Evidence of isomerization of 5-methylenebicyclo[2.2.1] hept-2-ene cation by13C NMR spectroscopy

Summary Cations obtained by reaction of various protonic acids with 5-Methylenebicyclo [2.2.1] hept-2-ene (5-methylene-2-norbornene) have been studied by C NMR spectroscopy. The isomerization of initial carbocation has been pointed out. A correlation of these results with the structure of the corresponding polymers has been establishedThe cationic polymerization of 5-Methylenebicyclo [2.2.1] hept2-ene (5-methylene-2-norbornene) has been investigated several times and KENNEDY (1974) published a review on this topic. A structure of the polymer obtained by classical cationic initiation has been suggested; this results from infrared and X.R. diffraction studies.In a recent work IVIN et al. (1980) reported the¹³C NMR spectrum of a poly[5-methylenebicyclo [2.2.1] hept-2-ene] resulting from a Ziegler-Natta initiation. We obtained the same¹³C NMR spectrum as IVIN et al. when the initiator were TiCl₄, CF₃ COOH, CCl₃COOH and concentrated H₂SO₄ (see fig.1). Chemical shifts and coupling constants fit with the generally accepted structure of the polymers: KENNEDY and MAKOWSKY (1967) suggested an isomerization of the active species:     

Ring-opening polymerization of 1 -ethylbicyclo[2.2.1] hept-2-ene

1-Ethylbicyclo[2.2.1]hept-2-ene has been polymerized using a range of metathesis catalysts and the structure of the polymers determined by ¹³C n.m.r. spectroscopy. For a given catalyst the cis double bond content was lower and the head-tail bias greater than for polymers of the 1-methyl analogue. This is interpreted in terms of enhanced steric and polar effects brought about by the ethyl substituent.     

Metathesis ring opening polymerization of 5,6-dimethylenebicyclo[2.2.1]hept-2-ene

5,6-Dimethylenebicyclo[2.2.1]hept-2-ene ( I ) polymerizes in the presence of the two-component ring opening metathesis polymerization (ROMP) initiators WCl₆/(CH₃)4Sn and MoCl₅/(CH₃)4Sn. The product polymers were insoluble in all of many solvents investigated and are presumably cross-linked. The product polymers were investigated by IR and solid state ¹³C NMR spectroscopy, which established that the material consisted predominantly of poly(1,4-(2,3-dimethylene-cyclopentylene)vinylene) ( II ). A possible alternative route to II via thermal dehydrochlorination of poly(1,4-(2,3-bis(chloromethyl)cyclopentylene) vinylene) ( IV ) was also examined.     

二环[2.2.1]庚烷-2,3-二羧酸二钠的合成及表征

以用量为原料质量24.33％的380～830?μm的Raney?Ni为催化剂,在常温常压条件下对二环[2.2.1]庚-5-烯-2,3-二羧酸二钠进行加氢,反应时间90?min,得到聚丙烯成核剂二环[2.2.1]庚烷-2,3-二羧酸二钠,收率达90％以上.在同样条件下,将50％(w)的再生催化剂与50％(w)的新鲜催化剂...     

Synthesis and lithographic characterization of poly[(dihydrocarveol)-co-(1,1-dimethylethyl bicyclo[2.2.1]hept-5-ene-2-carboxylate)-co-(maleic anhydride)]

A new ArF single-layer resist polymer, poly(dihydrocarveol-co-1,1-dimethylethyl bicyclo[2.2.1]hept-5-ene-2-carboxylate-co-maleic anhydride) has been synthesized by radical polymerization. The molar composition of synthesized resist polymer was confirmed by elemental analysis. The obtained molar composition was 0.25:0.35:0.40. This resist polymer was found to be stable up to 230 °C, but above 250 °C it underwent rapid thermal deprotection of the tert-butyl groups by releasing carbon dioxide and 2-methylpropene. The deprotection temperature was established by DSC and TGA. Using the resist, 0.14 µm L/S pattern was obtained at 26 mJ/cm⁻² doses, using an ArF stepper and the developer of 2.38 wt% tetramethyl ammonium hydroxide aqueous solution. © 1999 Society of Chemical Industry     

Synthesis and pH-dependent micellization of 2-(diisopropylamino)ethyl methacrylate based amphiphilic diblock copolymers via RAFT polymerization

