Tris HCl buffer solution (pH:7.0) to represent the interaction with ct-DNA. The UV–vis absorption spectra of TXCH 2 COOH in the presence of ct-DNA showed hypochromism and the intrinstic binding constant (K b ) was determined as 6 × 10 3  L mol −1 . The fluoresence intensity of TXCH 2 COOH with ct-DNA clearly increased up to 101% which indicated that the fluorescence intensity was very sensitive to ct-DNA concentration. The binding constant ( K ) and the values of number of binding sites ( n ) and were calculated as 1.8 × 10 3  L mol −1 and 0.69, respectively. When the quenching constants (K sv ) of free TXCH 2 COOH and TXCH 2 COOH, which were bonded with ct-DNA were compared, slightly changed values of Ksv were seen. Moreover, displacement assay with Hoechst 33,258 and viscosity measurements in the presence and absence of NaCl salt also confirmed the binding mode which noted the electrostatic interaction following groove binding between TXCH 2 COOH and ct-DNA. Last but not least, the salt effect was examined on ct-DNA binding with TXCH 2 COOH. The results of the experiments indicated that the groove binding was strengthened by NaCl whereas in the high NaCl concentration, the binding ability of TXCH 2 COOH to ct-DNA was inversely affected. [ABSTRACT FROM AUTHOR]

Self-assembled silver nanoparticles (Ag NPs) on calf thymus DNA (ct-DNA) chains were synthesized in the presence of 2-mercaptothioxanthone (TX-SH) by use of UV irradiation technique. Thioxanthone itself and its derivatives show interesting photochemical and biological properties. The formation of Ag NPs on the ct-DNA was achieved with and without TX-SH as a thioxanthone derivative photoinitiator which played a photoreducing role for the formation of Ag NPs. The photoreducing reaction of Ag ions to Ag NPs was followed by UV–vis absorption spectroscopy. A new band was observed at 428 nm which was a good sign of the surface plasmon resonance (SPR) of Ag NPs. Fluorescence quenching was effectively observed depending on the irradiation time of the solution, possibly as a result of Ag NPs size. Particle size analysis and Scanning Electron Microscopy (SEM) imaging confirmed the size of the formed Ag NPs and silver nanoclusters (Ag NCs) effectively. In this study, we report for the first time the formation of self–assembled Ag NPs on ct-DNA in the presence of 2-mercaptothioxanthone by photoirradiation technique. TX-SH played two important roles; photoreducing and photostabilizing agent for the formation of Ag NCs on ct-DNA. Fluorophore character of synthesized Ag NPs on DNA may help to develop new techniques for biological and medical aspects. [ABSTRACT FROM AUTHOR]

Dual effect. Carborane- and anthracene-bearing copolymers are obtained via ring-opening metathesis polymerization (ROMP). Depending on the composition, aggregation-induced emission (AIE) and photoreversible dimerization in solution are observed. [Display omitted] • ROMP type copolymers possesing pendant anthracene and carborane units. • Photoswitchable properties. • The copolymers exhibited emission behaviors in solution. • Mechanochromic behavior as solids. • High char yield under air atmosphere at 600 °C (>50 %). Random copolymers with pendant anthracene and carborane units were obtained by ring-opening metathesis polymerization (ROMP). The copolymers exhibit a variety of emission behaviors in solution and mechanochromic behavior as solids. Photodimerization and photocleavage of the anthracene groups in the copolymers at 350 and 254 nm, respectively, was studied by UV–vis spectroscopy. Thermal properties of the copolymers were evaluated under nitrogen and in air in the range of 25–600 °C. [ABSTRACT FROM AUTHOR]

Photoinitiators for free radical polymerization based on the thioxanthone chromophore that contains benzothiophene were synthesized and characterized. Compared to thioxanthone, these compounds show a bathochromic shifted absorption up to ∼460 nm. High quantum yields for intersystem crossing generate sufficient amounts of triplet states. Initiator radicals are generated by reaction of the triplet states with tertiary amines, such as diethanolamine with high rate constants (2–6 × 10 9 M −1 s −1 ) as determined by laser flash photolysis. Photoinitiated polymerization experiments of MMA showed efficient polymerization with initiator concentrations as low as 0.1 mM. [ABSTRACT FROM AUTHOR]

