POM Analyses Research Articles

Synthesis, characterization, bioactivity, and POM analyses of isothiochromeno[3,4-e][1,2]oxazines

A series of 18 new 3,4-disubstituted-isothiochromeno[3,4-e][1,2]oxazines 28–45 has been obtained from the 3′,4′-di-substituted-4′H-spiro[isothiochromene-3,5′-isoxazol]-4(1H)-ones 10–27 in refluxing HCl acid/ethanol. A series of 15/18 compounds 28–45 was selected by the National Cancer Institute (NCI, Bethesda, USA) and were evaluated against a full panel of 60 primary human tumor cell lines derived from nine human cancer types, all of which showed antiproliferative activity in the micromolar range. The most active compound number 37 (S722910) showed high potency against all the tested cell lines with a GI50 mean value in the range of 30–80 μM; TGI and LC50 values were 12–16 μM having positive response on 98 and 63 % of the tested cell lines (Breast-MCF7 and NCS-SF-268) respectively.

Tris-Alkoxylphenylterpyridine Cobalt(II) Complexes: Synthesis, Structure, and Magnetic and Mesomorphic Behaviors

Two novel cobalt(II) complexes [Co(L1)2](BF4)2·CH3CN·0.5H2O (1) and [Co(L2)2](BF4)2 (2) (L1 = 4′-(3,4,5-trimethoxy-phenyl)-[2,2′:6′,2″]terpyridine, L2 = 4′-(3,4,5-tris-hexadecyloxy-phenyl)-[2,2′:6′,2″]terpyridine) have been synthesized, and their structural, magnetic and mesomorphic properties were characterized by single crystal X-ray diffraction (XRD) analysis, temperature-dependent magnetic susceptibility, POM, DSC, and powder XRD analysis. The molecular structure of the complex 1 with short alkyl substituents exhibited that the metal ion has an N6 coordination sphere of distorted octahedral geometry and various intermolecular π–π interactions are important factors influencing the crystalline array. The magnetic behaviour of 1 displayed a typical of gradual spin transition for cobalt(II) terpyridine complexes. On the other hand, the complex 2 possessing linear long alkyl chains showed a gradual spin transition between low-spin and high-spin with a thermal hysteresis loop (T 1/2↑ = 338 and T 1/2↓ = 327 K) triggered by the crystal-to-mesophase transition. The powder XRD and POM analyses were indicative of the liquid crystalline lamellar phase of 2.

POM theoretical calculations and experimental verification of the antibacterial potential of 5-hydroxy-4-(substituted-amino)-2(5H)-furanones

The structure and antibacterial activity of previously synthesized and tested compounds 4-amino-5-hydroxy 2(5H)-furanones 2a–h have been investigated. These compounds have previously been screened against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, and Pseudomonas aeruginosa ATCC 27853. Here we report results from POM analysis of their interaction with bacterial targets. The structure and governing force of the antibacterial pharmacophore site of furanones 2a–h were established on the basis of a hypothetical and semi-empirical antibacterial (Xδ+–Yδ−) pharmacophore site. From structure–activity relationship studies, it seems that the functionalized moiety (HO-C-C-NH-R) of the five membered furanone ring and the supplementary halogen substituent are essential for the anti-bacterial activity of this series.

Liquid crystalline H-bonded polymers influenced by chiral and achiral spacers

A new series of main chain H-bonded liquid crystalline polymers were derived from binary mixtures of mesomorphic polymer (I or II) and non-mesomorphic guest molecules like suberic acid, tartaric acid and alkylated tartaric acid. The role of flexible chiral (tartaric acid and alkylated tartaric acid) and achiral (suberic) guest molecules on mesomorphism has been studied. Liquid crystalline properties of polymers and its guest acid complexes were investigated by DSC and POM analysis. The isotropic and melting temperatures of the polymers have been drastically reduced by mixing with flexible guest molecules.