The polymerization of 2-(diisopropylamino)ethyl methacrylate (DPA) by RAFT mechanism in the presence of 4-cyanopentanoic acid dithiobenzoate in 1,4-dioxane was studied. The DPA homopolymer was employed as a macro chain transfer agent to synthesize pH-sensitive amphiphilic block copolymers using poly(ethylene glycol) methyl ether methacrylate (PEGMA) as the hydrophilic block. ¹H NMR and GPC measurements confirmed the successful synthesis of these copolymers. Potentiometric titrations and fluorescence experiments proved that the copolymers underwent a sharp transition from unimers to micelles at a pH of ∼6.7 in phosphate buffered saline solutions. It was found that the hydrophilic/hydrophobic balance of these block copolymers had no apparent effect on their pH-induced micellization behaviors. The DLS investigation revealed that the micelles have a mean hydrodynamic diameter below 60 nm with a narrow size distribution.     

环己烷-乙烯基降冰片烯体系汽液平衡数据测定及关联

采用改进的Rose汽液平衡釜,测定了在12.0kPa压力下的乙烯基降冰片烯精馏体系中环己烷(CH)-乙烯基环己烯（VCH）,环己烷(CH)-乙烯基降冰片烯(VNB),环己烷(CH)-四氢茚(THI)的汽液平衡数据,并进行了热力学一致性验证,由所测数据回归出三组用于该体系Wilson方程的配偶参数,并证明了Wilson方程可以较好地关联环己烷-乙烯基降冰片烯体系的汽液平衡.为乙烯基降冰片烯精馏体系的开发与设计提供了基础数据.     

13C n.m.r. spectra of polymers made by ring-opening polymerization of (±)- and (+)-exo-5-methylbicyclo [2.2.1] hept-2-ene using metathesis catalysts

A range of olefin metathesis catalysts has been used to prepare ring-opened polymers of (±)- and (+)-exo-5-methylbicyclo [2.2.1] hept-2-ene, (l), having cis double bond contents of 11–100%. The ¹³C n.m.r. spectra of these polymers are interpreted in terms of TH, TT, HH, HT and tt, tc, ct, cc structures (T = tail, H = head, referring to methyl groups; t = trans, c = cis, referring to double bonds). The all-cis polymer has a fully-syndiotactic ring sequence, but polymers with less than 55% cis double bonds have an atactic ring sequence. The substitution shift parameters indicate that the cyclopentane rings in the polymer chain adopt the puckered conformation which minimizes non-bonded repulsion between the cis-1,3-olefinic substituents.     

Novel fluorescent polynorbornenes with multi-functional armed structure by using highly stable block macroinitiators via a combination of living ring-opening metathesis polymerization and atom transfer radical polymerization

Novel organosoluble fluorescent polynorbornenes with multi-functional armed structure were designed and prepared by using highly stable block macroinitiators via a combination of living ring-opening metathesis polymerization (ROMP) and atom transfer radical polymerization (ATRP). A bromo-containing functional norbornene (NBMBr) was prepared from the Diels-Alder reaction of cyclopentadiene and allyl bromide. The diblock copolymer of 5-(N-carbazolyl methyl)bicycle[2.2.1]hept-2-ene (CbzNB) and NBMBr was successfully prepared using living ROMP and used as a novel macroinitiator [poly(CbzNB-b-NBMBr)] for ATRP. Carbazoyl-containing multi-functional armed copolymer with poly(methyl methacrylate) (PMMA) was prepared by using poly(CbzNB-b-NBMBr) as a macroinitiator for ATRP. Strong fluorescence emissions (370-450 nm) were observed in the low excimer-forming multi-functional armed fluorescent polynorbornenes. The fact is that low excimer-forming carbazole-containing polymeric compound would apparently be favorable in photoconductive materials. The multi-functional armed structure make this compound an attractive candidate for applications as multi-modified hole transport materials in molecular electronic devices. Multi-modification could be further considered to be carried out by using such a functional bromo group at the end of multi-arms.     