Here we report an environmentally friendly, fast, efficient and low cost method for in-situ preparation of ZnO nanorods in polymer matrix which is obtained using epoxydiacrylate formulation by UV irradiation. Compared to our previous study, the shape of the ZnO nanoparticles even with the same photoinitiator was found to mainly depend on the polymer matrix, but another important finding that was seen from the SEM images is that the type of photoinitiator helped for spontaneous self-assembly and orientation of ZnO nanoparticles. This very important issue arose when the one component Type II photoinitiator, namely, 2-mercapto thioxanthone was used in formulation. Self-assembly and orientation of ZnO nanorods in polymer were not the case either with Thioxanthone and Thiophenol or in the presence of Type I photoinitiator. All these experimental results for synthesis of ZnO nanoparticles in hydrophilic and hydrophobic polymer matrices may help to understand the effect of photoinitiator and polymer. [Display omitted] • Self-assembled and oriented ZnO nanorods in a polymer matrix are prepared by photochemical synthesis. • Mercaptothioxanthone as the photoinitiator plays an important role for spontaneous self orientation of ZnO nanorods. • Self orientation and assembly of ZnO nanorods are not observed in the presence of Type I photoinitiator. [ABSTRACT FROM AUTHOR]

Abstract: Various methods were employed to prepare precipitated calcium carbonate (PCC) particles. Particle size and morphology were dependent on reaction conditions as well as temperature, reagents and stirring, either mechanical or by ultrasound probe sonication. Sonication helped to reduce the size of CaCO3 particles as well as the precipitation time. Sonication was also used to disperse PCC particles in the UV-curable formulations as well as for preparation of the PCC. Formulations containing precipitated calcium carbonates and ground calcium carbonates in various grades were cured by a Mini UV-Cure device. Mechanical and thermal properties of films were characterized with a Dynamic Mechanical Analyzer (DMA). SEM analysis was also used to determine the shape and the size of the PCCs. Sonication decreased the precipitation time of calcium carbonate at least four times more than that of conventional precipitation procedures and the dispersion of particles in the formulations increased to a great extent. [Copyright &y& Elsevier]

Bimetallic nanoparticles are widely used in chemical catalysis. Their practical performance can be better exploited through morphological control by adjusting the synthetic strategy. Herein, a photochemical synthesis route was used to achieve the controlled preparation of bimetallic Au/Ag BNps. Size and shape control is achieved depending on the type of initiating radical therefore synthesized new one-component Type II photoinitiator, namely 2-thioxanthone thioacetic acid-dioxide was employed for the synthesis of Au/Ag BNp both in solution and polymer matrix. The effect of the gold/silver ratio on the nanoparticle size, shape and distribution was investigated, and the characterization of the obtained nanoparticles was performed by UV–Vis spectrophotometry, DLS and SEM techniques. Additionally, photocatalytic oxidative degradation of methylene blue was achieved with the prepared Au/Ag bimetallic nanocomposite films. By evaluating the photocatalytic oxidation degradation of methylene blue under UV–Vis light irradiation, 2:1 ratio of Au/Ag nanoparticles containing nanocomposite film exhibit the best activity compared with other composition of Au/Ag. The size and high SPR absorption band are thought to be responsible for superior photocatalytic activity. [Display omitted] • A new one component type II photoinitiator, TX-SCH 2 COOH-DO was synthesized. • TX-SCH 2 COOH-DO was used as photoreducing agent for photochemical synthesis of Au/Ag BNps. • Au/Ag BNps was prepared with different ratios both in solution and polymer matrix. • The catalytic oxidation of MB was examined in the presence of fabricated films. • It is found that when the Au ratio is increased, photocatalytic activity is increased. [ABSTRACT FROM AUTHOR]

• Dithioxanthone-disulfide was prepared as a new photoinitiator. • Thiyl radical formation was determined after photolysis of initiator. • Thiyl radicals helped for formation and stabilization of Au NPs. • In-situ formation of Au NPs in polymer matrix was achieved in one pot reaction. • Prepared nanocomposite films were used for BTX gas sensing and valuable results obtained for gas detection. Thioxanthonation of diphenyl units of diphenyl disulfide was achieved successfully. The photoreduction and photostabilization ability of 2, 2′-disulfanediylbis (9H-thioxanthen-9-one) was used for in-situ preparation of Au nanoparticles either in solution or in poly(ethylene glycol) methyl ether acrylate / poly(ethylene glycol) diacrylate polymer matrix. SPR(Surface Plasmon Resonance) absorption band of formed Au NPs were recorded at 550 nm by UV–vis spectroscopy. Indeed, formation of elliptical shaped nanoparticles (4–8 μm) as well as spherical ones (11–14 nm) in nanocomposite films were obtained depending on UV irradiation time. DLS (Dynamic Light Scattering) measurements also changed from 440 nm to about 200 nm as a function of irradiation time. The potential of Au NPs/ polymer nanocomposite film as a sensing element for benzene, toluene, xylene (BTX) sensing was studied at different temperatures. An overall evaluation of the experimental results showed that Au NPs/ polymer nanocomposite film has good potential as a sensing element for the detection of BTX vapours. [ABSTRACT FROM AUTHOR]

