Branched poly(vinyl alcohol) (PVA) was synthesized via chemical modification of linear PVA with epichlorohydrin in an alkaline aqueous medium under conditions preventing crosslinking. Branching was confirmed by IR and Heteronuclear Single Quantum Coherence (HSQC) spectroscopy, as well as by viscometric analysis. An iterative procedure is proposed for refining the branching factor (g) and the viscosity-average molecular weight of the branched macromolecules. Coil diameters determined by viscometry and dynamic light scattering showed satisfactory agreement. While an increase in the viscosity-average molecular weight of branched PVA enhances its surface activity in the low-adsorption region, the branched geometry itself hinders subsequent adsorption due to steric shielding of the interface. This correlates with wetting behavior on Teflon: lightly branched PVA requires a higher concentration to induce wetting inversion than its linear counterpart but further increase in molecular weight shifts the inversion point to lower concentrations due to a higher density of hydroxyl groups. Concurrently, the concentration dependence of the work of adhesion degenerates with increasing molecular weight. Despite their reduced adsorption capacity, the specific geometry of branched PVA macromolecules provides effective steric stabilization of micrometer-sized particles during styrene suspension polymerization. These results demonstrate that chain branching in PVA is a powerful tool for tuning its adsorption properties, stabilizing ability, and interfacial activity.

Although the Knoevenagel condensation of aldehydes with various CH-acids has been known for more than 130 years, the efficiency of this reaction for phosphonoacetates remains poorly understood. We found that the preferred conditions for the formation of target 3-(hetero)aryl-2-(dialkoxyphosphoryl)acrylates depend on the electronic properties of the aldehyde used. Specifically, for the Knoevenagel condensation of trialkyl phosphonoacetates with electron-deficient (hetero)aromatic aldehydes, the best results are achieved using a combination of piperidine and acetic acid as a catalyst, whereas for aldehydes containing an electron-rich aromatic group, higher yields were obtained using the pyrrolidine/acetic acid catalytic system. Preferred amines for catalyzing the reactions of aldehydes with diverse electroneutral aromatic groups were also identified. Secondary amines themselves can also be used to carry out this reaction without loss of efficiency. In contrast, tertiary amines were ineffective both alone and in combination with carboxylic acids. Based on the obtained data, the mechanistic picture of the Knoevenagel condensation of trialkyl phosphonoacetates and its competition with the Horner-Wadsworth-Emmons condensation was refined.

Currently the interest to the synthesis of phosphacycles increases due to the possibility of their application as functional materials for organic electronics, imaging, and analysis in biological systems. lambda 5-Phosphinolines with six-membered phosphacycles can be easily synthesized in the reaction between mixed phosphonium-iodonium ylides and alkynes. In addition to lambda 5-phosphinolines substituted furan derivatives are formed for some carbonyl mixed ylide-terminal alkyne compositions. Herein, a mechanistic study of the reaction between benzoyl phosphonium-iodonium ylide with a series of terminal alkynes is presented. The study combines in situ 31P NMR spectroscopy, ESI-MS of intermediate products, and computational chemistry. Furan derivatives are formed in a radical pair generated as a result of SET to ylide from alkynes with the ionization potentials lower than a critical value. CIDNP effect is registered in this case by 31P NMR spectroscopy. lambda 5-Phosphinolines are formed in two parallel reactions: the minority in the radical pair and the majority in multistep reaction with participation of intermediate radicals giving dimers in the recombination reaction and subsequent transformations of these dimers.

Approaches to the design of new homo- and heterofunctionalized derivatives of 1,1'-dinaphthylmethane and resorcincalix[4]arenes that differ in the number, nature and spatial orientation of azole rings conjugated with polycyclic platform were found. Developed methods of synthesis were based on varying the combination of Oalkylation, nitrile-azide and alkyne-azide cycloaddition reactions. As a result following new compounds were synthesized, isolated with high yields and characterized: 2,2'-di- and 2,2',7,7'-tetra-tetrazolyl-1,1'-dinaphthylmetanes, 2,2'-di- and 2,2',7,7'-tetra-triazoletetrazolyl-1,1'-dinaphthylmethanes; rccc octa-tetrazolyl- and octa-triazoletetrazolyl-tetra-C-phenethylresorcincalix[4]arenes; rctt octa-tetrazolyl- and octa-triazoletetrazolyltetra-C-naphthylresorcincalix[4]arenes containing azole fragments located on horizontal and vertical benzene rings of macrocycle; rctt tetra-triazoletetrazolyl-tetra-phosphato-tetra-C-naphthylresorcincalix[4]arenes, in which azole groups are linked only to vertically oriented benzene rings of macrocycle, and phosphate moieties are immobilized on horizontally arranged benzene rigs. Using UV-spectroscopic method, the ionophore abilities of obtained polyazole systems towards some cations of d- (Cu2+, Ag+) and f- (Tb3+, Yb3+) elements were evaluated. It was shown that all examined compounds accepted Cu2+ cations, affinity to Ag+ cations was characteristic only of dinaphthylmethane derivatives, and ability to bind Tb3+, Yb3+ cations was exhibited by 2,2',7,7'tetra-triazoletetrazolyl-1,1'-dinaphthylmethane and rctt octa-triazoletetrazolyl-tetra-C-naphthylresorcincalix[4] arenes with the most spatially separated heterotopic functional branches.

