Synthesis of 3,3′-(1,6-hexanediyl)bis-pyrimidine derivatives and 3,4-dithia[6.6](1.3)pyrimidinophane

Several 3,3′-(1,6-hexanediyl)bis[6-methyl-2,4(1H,3H)-pyrimidinedione] derivatives ( 4a, 4b , and 4c ) were synthesized from 1,6-(hexanediyl)bis[6-methyl-2H-1,3-oxazine-2,4(3H)-dione] (3) . Compound 4c was converted to 6, which reacted with thiourea giving thiuronium salt 7 . 3,3′-(1,6-Hexanediyl)bis [1-(2-mercaptoethyl)-6-methyl-2,4(1H,3H)-pyrimidinedione] (9) was obtained by the hydrolysis of 7 , and then 9 was oxidized to 12,22-dimethyl-3,4-dithia[6.6] (1.3)-1,2,3,4-tetrahydro-2,4-dioxopyrimidinophane (10) .     

Synthesis and characterization of poly[4,4-bis(pivaloxymethyl)-1,6-heptadiyne] having high oxygen permselectivity

Cyclopolymerization of 4,4-bis(pivaloxymethyl)-1,6-heptadiyne containing a bulky ester group was examined by group 5,6-transition metal catalysts. Both of the MoCl₅-based and WCl₆-based catalysts were effective for the cyclopolymerization. The obtained polymer was characterized to have planar backbone and recurring cyclic ring structure by various spectroscopy. The poly[4,4-bis(pivaloxymethyl)-1,6-heptadiyne] was soluble in common organic solvents to easily cast the free standing film. The polymer film had good mechanical property and high oxygen permselectivity to nitrogen. The oxygen permeability coefficient (PO₂) and permselectivity of oxygen to nitrogen (PO₂/PN₂) of poly[4,4-bis(pivaloxymethyl)-1,6-heptadiyne] were 19.7 barrer and 5.71, respectively. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 4135–4139, 1999     

1,6-Additionen an 3-Methyl-5-methyliden-2-(5H)-furanon-Derivate

1,6-Additions to 3-Methyl-5-methylidene-2(5H)-furanone Derivatives The anions of thiophenol, methyl malonate and malononitrile react with 3-methyl-5,6-dihydro-2 (4H)-benzofuranone ( 1c ) by the formation of the corresponding 1,6-addition products cis- 5c (63%), trans- 6 (42%) and trans- 7 (76%), respectively. Likewise, the reaction of 3-methyl-5-methylidene-2 (5H)-furanone ( 1b ) with thiophenol yields the 1,6-addition product 5b (66%), and with the sodium salt of methyl aceto-acetate the 1,6-addition product 8 (11%) and the dispiro-dilactone 9 (39%).     

High-resolution proton magnetic resonance and infrared spectra of poly(vinyl formal) and its model compounds

High-resolution proton magnetic resonance and infrared spectra of poly(vinyl formal) were studied in comparison with those of the model formals obtained from stereoisomers of pentane-2,4-diol and heptane-2,4,6-triol in order to learn spectral changes due to differences of the steric structures of the polymer. In the NMR spectrum of transformal obtained from dl diol or dl,dl (syndiotactic) triol, all proton signals were well interpreted by assuming a rapid chair-chair inversion of the formal ring. On the other hand, no such inversion was observed spectroscopically in cis-formal obtained from the meso diol or meso,meso (isotactic) triol, and the cis-formal ring was supposed to take a diequatorial form preferentially. Consequently, dioxymethylene protons gave a single peak (equivalent) in trans-formal and an AB quartet (nonequivalent) in cis-formal. In the spectra of poly(vinyl formal), the dioxymethylene signal was an overlap of the singlet and quartet in dimethylsulfoxide solution. Observations of the spectra of various poly(vinyl formals) obtained from poly(vinyl alcohols) of different tacticities and study of temperature dependence of the signal have shown that the singlet and quartet are attributed to trans- and cis- formals, respectively, in the polymer spectrum also. In the infrared spectra of poly(vinyl formals), the 800 and 785 cm^-1 bands were found to be related to cis- and trans-formal rings respectively. A linear relationship was confirmed between D₇₈₅/D₈₀₀ and trans/cis ratios determined from the peak intensities of the dioxymethylene proton signals.     

