Guanidincontaining Oligomeric Cationic Potonic Ionic Liquids With Biocide Activity

Oligomeric ionic liquids occupy an intermediate position between low molecular weight and polymeric. They are promising as polymer electrolytes in electrochemical devices for various purposes, membranes for the separation of gas mixtures, in sensor technologies, and so on. Oligomeric guanidinium ionic liquids are practically not described in the literature. In terms of studying the effect of the structure of the epoxy component on the properties of oligomeric ionic liquids of this type, it is advisable to introduce into its composition an aliphatic oligoether component. The choice of aliphatic oligoepoxide for the synthesis of guanidinium oligomeric ionic liquids is based on the fact that it is structurally similar to poly - and oligoethylene oxides, which are known to be non-toxic, biodegradable, and reactive oligomeric ionic liquids at elevated temperatures. A new type of reactive oligomeric proton cationic ionic liquid was synthesized by the reaction of oligomeric aliphatic diepoxide with guanidine, followed by neutralization of the product with hydrochloric acid. In this study, the synthesis of proton cationic oligomeric ionic liquids was based on the introduction of guanidinium fragments as end groups of the oligoether aliphatic chain. This reaction is attractive because of the ease of opening the oxirane ring with such a strong nucleophile as guanidine.The reaction forms a fragment with an aliphatic C-N bond, which retains the high basicity of the nitrogen atom. Its structure is characterized by the presence of guanidinium groups at the ends of the aliphatic hydroxyl-containing oligoether chain. The chemical structure of this compound is characterized by IR -, 1H ,13 C NMR spectroscopy methods, and its molecular mass characteristics are determined.The average molecular weight of the synthesized oligomeric ionic liquids is 610 g / mol.The value of the coefficient of polydispersity of the synthesized oligomeric ionic liquids is equal to 1.2. Determination of the content of amino groups in the guanidine-containing oligomer in the basic form by titrometric method allowed to establish that the value found is close to the theoretically calculated value. The synthesized oligomeric proton ionic liquid is characterized by an amorphous structure with two glass transition temperatures. The first lies in the range -70 °C, the second in the region of 70 °C, and the beginning of thermal oxidative destruction is located in the region of 148 °C. The temperature dependence of the ionic conductivity for this compound is nonlinear in the Arrhenius coordinates, which indicates the realization of ionic conductivity mainly due to the free volume in the system. The proton conductivity of this compound is 6.4·10-5–1·10-2Cm/cmin the range of 20–100 °C. The obtained compound exhibits surface-active properties characteristic of classical surfactants, as evidenced by the value of the limiting surface activity – 2.8·102 Nm2 / kmol. The value of CCM is 1.8·10-2 mol/l., and the value of the minimum surface tension – 37.70 mN / m. The synthesized oligomeric ionic liquid is of interest as electrolytes operating under anhydrous conditions, surfactants, disinfectants, and starting reagents for the synthesis of ion-containing blockopolymers.

Oligomeric Guanidine-Containing Proton Cationic Ionic Liquid

Vortman¹,

Лемешко²,

Goncharenko³

et al. 2021

Guanidiniium-Containing Oligomer Cationic Protonic Ionic Liquids

Shevchenko¹,

Vortman²,

Лемешко³

et al. 2022

By reacting a dian epoxy oligomer with guanidinium hydrochloride, a synthesis method of guanidinium-containing cationic proton oligomeric ionic liquids (OIL) capable of condensation reactions was developed. These compounds are characterized by an amphiphilic structure combining a flexible oligoether or hydroxyl-containing guanidinium oligoether block with terminal hydroxyl-containing guanidinium fragments. These compounds are capable of supramolecular organization due to the self-association of flexible oligoether blocks with terminal hydroxyl-containing guanidinium fragments from the outside of the formed cluster. They are characterized by two glass transition temperatures, which differ significantly in magnitude. The structure formed by the flexible oligoether component is determined by its segmental mobility with the glass transition temperature in the range (70–85 °C), and the terminal guanidinium fragments are responsible for the manifestation of the cohesive nature of the glass transition of the oligomer as a whole with the glass transition temperature in the range (-70)–(-60 °C), which characteristic of classical ionic liquids. The proton conductivity of the synthesized compounds in anhydrous conditions reaches a value of 1,94·10-3 S/cm at 120 °C and is determined not by the absolute value of the introduced protons, but by their specific number in relation to the MW oligomers. The synthesized OIL are of interest as electrolytes with an anhydrous conduction mechanism and starting reagents for the synthesis of ion-containing block copolymers of various functional purposes.

Guanidine-Containing Aliphatic Oligomers With Bactericidal Activity

VORTMAN,

FURTAT,

VAKULIUK

et al. 2024

A method for the synthesis of reactive aliphatic guanidine oligomers (GO) of different MM by the reaction of oligomeric oxyalkylaliphatic diepoxide with guanidine by varying the ratio of the starting components with subsequent neutralization of the obtained product with hydrochloric acid was developed. A characteristic feature of the structure of the obtained GO oligomers is their amphiphilicity, with the presence of hydroxy-containing guanidine fragments both at the ends and inside the chain. The obtained oligomers are reactive to further chemical transformations. The chemical structure of GO was characterized by FTIR and 1H-NMR spectroscopy, molecular weight was determined by liquid chromatography and titration data. The bactericidal properties of aliphatic guanidine oligomers against a number of gram-positive (Micrococcus luteus, Rhodococcus erythropolis, Rhodococcus rubber, Bacillus megaterium, Bacillus subtilis, Bacillus cereus) and gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Serratia marcescen), depending on the MW of GO were investigated. The minimum inhibitory concentration of aliphatic guanidine oligomers against the studied bacterial strains was determined. It has been shown that the oligomer with the highest content of guanidine fragments has the greatest bactericidal activity and, accordingly, the lowest minimum inhibitory concentration against gram-positive and gram-negative bacteria. The reactive guanidine oligomers obtained by analogy with polyhexamethylene guanidine chloride can be recommended as substances with biocidal and fungicidal properties. In addition, the inherent reactivity of the synthesized GO makes them promising for obtaining various new types of polymers and composites based on them.