Grafting of magnetic particles with poly(2-isopropenyl-2-oxazoline)

Magnetic particles play an important role in modern biomedical applications including targeted drug delivery, local embolization of blood veins, hyperthermia etc. Therefore, the development of more effective systems with high biocompatibility is of interest for many researchers. Nevertheless, these magnetic systems have to meet certain criteria necessary for in vivo applications. We have considered key requirements desired from such materials, and we have prepared a promising system based on core-shell particles via surface-initiated atom transfer radical polymerization (ATRP). The finest grade of the carbonyl iron particles was used as a suitable core and the treatment of its surface in acidic environment ensured the presence of hydroxyl groups, which were further coupled with ethoxy groups of (3-Aminopropyl)triethoxysilane. After the functionalization, the immobilization of 2-Bromoisobutyryl bromide, which served as an initiator, was performed. Finally, the initiator-treated particles were grafted with poly(2-isopropenyl-2-oxazoline) (PIPOx) under ATRP conditions as the PIPOx has recently shown a great potential in biomedical applications. The cleaning and washing procedures ensured high purity of the product. The reaction conversion, molar mass and dispersity of PIPOx grafts were investigated using nuclear magnetic resonance and gel permeation chromatography, respectively. The presence of grafted PIPOx was confirmed using Fourier-transform infrared, and energy-dispersive X-ray spectroscopies. The grafted PIPOx layer had negligible effect on particle magnetization as revealed via vibration-sample magnetometry. Synthesized core-shell structures may find utilization as a promising material for local embolization or may serve as a drug delivery system due to the presence of PIPOx bearing the active sites allowing the drug bonding. © 2018 TANGER Ltd. All Rights Reserved.Grant Agency of the Czech Republic [17-24730S]; Internal Grant Agency of Tomas Bata University in Zlin [IGA/CPS/2017/004]; Ministry of Education, Youth and Sports of the Czech Republic - Program NPU I [LO1504]; [APVV-15-0545

Cytotoxicity of 2-oxazines and poly(2-oxazine)s in mouse fibroblast

Poly(2-oxazoline)s are a polymer family that has received much attention in the last decade as biomaterials. In contrast, poly(2-oxazine)s, which can be viewed as their higher backbone homologue, have received much less attention. A first step towards the assessment as potential biomaterials is the evaluation of the cytotoxicity of the polymers. Therefore, a small selection of water soluble poly(2-oxazine)s are evaluated with respect to their cytotoxicity against 3T3 mouse fibroblasts. The polymers were tested at concentrations of up to 100 g/L for 24h. In addition, we studied the cytotoxicity of the monomers, namely 2-methyl-2-oxazine, 2-ethyl-2-oxazine and 2-propyl-2-oxazine in the same cell line. We found that neither monomers nor polymers exhibit a pronounced cytotoxicity. None of the monomers lead to any discernable effect on the cell viability in concentrations of up to 1 g/L with IC50 values ranging from 4 g/L to 20 g/L. Not surprisingly, the polymers poly(2-methyl-2-oxazine) and poly(2-ethyl-2-oxazine) exhibit even lower cytotoxicity with IC50 values ranging from 20 to 70 g/L. These preliminary but positive evaluation of the cytotoxicity of poly(2-methyl-2-oxazine) and poly(2-ethyl-2-oxazine) warrants further investigations on their use as biomaterials

2-(2-Oxazolin-2-yl)benzene-1,4-diol: X-ray and density functional theory studies

In the crystal structure of the title compound, C9H9NO3, there are strong intramolecular O-H...N and intermolecular O-H...O hydrogen bonds which, together with weak intermolecular C-H...O hydrogen bonds, lead to the formation of infinite chains of molecules. The calculated intermolecular hydrogen-bond energies are -11.3 and -2.7 kJ mol-1, respectively, showing the dominant role of the O-H...O hydrogen bonding. A natural bond orbital analysis revealed the electron contribution of the lone pairs of the oxazoline N and O atoms, and of the two hydroxy O atoms, to the order of the relevant bonds

2-(2-Oxazolin-2-yl)benzene-1,4-diol: X-ray and density functional theory studies

In the crystal structure of the title compound, C9H9NO3, there are strong intramolecular O-H...N and intermolecular O-H...O hydrogen bonds which, together with weak intermolecular C-H...O hydrogen bonds, lead to the formation of infinite chains of molecules. The calculated intermolecular hydrogen-bond energies are -11.3 and -2.7 kJ mol-1, respectively, showing the dominant role of the O-H...O hydrogen bonding. A natural bond orbital analysis revealed the electron contribution of the lone pairs of the oxazoline N and O atoms, and of the two hydroxy O atoms, to the order of the relevant bonds

ABA and BAB Triblock Copolymers Based on 2-Methyl-2-oxazoline and 2-n-Propyl-2-oxazoline: Synthesis and Thermoresponsive Behavior in Water

Inspired by the well-known amphiphilic block copolymer platform known as Pluronics or poloxamers, a small library of ABA and BAB triblock copolymers comprising hydrophilic 2-methyl-2-oxazoline (A) and thermoresponsive 2-n-propyl-2-oxazoline (B) is synthesized. These novel copolymers exhibit temperature-induced self-assembly in aqueous solution. The formation and size of aggregates depend on the polymer structure, temperature, and concentration. The BAB copolymers tend to agglomerate in water, with the cloud point temperature depending on the length of poly(2-n-propyl-2-oxazoline) chain. On the other hand, ABA copolymers form smaller aggregates with hydrodynamic radius from 25 to 150 nm. The dependence of viscosity and viscoelastic properties on the temperature is also studied. While several Pluronic block copolymers are known to form thermoreversible hydrogels in the concentration range 20–30 wt%, thermogelation is not observed for any of the investigated poly(2-oxazoline)s at the investigated temperature range from 10 to 50 °C. (Figure presented.). © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimINST 93/774-1 FUGG, DFG, Deutsche Forschungsgemeinschaft; LO1504, MŠMT, Ministerstvo Školství, Mládeže a TělovýchovyMinistry of Education, Youth, and Sports of Czech Republic - Program NPU I [LO1504]; Slovak Grant Agency VEGA [2/0163/15]; Deutsche Forschungsgemeinschaft [INST 93/774-1 FUGG]; State of Bavaria; University Wurzburg; SKZ Das Kunststoff-Zentru

