Polar Aprotic Solvents Research Articles

Water-solvent regulation on complete hydrolysis of thermosetting polyester and complete separation of degradation products

As one of the largest productions of thermosetting plastics, unsaturated polyester resin (UPR) is difficult to be effectively chemcycled after it is discarded due to its dense network structure. Herein, we demonstrate a mild method for efficient alkaline hydrolysis of UPR into useful feedstocks in mixed solvents of polar aprotic solvent and a small amount of H2O by utilizing the fragmentation effect of the solvent on the UPR and the swelling effect of H2O on the subsequent partially hydrolyzed UPR respectively. The mixed solvents also play a key role in the aggregation and solubility of the degradation products. It is worth noting that the tetrahydrofuran (THF)-H2O system achieved 100 % separation of degradation products in an energy-efficient way taking advantage of the insolubility of the carboxylate-containing products in THF and the low boiling point of THF. The participation of non-reactive mixed solvents greatly promotes both the degradation and the separation process of thermosetting polymers.

Fundamental Understanding of Ultrathin, Highly Stable Self-Assembled Liquid Crystalline Graphene Oxide Membranes Leading to Precise Molecular Sieving through Non-equilibrium Molecular Dynamics

Self-assembled graphene oxide lyotropic liquid crystal (GO LLC) structures are mostly formed in aqueous medium; however, most GO derivatives are water insoluble, so processing GO LLCs in water poses a practical limitation. The use of polar aprotic solvent (like dimethyl sulfoxide) for the formation of GO LLC structures would be interesting, because it would allow incorporating additives, like photoinitiators or cross-linkers, or blending with polymers that are insoluble in water, which hence would expand its scope. The well-balanced electrostatic interaction between DMSO and GO can promote and stabilize the GO nanosheets' alignment even at lower concentrations. With this in mind, herein we report mechanically robust, chlorine-tolerant, self-assembled nanostructured GO membranes for precise molecular sieving. Small-angle X-ray scattering and polarized optical microscopy confirmed the alignment of the modified GO nanosheets in polar aprotic solvent, and the LLC structure was effectively preserved even after cross-linking under UV light. We found that the modified GO membranes exhibited considerably improved salt rejection for monovalent ions (99%) and water flux (120 LMH) as compared to the shear-aligned GO membrane, which is well supported by forward osmosis simulation studies. Additionally, our simulation studies indicated that water molecules traveled a longer path while permeating through the GO membrane compared to the GO LLC membrane. Consequently, salt ions permeate slowly across the GO LLC membrane, yielding higher salt rejection than the GO membrane. This begins to suggest strong electrostatic repulsion with the salt ions, causing higher salt rejection in the GO LLC membrane. We foresee that the ordered cross-linked GO sheets contributed to excellent mechanical stability under a high-pressure, cross-flow, chlorine environment. Overall, these membranes are easily scalable, exhibit good mechanical stability, and represent a breakthrough for the potential use of polymerized GO LLC membranes in practical water remediation applications.

Threonine functionalized colloidal cadmium sulfide (CdS) quantum dots: The role of solvent and counterion in ligand induced chiroptical properties

The functionalization of semiconductor nanocrystals, quantum dots (QDs), with small organic molecules has been studied extensively to gain better knowledge on how to tune the electronic, optical and chiroptical properties of QDs. Chiral QDs have progressively emerged as key materials in a vast range of applications including biosensing and biorecognition, imaging, asymmetric catalysis, optoelectronic devices, and spintronics. To engage the full potential of the unique properties of chiral nanomaterials and be able to prepare them with tailorable chiroptical characteristics, it is essential to understand how chirality is rendered from chiral molecular ligands at the surface of nanocrystals to the electronic states of QDs. Using a series of polar protic and aprotic solvents together with ammonium (NH4+), tetramethylammonium (TMA+), and tetrabutylammonium (TBA+) countercations in the preparation of threonine-functionalized cadmium sulfide (Thr-CdS) QDs by phase transfer ligand exchange approach, we demonstrated the significance of the role both the solvent and the countercations play in the transfer of chirality from chiral molecular ligand to achiral semiconductor QDs as apparent by the modulations of the signatures and anisotropy of the circular dichroism (CD) spectra. Moreover, we have utilized tetrabutylammonium countercation to successfully synthesize chiral QDs in nonpolar cyclohexane solvent for the first time. This study provides further insights into the origin of the ligand induced chirality of colloidal nanomaterials and facilitates the synthesis of tailormade chiral QDs.