[Display omitted] • An annelated thioxanthone thioacetic acid is synthesized and characterized. • High molar absorptivity in visible region made photoinitiator attractive. • Low fluorescence quantum yield and triplet energy leaded production of initiating radicals. • Type II initiation mechanism is responsible. Thioxanthonation of naphthalene thioacetic acid (TXNPSCH 2 COOH) resulted a visible light photoinitiator with the high molar absorptivity (ε 405 : 5680 L.mol−1.cm−1) in the visible spectral region and made this compound an attractive photoinitiator for free radical polymerization reactions. Low fluorescence quantum yield (Φ F : 0.06 in 2-MeTHF) and comparatively low triplet energy (186 kJ/mol in 2-MeTHF) was in favorable for efficient intersystem crossing to the triplet state which is necessary for production of initiating radicals. Indeed, photopolymerization of methyl methacrylate along with TXNPSCH 2 COOH (1 × 10−3 M) and a tertiary amine namely MDEA yielded nearly 25% conversion of monomer to polymer. All spectrophotometric studies including laser flash photolysis which gives triplet lifetime of initiator which is very important information for initiation mechanism of photoinitiators, indeed a long enough triplet lifetime of TXNPSCH 2 COOH (τ T : 1000 ns) allows for efficient reactions with co-initiators to generate radicals. [ABSTRACT FROM AUTHOR]

Dielectric properties and AC conductivity of in-situ formed AuNPs/PEGMEA/PEGDA nanocomposite film was investigated at room temperature. Frequency dependent dielectric constant shows that there are two main relaxation mechanisms for both samples. First of these mechanisms which correspond to dipolar polarization of long polymer chain was observed at frequencies between 0.1 – 10 3  Hz, 0.1–10 4  Hz for PEGMEA/PEGDA film and AuNPs/PEGMEA/PEGDA nanocomposite film, respectively. This mechanism has dielectric constant of 10.8, 14.1 for PEGMEA/PEGDA film and AuNPs/PEGMEA/PEGDA nanocomposite film, respectively. The second mechanism which was attributed to dipolar polarization of chain branches was observed at frequencies between 10 2 – 10 6  Hz, 10 5 –10 7  Hz for PEGMEA/PEGDA film and AuNPs/PEGMEA/PEGDA nanocomposite film, respectively. This mechanism has dielectric constant of 9.6 for PEGMEA/PEGDA film and 10.3 for AuNps/PEGMEA/PEGDA nanocomposite film which cured in the presence of Irg-907 as Type I initiator by using medium pressure mercury light. These relaxation mechanisms can also be detected at frequency dependence of dielectric dissipation (tan δ) as Cole-Cole fitted relaxation peaks and of AC conductivity graphs as frequency independent (DC-like), and frequency dependent regions. DC-like region, it was thought that the main effect of AuNPs was observed, has values for AuNPs/PEGMEA/PEGDA nanocomposite film and PEGMEA/PEGDA film as 6 × 10 −7 and 2 × 10 −8  S/cm, respectively. In addition to these two polarization mechanisms, electrode polarization was observed at frequencies lower than 1 Hz for AuNps/PEGMEA/PEGDA nanocomposite film due to accumulation of AuNPs. [ABSTRACT FROM AUTHOR]

Thioxanthone (TX) and its derivatives are playing an important role as photoinitiators for photopolymerizable formulations. But another significant role of the photoinitiators was recently discovered, namely, the photoreduction of metal salts to metal nanoparticles, in which mainly ketyl radicals were responsible for this process. Functionalization of Polyhedral Oligomeric Silsesquioxanes (POSS) with TX is reported here and used for simultaneous preparation of self-assembled silver nanoparticles (Ag NPs) with POSS cage and polymer matrix. Covalent attachment of POSS-TX to the polymer matrix resulted in self-assembled Ag NPs in a self-wrinkled pattern. [ABSTRACT FROM AUTHOR]

