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1.
Ring-opening polymerization (ROP) of various oxirane derivatives of the type, 2,2-R1,R2-CCH2O [R1 = H (1), CH3 (2); R2 = CH3 (a), CH2Cl (b), CH2OCH3 (c)], using organotin phosphate (Bu2SnO-Bu3PO4) condensate has been explored. The ROP of monosubstituted oxiranes (1a-c) afforded ring-opened polymers in high yields (1a, 1c = 99% and 1b = 69%); the resultant polymers from monomers 1a and 1b possessed high molecular weights (Mn = 9.49 × 104, 10.60 × 104, respectively). In contrast, both polymer yields and molecular weights for resultant polymers in the polymerization of disubstituted oxiranes (2a-c) were considerably lower than those in the polymerization of monosubstituted monomers (1a-c). ROP of glycidyl 2-methylglycidyl ether (3) possessing two oxirane groups with different reactivity was thus conducted by organotin catalyst; the high molecular weight polyether (Mn = 9.17 × 104) containing oxirane ring in the side chain has successfully been obtained in moderate yield.  相似文献   

2.
1,4-Diiodobenzenes bearing oligo-ethylene glycols [IRC6H2IR, R = OCH2CH2OCH3 (1a), O(CH2CH2O)2CH3 (1b), O(CH2CH2O)3CH3 (1c)] were polymerized with 1,4-diethynylbenzene in the presence of Pd/Cu catalyst to afford poly(p-phenyleneethynylene)s bearing oligo-ethylene glycols (2ac), respectively. Polymer 2a was insoluble in any solvents, but the other polymers (2b, 2c) were soluble in CHCl3. The weight-average molecular weights of 2b and 2c were 5.4 × 104 and 9.6 × 104, respectively, and they gave free-standing membranes by solution-casting method. The densities of membranes of 2b and 2c were 1.26 and 1.22 g/cm3, respectively, and their carbon dioxide permeability coefficients were 12.9 and 13.5 barrers, respectively. The CO2/N2 separation factor of membrane of 2b was as large as 33.7. Membrane of 3b, which contains triethylene glycols, exhibited higher CO2 permselectivity, and the CO2/N2 separation factor was 50.0.  相似文献   

3.
Copper(II) polymer complexes of empirical formula [Cu(ligand)2X2] (where X = Cl, Br, I, NO3, and SO4) and [Cu(ligand)(CH3COO)2] have been prepared with poly(3-phenylacrylidine semicarbazone). All the polymer complexes prepared have been characterized by elemental analysis, magnetic moment, conductance, IR, electronic, 1H-NMR, and electronic paramagnetic resonance spectral studies. The polymer complexes [Cu(ligand)2X2] and [Cu(ligand) (CH3COO)2] may have tetragonal symmetry while the [Cu(ligand)2( SO4)2] may be five-coordinate trigonal bipyramidal in structure. All complexes exhibit normal magnetic moments corresponding to one unpaired electron except [Cu(ligand)(CH3COO)2] which shows a subnormal magnetic moment. EPR spectra of the polymer complexes have been studied with a view to assigning their stereochemistries. Various EPR parameters have been calculated. The g, A, G values for all the polymer complexes are consistent with a tetragonal 15 and trigonal bipyramidal 6 stereochemistry in the Cu(II) polymer complexes of homopolymer.  相似文献   

4.
Atomic Force Microscopy (AFM) images have been recorded from the surfaces of platelet type monocrystals of linear alkanes, n-tritriacontane, C33H68, and n-hexatriacontane, C36H74. Structural details have been revealed in the range from several hundreds of nanometers down to the atomic scale. High resolution AFM micrographs of the linear alkanes show a regular pattern of elevations characterized by two main periodicities: aAFM=.70±.02 nm, bAFM=.52±.05 nm, , and aAFM=.79±.05 nm, bAFM=.61±.05 nm, , for C33H68 and C36H74 respectively. This structure is in fair agreement with the orthorhombic subcell of the bulk structure as confirmed by electron diffraction. Further, AFM results are in accordance with an orthorhombic unit cell for C33H68, and a monoclinic one for C36H74 under investigation. Consequently, the elevations in the AFM images can be assigned to individual methyl groups, which form the surface layer of a paraffine crystal. A regular surface structure has also been observed in AFM images of platelet crystals of cyclic alkanes, cyclooctatetracontane (CH2)48, and cyclodoheptacontane (CH2)72. In these cases, the periodicities are characterized by aAFM=1.10±.01 nm, bAFM=.85±.01 nm, yAFM=89±1o, and aAFM=1.11±.06 nm, bAFM=.91±.05, and , for (CH2)48 and (CH2)72, respectively. The images are consistent with the arrangement of the adjacent reentry folds obtained from crystallographic data.Herrn Prof. Dr. Harald Cherdron zu seinem 60. Geburtstag herzlich gewidmet  相似文献   