Cyrene™, a Sustainable Solution for Graffiti Paint Removal

Graffiti can create detrimental aesthetic and environmental damage to city infrastructure and cultural heritage and requires improved removal methods. Incumbent laser, mechanical and chemical removal techniques are often not effective, are expensive or damage the substrate. Solvents are generally hazardous and not always effective because of the insolubility of the graffiti paint. This study proposes a simple strategy for safe and effective graffiti removal, using the bio-based, non-toxic and biodegradable solvent dihydrolevoglucosenone (Cyrene™). The results showed that the type of substrate influenced the cleaning performance; in benchmark studies a non-porous substrate was easy to clean, while porous ceramic showed the presence of residual paint and yellowing when the conventional polar aprotic solvents were used. Cyrene, however, showed good removability of graffiti paint from both glazed and porous substrates, with little paint remaining in the pores of ceramic tiles. The paint suffered a reversible change in colour and a selective solubility of its components when using N-methyl-2-pyrrolidone; no changes occurred when Cyrene was used. While N-methyl-2-pyrrolidone and N,N′-dimethylformamide were only effective when neat, a Cyrene–water mixture showed some cleaning results. The performance of Cyrene was validated with Hansen solubility parameters and represents a greener and more sustainable solvent for paint removal.

Thermoresponsive and co-nonsolvency behavior of poly(N-vinyl isobutyramide) and poly(N-isopropyl methacrylamide) as poly(N-isopropyl acrylamide) analogs in aqueous media

Sets of the nonionic polymers poly(N-vinyl isobutyramide) (pNVIBAm) and poly(N-isopropyl methacrylamide) (pNIPMAm) are synthesized by radical polymerization covering the molar mass range from about 20,000 to 150,000 kg mol−1, and their thermoresponsive and solvent-responsive behaviors in aqueous solution are studied. Both polymers feature a lower critical solution temperature (LCST) apparently of the rare so-called type II, as characteristic for their well-studied analogue poly(N-isopropyl acrylamide) (pNIPAm). Moreover, in analogy to pNIPAm, both polymers exhibit co-nonsolvency behavior in mixtures of water with several co-solvents, including short-chain alcohols as well as a range of polar aprotic solvents. While the cloud points of the aqueous solutions are a few degrees higher than those for pNIPAm and increase in the order pNIPAm < pNVIBAm < pNIPMAm, the co-nonsolvency behavior becomes less pronounced in the order pNIPAm > pNVIBAm > pNIPMAm. Exceptionally, pNIPMAm does not show co-nonsolvency in mixtures of water and N,N-dimethylformamide.Graphical

Structural studies of a novel tautomeric Schiff base derived from 4-(N,N’-diethylamino)salicylaldehyde and 2-amino-4-methyl phenol: An experimental and theoretical study

A novel Schiff base, LMAP synthesized from 4-(N,N’-diethylamino)salicylaldehyde and 2-amino-4-methyl phenol has been characterized by single crystal X-ray diffraction and spectroscopic methods. DFT methods is used to investigate the enol-imine (EI) ⇄ keto-amine (KA) tautomeric behavior with respect to phase and in solvent media. The synthesized Schiff base crystallizes in the keto-amine (KA) form in the orthorhombic lattice and Pna21space group with four atoms per unit cell (Z = 4). Bond length analysis indicates that the KA form possesses significant zwitter ionic character. Study of electronic absorption and emission properties was conducted in the solid state as well as in different solvents. The UV–Vis result reveals the varied structural preference of the compound depending on the solvent media: polar protic solvents stabilize the KA form, while nonpolar and polar aprotic solvents favor the EI form. Quantum mechanical computations using DFT and TD-DFT also confirm these findings. Fluorescence emission spectra show multiple emission bands which indicate both excited state intramolecular proton transfer (ESIPT) and charge transfer (CT) phenomena occur simultaneously within the molecule. DFT predicted NLO responses of KA and EI were compared and found that the NLO response of KA is superior to that of EI.