Conformational studies of poly(cis-5-ethyl-D-proline)

Two possible conformations for poly(cis-5-ethyl-D -proline) have been identified and characterized by using combinations of ¹H- and ¹³C-NMR, CD, and ORD spectroscopic techniques. Both forms have helical conformations similar to those of poly(L -proline) characterized by different amide bonds (cis and trans). However, the carbonyl group of the amide in poly(cis-5-ethyl-D -proline) form II (trans) seems to be closer to perpendicular orientation with respect to the helical axis than in poly(L -proline) form II. The pyrrolidine ring conformation of form I (cis) is probably β⁺γ^?-puckered, whereas for form II it is probably β⁺-puckered in nature. The side-chain ethyl groups prefer to adopt anti conformations to the C₅? H bond, or prefer to have χ = 180°, regardless which of the two forms poly(cis-5-ethyl-D -proline) may like to assume. The experimental results agree well with our previous theoretical conformational energy calculations.     

Mutarotation of optically active poly(cis-5-ethyl-D-proline)

The mutarotation between form I and form II of poly(cis-5-ethyl-D -proline) has been experimentally realized. A number of hydrogen-bond-forming solvents have been found effective in initiating the mutarotational process. The rate of mutarotation seems to be proportional to the acidity of the active solvent. The enthalpy of activation energy for the mutarotation is estimated from the first-order kinetics at the lower conversion by means of the Arrhenius equation to be approximately 16.7 kcal/mol. The solvent-polymer interactions are proven to be one of the important driving forces for the mutarotation. The specific site at which hydrogen bonding takes place has been determined to be the carbonyl group of the amide by infrared spectroscopic techniques. The molecular reason for the greater susceptibility of poly(cis-5-ethyl-L -proline) II to the solvent effect than poly(cis-5-ethyl-L -proline) I can be satisfactorily explained by the relatively more extended structure of form I than form II. The mechanism for the mutarotation undoubtedly involves a cis-trans isomerization of the amide bond. The conformation of the transient states during the mutarotational process is still evidently helical in nature, probably consisting of long poly(cis-5-ethylproline) I and II segments.     

Hindered amine stabilizers investigated by the use of packed capillary temperature-programmed liquid chromatography. I. Poly((6-((1,1,3,3-tetramethylbutyl)-amino)-1,3,5-triazine-2,4- diyl)(2,2 ,6,6-tetramethyl-4-piperidyl)imino)-1,6-hexanediyl ((2,2,6,6-tetramethyl-4-piperidyl)imino))

Three different trademarks of a hindered amine stabilizer with the IUPAC name poly((6-((1,1,3,3-tetramethylbutyl)-amino)-1,3,5-triazine-2,4-d iyl)(2,2,6,6-tetramethyl-4-piperidyl)imino)-1,6-hexanediyl(( 2,2 ,6,6-tetramethyl-4-piperidyl)imino)), have been analyzed and compared to each other by the use of non-aqueous packed capillary temperature-programmed liquid chromatography and light scattering detection. The analysis by this method has shown that the products contained almost 40 different homologues and other components. This is in contrast to what has been assumed earlier based on results achieved with size exclusion chromatography. The method demonstrated significant differences between the products from different manufacturers.     

Photochemical behavior of poly(ethylacryloylacetate) and poly(acryloylacetone) films

Films of poly(ethylacryloylacetate) (PEAA) and poly(acryloylacetone) (PAA) were subjected to UV irradiation (λ = 254 nm) at room temperature. The photoinduced structure transfer from cis-enol onto a diketo forms has been investigated. The structure transfer caused by UV light was found to be slower than for the corresponding process in solution. The spectral investigations (UV, IR) showed reversible process of photoketonization. The results were analyzed in terms of the model for the participation of the trans-enol form in the process of the ketonization. Based on the results obtained, some general conclusions were made about the organization of the units in the polymer chain. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 3683–3688, 1997     

Thermal decomposition of poly(sec-amyl methacrylate)

The thermal decomposition of poly(sec-amyl methacrylate) is studied by simultaneous thermogravimetry–gas chromatography–mass spectrometry and by pyrolysis–gas chromatography. The TG curve has four distinct breaks and a plateau. Results of the identification of the evolved gas at the individual breaks by GC–MS techniques lead to the conclusion that these breaks correspond to the individual processes in the decomposition mechanism like that of poly(tert-butyl methacrylate): the first break, the depolymerization initiated at the unsaturated chain ends; the second break, the depolymerization initiated at the saturated chain ends; the third break, the ester decomposition; the plateau, the inhibition of decomposition by the formation of poly(methacrylic anhydride); the fourth break, the decomposition of poly(methacrylic anhydride). The extent of ester decomposition is related to the substituent constants based on Hammett equation. The ester decomposition product is separated into three pentene isomers by pyrolysis–gas chromatography: trans-2-pentene, cis-2-pentene, and 1-pentene. As raising decomposition temperature, the composition ratio of trans-2-pentene decreases and becomes constant above 620 K, and the composition ratios of cis-2-pentene and 1-pentene increase and also become constant above 620 K. These results are accounted for by mobility of atoms included in the substituent at forming a ring transition state.     