5.
Aiko Takeda  Tamotsu Hashimoto 《Polymer》2009,50(21):5031-1051
Diphenylacetylenes having both a trimethylsilyl group and an alkyl group at para positions [Me3SiC6H4CCC6H4R; R = Et (1a), n-Bu (1b), t-Bu (1c), n-C8H17 (1d)] and having only an alkyl group [PhCCC6H4R; R = n-Bu (1B), n-C8H17 (1D)] were synthesized and then polymerized with TaCl5/n-Bu4Sn catalyst to provide the corresponding poly(diphenylacetylene)s (2a, 2b, 2c, 2d, 2B, and 2D). The formed polymers except 2c afforded tough free-standing membranes by casting from toluene solutions. Desilylation reaction of the Si-containing polymer membranes (2a, 2b, 2d) was carried out with trifluoroacetic acid, and the desilylated polymer membranes (3a, 3b, 3d) were obtained. The permeability to O2, N2, and CO2 were determined for the obtained polymer membranes. All the desilylated membranes showed lower gas permeability than the Si-containing counterparts. To clarify the effects of the desilylation further, CO2 diffusivity, CO2 solubility, and fractional free volume (FFV) of the polymer membranes were investigated. The FFV and CO2 diffusivity decreased upon desilylation, while CO2 solubility hardly varied.  相似文献   

6.
Bulk SiBCN ceramics derived from polyborosilazanes of the type [B(C2H4SiRNH)3]n (1a, R = CH3; 2a, R = H; C2H4 = CHCH3, CH2CH2) exhibit an exceptional structural stability at high temperature. Therefore, such quaternary systems are of great scientific and technical interest as fibrous reinforcements intended for high-temperature applications. In this context, the design of novel polyborosilazanes, which display properties tailored for the preparation of SiBCN fibers, is studied. Boron-modified polysilazanes of the type [B(C2H4SiRNCH3)3]n (1b, R = CH3; 2b, R = H) are prepared via aminolysis of the tris(dichlorosilylethyl)boranes B(C2H4SiRCl2)3 (1, R = CH3; 2, R = H). It is shown that the functionalisation of the precursors with NCH3 units improves their processability (i.e. solubility) compared to that of their ammonolysed analogs [B(C2H4SiRNH)3]n (1a, R = CH3; 2a, R = H). In addition to the influence of the NCH3 units, the presence of the SiCH3 functions in such polymers offers the best potential for the preparation of fibers by melt-spinning. As-spun fibers are then converted under controlled atmosphere into high-temperature stable SiBCN fibers according to the polymer-derived ceramic route.  相似文献   

7.
Summary The efficient synthesis of symmetrical telechelic polyisobutylenes carrying CH2C(CH3)2Cl groups at either end of the molecule, , has been accomplished by rapid living polymerization using aromatic di-tert.-ether/BCl3 initiator system in CH3Cl at –70°. The living nature of the polymerization was demonstrated by linear Mn versus amount of PIB formed (WPIB) plots starting at the origin. The effect of temperature and solvent composition (polar/nonpolar) on the polymer structure has been investigated. Undesirable indanyl end groups which form during polymerizations carried out at –30° and –50°C can be eliminated by decreasing the temperature to –70°C. The apparent activation energy differences have been determined in the –30 to –70°C range at different polar/nonpolar solvent compositions: Ea of decreases from 2.6 to 1.0 kcal/mole by decreasing the polarity of the medium from 100% CH3Cl to a 60/40 v/v CH3Cl/hexanes mixture.  相似文献   

8.
Dipropynylbenzenes with alkyl groups (CH3C ≡ CRC6H2RC≡CCH3, R=n-C6H13, n-C8H17, n-C10H21, 1ac, respectively) were polymerized with Mo(CO)6 to afford solvent-soluble poly(2,5-dialkyl-p-phenyleneethynylene)s (2ac). The polymers (2ac) had high molecular weight over 3×104, and gave free-standing membranes by solution casting method. According to thermogravimetric analysis (TGA), these poly(p-phenyleneethynylene)s showed high thermal stability (T0 ≥380 °C). The densities of membranes of poly(2,5-dialkyl-p-phenyleneethynylene)s (2ac) were 0.936–0.965, and their fractional free volume (FFV) were relatively large (ca. 0.14–0.15). The oxygen permeability coefficients (PO2) of membranes of 2ac were 4.88, 7.06, and 16.6 barrers, respectively.  相似文献   