Synthesis of Triazolo[c]coumarins and Differences in the Fluorescence Properties of Their Isomers

AbstractDespite the simple structures of 3,4‐fused tricyclo coumarins, their fluorescence properties have not been studied extensively. We have synthesized triazolo[c]coumarins using Huisgen cycloaddition and investigated their fluorescence properties. The Huisgen cycloaddition was found to proceed in excellent yields when subjected to heating under solvent‐free conditions. As is generally known, fluorescence is enhanced with an increase in the electron‐donating group at the 7‐position. The 7‐NEt2‐triazolo[c]coumarin derivatives showed useful fluorescence, and their relative fluorescence quantum yields in aprotic polar organic solvents were high. It revealed that fluorescence properties of triazolo[c]coumarins depended on the regio isomer. The electron distribution was hardly extended to alkyl side chain on triazole from the molecular orbital calculation by density functional theory (DFT) and time‐dependent DFT (TD‐DFT). This result suggests that the trend of fluorescence properties is similar to the present result even when various substituents are introduced on triazole.

Effect of the π-bridge structure on the intramolecular charge transfer of push–pull 2-phenylthiophene and 2-(furan-2-yl)pyridine derivatives

Effect of the bridge structure on the photophysical properties of D-π-A of structurally similar 2,5-diphenylthiophene (cpd. I) and 2-(5-phenylfuran-2-yl)pyridine (cpd. 2) derivatives having the same electron donating and electron withdrawing groups were studied in different solvents. Solvent effect on the absorption and fluorescence emission spectra as well as their excited state decay were studied in detail. Introduction of 2,5-diphenylthiophene and 2-(5-phenylfuran-2-yl)pyridine between methoxy and carbonitrile groups lead to a shift of about 20 nm in both the absorption and fluorescence emission maxima of the former. Stokes shift of about 90 nm was observed for both compounds in protic solvents and polar aprotic solvents and decreases as the solvent polarity decreases. The solvatochromism in the fluorescence emission spectra was higher than the observed in absorption spectra, indicating higher dipole moment in the excited state than in the ground state for both compounds. DFT and TD-DFT optimized geometry calculations show that (I) is planar in the excited state while (II) is planar in both the ground and excited states reflecting the importance of the bridge structure on the geometry in the ground and excited states. Theoretical calculations of the dipole moment change from the ground to the excited states were consistent with the values obtained from Lippert-Mataga relationship and higher than values obtained from Reichardt-Ravi relationship. It has been found that the fluorescence lifetime of both compounds was found to decrease as the emission energy increases and being higher for (II) than for (I), and also was found to increase as the solvent’s dielectric constant increases. All photophysical properties were found to correlate well with Reichardt’s solvent polarity parameter, ETN. We have employed Kamlet-Taft, Catalán and Laurence et al. multi-parametric relationships to assign the contribution of the specific and non-specific solute–solvent interactions. Non-specific interactions were found to be mostly dominating in all cases.

Sustainable solvent metal lift-off for compound semiconductor fabrication with improved manufacturability

Due to concerns regarding substrate damage, wet photoresist removal has been adopted over dry etch techniques for certain metal lift-off processes on substrates and metals that are susceptible to plasma damage. Wet photoresist removal generally requires the use of polar aprotic solvents and historically n-methyl pyrrolidone (NMP) has been broadly adopted. A successful lift-off process requires consideration of both the solvent used to remove the photoresist as well as the correct photoresist retrograde profile. As features become smaller and more critical, the overall photoresist profile becomes more challenging. The use of bottom anti-reflective coatings (BARC) has become necessary to better control the reflected light and minimize potential defectivity during patterning. However, addition of the BARC layer complicates the resist removal process by requiring a secondary cleaning step since wet photoresist strip chemistries, such as NMP, generally do not remove it. There have been several developmental efforts in the metal lift-off industry to formulate a solvent, which could remove both photoresist and BARC, concurrently. In the first half of this paper, various wet photoresist removers are compared to determine the most effective wet resist strip for removal of both photoresist and BARC in one step. The second half of the paper summarizes two different metal liftoff processes and compares the performance of the best chemistry from initial experimentation, Technistrip® MLO-07, to NMP.