The effect of bicyclo[2.2.1]hept‐5‐ene‐2,3‐dicarboxylate on the mechanical properties and crystallization behaviors of isotactic polypropylene

The mechanical and optical properties of iPP nucleated with bicyclo[2.2.1]heptenedicarboxylate salts (BCHED) have been investigated. The results showed that aluminum bicyclo[2.2.1]heptenedicarboxylate (BCHE13) is the most effective nucleating agent to improve the mechanical and optical properties. Then the effects of the BCHE13 concentration on mechanical and optical properties and crystallization behaviors were studied. The results indicated that the saturated concentration of BCHE13 is about 0.2 wt %, at which nucleated iPP showed the better comprehensive mechanical and optical properties and high crystallization peak temperature. Nonisothermal crystallization kinetics of iPP nucleated with different BCHE13 contents have been investigated by Caze method. The results indicated Avrami exponents of nucleated iPP gradually increased with the increasing of BCHE13 concentration. The results can be explained that crystallization and growth model of nucleated iPP is heterogeneous nuclei followed by more than three‐dimension spherical growth during nonisothermal crystallization, which can be proved by agglomeration of BCHE13 in melt iPP. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Zur Heck-Reaktion von 1-Chloralk-1-inen – Synthese und Charakterisierung von 1,3-disubstituierten 7-(Prop-2-inyliden)bicyclo[2.2.1]heptanen und anderen Bicyclen

The Heck reaction of cyclohexene with 1-chloroalk-1-ynes ClC≡CR 1 (R = Ph a , c-Hex b , n-Bu c , n-Oct d ) using [Pd(OAc)₂]/NaO₂CH/[NEt₃Bz]Cl as catalyst system (DMF, 25 °C) affords 1,3-disubstituted 7-(prop-2-ynylidene)bicyclo[2.2.1]heptanes 2 as tandem products by reaction of cyclohexene and ClC≡CR in a ratio of 1:2. To a smaller extent, substituted 7-[(cyclohexenyl)methylidene]bicyclo-[2.2.1]heptanes 3 (tandem products by reaction of cyclohexene and ClC≡CR in a ratio of 2:1) and the regular Heck products (alkynylcyclohexenes 4 ) are formed. The homocoupling of 1 to give RC≡C–C≡CR does not take place, except for R = n-Oct where it proceeds as side reaction. The analogous reaction of ClC≡CR with cycloheptene affords the 2:1 products (substitued 8-[(cycloheptenyl)methylidene]biyclo[3.2.1]octanes 6 ) as main products and the 1:2 products (1,3-disubstituted 7-(prop-2-ynylidene)bicyclo[3.2.1]-octanes 5 ) as well as the regular Heck products (alkynylcycloheptenes 7 ) as side products. The ratio 5 : 6 is strongly influenced by the ratio cycloheptene : 1 . The products 2 , 5a and 6 were isolated and characterized by means of ¹H and ¹³C NMR spectroscopy. The molecular structures of 7-(1,3-diphenylprop-2-ynylidene)bicyclo[2.2.1]heptane ( 2a ) and 8-[(cyclo-heptenyl)phenylmethylidene)]bicyclo[3.2.1]octane ( 6a ) (as mixture of the cyclohept-3- and -4-enyl double bond isomers) were determined by single-crystal X-ray structure analysis.     

The amphiphilic block copolymers of 2-(dimethylamino)ethyl methacrylate and methyl methacrylate: Synthesis by atom transfer radical polymerization and solution properties

Amphiphilic di- and tri-block copolymers of poly(methyl methacrylate) (PMMA) and poly(2-dimethylamino)ethyl methacrylate (PDMAEMA) have been synthesized by atom transfer radical polymerization (ATRP) at ambient temperature (35 °C) in the environment-friendly solvent, aqueous ethanol (water 16 vol%) using CuCl/o-phenanthroline as the catalyst. The PDMAEMA blocks are contaminated with ethyl methacrylate (EMA) residues to the extent of 1-2 mol% of DMAEMA depending on the length of the PDMAEMA block. The EMA forms through the autocatalyzed ethanolysis of the DMAEMA monomer and undergoes random copolymerization with the latter. The rate of ethanolysis is unexpectedly greater in the aqueous ethanol than in neat ethanol, which has been attributed to the higher polarity of the former than of the latter. In contrast to the ethanolysis no hydrolysis of DMAEMA in the aqueous ethanol medium could be detected for 133 h. The block copolymers form micelles in water. Their solubility and CMC in neutral water have been studied. Dynamic light scattering (DLS) studies reveal that for a fixed degree of polymerization (DP) of the PMMA block the hydrodynamic diameter of the micelles in methanolic water (water 95 vol%) increases at a faster rate with the DP of the PDMAEMA block when it is much greater than that of the PMMA block compared to when it is less than or close to that of the latter.     