9.
10.
Diphenylacetylenes having a dimethyloctylsilyl group and an alkyl group at para positions [Me2n-C8H17SiC6H4CCC6H4R; R = H (1a), i-Pr (1b), t-Bu (1c), n-Bu (1d)] and having only an alkyl group [PhCCC6H4R; R = i-Pr (1B), t-Bu (1C)] were synthesized and then polymerized with TaCl5/n-Bu4Sn catalyst to provide the corresponding poly(diphenylacetylene)s (2a, 2b, 2c, 2d, 2B, and 2C). The formed polymers afforded tough free-standing membranes by casting from toluene solutions. Desilylation reaction of Si-containing membranes (2a-d) was carried out with trifluoroacetic acid to give the desilylated membranes (3a-d). The permeability of these membranes to O2, N2, and CO2 were determined. All the Si-containing membranes exhibited almost the same gas permeability. The desilylation of Si-containing membranes of 2a-c resulted in large increase of gas permeability. No apparent increasing of gas permeability was observed in the desilylation of 2d. To clarify the effects of desilylation, CO2 diffusivity (D(CO2)), CO2 solubility (S(CO2)), and fractional free volume (FFV) of the polymer membranes were investigated. The S(CO2) values of desilylated membranes were much larger than that of Si-containing counterparts. The D(CO2) and FFV of membranes of 2a-c increased through desilylation. The desilylated membrane of 3d had small D(CO2) value and almost the same FFV compared with 2d. Further, the comparison of the permeability between three types of membranes with the same chemical structure revealed that the microvoids were not generated by the desilylation of membranes of poly(diphenylacetylene)s containing alkyl groups.  相似文献   

11.
Diarylacetylene monomers having trimethylsilyl groups and other substituents (substituted biphenyl, 1a and 1b; trimethylsilylmethylphenyl, 1c-e) were synthesized and polymerized with TaCl5-n-Bu4Sn catalyst to produce the corresponding poly(diarylacetylene)s (2a-d). Polymers 2a-c had high molecular weights and were soluble in common organic solvents. Free-standing membranes of 2a-c as well as previously reported 2f-h were prepared by the solution-casting method. Desilylation of these Si-containing polymer membranes was carried out with trifluoroacetic acid to afford 3a, 3b, and 3f-h. Upon desilylation, biphenyl-containing membranes became less permeable (3a, b), whereas fluorene-containing membranes became more permeable (3f-h). In particular, 3h exhibited extremely high gas permeability (PO2 = 9800 barrers), which is about the same as that of poly(1-trimethylsilyl-1-propyne). Desilylated membranes 3a and 3f-h showed different gas permeability from that of polymers 2i-k which have the identical chemical structures and obtained directly by the polymerization of the corresponding monomers.  相似文献   

12.
Summary The radical polymerizations of 2-, 3-, and 4-(phenylethynyl)styrenes (1a–c) and the copolymerizations of 1a–c (M1) with styrene (M2) were carried out using AIBN as the initiator in toluene at 60°C. The number-average molecular weights (M ns) were extremely low for poly(2-phenylethynylstyrene) (2a) and poly[(phenylethynyl)styrene-co-styrene] (3a), and increased in the order of 2a, 3a << 2b, 3b < 2c, 3c. Monomer reactivity ratios were determined as r 1= 1.80 and r 2= 0.51 for 1a, r 1= 1.72 and r 2= 0.53 for 1b, and r 1= 3.17 and r 2= 0.24 for 1c. Polymers 2a–c and 3a–c underwent an exothermic reaction at elevated temperature to form organic solvent-insoluble polymers. Although the decomposition of 2a was observed from 200°C, 2b and 2c exhibited a high heat-resistance property in both nitrogen and air atmospheres, in particular, 2b showed no significant weight loss below 450°C. Received: 28 January 1998/Accepted: 5 March 1998  相似文献   