Kinetic and Mechanistic Studies of the Selective Hydrogenation of (E)‐Chalcones in Biomass‐Derived γ‐Valerolactone Catalyzed by Rh−PPh3 Complexes

Abstractγ‐Valerolactone as a renewable, polar aprotic solvent was evaluated in the selective hydrogenation of carbon‐carbon double bond of chalcones from both catalytic and mechanistic aspects. By using triphenylphosphine‐modified cationic rhodium catalyst systems reasonably high activities (TOFinitial∼1200 h−1) were achieved in the selective hydrogenation of (E)‐chalcone (CHL), as a common model substrate for α,β‐unsaturated ketones, to dihydrochalcone (DHC). Various derivatives of CHL, which were substituted on the styryl phenyl groups also showed exclusive selectivity for the hydrogenation of the C=C double bond. The optimal PPh3/Rh ratio was between 2.5 to 3, but higher ratios were advantageously also tolerated, which is beneficial for the process chemistry. The solvent GVL proved to stable enough under the reaction conditions for waste‐free recycling. Kinetic studies and NMR spectra from the analogous deuteration of chalcone by using the cationic Rh‐PPh3 system clearly show the olefin insertion as the rate‐determining step with definite irreversibility. By investigating the substituent effect on the phenyl ring of the styryl moiety of chalcone, a quasi‐linear correlation was found between the electronic parameters of the para‐substituents and the activity with electron donor groups being favorable for the reaction rate. In summary, an environmentally friendly and feasible method is presented for the production of valuable DHC intermediates in view of their pharmaceutical importance.

Catalyst-Free Thia-Michael Addition to α-Trifluoromethylacrylates for 3D Network Synthesis.

Thia-Michael additions (1,4-additions of a thiol to a Michael acceptor) are generally catalyzed by an external Brønsted or Lewis base. A spontaneous (uncatalyzed) Michael addition of thiols to α-trifluoromethyl acrylates is described, as well as its application to the very efficient preparation of a thermoset. A thorough mechanistic investigation, based on an experimental kinetic study and on DFT calculations, is presented for the addition of arene- and alkanethiols to tert-butyl trifluoromethyl acrylate in polar aprotic solvents, unveiling a probable solvent-assisted proton transfer in the rate-determining step and a considerable lowering of the energy barrier induced by the CF3 group.

Reversible thermochromic systems based on a new library of flavylium spirolactone leuco dyes

The aim of this work was the design, synthesis, and characterization of new chromogenic spirolactone dyes based on a 2-phenyl-1-benzopyrylium (flavylium) backbone for further development of thermochromic smart labels. The influence of electron-donating and electron-withdrawing groups on the five synthesized dyes was studied in terms of color modification, acid-base behavior and thermochromic properties. By using UV–Vis absorption and emission spectroscopies, molar absorptivity, oscillator strength, Stokes shift, and fluorescence quantum yield were determined for each dye to evaluate the impact on color and excited state properties of the designed structures. The acid-base behavior and the ability to evolve towards leuco species was assessed by titrations with triethylamine and N,N-diisopropylethylamine in non-polar and polar aprotic solvents such as acetonitrile and octan-1-ol. In addition, the reversibility of the color was also evaluated by titrations with polar protic solvents (water and ethanol) and Lewis acids (gallic acid and iron(III) chloride). The number of equivalents of base/acid required to reach the leuco product and then to reverse the color were determined by representing the absorption maximum as a function of added base/acid in acetonitrile (water content less than 0.01-v/v). Finally, the thermochromic properties were evaluated in the presence of long-chain organic amines and water-insoluble solvents with melting points close to room temperature. The synthesized compounds can switch between two species if the appropriate conditions are used. Moreover, the tests carried out to assess their thermochromic behavior concluded that all dyes display thermochromism to some extent. The dyes that have electron-withdrawing groups attached, such as cyano, display stronger chromogenic effects useful for future applications.