A method for one-step conversion of (3-formylindol-4-yl)-substituted donor-acceptor cyclopropanes to 5,6-dihydro-1H-[1,2]diazepino[4,5,6-cd]indoles has been developed. The scope and limitations of this reaction, as well as the Lewis acid effect on the process chemoselectivity, have been determined. Straightforward transformations of the obtained products provide direct access to alkaloid-like tetracyclic compounds.

Fluorescent conjugates of carbocyanine dyes with a ligand selective to prostate-specific membrane antigen were accessed by either peptide synthesis or CuAAC methodology, with the latter being more promising. The introduction of a propargylamino moiety at the meso-position of the polymethine chain of the fluorophores afforded the alkyne counterparts for the CuAAC reaction toward the ligand bearing azido group. The photochemical studies showed that the quantum yields of the obtained conjugates exceeded those for the unmodified fluorophores by more than 20 times.

Thiocyanate-containing protic ionic liquids (PILs) have previously proven to be useful reagents for conducting diverse chemical transformations. A fundamentally new concept of multi-purpose application of these PILs opens up new opportunities in organic synthesis. However, their safety has not been thoroughly assessed so far. In this work, we carried out a systematic investigation of cytotoxicity of a series of synthetically valuable thiocyanate-containing PILs towards normal human dermal fibroblasts (DF-1) and human embryonic kidney cells (HEK293T). In particular, the impact of anion on the cytotoxicity was studied for dual-purpose triethylamine-based PILs. The study of cellular damage markers yielded additional insights into the mechanisms of PILs’ cytotoxicity.

Multi-purpose thiocyanate-containing protic ionic liquids were utilised in concert as a solvent, a Brønsted acidic catalyst, and a nucleophile source for the conversion of 4,5-dihydroxy-4,5-diarylimidazolidine-2-(thi)ones into imidazo[4,5-d]oxazolethiones and imidazo[4,5-d]thiazolones. A key advantage of this process is chemoselectivity switching by tuning the electron-donating nature of aryl substituents while carefully controlling the reaction temperature. In the case of unactivated arenes, oxazolethione was forced to rearrange into thiazolone in the new highly acidic protic ionic liquid, 1-methylpyrazolium triflate. The operationally simple experimental set-up is complemented by an eco-friendly aqueous work-up/filtration procedure providing pure crystalline products.

For sensing small organic molecules, the tricarbocyanine derivatives are particularly efficient if contain at least two binding sites. As a step toward such ditopic structures, we synthesized the tricarbocyanines bearing ionogenic functional groups in the meso-position and studied their complexes with transition metals. New compounds exhibited a differential colorimetric response to individual pharmaceutical compounds tentatively due to the formation of mixed-ligand complexes.

Ytterbium triflate catalysed domino reaction of (3-formyl-4-indolyl)-derived donor-acceptor cyclopropane with primary amines provides a simple approach to an unprecedented tetracyclic skeleton in which tropane system is peri-annulated with an indole core. This process involves the formation of an imine and its (3+2)-cross-cycloaddition with donor-acceptor cyclopropane moiety, yielding tropane-fused indole core under mild reaction conditions. These products are of significant interest for pharmacology as potential hybrid molecules with a dual mode of action.

The reactivity of ylides possessing additional iodonium functionality is driven by the departure of the iodonium group, which generates highly reactive intermediates. The scope of these reactions depends on both the nature of the reacting partner and the functional groups present at the ylidic center. In this study, we investigate the reactivity of phosphonium-iodonium ylides, where the ylidic carbon atom is bonded to a cyclic phenoxaphosphonium moiety and various electron-withdrawing substituents. The study examines these ylides in reactions with nitriles and alkynes, continuing our investigation of acyclic phosphonium-iodonium ylides with triple-bond-containing compounds. The incorporation of phosphorus into a cyclic structure reveals new bond-making and bond-breaking patterns in reactions with alkynes, leading to novel reaction pathway and the formation of enone-functionalized phosphonates. Phenoxaphosphonium-iodonium ylides and furans have been shown to have antiproliferative activity in vitro against several human cancer cell lines.

Treatment of mixed phosphonium-iodonium ylides featuring a six-membered phenoxaphosphonium fragment with aqueous tetrafluoroboronic acid induces a rearrangement, resulting in expansion of the phosphacycle and oxidation of the phosphorus atom. The target difficult-to-access dibenzo[b,f][1,4]oxaphosphepine oxides (3 examples) were isolated in excellent yields (up to 95%) as mixtures of stereoisomers. Hydrolysis of a five-membered mixed ylide, a dibenzophosphole derivative, predominantly preserves the phosphole system with cycle expansion occurring as a side process.