13.
Cobalt(II)-phthalocyanines in different environments are investigated as catalysts for the oxidation of thiols. Water-soluble low molecular weight 2,9,10,23-tetracarboxyphthalocyanine (1b) and polymeric phthalocyanine (2b) with carboxylic end groups are prepared. Compound1b is covalently bound at linear and cross-linked poly(chloromethylstyrene) in the presence of pyridine to obtain the water-soluble polymers (3a, b) and gel-type polymers (4a, b). Covalent binding of1b to surface modified silica was also realized. Low molecular weight and polymeric phthalocyanines (1a, 2a) are synthesized on silica, alumina, and charcoal. In addition,1a is encapsulated in the interior of NaX zeolite. All materials are efficient catalysts for the oxidation of 2-mercaptoethanol. The mechanism employing water-soluble catalysts is discussed in the direction of a mononuclear complex coordinating dioxygen and thiol. Heterogeneous catalysts containing1a and2a on the carriers show enhanced activity with increasing dispersion. The proposed mechanism considers different reaction sites for the coordination of O2 and thiol.  相似文献   

14.
Three new metal alkoxides, [(MMPEP)Al(μ-OCH2C6H4CH2Cl)]2 (1), [(MMPEP-H)Li·(BnOH)]2 (2) and [(MMPEP-H)Li·(HOCH2C6H4CH2Cl)]2 (3) (MMPEP-H2: 2,2′-methylene-bis{4,6-di(1-methyl-1-phenylethyl)phenol}) have been synthesized and characterized. Complex 1 was prepared by the reaction of [(MMPEP)Al(CH3)(Et2O)] with p-(chloromethyl)benzyl alcohol. Followed by the reaction of MMPEP-H2 with nBuLi, BnOH or p-(chloromethyl)benzyl alcohol was added to give complexes 2 and 3, respectively. Complex 1 has shown excellent catalytic activity towards ring-opening polymerization (ROP) of ?-caprolactone. Both complexes 2 and 3 are active for ROP of l-lactide. Block copolymers of poly(?-caprolactone)-b-polyacrylonitrile (PCL-b-PAN) and poly(l-lactide)-b-polyacrylonitrile can be synthesized by combining a technique of atom transfer radical polymerization (ATRP) and ROP using a double-headed initiator. Microphase-separated morphology of PCL-b-PAN has been observed by transmission electron microscopy, indicating the formation of self-assembled nanostructure.  相似文献   

15.
16.
The radical polymerizations of 2-, 3-, and 4-(trimethylsilylethynyl)styrenes (1 a – c) and copolymerizations of 1 a – c (M1) with styrene (M2) have been studied. Copolymerization parameters were determined as r1 = 1.22 and r2 = 0.54 for 1 a, 1 = 1.10 and r2 = 0.90 for 1 b, and r1 = 1.42 and r2 = 0.38 for 1 c. The deprotection of the trimethylsilyl groups in poly[(trimethylsilylethynyl)styrene] (2 a – c) and poly[(trimethylsilylethynyl)styrene-co-styrene] (4 a – c) using (C4H9)4NF smoothly proceeded to yield poly(ethynylstyrene) (3 a – c) and poly(ethynylstyrene-co-styrene) (5 a – c), respectively, which underwent curing reactions at elevated temperature to form crosslinking polystyrenes. Received: 31 March 1997/Revised: 2 June 1997/Accepted: 3 June 1997  相似文献   

17.
The dimeric complex of Cu(I) [Cu2(PPh3)4(MeCN)2(Bpy)](BF4)2 (1a, Bpy = 4,4′-dipyridyl) self-assembles in CH2Cl2 or acetone and shows intense photoluminescence (excitation λmax = 356 nm, emission λmax = 486 nm, ? = 0.47). The MeCN ligands are readily removed from 1a, producing [Cu2(PPh3)4(Bpy)](BF4)2 (1b) and altering the photophysical behavior (excitation λmax = 336 nm, emission λmax = 568 nm, ? = 0.07). The desolvated compound 1b reversibly absorbs many vapor phase nucleophiles, as revealed by thermogravimetry. Intense luminescence emission is restored for 1b/Nu, Nu = MeCN (1a), acetone, tetrahydrothiophene (THT), and Et2S. Films of 1b are produced when CH2Cl2 solutions of 1a are cast onto glass. The films also react with Nu vapor, again producing intense emission. The pyrazine-bridged dimer [Cu2(PPh3)4(MeCN)2(Pyz)](BF4)2 (2a) is produced in CH2Cl2, while [Cu2(PPh3)4(MeCN)(acetone)(Pyz)](BF4)2?½[Cu2(PPh3)4(MeCN)2(Pyz)](BF4)2 (2b) is formed in acetone. The crystal structure of the polymer {[Cu(PPh3)2(Bpy)](BF4)?acetone} n (3) is reported, as is the mixed polymer/dimer structure {[Cu(PPh3)2(Pyz)](BF4)} n n[Cu2(PPh3)4(BF4)2(Pyz)] (4b) in which the dimer units show Cu–FBF3 coordination. The Pyz dimer and the Pyz and Bpy polymers show much weaker luminescence behavior than that of Bpy dimers 1a and the related 1b/Nu adducts. Nucleophile adduct structures [Cu2(PPh3)4(THT)2(Bpy)](BF4)2?½ethyl ether (5) and [Cu2(PPh3)4(Py)2(Bpy)](BF4)2?CH2Cl2 (6) confirmed the coordination of one Nu per Cu to 1b.  相似文献   