Enhanced Photoluminescence of Crystalline Alq3 Micro-Rods Hybridized with Silver Nanowires

An enhancement of the local electric field at the metal/dielectric interface of hybrid materials due to the localized surface plasmon resonance (LSPR) phenomenon plays a particularly important role in versatile research fields resulting in a distinct modification of the electrical, as well as optical, properties of the hybrid material. In this paper, we succeeded in visually confirming the LSPR phenomenon in the crystalline tris(8-hydroxyquinoline) aluminum (Alq3) micro-rod (MR) hybridized with silver (Ag) nanowire (NW) in the form of photoluminescence (PL) characteristics. Crystalline Alq3 MRs were prepared by a self-assembly method under the mixed solution of protic and aprotic polar solvents, which could be easily applied to fabricate hybrid Alq3/Ag structures. The hybridization between the crystalline Alq3 MRs and Ag NWs was confirmed by the component analysis of the selected area electronic diffraction attached to high-resolution transmission electron microscope. Nanoscale and solid state PL experiments on the hybrid Alq3/Ag structures using a lab-made laser confocal microscope exhibited a distinct enhancement of the PL intensity (approximately 26-fold), which also supported the LSPR effects between crystalline Alq3 MRs and Ag NWs.

Eco-Friendly OSN Membranes Based on Alginate Salts with Variable Nanofiltration Properties

In this work, membranes for organic solvents nanofiltration (OSN) based on a natural polymer, sodium alginate, were fabricated. They are chemically stable in organic solvents, including aprotic polar solvents. The unique advantage of these membranes is the absence of toxic reagents and solvents during their production. This ensures the safety and environmental friendliness of the production process. It has been shown that an operation as simple as changing the cation in alginate (Cu2+, Fe3+, Cr3+, Al3+, Zn2+, Ca2+) makes it possible to control the transport and separating properties of membranes, depending on the organic solvent being separated. Therefore, to isolate RemazolBrilliant Blue with MM = 626 g·mol-1 from ethanol, membranes based on iron alginate with a rejection R = 97% and a permeability of 1.5 kg·m-2·h-1·bar-1 are the most efficient. For isolation of the same solute from DMF and MP, membranes based on calcium alginate with an R of about 90% and a permeability of 0.1-0.2 kg·m-2·h-1·bar-1 are the most efficient. The resulting membranes based on natural biodegradable sodium alginate are competitive compared to membranes based on synthetic polymers.

Synthesis of 2-[2,3-dihydro-1,4-benzodioxin-6-yl(phenylsulfonyl)amino]-N-(un/substituted-phenyl)acetamides as anti-diabetic agents

Purpose: To synthesize a series of new 2-[2,3-dihydro-1,4-benzodioxin-6-yl(phenylsulfonyl)amino]-N-(un/substituted-phenyl) acetamides, and evaluate their anti-diabetic potentials.&#x0D; Methods: Synthesis of the parent compound N-(2,3-dihydro-1,4-benzodioxin-6-yl) benzenesulfonamide (3) was carried out by reacting 2,3-dihydro-1,4-benzodioxin-6-amine (1) with benzenesulfonylchloride (2) in aqueous basic medium under definite pH controls. After that 3 was further treated with various 2-bromo-N-(un/substituted-phenyl)acetamides (6a-l) to yield new compounds (7a-l) in polar aprotic solvent, DMF (dimethylformamide), using LiH as activator. The proposed structures of the synthesized compounds were confirmed using proton-nuclear magnetic resonance (1H-NMR) and infra-red spectroscopy (IR), and CHN analysis. Their anti-diabetic potential was evaluated by α-glucosidase enzyme inhibitory studies.&#x0D; Results: All the new compounds demonstrated weak (7a-h, 7j and 7l) to moderate (7i and 7k) inhibitory activities against α-glucosidase enzyme. IC50 (50 % inhibition concentration) values for 7i and 7k were 86.31±0.11 μM and 81.12±0.13 μM, respectively relative to acarbose (reference standard) with IC50 of 37.38±0.12 μM.&#x0D; Conclusion: All the synthesized compounds have weak to moderate activity against α-glucosidase enzyme. These compounds can thus be considered as possible therapeutic entrants for type-2 diabetes.