The interaction of a multi-component system consisting of benzene-1,4-diyldimethanimine-bridged dimeric zinc-phthalocyanine groups (4OMPCZ) with calf thymus DNA (ct-DNA) was investigated using UV–Vis absorption, fluorescence emission spectroscopy methods, and viscosity measurements. The binding constant, K b , which is an important parameter to gain information about the binding mode, was found as 9.7 × 107 M−1 from the UV–Vis absorption studies. Another important spectrophotometric tool is competitive displacement assays with Ethidium bromide and Hoechst 33342. Through this experiment, a higher K SV value was obtained with Hoechst for the phthalocyanine derivative, 4OMPCZ, and the ct-DNA complex than with ethidium bromide. Additionally, molecular docking studies were conducted to calculate the theoretical binding constant and visualize the interactions of 4OMPCZ with a model DNA. According to docking results, although the interactions are mainly located in the major groove of the DNA helix, due to the wrapping, these interactions can also be extended to the minor groove of the DNA. Spectrophotometric, molecular docking, and viscosity studies revealed that the interaction of 4OMPCZ with DNA is likely to be via the major and minor grooves. The in vitro cytotoxic activity of 4OMPCZ was evaluated by MTT assay on human colon cancer cells (HT29) after 72 h of treatment. 4OMPCZ indicated significant cytotoxic activity when stimulated with UV light compared to the standard chemotherapy drugs, fluorouracil (5-FU), and cisplatin on HT29 colon cancer cells. The IC 50 value of 4OMPCZ displayed considerably lower concentrations compared to the standard drugs, 5-FU, and cisplatin. [Display omitted] • Groove binding mode of 4OMPCZ with ct-DNA is confirmed by Ethidium bromide and Hoechst displacement experiments. • In vitro cytotoxic activity of 4OMPCZ is evaluated by MTT assay on human colon cancer cells (HT29). • UV-stimulation effect on cytotoxicity is investigated. • Cytotoxic activity and IC 50 value of 4OMPCZ is compared with standard chemotherapy drugs, fluorouracil and cisplatin. [ABSTRACT FROM AUTHOR]

• DS results supports the structural and thermal analyze results. • For A1 and A2, it is looking there is a bonding situation of ε-Fe 2 O 3 Nps to the polymer matrix. • Glass transition temperatures for A1 and A2 indicates a critical ration of ε-Fe 2 O 3 Nps in PEGMEA/PEGDA structure. • Results for A3 show the presence of non-bonding excess ε-Fe 2 O 3 Nps in structure if the ratio becomes 20%. Photopolymerization of PEGMEA/PEGDA monomer mixture consisting of FeCl 3.6H 2 O metallic salt was performed using a Type I photoinitiator, namely 2-Hydroxy-4′-(2-hydroxyethyl)-2-methyl propane (Irgacure 2959). Herein, we report the easy and one-step in-situ synthesis method of a rare ε-Fe 2 O 3 polymorph in a polymer matrix with different concentrations of Fe3+ salt. Thermal gravimetric analyses of the nanocomposites indicate an increase of char yield depending on both the synthesized nanoparticle concentration and good distribution of Nps. SEM images are also proof of formation of ε-Fe2O3 Nps in polymer matrix. The obtained results indicate 4 and 20%w/w Fe3+ salt loading in the formulations resulted in higher char yield. Dielectric spectroscopy analysis and calculated glass transition temperatures show that there may be a critical ratio between 4 and 8% in the A1 and A2 samples, in comparison with the sample A3 which is the nanocomposite with 20% ε-Fe 2 O 3 Nps. A3 probably has excess free charges contributing to additional conduction. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • AuNps and AuNps@ GO were prepared by photochemical reduction method. • The colorimetric detection of L-cysteine was demonstrated in a nanomolar order concentration. • 4-Hydroxybenzophenone was used as photoreducing agent for Au ions. • AuNps and AuNps@ GO acted as simple and sensitive nano-sensors for L-cysteine. This study aimed for the development of a cost effective and efficient method for L-cysteine detection, without employing expensive instrumentation within a short analysis time. The proposed method has been involved in the photochemical preparation of gold nanoparticles and gold nanoparticles on graphene oxide nanostructures. The gold nanoparticles and gold nanoparticles on graphene oxide acted as simple and sensitive nano-sensors for L-cysteine, due to the molecular structure of the L-cysteine presented –NH 2 and –SH, which is very attractive for coordination to gold nanoparticles and crosslink gold nanoparticles causing aggregation and color change. By using the gold nanoparticles on graphene oxide as a probe, the colorimetric detection of L-cysteine in a nanomolar order concentration was demonstrated. [ABSTRACT FROM AUTHOR]