Addition polymerisation vs. ROMP on cyclic and strained olefins with the Mo(CO)5PPh3/alkylaluminums catalysts

The polymerisation of cyclic and strained monomers such as bicyclo[2.2.1]hept-2-ene (norbornene, NBE) and bicyclo[2.2.1]hepta-2,5-diene (norbornadiene, NBDE) with the catalytic systems Mo(CO)₅PPh₃/alkylaluminums was studied. From the polymers produced we demonstrate the existence of an antagonism between the ROMP (Ring-Opening-Metathesis-Polymerisation) mecanism and the olefin addition polymerisation mecanism. In addition ROMP mecanism is affected by the solvent. These catalysts also promotes the isomerisation of double bonds, as indicated by the ESR signal observed for the conjugated crosslinked polyNBDE produced by ROMP. Received: 5 August 1996/Revised version: 22 October 1996/Accepted: 25 October 1996     

Synthesis and characterization of amphiphilic comb-polymers via ring-opening metathesis polymerization of exo,exo-5,6-bis(alkoxymethyl)-7-oxabicyclo[2.2.1]hept-2-enes

Summary A number of exo,exo-5,6-bis(alkoxymethyl)-7-oxabicyclo[2.2.1]hept-2-enes (exo,exo-5,6-bis(alkoxymethyl)-7-oxanorbornenes) with long alkyl chains were prepared by reduction of the Diels-Alder adduct of furan and maleic anhydride, followed by alkylation with a series of different n-alkylbromides. These monomers were polymerized via ring-opening metathesis polymerization (ROMP) catalyzed by ruthenium trichloride in ethanolic solution. Contrary to a helical conformation as it was predicted by a previous molecular model study the poly(7-oxanorbornenes) adopt a coil conformation in solution. In bulk the materials show side chain crystallization.     

Preparation and self-assembly of double hydrophilic poly(ethylethylene phosphate)-block-poly[2-(succinyloxy)ethyl methacrylate] diblock copolymers for drug delivery

This work focuses on the synthesis and self-assembly of biodegradable and anionic double hydrophilic diblock copolymers (DHBCs) poly(ethylethylene phosphate)-block-poly[2-(succinyloxy)ethyl methacrylate] (PEEP-b-PSEMA) with different molecular weights and compositions, which were prepared via a combination of ring opening polymerization (ROP), atom transfer radical polymerization (ATRP) and polymer reaction. The chemical structures of these well-defined diblock copolymers were confirmed by ¹H NMR and FT-IR analyses. GPC results indicated that the copolymers showed symmetric peak and relatively narrow polydispersities. Subsequently, pH-responsive micellization behaviors of PEEP-b-PSEMA diblock copolymers were investigated by fluorescence probe method, dynamic light scattering (DLS) and transmission electron microscopy (TEM) measurements. The results demonstrated that these diblock copolymers were able to self-assemble into micelles with various sizes depending on the variation of pH values. Naproxen (NAP), a poorly water-soluble drug, was selected as the model drug and encapsulated into the core of micelles via dialysis method. The in vitro release behavior of NAP from these micelles was pH-dependent and could be accelerated in the presence of phosphodiesterase I which could promote the degradation of polyphosphoesters. Cytotoxicity tests by MTT assay showed that these block copolymers possessed favorable biocompatibility against HeLa cells, revealing that this kind of biodegradable, biocompatible and pH-responsive block copolymer would be served as a promising material for drug delivery.     

Diels-Alder-Reaktionen. VIII. Kinetische Untersuchungen zur Bildung und zur Pyrolyse von Tetracyclo[6.2.1.13.6.02.7]dodec-4-en

Diels-Alder-Reactions. VIII. Kinetic Investigations of the Formation and the Pyrolysis of Tetracyclo [6.2.1.1^3.6.0^2.7]-dodec-4-en The formation of tetracyclo[6.2.1.1^3.6.0^2.7]dodec-4-ene by codimerisation of cyclopentadiene with bicyclo[2.2.1]hept-2-ene between 60 and 140°C in the liquid phase and the inverse reaction by gas phase pyrolysis between 240 and 300°C were studied kinetically. The activation parameters were determined.     