Characterization of isolated starch from Isatis indigotica Fort. root and anhydro-sugars preparation using its decoction residues.

Isatis indigotica Fort. root (Ban-lan-gen, IIR), a traditional Chinese medicine (TCM), has an ancient and well-documented history for its medicinal properties. Aside from epigoitrin, indole alkaloids, and their corresponding derivatives as medicinal ingredients, it also contains lots of biomass such as starch. Herein, a new starch was isolated from IIR and the physicochemical properties such as amylose content, moisture content, ash content, morphology, thermal properties, and crystallography were characterized systematically. The amylose content of IIR starch was 19.84 ± 0.85%, and the size and shape of starch granules is ellipsoidal shape with sizes from 2 to 10μm. IIR starch exhibited a C-type pattern and had 25.92% crystallinity (higher than that of corn starch). The gelatinization temperature of IIR starch was 58.68-75.41°C, and its gelatinization enthalpy was ΔH gel = 4.33J/g. After decocting, the IIR's residues can be used to prepare anhydro-sugars in a polar aprotic solvent. The total carbon yield of levoglucosan (LG), levoglucosenone (LGO), 5-hydroxymethylfurfural (HMF), and furfural (FF) could reach 69.81% from IIR's decoction residues in 1,4-dioxane with 15mM H2SO4 as the catalyst. Further, the residues after dehydration were prepared into biochar by thermochemical conversion and the BET surface area of biochar was 1749.46 m2/g which has good application prospect in soil improvement and alleviates obstacles of IIR continuous cropping.

Synthesis and characterization of poly(1,2,3‐triazole)s with inherent high sulfur content for optical applications

AbstractThe synthesis of solution‐processable sulfur‐containing polytriazoles for optoelectronic applications is a relatively less explored domain in polymer research. The synthesis of novel bifunctional (DA) and trifunctional (TA) azido‐monomers with inherent high sulfur content and of organo‐soluble high refractive index poly(1,2,3‐triazole)s using the azido‐monomers via Cu(I) assisted click polymerization reactions are reported in this work. The azido‐monomers were synthesized by the conversion of previously reported amine‐functionalized compounds to azides using azidotrimethylsilane in a polar aprotic solvent. Dialkyne monomers were also synthesized and reacted with the azides to prepare a series of five linear and two hyperbranched poly(1,2,3‐triazole)s. Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, differential scanning calorimetry and thermogravimetric analysis were used to characterize the synthesized polymers. It was also demonstrated that the use of the trifunctional azide in optimized conditions resulted in increased solubility of an otherwise insoluble linear poly(1,2,3‐triazole). The optical characterization of the polymers was carried out on thin polymer films with thickness in the nanometer range, which were successfully prepared by spin‐coating on silicon wafers. It was found that the increase in the sulfur and aromatic content in the polymer backbone successfully increased the refractive index of the polymers up to 1.743 at 589 nm.

Weak Interactions in Dimethyl Sulfoxide (DMSO)–Tertiary Amide Solutions: The Versatility of DMSO as a Solvent

The structures of equimolar mixtures of the commonly used polar aprotic solvents dimethylformamide (DMF) and dimethylacetamide (DMAc) in dimethyl sulfoxide (DMSO) have been investigated via neutron diffraction augmented by extensive hydrogen/deuterium isotopic substitution. Detailed 3-dimensional structural models of these solutions have been derived from the neutron data via Empirical Potential Structure Refinement (EPSR). The intermolecular center-of-mass (CoM) distributions show that the first coordination shell of the amides comprises ∼13-14 neighbors, of which approximately half are DMSO. In spite of this near ideal coordination shell mixing, the changes to the amide-amide structure are found to be relatively subtle when compared to the pure liquids. Analysis of specific intermolecular atom-atom correlations allows quantitative interpretation of the competition between weak interactions in the solution. We find a hierarchy of formic and methyl C-H···O hydrogen bonds forms the dominant local motifs, with peak positions in the range of 2.5-3.0 Å. We also observe a rich variety of steric and dispersion interactions, including those involving the O═C-N amide π-backbones. This detailed insight into the structural landscape of these important liquids demonstrates the versatility of DMSO as a solvent and the remarkable sensitivity of neutron diffraction, which is critical for understanding weak intermolecular interactions at the nanoscale and thereby tailoring solvent properties to specific applications.