Computational POM and 3D-QSAR evaluation of experimental in vitro HIV-1-Integrase inhibition of amide-containing diketoacids

A computation model has been developed for the rational design of bioactive pharmacophore sites as anti-viral candidates based on available X-ray structures of drugs. The compounds have been previously screened for anti-viral activity against HIV-Integrase (HIV IN). Amongst the series, the most potent compounds, 4k and 4d (low μM IC50) were tested in viral cultures for their ability to present potentials (O 1 δ− –O 2 δ− –O 3 δ− ) for anti-viral pharmacophore site but represent a potential risk of toxicity. Furthermore, the compounds 4k and 4d showed potent anti-HIV IN activity. A good correlation was obtained between the theoretical predictions of bioavailability using POM suite (Petra/Osiris/Molinspiration containing Lipinski’s rule-of-five) and experimental verification. The structure–activity relationships were also analyzed to vindicate the POM results. A series of known anti-HIV agents; the amide-containing diketoacids were POM and 3D-QSAR analyzed in goal to understand and develop more potent/selective HIV IN inhibitors. Their inhibition of HIV IN was attributed to them containing O1,O2,O4-pharmacophore site. The structure–activity relationships were discussed on the basis of POM analyses.

Novel miscible blends of poly(p-dioxanone) with poly(vinyl phenol)

Poly(p-dioxanone) (PPDO) has been blended with poly(vinyl phenol) (PVPh) and the PPDO/PVPh blends have been investigated using DSC, FTIR and POM. According to the single Tg criterion, miscibility has been found in the whole composition range for the blends obtained by solvent casting from dioxane solutions. The dependence of the Tg on composition shows negative deviation from the Fox equation. The interaction parameter, obtained from melting point depression analysis, χ12=−1.0, confirms a thermodynamically miscible blend. Specific interactions have been analyzed by FTIR. The OH stretching region of PVPh indicates that upon addition of PPDO the hydroxyl–hydroxyl autoassociation interactions are mainly replaced by hydroxyl–carbonyl interassociation contacts, in detrimental of the possible hydroxyl–ether interactions. The carbonyl stretching region of pure PPDO is sensitive to intramolecular ether-ester interactions occurring in the oxyethanoate structures (–O–CH2–CO–O–) present along the PPDO chain. The –O–CH2–CO–O– structure presents only two minimum energy conformations, trans and cis, resulting in two different absorptions in the CO stretching region located respectively at about 1757 and 1732cm−1. Blending with PVPh promotes two new contributions red shifted by about 23cm−1 relative to the “free” CO components. Finally, POM analysis shows that the addition of PVPh to PPDO significantly decreases the crystallization rate of PPDO.

Synthesis and characterization of rodlike liquid crystalline polyester/multi-walled carbon nanotubes and study of their thermal stability

Rodlike thermotropic liquid crystalline polyester (TLCP) was synthesized from 4,4′-oxydibenzoyl chloride and resorcinol containing modified multi-walled carbon nanotubes (MWCNTs) by in situ high-temperature solution polymerization. The liquid crystalline properties and thermal stability of the resulted TLCP nanocomposites were characterized by XRD, DSC, TGA, SEM, POM, and optical analysis. The addition of small amount of MWCNTs into TLCP matrix could significantly improve the thermal stability. The mesophase temperature range of nanocomposites were widened and shifted to higher temperatures. This nanocomposite melting phase transition ( T m) value increases maximally to 38.4 °C compared with pure copolymer. Using the Horowits–Metzger kinetic method, the PE/M-0.5 gave the best performance in terms of the thermal stability. This result can be explained that the incorporation of MWCNTs into TLCP caused an interaction between TLCP and MWCNTs through π–π* conjugation.

SYNTHESIS AND CHARACTERIZATION OF THERMOTROPIC POLYAMIDE LIQUID CRYSTALLINE BLOCK COPOLYMERS

A specific polyamide-amide block copolymer with monomers of triethyleneglycol bis(4-carboxypheny)ether(PEG3),4,4'-diamino-3,3'-dimethylbiphenyl and e-caprolactam was synthesized via condensation copolymerization.FT-IR,1H-NMR,POM,DSC and WAXD analyses of samples elicit that this new type of block copolymer can demonstrate liquid crystalline characteristics.By contrast to thermotropic homopolyamide liquid crystalline(TLCP),the thermal dynamic properties of the thermotropic liquid crystalline copolyamide containing N6(TLCP-N6)were modified.This block copolymer can show nematic phase in a wide temperature range,and is able to form morphologic textures of solidification-induced band and shear stripes under certain conditions.