Triple-purpose protic ionic liquids were employed as a solvent, a Br & oslash;nsted acid catalyst, and a source of the nucleophile (thiocyanate-ion) for the chemodivergent transformation of dihydroimidazolones into 2-thioxohexahydro-5H-imidazo[4,5-d]oxazol-5-ones and tetrahydro-2H-imidazo[4,5-d]thiazole-2,5(3H)-diones. An important feature of this process is the switching of its chemoselectivity by simple variation of the reaction temperature, other conditions being the same; this allowed both types of products to be obtained selectively. Straightforward aqueous work-up of reaction mixture provided solid bicyclic products in pure form in an environmentally friendly manner.

Annulation of mixed phosponium-iodonium ylides and compounds with a triple bond is an interesting example of the synthesis of different types of heterocycles in one-pot, metal-free systems at ambient temperature to give substituted oxazoles in the reaction with nitriles and phosphorus-containing lambda(5)-phosphinolines and substituted furans in the reaction with acetylenes. The iodonium group in the mixed ylides provides the possibility for the radical initiation of the reaction. Herein, we investigated the generation of primary radicals and the formation of phosphorus-containing products in the photolysis of benzoyl phosphonium-iodonium ylide alone and in its reaction with acetylenes in DCM by EPR and P-31 NMR spectroscopies with the use of two most popular spin traps, PBN and DMPO. The results allowed us to account the crucial difference in the registered radicals in the two systems for the aggregation of the components, with ylide molecules forming a core and acetylene molecules being a shell of the aggregates in DCM, in which the annulation occurs. The peculiarities of the reactions of PBN and DMPO with generated radicals are discussed.

In our study, we investigated the accelerated aging process of PLA under 253.7 nm UV-C irradiation with the use of the GPC, NMR, FTIR, and DSC methods and formal kinetic analysis. The results of GPC and DSC indicated a significant degree of destructive changes in the PLA macromolecules, while spectroscopic methods NMR and FTIR showed maintenance of the PLA main structural elements even after a long time of UV exposure. In addition to that, the GPC method displayed the formation of a high molecular weight fraction starting from 24 h of irradiation, and an increase in its content after 144 h of irradiation. It has been shown for the first time that a distinctive feature of prolonged UV exposure is the occurrence of intra- and intermolecular radical recombination reactions, leading to the formation of a high molecular weight fraction of PLA decomposition products. This causes the observed slowdown of the photolysis process. It was concluded that photolysis of PLA is a complex physicochemical process, the mechanism of which depends on morphological changes in the solid phase of the polymer under UV radiation.

A series of phosphonium ylides and mixed phosphonium‐iodonium ylides based on cyclic phenoxaphosphinine has been synthesized, representing a new structural type of ylides. The influence of the electron‐withdrawing substituents of various nature on the stability and physicochemical properties of phenoxaphosphonium ylides is discussed. Our findings reveal a progressive reduction in ylide stability as the carbonyl group is replaced first with a phosphonate group and then with a nitrile group. NMR data indicates that the presence of a cyclic phosphonium group results in a lowered energy barrier to rotation about the carbon‐carbon bond, both in phosphonium and mixed phosphonium‐iodonium ylides with α‐carboxyl substituents when compared to triarylphosphonium ylides. These experimental results are further supported and analyzed in the context of density functional theory (DFT) calculations.

Triple-role thiocyanate-containing protic ionic liquids (PILs) were employed as a regenerable solvent, a Bronsted acid catalyst, and a source of the nucleophile for the ring-opening of 1,3-indanedione-based donor-acceptor cyclopropanes.

Traditional butyl rubber halogenation technology involves the halogenation of IIR using molecular chlorine or bromine in a solution. However, this method is technologically complex. This study investigated a novel method for the halogenation of butyl rubber to enhance its stability and resistance to thermal oxidation and aggressive media. The butyl rubber was modified through mechanochemical modification, induced by solvent swelling in a polychlorinated n-alkane solution. During the modification, samples were obtained with chlorine content ranging from 3 to 15%. After extraction, the halogen content was quantitatively determined with the oxygen flask combustion method and X-ray photoelectron spectroscopy. It was shown that for samples with total chlorine content of up to 6%, there was almost no leaching of chlorine from the samples. The chemical structure of the extracted rubbers was ascertained using FT-IR and 1H NMR spectroscopy, and it was demonstrated that all samples showed absorption peaks and signals typical for chlorobutyl rubbers. It was observed that modification with polychlorinated n-alkanes improved the thermal and oxidative stability (the oxygen absorption rate decreased by 40%) and chemical resistance, estimated by the degree of swelling, which decreased with the increase in the chlorine content. This technology allows the production of a chlorinated rubber solution that can be directly used by rubber goods manufacturers and suppliers.