On the morphological behavior of ABC miktoarm stars containing poly(cis 1,4-isoprene), poly(styrene), and poly(2-vinylpyridine)

Fundamental understanding of microphase separation in ABC miktoarm copolymers is vital to access a plethora of nonconventional morphologies. Miktoarm stars based on poly(cis 1,4-isoprene) (I), poly(styrene) (S), and poly(2-vinylpyridine) (V) are model systems, which allow systematic studies of the effects of composition, chemical microstructure, and temperature on the thermodynamics of microphase separation. Eleven ISV-x (I:S:V = 1:1:x, v:v:v) miktoarm copolymers were synthesized by anionic polymerization affording well-defined copolymers with a variable V arm. Equilibrium bulk morphologies of all samples, as evidenced by small-angle X-ray scattering, transmission electron microscopy (TEM), and self-consistent field theory, showed a systematic transition from lamellae (x ≈ 0–0.2) to [8.8.4] tiling (x ≈ 0.6–0.9) to cylinders in undulating lamellae (x ≈ 2–4) and, finally, to hexagonally packed core–shell cylinders (x ≈ 5–8). Chemical microstructure of the I arm [poly(cis 1,4-isoprene)] versus poly(3,4-isoprene) is shown to play important role in affecting morphological behavior. To reconcile differences between ISV-x star morphologies reported in the literature and those reported herein, even for the same composition, effects of the microstructure of I arm on the Flory–Huggins parameter between I and V arms were taken into account in a qualitative manner. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018 , 56, 1491–1504     

Synthesis and absorption/emission properties of novel poly(silylenearylenevinylene)s

Polymerization of p-(dimethylsilyl)phenylacetylene in toluene at 25 and 80 °C with RhI(PPh₃)₃ catalyst afforded highly regio- and stereoregular poly(dimethylsilylene-1,4-phenylenevinylene)s [cis- and trans-poly( 1a )s] containing 98% cis- and 99% trans-vinylene moieties, respectively. The trans-type polymers exhibited redshifts and hyperchromic effects in the ultraviolet–visible spectrum as compared with the cis-type counterparts. Photoirradiation of cis- and trans-poly( 1a )s gave cis-rich mixtures at equilibrium states. The trans and cis polymers exhibited different emission properties, for example—trans polymer, emissn λ_max = 400 nm, quantum yield: 3.4 × 10⁻³ and cis polymer, emissn λ_max = 380 nm, quantum yield: 1.5 × 10⁻³. Besides poly( 1a ), poly(dimethylsilylenearylenevinylene)s containing biphenylene and phenylenesilylenephenylene units [poly( 3 )] were prepared. The extent of conjugation in these polymers decreased in the orders of biphenylene > phenylene > phenylenesilylenephenylene as well as trans-vinylene > cis-vinylene. The quantum yield of the trans-rich polymer with biphenylene moiety was fairly large and 0.15. Polyaddition of 1,4-bis(dimethylsilyl)benzene and three types of diethynylarenes (4,4′-diethynylbiphenyl, 2,7-diethynylfluorene, and 2,6-diethynylnaphthalene) catalyzed by RhI(PPh₃)₃ provided novel regio- and stereoregular polymers [poly( 6 )]. These polymers displayed blue light emission with high quantum yields (4–81%). © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3615–3624, 2003     

Addition of chlorofluorocarbene to poly(1-methyl-1-phenyl-1-sila-cis-pent-3-ene) and poly(1,1-dimethyl-1-sila-cis-pent-3-ene): Characterization of chlorofluorocyclopropanated polymer microstructures by 1H-, 13C-, 19F-, and 29Si-NMR spectroscopy

Chlorofluorocarbene, generated by the sodium iodide catalyzed decomposition of phenyl(dichlorofluoromethyl)mercury, adds to the carbon-carbon double bonds of poly(1-methyl-1-phenyl-1-sila-cis-pent-3-ene) (I) and poly(1,1-dimethyl-1-sila-cis-pent-3-ene) (II) to yield poly(3,4-chlorofluoromethylene-1-methyl-1-phenyl-1-sila-cis-pent-3-ene) (CIFC-I) and poly(3,4-chlorofluoromethylene-1,1-dimethyl-1-sila-cis-pent-3-ene) (CIFC-II). Similarly, two series of random partially chlorofluorocyclopropanated polymers have been prepared. The microstructures of these adduct polymers have been determined by ¹H-, ₁₃C-, ¹⁹F-, and ²⁹Si-NMR spectroscopy. The glass transition temperatures (T_g's) depend on the extent of chlorofluoropropanation of these polymers. These copolymers become less thermally stable as the extent of chlorofluorocyclopropanation increases. © 1993 John Wiley & Sons, Inc.     