Freezing the orientation of a nematic stretched elastomer by photocrosslinking

In this paper we tried to prepare shape memory main chain LC materials, by photopolymerizing (UV-curing) LC elastomers subjected to uniaxial stress. For this purpose, we prepared blends, having different compositions, of a well-known mesogenic diglycidyl-terminated monomer, namely 4,4′-diglycidyloxybiphenyl (DIF), with its homologous bearing lateral photocurable allyl groups (AllDIF). The obtained blends were thermally cured with an aliphatic diacid (decandioic acid, SA), and gave LC networks in all the cases but 100% AllDIF composition. LC networks corresponding to a selected blend composition were subsequently conditioned with a radical photoinitiator, namely 2-hydroxy-2-methyl-1-phenyl propan-1-one and photocrosslinked by UV-curing either as such or while subjected to uniaxial stress. The characteristics of the resulting networks were investigated by means of DSC, XRD, POM, FT-IR, DMTA, and TMA analyses. The effect of UV-curing under stretching and of photoinitiator uptake on the LC phase stability and on the orientation of the networks, as well as on their dynamic-mechanical and thermomechanical response are discussed.

Synthesis of Symmetric Liquid Crystal Dimers Based on Azo and Imine Groups and Investigation of Phase Behaviour by Varying Alkoxy Terminal Chain Length

With the objective to study the effect of alkoxy terminal chain length on mesomorphic properties of liquid crystals, we have synthesized two (Azo and Imine) different series of dimesogens by varying terminal alkoxy chain length (n = 6–12) with a short spacer unit in between two mesogens. Transition temperatures and phase characterization were studied by DSC, POM and XRD analysis. It was found that all the dimers show mesomorphic properties and the change in terminal alkoxy chain length has pronounced effect on the smectic phase window. In the DSC cooling scan, the smectic phase window of azo compounds increased from 6.4°C (2A6) to 16.0°C(2A12), whereas in Schiff base compounds, it increased from 9.2°C (2S6) to 31.0°C(2S12). Further, the 2A11 dimer was found to undergo photo induced configurational changes.

Synthesis and liquid crystalline properties of poly(1‐alkyne)s carrying triphenylene discogens

AbstractTriphenylene‐containing 1‐decynes with different alkyl chain lengths and their polymers are synthesized and the effects of the structural variables on their mesomorphic properties are investigated. The monomers [HCC(CH2)8CO2C18H6 (OCmH2m+1)5; m = 4–9] are prepared by consecutive etherization, coupling, and esterification reactions. The monomers form columnar phases at room temperature. The polymerizations of the monomers are effected by [Rh(nbd)Cl]2, producing soluble polymers in high yields (up to 84%). The structures and properties of the polymers are characterized and evaluated by IR, NMR, TGA, DSC, POM, and XRD analyses. All the polymers are thermally stable, losing little of their weights when heated to 300 °C. The isotropization temperature of the polymers increases initially with the length of alkyl chain but decreases on further extension. Although the polymers with shorter and longer alkyl chain lengths adopt a homogeneous hexagonal columnar structure, those with intermediate ones form mesophases with mixed structures. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2960–2974, 2008

Diversification of Self-Organized Architectures in Supramolecular Dye Assemblies

Upon complexation with bismelamine receptors (BMn) featuring different alkyl linker lengths (number of methylene groups (n) = 5-12), a barbituric acid merocyanine dye (1) can be loaded into diverse self-organized superstructures through multiple hydrogen-bonding interactions. UV/vis, dynamic light scattering, and NMR studies in cyclohexane demonstrate that the diversification of the primarily formed hydrogen-bonded species in solution occurs by varying the linker length of BMn. Hierarchical organization of the hydrogen-bonded species is achieved by slow evaporation of the solvent (forming solvent-free films), and the resulting superstructures are evaluated by polarized optical microscopy, X-ray diffraction, SEM, and AFM techniques. The formation of columnar structures with and without two-dimensional ordering are revealed for shorter (n = 5-7) and longer (n = 11, 12) linker bis(melamines), respectively. On the contrary, in the cases of n = 8-10, the formation of lamellar structures is unveiled. Several assemblies (n = 5, 7, 11) indicate the formation of a liquid crystalline mesophase in POM and DSC analyses. Hierarchical organization is also achieved in solution by prolonged aging, affording phase-separated crystalline nanofibers (n = 5, 7) and soft nanofibrils agglomerating into wormlike objects (n = 8), gel-forming continuous globular networks (n = 10), and nanofibers (n = 11, 12). These superstructural and morphological diversifications are an outcome of the variation in the primarily formed hydrogen-bonded supramolecular architectures. Using this strategy, diverse self-assembled materials will be obtained from a single dye component.