Phthalocyanine photosensitizers with bathochromic shift, of suitable brightness, capable of producing singlet oxygen with effective efficiency

• New phthalocyanine derivatives as photosensitizers were designed and synthesized. • The phthalocyanines dissolve well in common solvents without aggregation. • The phthalocyanines have improved fluorescence and optical absorption properties. • The phthalocyanines have improved photochemical properties and photostability. • The phthalocyanines can be used as photosensitizers in photocatalytic applications. In this study, novel 3-(2,3-dimethoxyphenoxy)phthalonitrile 2 and its non-peripheral tetra-2,3-dimethoxyphenoxy substituted metal-free phthalocyanine 3 compounds were synthesized. Then, the magnesium(II), zinc(II), and indium(III) acetate phthalocyanine complex derivatives ( 4-6 ) of compound 3 were synthesized using the corresponding metal salts by the template effect. The structures of novel phthalonitrile derivative 2 and its metal-free phthalocyanine compounds 3 as well as different metal-containing phthalocyanine complexes ( 4-6 ) were characterized by elemental analysis, FTIR, UV-vis, 1 H NMR, and MALDI-TOF mass spectroscopic techniques. The phthalocyanines ( 3-6 ) can dissolve well in different polar protic, polar aprotic, and non-polar solvent types without aggregation, with maximum absorption intensity and bathochromic effect. Photophysicochemical properties of the phthalocyanines ( 3-6 ) in dimethyl sulfoxide and important spectral parameter values such as molar extinction coefficient, oscillator strength, and electrical dipole strength were determined, and they were also compared with each other and with their unsubstituted counterparts. It was determined that the phthalocyanines ( 3-6 ) have suitable and sufficient fluorescence quantum yields, fluorescence lifetimes, fluorescence brightness, and other photophysical properties, as well as singlet oxygen generation, phototoxic power, and photostability properties. The phthalocyanines ( 3-6 ), particularly zinc(II) and indium(III) acetate phthalocyanines have remarkable potential for use as Type II photosensitizers for cancer therapy in photodynamic therapy. The phthalocyanines ( 3-6 ) may be promising candidates for various applications as photosensitizers for photodynamic therapy, especially in combination with fluorescent imaging.

Highly rigid and functional poly(benzimidazole sulfone)s from 5,6‐dimethoxy‐1,3‐dihydro‐2H‐benzo[d]imidazol‐2‐one monomer

AbstractA series of poly(benzimidazole sulfone)s (PBSs) and poly(benzimidazole ketone)s (PBKs) containing 5,6‐dimethoxy‐1,3‐dihydro‐2H‐benzo[d]imidazol‐2‐one (MBIO) have been synthesized by C–N/C–O coupling with different percentages of three other diphenol monomers under similar conditions. The structure of PBS‐MBs and PBK‐MBs was confirmed using 1H NMR and Fourier transform infrared spectroscopies, and X‐ray diffraction data revealed that all the polymers are in an amorphous state. Due to the introduction of methoxy, the polymers were more soluble in common aprotic polar solvents. The intrinsic viscosity of the synthesized polymers was measured with an Ubbelohde viscometer, ranging from 0.38 to 1.35 dL g−1. The MBIO‐based polymers have a remarkably good thermal stability with a high glass transition temperature of up to 305.1 °C. Furthermore, the wavelength of maximum fluorescence emission from homopolymers is around 414 nm with emission of blue light in N‐methyl‐2‐pyrrolidone solution (1 mg L−1) and around 530 nm in films. They also showed low dielectric constants (κ = 2.60–3.10 at 1 MHz) and low water absorption (0.22–0.58%). It was encouraging to discover that these polymers have potential utility for the microelectronics industry, in which good solubility facilitates processing and molding, excellent thermal stability allows devices to be used under harsh conditions, low water absorption prevents device expansion and shrinkage and low dielectric constant is desired to prevent crosstalk between conducting paths. © 2023 Society of Industrial Chemistry.