Studies on partially polymerized 2,4-hexadiyn-1,6-bis(p-toluenesulfonate)

An improved procedure for the synthesis of high-purity 2,4-hexadiyn-1,6-bis(p-toluenesulfonate) (PTS) is described. The melting point of partially polymerized PTS increases monotonically with increasing polymer conversion (<12%). The increase in melting point is due to formation of a solid solution of unreacted monomer and polymer chains. The relation between the melting point and polymer conversion can be used for determination of polymer conversion. The low-conversion (<12%) poly PTS is soluble in dimethylformamide. The solution is yellow (λ_max ? 450 nm) and does not undergo a color change when the temperature is lowered or a nonsolvent is added. Gel permeation chromatography (GPC) studies show that the molecular weight distribution of poly PTS is very broad and does not change with increasing polymer conversion up to <12%. The degree of polymerization for the low-conversion polyPTS is very low, about 20 repeat units. The G value for initiation centers (radicals) is about 2. The properties of the low-conversion partially polymerized PTS are compared with the corresponding properties of poly(diacetylene diurethanes).     

Spectroscopic studies of solutions,suspensions, and precipitates of poly(1,6-di-p-toluene sulfonyloxy-2,4-hexadiyne)

Optical-absorption, fluorescence, and Raman spectra for solutions, suspensions, and precipitates of poly(1,6-di-p-toluene sulfonoxy-2,4-hexadiyne) in and from nitrobenzene, acetone, and chloroform are presented. These are interpreted in terms of the occurrence of two forms of the polymer chain; a quasicrystalline form with properties close to those of single crystal polymer and a chain-extended form occurring in solution and colloidal particles, with an absorption energy of about 2.5 eV (20,000 cm^?1). No evidence is found for the presence of very short polymer chains in partially polymerized monomer at low conversion. The relationship of these results to those for deformed single crystals is briefly discussed.     

Raman spectroscopy of poly[BIS(P-toluene sulfonate) of 2,4-Hexadiyne-1,6-DIOL] crystals at high pressure

The resonance Raman spectrum of crystalline poly[bis(p-toluene sulfonate) of 2,4-hexadiyne-1,6-diol] has been studied as a function of applied pressure to 50 kbar. The Raman bands are observed to shift to higher frequency and change in relative intensity. The origins of these effects are discussed. One of the Raman bands is observed to split into two bands of approximately equal intensity at high pressure. This effect is attributed to correlation field splitting within the unit cell and is possibly the first such observation in a conjugated polymer.     

Synthesis of polybutadiene‐graft‐poly(dimethylsiloxane) and polyethylene‐graft‐poly(dimethylsiloxane) copolymers with hydrosilylation reactions

We report preliminary results for the synthesis of polyethylene‐graft‐poly(dimethylsiloxane) copolymers obtained by catalytic hydrogenation of polybutadiene‐graft‐poly(dimethylsiloxane) copolymers (PB‐g‐PDMS). These last copolymers were synthesized by hydrosilylation reactions between commercial polybutadiene and ω‐silane poly(dimethylsiloxane). The reaction was carried in solution catalyzed by cis‐dichloro bis(diethylsufide) platinum(II) salt. The PB‐g‐PDMS copolymers were analyzed by ¹H and ¹³C NMR spectroscopies, and the relative weight percentages of the grafted poly(dimethylsiloxane) macromonomer were determined from the integrated peak areas of the spectra. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2920–2930, 2004     

A novel aromatic–aliphatic copolyester consisting of poly(1,4‐dioxan‐2‐one) and poly(ethylene‐co‐1,6‐hexene terephthalate): Preparation,thermal, and mechanical properties