Amphiphilic biodegradable poly(CL- b-PEG- b-CL) triblock copolymers prepared by novel rare earth complex: Synthesis and crystallization properties

Amphiphilic biodegradable poly(CL- b-PEG- b-CL) triblock copolymers have been successfully prepared by the ring-opening polymerization of ε-caprolactone (CL) employing yttrium tris(2,6-di-tert-butyl-4-methylphenolate) [Y(DBMP) 3] as catalyst and double-hydroxyl capped PEGs (DHPEG) as macro-initiator. The triblock architecture, molecular weight, thermal and crystallization properties of the copolymers were characterized by NMR spectra, SEC, DSC and WAXD analyses. The isothermal crystallization behavior of the copolymers was investigated by POM analysis in detail, which is greatly influenced by the length of PCL and PEG blocks. On the POM micrograph of PEG 10,000–(PCL 8600) 2, a unique morphology of concentric spherulites was observed due to the sequent crystallization of the PCL and PEG blocks.

Functional Disubstituted Polyacetylenes: Synthesis, Liquid Crystallinity, Light Emission, and Fluorescent Photopatterning of Biphenyl-Containing Poly(1-phenyl-octyne)s with Different Functional Bridges

Biphenyl (Biph)-containing 1-phenyl-1-octynes and their polymers are synthesized, and the effects of functional bridge groups on the mesomorphic and optical properties of the polymers are studied. The nonmesomorphic disubstituted acetylene monomers (C6H13)C[triple bond]C(C6H4)O(CH2)12O-Biph-OC7H15 (1), (C6H13)C[triple bond]C(C6H4)O(CH2)11OOC-Biph-OC7H15 (2), and (C6H13)C[triple bond]C(C6H4)CO2(CH2)12OOC-Biph-OC7H15 (3) are prepared by multistep reaction routes and converted into their corresponding polymers P1-P3 by a WCl6-Ph4Sn catalyst. The structures and properties of the polymers are characterized and evaluated by NMR, TGA, DSC, POM, XRD, UV, and PL analyses. The mesogenic pendants have endowed the polymers with high thermal stability (> or =400 degrees C). While P1 exhibits no liquid crystallinity, P2 and P3 form enantiotropic S(A) phase with a monolayer structure. Upon photoexcitation, the polymers emit blue and blue-green lights of 460 and 480 nm, respectively, in THF with quantum efficiencies larger than 30%. UV irradiation of a thin film of P2 through a mask oxidizes and quenches the light emission of the exposed regions, generating a two-dimensional luminescent photoimage.

Novel bent-shaped liquid crystalline compounds: III. Synthesis of Schiff base liquid crystal dimers

A group of new bent-shaped mesomorphic compounds with two identical mesogens (Schiff base), which have 2-hydroxy-1,3-dioxypropylene (–OCH 2CH(OH)CH 2O–) as a short spacer unit, and different lengths of terminal alkoxy chains (–OC n H 2 n+1 ; n = 5–10, 12), are synthesized. Transition temperatures and phase characterization were studied by DSC, POM and XRD analyses. The dependence of phase transition temperatures on the terminal alkoxy chain lengths is discussed. With the increase in the terminal chain lengths, the thermal stability of the smectic mesophases of these liquid crystals was increased, and the smectic–isotropic transition temperatures in this series showed an even–odd effect.

Synthesis of liquid crystalline poly(1‐pentyne)s and fabrication of polyacetylene–perovskite hybrids

AbstractPoly(1‐pentyne)s containing biphenyl and phthalimido pendant groups with different spacer lengths {P1(m); [HCC(CH2)3OBiphOCO(CH2)mN(CO)2C6H4]n, Biph4,4′biphenylyl; m = 7, 10} are synthesized in satisfactory yields by WCl6‐Ph4Sn catalyst in toluene at elevated temperatures. The structures and properties of the polymers are characterized and evaluated by IR, NMR, TGA, DSC, POM, and XRD analyses. Both of the polymers are thermally stable (Td ≥ 300 °C) and exhibit nematicity at high temperatures. Their phthalimido groups are converted into amino groups by hydrolysis, which can, after acidification, complex with lead(II) bromide to furnish polyacetylene–perovskite hybrids in high yields. The organic components contribute good solubility to the hybrids, while the perovskite framework induces the polyacetylene chains to align within the inorganic sheets. The hybrids emit a strong UV light of 374 nm upon photoexcitation, whose quantum yield increases with an increase in the spacer length. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3538–3550, 2006

