A novel addition polymerization of 1,4-benzenediselenol (BDSe) to 1,4-diethynylbenzene (DEB) was carried out by UV-irradiation in toluene at 60°C under nitrogen atmosphere. The polymerization proceeded at such a fast rate as to give 60–70% yield for 6 min. A paleyellowish polymer (M?n = 20000–30000) precipitated with the progress of the polymerization. In the presence of BPO, the polymerization also proceeded rapidly to give the polymer (M?n = 18000) in 50% yield for 4 min. The polymer was insoluble in conventional organic solvents. In the IR spectrum of the polymer, the characteristic absorption bands of cis- and trans-vinylene groups appeared at 1340 and 940 cm?1, respectively. The microstructures of polymers were evaluated as the cis content was 90% and the trans one was 10%, based on the model adducts of benzeneselenol and ethynylbenzene. The cis ← trans isomerization occurred with UV-irradiation: the cis vinylene group of the polymer decreased from 90 to 40% for 18 h. The electrical conductivity of the polymer was in the order of 10?13 S/cm without dopant, but increased up to 10?5 S/cm on I2 doping. DSC and TG thermograms of the polymer indicated its decomposition point as 465°C under nitrogen atmosphere. 相似文献
Summary: An advanced isoconversional method has been applied to determine the effective activation energies (E) for the glass transition in polystyrene (PS), poly(ethylene terephthalate) (PET), and boron oxide (B2O3). The values of E decrease from 280 to 120 kJ · mol−1 in PS, from 1 270 to 550 kJ mol−1 in PET, and from 290 to 200 kJ mol−1 in B2O3. It is suggested that a significant variation in E should be observed for the fragile glasses that typically include polymers.
Variation in the effective activation energy of PS, PET, and B2O3 with temperature. 相似文献
In the title compound, C8H12N+·C2H4O5P−, the anions are linked by two O—H⋯O hydrogen bonds [H⋯O both 1.75 Å, O⋯O = 2.5781 (15) and 2.5834 (15) Å, and O—H⋯O = 169 and 176°] into sheets built from alternating (8) and (32) rings. Each cation is linked to an anion sheet by three N—H⋯O hydrogen bonds [H⋯O = 1.88–2.04 Å, N⋯O = 2.7603 (16)–2.9334 (17) Å and N—H⋯O = 162–166°], such that all the cations pendent from one face of the sheet are of the R configuration, while all those pendent from the opposite face are of the S configuration. 相似文献
In the title compound, [Na4(C8H16BO4)4(C4H10O2)]n, there are two coordination types for the four independent Na+ cations: two Na+ cations bond to six diolate O atoms [Na—O = 2.305 (2)–2.609 (2) Å], while the other two are five‐coordinate via one 1,4‐butanediol [2.289 (2) and 2.349 (3) Å] and four diolate O atoms [2.295 (2)–2.408 (2) Å]. Corresponding to this, there are three‐ and four‐coordinate diolate O atoms, the latter bridging Na atoms. The 1,4‐butanediol molecules lie on inversion centres. The boron stereochemistry shows minor local perturbations from its usual tetrahedral state [B—O = 1.457 (4)–1.503 (4) Å]. The resulting polymer packs as sheets parallel to the (10) plane crosslinked by the butanediol molecules. The structure was solved using data from a multiple crystal. 相似文献
A poly(acrylamide) was synthesized from Nα -Boc-N? -acrolyl-l-lysylglycine methyl ester via radical polymerization. This polymer typically had Mn ~ 100,000 g/mol, Mw ~ 300,000 g/mol, and a Tg of 93°C. Removal of Boc with TFA and cyclization with DABCO? in DMSO at 65°C afforded a soluble piperazinedione-containing polymer that had a Tg of 157°C and thermal stability up to 300°C. These results demonstrate a viable and efficient synthetic route to piperazinedione-containing polyacrylamides of high molecular weight. Related polymers that incorporate substituted indane moieties could be useful high Tg materials for fabrication of LC and NLO devices. 相似文献
A thermally stable carbocationic covalent organic network (CON), named RIO-70 was prepared from pararosaniline hydrochloride, an inexpensive dye, and triformylphloroglucinol in solvothermal conditions. This nanoporous organic material has shown a specific surface area of 990 m2 g−1 and pore size of 10.3 Å. The material has CO2 uptake of 2.14 mmol g−1 (0.5 bar), 2.7 mmol g−1 (1 bar), and 6.8 mmol g−1 (20 bar), the latter corresponding to 3 CO2 molecules adsorbed per pore per sheet. It is shown to be a semiconductor, with electrical conductivity (σ) of 3.17×10−7 S cm−1, which increases to 5.26×10−4 S cm−1 upon exposure to I2 vapor. DFT calculations using periodic conditions support the findings. 相似文献