A novel multiblock aromatic–aliphatic copolyester poly(ethylene‐co‐1,6‐hexene terephthalate)‐copoly(1,4‐dioxan‐2‐one) (PEHT‐PPDO) was successfully synthesized via the chain‐extension reaction of dihydroxyl teminated poly(ethylene‐co‐hexane terephthalate) (PEHT‐OH) with dihydroxyl teminated poly(1,4‐dioxan‐2‐one) (PPDO‐OH) prepolymers, using toluene‐2,4‐diisocyanate as a chain extender. To produce PEHT‐OH prepolymer with an appropriate melting point which can match the reaction temperature of PEHT‐OH prepolymer with PPDO‐OH prepolymer, 1,6‐hexanediol was used to disturb the regularity of poly(ethylene terephthalate) segments. The chemical structures and molecular weights of PEHT‐PPDO copolymers were characterized by ¹H NMR, FTIR, and GPC. The DSC data showed that PPDO‐OH segments were miscible well with PEHT‐OH segments in amorphous state and that the crystallization of copolyester was predominantly contributed by PPDO segments. The TGA results indicated that the thermal stability of PEHT‐PPDO was improved comparing with PPDO homopolymer. The novel aromatic–aliphatic copolyesters have good mechanical properties and could find applications in the field of biodegradable polymer materials. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2828–2837, 2010     

Semiconducting poly(monocyanoacetylenes)

Poly(monocyanoacetylenes) (PMCA) were synthesized by anionic, Ziegler–Natta, metathesis, and photo initiations. The Ziegler–Natta-catalyzed polymers probably have highly stereoregular cis-transoid structure that contains very few defects and the nitrile groups are difficultly cyclized. It has M?_n = 1100. PMCA obtained by anionic polymerization at ?78°C has M?_n ～ 4800; it is rich in trans-transoid structures but probably contains other isomeric units as well. The unpaired spin concentrations in these polymers are very high, comparable to that in trans-polyacetylene (PA) isomerized above 150°C. UV irradiation initiated rapid polymerization of cyanoacetylene in solid state at low temperature but the products were bleached in color after long irradiation. The unpaired spins in PMCA are immobile; nitrile cyclization causes some decrease in EPR linewidth and increase in room-temperature conductivity (σ_RT). There was also a large increase in unpaired spin concentrations to about 200 monomer units/spin. Iodine doping increases σ_RT to about 10^?3 (ω cm)^?1 but the dopant is readily removed by evacuation and the polymer returns to its original insulating state. The properties of pristine and doped PMCA, such as EPR g-value, ΔH_pp, T₁, T₂, and σ_RT are very similar. The similarities persist after cyclization and doping for this pair of polymers. These properties are also compared with those of poly(methylacetylene), poly(phenylacetylene), poly(dicyanoacetylene) and PA, and the significance is discussed.     

A new luminescent poly(phenylenevinylene) having an alternating cis- and trans-vinylene structure,poly(phenylenevinylene-phenylene-3-cyclobutene-1,2-dione)

A novel cyclobutenedione-containing poly(phenylenevinylene) (PPV) was obtained from 3,4-bis(4-bromomethylphenyl)-3-cyclobutene-1,2-dione via modified 1,12-polydehydrohalogenation. This resultant polymer, soluble in polar aprotic solvents, exhibits a regioregular structure of alternating cis- and trans-vinylene units. The present polymer exhibits photoluminescence with a maximum at 472 nm, corresponding to the blue emission region, in DMAc solution, and a red-shift emission at 574 nm in the film.     

Reaction of poly(vinyl alcohol) with formaldehyde and polymer stereoregularity. Model compounds

The reaction of stereoisomers of pentane-2, 4-diol and heptane-2, 4, 6-triol with formaldehyde was investigated as a model for the formalization reaction of poly(vinyl alcohol) in order to determine effect of the stereochemical configuration of the polyol molecules on the reaction. The isotactic (meso) diol portion reacted with formaldehyde to give cis-formal several times faster than did the syndiotactic (dl) diol portion to give trans-formal at 30–80°C. In the reaction of heterotactic (meso-dl) triol which provides both the isotactic and syndiotactic diol portions in a molecule, the proportion of trans-formal in the total formal decreased as the reaction proceeded. This shows that the formation of cis-formal is also favored thermodynamically to a greater extent, and hence the intramolecular migration of trans-formal to cis-formal did occur during the reaction. The rates of hydrolysis of formals of the diols were compared with those of the triols in order to see the effect of a hydroxyl group adjacent to the formal ring on the reaction. No appreciable rate difference was observed between the dimer and trimer models both in cis- and trans- formals. Therefore it was deduced from these results that the increase of the rate of hydrolysis of poly(vinyl formal) with the increase of hydroxyl groups along the polymer chain is a characteristic of macromolecules that is not observed in the low molecular weight models.