两亲性无规聚合物P(MMA-co-MAA)的合成及其自组装研究

由疏水性单体甲基丙烯酸甲酯(MMA)和亲水性单体甲基丙烯酸(MAA)进行自由基溶液共聚,合成了一系列配比不同的两亲性无规聚合物P(MMA-co-MAA),用红外光谱、核磁共振和凝胶渗透色谱对聚合物结构进行了表征。采用一种操作过程简单、快捷、环保的新方法制备了聚合物胶束,即将一定质量的聚合物溶于碱性水溶液中,通过中和原理进行自组装,并得到球形胶束。通过透射电子显微镜(TEM)和激光光散射(DLS)法,研究了聚合物中基团摩尔比例不同时对胶束形貌和流体动力学半径(Rh)的影响。     

Synthesis and characterization of amphiphilic graft copolymers with hydrophilic poly(acrylic acid) backbone and hydrophobic poly(methyl methacrylate) side chains

A series of well-defined amphiphilic graft copolymers containing hydrophilic poly(acrylic acid) backbones and hydrophobic poly(methyl methacrylate) side chains were synthesized by successive atom transfer radical polymerization followed by the selective hydrolysis of poly(methoxymethyl acrylate) backbone. Grafting-from strategy was employed for the synthesis of graft copolymers with narrow molecular weight distributions. Hydrophobic side chains were connected with the backbone through stable C-C bonds instead of ester connections. The backbone can be easily hydrolyzed to poly(acrylic acid) with HCl without affecting the hydrophobic side chains. The amphiphilic graft copolymers can form stable micelles in water. The critical micelle concentration was determined by fluorescence spectroscopy. The micellar morphologies were found to be vesicles by transmission electron microscopy and changed to spheres with the addition of NaCl.     

Vesicular and micellar self‐assembly of stimuli‐responsive poly(N‐isopropyl acrylamide‐b‐9‐anthracene methyl methacrylate) amphiphilic diblock copolymers

Dually responsive amphiphilic diblock copolymers consisting of hydrophilic poly(N‐isopropyl acrylamide) [poly(NIPAAm)] and hydrophobic poly(9‐anthracene methyl methacrylate) were synthesized by reversible addition fragmentation chain‐transfer (RAFT) polymerization with 3‐(benzyl sulfanyl thiocarbonyl sulfanyl) propionic acid as a chain‐transfer agent. In the first step, the poly(NIPAAm) chain was grown to make a macro‐RAFT agent, and in the second step, the chain was extended by hydrophobic 9‐anthryl methyl methacrylate to yield amphiphilic poly(N‐isopropyl acrylamide‐b‐9‐anthracene methyl methacrylate) block copolymers. The formation of copolymers with three different hydrophobic block lengths and a fixed hydrophilic block was confirmed from their molecular weights. The self‐assembly of these copolymers was studied through the determination of the lower critical solution temperature and critical micelle concentration of the copolymers in aqueous solution. The self‐assembled block copolymers displayed vesicular morphology in the case of the small hydrophobic chain, but the morphology gradually turned into a micellar type when the hydrophobic chain length was increased. The variations in the length and chemical composition of the blocks allowed the tuning of the block copolymer responsiveness toward both the pH and temperature. The resulting self‐assembled structures underwent thermally induced and pH‐induced morphological transitions from vesicles to micelles and vice versa in aqueous solution. These dually responsive amphiphilic diblock copolymers have potential applications in the encapsulation of both hydrophobic and hydrophilic drug molecules, as evidenced from the dye encapsulation studies. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46474.     

Poly(2,5-(3,4-bis(methoxymethyl)furanylene)vinylene)s prepared by aqueous ring opening metathesis polymerisation

Summary Poly(2,5-(3,4-bis(methoxymethyl)furanylene)vinylene)s of various microstructures, prepared by aqueous Ring Opening Metathesis Polymerisation (ROMP) of exo,exo-5,6-bis(methoxymethyl)-7-oxabicylo[2.2.1]hept-2-ene, were characterised by high field NMR.