Functional Disubstituted Polyacetylenes and Soluble Cross-Linked Polyenes: Effects of Pendant Groups or Side Chains on Liquid Crystallinity and Light Emission of Poly(1-phenyl-1-undecyne)s

A group of new poly(1-phenyl-1-undecyne)s with different mesogenic and chromophoric pendant groups or side chains were successfully synthesized and the structural variations were found to greatly affect the mesomorphic and luminescent properties of the polymers. The 1-phenyl-1-undecyne monomers (C6H5)C⋮C(CH2)9OCOR with R = C6H4−C6H10−C5H11 (1), C6H4−OCO−C6H4−OC6H13 (2), and C6H4−C⋮C−C6H4−OC7H15 (3) were prepared by simple esterification and/or coupling reactions. The polymerizations of 1−3 were effected by WCl6−Ph4Sn in toluene at 60−80 °C, giving polymers with high molecular weights in good isolation yields. The structures and properties of the polymers were characterized and evaluated by GPC, IR, NMR, TGA, DSC, POM, XRD, UV, and PL analyses. The polymerizations of 1 and 2 yield linear poly(1-phenyl-1-alkyne)s P1 and P2, respectively, while that of 3 gives a nonlinear macromolecule with its poly(1-phenyl-1-alkyne) main chain cross-linked by the oligo(diphenylacetylene) side chains resulted from the parti...

Functional Polyacetylenes: Synthesis, Thermal Stability, Liquid Crystallinity, and Light Emission of Polypropiolates

Polypropiolates with different kinds and numbers of substituents (−{(R)CC[CO2(CH2)6−OCO−Biph−OC7H15]}n−; R = H (1), CH3 (2), C6H5 (3), Biph = 4,4‘-biphenylyl) were synthesized, and the effects of the structural variations on the mesomorphic and luminescent properties of the polymers were investigated. The propiolate monomers RC⋮CCO2(CH2)6OCO−Biph−OC7H15 [R = H (8), CH3 (9), C6H5 (10)] were prepared by esterification of (substituted) propiolic acids (RC⋮CCO2H) in high yields. While 8 and 9 formed enantiotropic SmA phases, 10 was nonmesomorphic. Polymerizations of the monomers were effected by Mo- and Rh-based catalysts and polypropiolates with high molecular weights (Mw up to 3.5 × 105 Da) were obtained in moderate yields. The polymers were characterized by IR, NMR, TGA, DSC, POM, XRD, UV, and PL analyses. All the polymers were thermally stable. Polymer 1 obtained from the Mo catalyst possessed a lower stereoregularity but exhibited a better-packed monolayer SmA mesostructure, in comparison to the polymer ...

Liquid Crystalline and Light Emitting Polyacetylenes: Synthesis and Properties of Biphenyl-Containing Poly(1-alkynes) with Different Functional Bridges and Spacer Lengths

Biphenyl- (Biph-) containing 1-alkynes (3 and 4) and their polymers (1 and 2) with varying bridge groups and spacer lengths were synthesized and the effects of the structural variation on their properties, especially their mesomorphism and photoluminescence behaviors, were studied. The acetylene monomers 3(3) [HC⋮C(CH2)3O−Biph−OCO(CH2)10CH3] and 4(m) [HC⋮C(CH2)mOCO−Biph−OCO(CH2)10CH3, m = 3, 4] were prepared by sequential etherization and esterification reactions of 1-alkynes. While 3(3) exhibits enantiotropic crystal E and SmB mesophases, its structural cousin 4(3) displays only a monotropic SmB phase. Enantiotropic SmA and SmB mesophases are, however, developed when the spacer length is increased to 4. Polymerizations of the monomers are effected by Mo-, W-, Rh-, and Fe-based catalysts, with the WCl6−Ph4Sn catalyst giving the best results (isolation yield up to 85% and Mw up to 59000). The polymers were characterized by IR, UV, NMR, TGA, DSC, POM, XRD, and PL analyses. Compared to 1(3), 2(3) shows a red...