18.
3-(4-Bromophenyl)-2-cyanoprop-2-enethioamide (1) reacted with ethyl 3-oxo-3-phenylpropanoate (2) to give ethyl 4-(4-bromophenyl)-5-cyano-2-phenyl-6-thioxo-1,6-dihydropyridine-3-carboxylate (3). Compound 3 was taken as a starting material for the synthesis of thio-substituted ethyl nicotinate derivatives 5ad, which underwent cyclization to the corresponding thieno[2,3-b]pyridines 6ad. Also 3 reacted with hydrazine hydrate to give the pyrazolo[3,4-b]pyridine derivative 7, which upon diazotization gave the diazonium derivative 8. Compound 6a condensed with dimethylformamide–dimethylacetal to afford thieno[2,3-b]pyridine derivative 9, which reacted with different amines 10ae to afford the pyridothienopyrimidine derivatives 12ae through the Dimroth rearrangement. Moreover, compound 6a reacted with different reagents to give pyridothienopyrimidine derivatives 14a and b, 17 and pyrazolothienopyridine derivative 18. In addition, acetylating compound 6c with chloroacetylchloride afforded the 3-[(2)-chloroacetylamino]thieno[2,3-b]pyridine derivative 20, which upon cyclization yielded the corresponding 2-chloromethylpyrido[3′,2′:4,5]thieno[3,2-d]pyrimidine derivative 21. Some of the newly synthesized compounds were screened in vitro for their antimicrobial activities.

  相似文献   

19.
A series of novel half-metallocene-type titanium complexes CpTiCl2[PhNC(R2)CHC(R1)O] (2a, R1 = Cy, R2 = CF3; 2b, R1 = tBu, R2 = CF3; 2c, R1 = Ph, R2 = CF3; 2d, R1 = Ph, R2 = CH3) have been synthesized by treating CpTiCl3 with the corresponding bidentate β-enaminoketonato ligands PhNC(R2)CHC(R1)OH in the presence of triethylamine. Single crystal X-ray diffraction revealed that complex 2b adopts distorted square-pyramid geometry around the titanium center. The complexes 2a-d were investigated as the catalysts for ethylene polymerization and the copolymerization of ethylene with norbornene. All the complexes were active towards ethylene (co)polymerization in the presence of modified methylaluminoxane, and produced high molecular weight (co)polymers. The catalytic activity and the norbornene incorporation were highly dependent upon catalyst and reaction conditions employed. Among four complexes, 2c exhibited both high catalytic activity and efficient norbornene incorporation under the same conditions, affording high molecular weight copolymers with unimodal molecular weight distributions.  相似文献   

20.
Toru Katsumata 《Polymer》2008,49(12):2808-2816
The polymerization of diphenylacetylene derivatives possessing tert-amine moieties, such as triphenylamine, N-substituted carbazole and indole, was examined in the presence of TaCl5-n-Bu4Sn (1:2) catalyst. A polymer with high molecular weight (Mw = 570 × 103) was obtained in good yield by the polymerization of diphenylamine-containing monomer 1b, whereas the isopropylphenylamine derivative (1c) gave a polymer with relatively low molecular weight (Mw = 2.4 × 103). The polymerization of monomer 1d containing cyclohexylphenylamine group did not proceed; however, carbazolyl- and indolyl-containing monomers also produced polymers. Poly(1b), poly(2f) and poly(4b) could be fabricated into free-standing membranes by casting toluene solutions of these polymers. The gas permeability of poly(1b) was too low to be evaluated accurately whereas poly(4b) possessing two chlorine atoms in the repeating unit showed higher gas permeability than that of poly(1b); furthermore, poly(2f) having trimethylsilyl and 3-methylindolyl groups exhibited relatively high gas permeability (). In the cyclic voltammograms of diphenylamino group-containing polymers, poly(1b) and poly(2b), the intensities of oxidation and reduction peaks decreased more than those of carbazolyl-containing poly(2a). The molar absorptivity (?) of poly(1b) at ∼700 nm increased with increasing applied voltage in the UV-vis spectrum.  相似文献   

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