2-(4-Hydroxyphenyl)-4,4-dimethyl-2-oxazoline: X-ray and density functional theory study

In the crystal structure of the title compound, C11H13NO2, there are strong intermolecular O-H...N hydrogen bonds which, together with weak intramolecular C-H...O hydrogen bonds, lead to the formation of infinite chains of molecules, held together by weak intermolecular C-H...O hydrogen bonds. A theoretical investigation of the hydrogen bonding, based on density functional theory (DFT) employing periodic boundary conditions, is in agreement with the experimental data. The cluster approach shows that the influence of the crystal field and of hydrogen-bond formation are responsible for the deformation of the 2-oxazoline ring, which is not planar and adopts a 4T3 (C3TC2) conformation

2-(4-Hydroxyphenyl)-4,4-dimethyl-2-oxazoline: X-ray and density functional theory study

In the crystal structure of the title compound, C11H13NO2, there are strong intermolecular O-H...N hydrogen bonds which, together with weak intramolecular C-H...O hydrogen bonds, lead to the formation of infinite chains of molecules, held together by weak intermolecular C-H...O hydrogen bonds. A theoretical investigation of the hydrogen bonding, based on density functional theory (DFT) employing periodic boundary conditions, is in agreement with the experimental data. The cluster approach shows that the influence of the crystal field and of hydrogen-bond formation are responsible for the deformation of the 2-oxazoline ring, which is not planar and adopts a 4T3 (C3TC2) conformation

‘Green’ synthesis of silver polymer Nanocomposites of poly (2-isopropenyl-2- oxazoline-co- N-vinylpyrrolidone) and its catalytic activity

Metal-polymer nanocomposites are of great interest and mainly focused on advanced catalytic and sensor applications. Resulting from this, new copolymers composed of poly(2-isopropenyl-2-oxazoline) (PIPOx) and poly(N-vinylpyrrolidone) (PNVP) segments were prepared from highly water soluble 2-isopropenyl-2- oxazoline (IPOx) and N-vinylpyrrolidone (NVP) monomers. Finally, silver polymer nanocomposites of poly(2-isopropenyl-2-oxazoline-co-N-vinylpyrrolidone) were synthesized and reporting for the first time. All polymerizations were done in an aqueous phase with potassium persulfate as an initiator at 60 °C. The reaction time varied from 1 to 6 h in accordance with stoichiometric ratios of PIPOx and PNVP, leading to insoluble copolymers; which are termed as PIPOx_PNVP (75:25), PIPOx_PNVP (50:50), PIPOx_PNVP (25:75) and PIPOx_PNVP (10:90). Only, PIPOx_PNVP (10:90) showed adequate swelling behavior in water and some other organic solvents. All the polymers were distinguished by various physicochemical spectroscopic techniques such as UV/Visible spectroscopy, Scanning electron microscope (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), and FTIR analysis. Thermogravimetry (TGA) and Differential scanning calorimetry (DSC) were used to investigate thermal stability of the samples. The metalo-polymer nanocomposites (PIPOx_PNVP-SNCs) showed an apparently improved stability even when the composites were stored in air, at room temperature. The PIPOx_PNVP-SNCs showed a remarkable catalytic activity during the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of sodium borohydride. © 2018, Springer Nature B.V.2/0124/18; LO1504, APVV, Agentúra na Podporu Výskumu a Vývoja; APVV-SK-CZ-2013-0206, MŠMT, Ministerstvo Školství, Mládeže a Tělovýchovy; MSMT-7 AMB14SK02

Three isomeric forms of hydroxyphenyl-2-oxazoline: 2-(2-hydroxyphenyl)-2-oxazoline, 2-(3-hydroxyphenyl)-2-oxazoline and 2-(4-hydroxyphenyl)-2-oxazoline

Crystal structures are reported for three isomeric compounds, namely 2-(2-hydroxyphenyl)-2-oxazoline, (I), 2-(3-hydroxyphenyl)-2-oxazoline, (II), and 2-(4-hydroxyphenyl)-2-oxazoline, (III), all C₉H₉NO₂ [systematic names: 2-(4,5-dihydro-1,3-oxazol-2-yl)phenol, (I), 3-(4,5-dihydro-1,3-oxazol-2-yl)phenol, (II), and 4-(4,5-dihydro-1,3-oxazol-2-yl)phenol, (III)]. In these compounds, the deviation from coplanarity of the oxazoline and benzene rings is dependent on the position of the hydroxy group on the benzene ring. The coplanar arrangement in (I) is stabilized by a strong intramolecular O-H...N hydrogen bond. Surprisingly, the 2-oxazoline ring in molecule B of (II) adopts a ³T₄ (^C2T_C3) conformation, while the 2-oxazoline ring in molecule A, as well as that in (I) and (III), is nearly planar, as expected. Tetramers of molecules of (II) are formed and they are bound together via weak C-H...N hydrogen bonds. In (III), strong intermolecular O-H...N hydrogen bonds and weak intramolecular C-H...O hydrogen bonds lead to the formation of an infinite chain of molecules perpendicular to the b direction. This paper also reports a theoretical investigation of hydrogen bonds, based on density functional theory (DFT) employing periodic boundary conditions