Two Cd(II) coordination polymers have been synthesized with derivatives of pyrazine-1,4-dioxide and thiocyanate anion as bridging ligands and structurally determined by X-ray crystallography. Complex 1, [Cd(μ1,3-SCN?)2(μ1,6-L1)]n (L1?=?2,5-dimethylpyrazine-1,4-dioxide), belongs to the triclinic, space group P1 with a?=?5.7627(18)?Å, b?=?7.182(2)?Å, c?=?7.509(2)?Å, α?=?74.042(3)°, β?=?84.766(4)°, γ?=?88.162(4)°; complex 2, [Cd2(μ1,3-SCN?)4(μ4-L2)]n (L2?=?2,3,5,6-tetramethylpyrazine-1,4-dioxide), crystallizes in a monoclinic system with space group C2/m with a?=?10.194(4)?Å, b?=?13.491(6)?Å, c?=?8.140(3)?Å, β?=?120.372(4)°. Complex 1 shows a two-dimensional sheet structure, and in a direction the Cd(II) ions were coordinated by μ1,3-SCN? forming the one-dimensional chain and the L1 bridging ligand made the chains connect in the c direction leading to formation of a two-dimensional sheet on the ac plane. For 2 the one-dimensional chains in the a axis were constructed by coordination of μ1,3-SCN? bridging ligands with the Cd(II) ions, and in b and c directions the chains were joined by L2 bridging ligands leading to a three-dimensional structure. In 2 L2 displays a μ4-bridging coordination mode. Both complexes exhibit strong fluorescence emission. 相似文献
Poly(dicyanoacetylene) (PDCA) has been synthesized and characterized. The pristine polymer has EPR g-value, linewidth, unpaired spin concentration, spin—spin relaxation time (T2), and room temperature dc conductivity (σRT) very similar to those of pristine cis-polyacetylene (PA), but shorter spin—lattice relaxation time (T1). Saturation doping with iodine has little effect on most EPR characteristics of the polymer except for a slight increase in T1. The doped PDCA has σRT value of only 5 X 10-9 (Ω cm)-1, indicating either low carrier concentration and/or carrier mobility. Partial cyclization of the nitrile groups by heating at 400°C of PDCA produces l-PDCA with significant increases in unpaired spin concentration and σRT but marginal effects on other properties. Saturation doping of l-PDCA with iodine increases σRT to 7 × 10-3 (Ω cm)-1 without appreciable changes in EPR characteristics. The dopants in both polymers can be removed by evacuation indicating only weak charge transfer interactions. The possible stereoelectronic contribution toward the property differences between the PDCA polymers and PA are discussed. 相似文献
The double salt 1 consisting of the hydrochloride of 6-amino-2,4-trans-hexadienoic acid and cadmium chloride in a 2:1 stoichiometry polymerizes in the crystalline state if exposed to UV or γ irradiation. A stereoregular polymeric ampholyte is formed in an extended chain macroconformation, embedded in an inorganic matrix. The crystal structure of the polymerized crystals and the solution properties of the polymer are reported. Polymerized crystals are triclinic, space group P1 , a = 7.2144 Å, b = 7.2447 Å, c = 18.5936 Å, α = 104.49°, β = 96.631°, γ = 95.706°, Z = 2. The structure consists of 2-dimensional layers of polymer and inorganic CdCl6 octahedra alternatively stacked in the third dimension. The cadmium ions can be separated from the polymer by a precipitation as insoluble CdS. After separation from the inorganic material the polymer is soluble in strong acids and bases and insoluble in neutral water. From viscosity measurements of alkaline solutions of the polymer, an average molar mass of 4 × 104 g/mol can be deduced. The polymer selectively adsorbs divalent transition metal ions if suspended in an aqueous solution of transition metal salts. The structure of the resulting polymer–metal complexes is discussed. 相似文献
In the title compound, C13H16N22+·2C2H4O5P−, the cation lies across a twofold rotation axis in space group Fdd2. The anions are linked into molecular ladders by two O—H⃛O hydrogen bonds [H⃛O = 1.73 and 1.77 Å, O⃛O = 2.538 (2) and 2.598 (3) Å, and O—H⃛O = 160 and 170°], these ladders are linked into sheets by a single type of N—H⃛O hydrogen bond [H⃛O = 1.75 Å, N⃛O = 2.624 (3) Å and N—H⃛O = 171°] and the sheets are linked into a three‐dimensional framework by a single type of C—H⃛O hydrogen bond [H⃛O = 2.48 Å, C⃛O = 3.419 (4) Å and C—H⃛O = 167°]. 相似文献
A new energetic material, 4,5‐diacetoxyl‐2‐(dinitromethylene)‐imidazolidine (DADNI), was synthesized by the reaction of 4,5‐dihydroxyl‐2‐(dinitromethylene)‐imidazolidine (DDNI) and acetic anhydride, and characterized by single crystal X‐ray diffraction. Crystal data for DADNI are monoclinic, space group C2/c, a=15.9167(3) Å, b=8.6816(4) Å, c=8.5209(3) Å, β=103.294(9)°, V=1145.9(3) Å3, Z=4, µ=0.150 mm−1, F(000)=600, Dc=1.682 g·cm−3, R1=0.0565 and wR2=0.1649. Thermal decomposition behavior of DADNI was studied and an intensely exothermic process was observed. The kinetic equation of the decomposition reaction is: dα/dT=(1016.64/β)×4α3/4exp(−1.582×105/RT). The critical temperature of thermal explosion is 163.76°C. The specific heat capacity of DADNI was studied with micro‐DSC method and theoretical calculation method. The molar heat capacity is 343.30 J·mol−1·K−1 at 298.15 K. The adiabatic time‐to‐explosion of DADNI was calculated to be 87.7 s. 相似文献