Poly(cis-norbornene-eco-2,3-dicarboxylic acid dialkyl esters) (alkyl = Me, Et, Pr, Bu, Pen, and Hex) are synthesized as a vinyl-type with a palladium(II) catalyst in high yield from easily prepared, pure exo-monomers. The polymers show good solubility in common organic solvents and excellent thermal stability up to 330degreesC. the polymers with alkyl groups larger than methyl exhibit a two-step thermal degradation profile of an initial thermal degradation of side-chains starting at 350degreesC, followed by thermal degradation of the norbornene backbone starting at ca. 430degreesC. the glass transition temperature decreases and the mechanical flexibility increases as the alkyl length of the side-chain increases.

The anionic polymerization of vinyl monomers with electron donating substituents was investigated. The 4- and 3-styryldiphenylphosphines were synthesized and homopolymerized at -85 degrees C in tetrahydrofuran using sec-butyllithium as initiator. Block copolymerization studies were carried out using styrene as a comonomer. 4-Styryldiphenylphosphine (I) forms a much more stabilized anionic chain end than styrene (III). Thus only the sequence III/I is effective in block copolymerization. In contrast, 3-styryldiphenylphosphine (II) can be combined in both ways to block copolymers.

Two different polyphenylene ethynylene derivatives, one partly hydrophobic and one hydrophilic, were investigated with a combination of X-ray and light scattering techniques and hydrodynamic techniques, as well as scanning force microscopy and transmission electron microscopy to elucidate their molecular structure and aggregation behavior in tetrahydrofuran and water, respectively. It turns out that both polymers possess a rod-like molecular architecture which, however, is the basis of a cascade of aggregation steps. Both, electron microscopy and X-ray analysis support the concept of a primary back-to-back aggregation of polymer chains into cylindrically shaped aggregates with high anisometry. The thickness of these aggregates was between 4.0 and 4.5 nm. The aggregates of the hydrophobic polymer further associate into fibrils and these fibrils form clusters of globular shape, though with high internal anisometry. Copyright 1999 Academic Press.

The amido silyloxy complexes [Na(12-crown-4)(2)][M{N(SiMe3)(2)}(3)(OSiMe3)] with M = Sm (la), Eu (Ib), To (Ic), and Lu (Id) were obtained from the trisamides M[N(SiMe3)(3)](3) and NaOSiMe3 in n-hexane in the presence of 12-crown-4; they form yellow to orange-red crystals, of which la and Ic were characterized crystallographically. The complexes crystallize isotypically with one another in the monoclinic space group I2/a with eight formula units per unit cell. The metal atoms of the complex anions are tetra-hedrally coordinated by the three nitrogen atoms of the N(SiMe3)(2)(-) ligands and by the oxygen atom of the OSiMe3- ligand. With 172.4 degrees for la and 179.3 degrees for Ic the bond angles M-O-Si are practically linear.With ethynylbenzene in the presence of NaN(SiMe3)(2) in tetrahydrofuran the trisamides M[N(SiMe3)2]3 react under formation of the complexes [Na(THF)(3)M{N(SiMe3)(2)}(3).(C = C-Ph)] with M = Ce (2a), Sm (2b), and Eu (2c), of which 2b was characterized crystallographically (monoclinic, space group P2(1)/n, Z = 4). 2b forms an ion pair in which the terminal carbon atom of the C = C-Ph- ligand is connected with the samarium atom of the Sm[N(SiMe3)(2)](3) group and the sodium ion is side-on connected with the acetylido group. According to the crystal structure determination (space group P2(1)2(1)2(1), Z = 4) [Na(THF)(6)] [Lu-2(mu-NH2) (mu-NSiMe3).{N(SiMe3)(2)}(4)] (3), which is formed as a by-product, consists of [Na(THF)6](+) ions and dimeric anions, in which the lutetium atoms are connected to form a planar Lu2N2 four-membered ring via a mu-NH2 bridge with average Lu-N distances of 227.2 pm and via a mu-NSiMe3 bridge of average Lu-N distances of 218.5 pm. According to the crystal structure determination (space group P (1) over bar, Z = 1) [NaN(SiMe3)(2)(THF)](2) (4) forms centrosymmetric dimeric molecules with Na-N distances of the Na2N2 four-membered ring of 239.9 pm and distances Na-O of the terminally bonded THF molecules which are 226.7 pm.The vinylic polymerization of methylmethacrylate (MMA) catalyzed by Ic resulted in high molecular weight polymethylmethacrylate (PMMA) with moderate yields. The reaction of 1a or 2b with MMA did not give PMMA. Insoluble polynorbornene was obtained in low yields by reaction of norbornene/methylaluminoxane (MAO) with 1a, 1c, or 2b. The ring opening polymerization of epsilon-caprolacton or delta-valerolacton catalyzed by 2b resulted in corresponding polylactones in quantitative yields.

The vinylic polymerization of norbornene and its copolymerization with norbornene carboxylic acid methyl esters were investigated. Norbornene was polymerized by us using di-mu-chloro-bis-(6-methoxy-bicyclo[2.2..1]hept-2-ene-endo-5 sigma,2 pi)-palladium(II) as catalyst. The polymerization time can be decreased by a factor of 100000 by activation of the catalyst with methylaluminoxane (MAO). With this palladium catalyst activated by MAO, 140 t of norbornene can be polymerized per mol palladium per h. This catalyst system was much more active than [Pd(CH3CN)(4)](BF4)(2) (I). The polymerization of norbornene by (6-methoxybicyclo[2.2..1]hept-2-ene-endo-5 sigma,2 pi)-palladium(II) tetrafluoroborate was also possible but it was not as fast as the polymerization by Pd catalysts activated with MAO. We were also able to obtain copolymers of norbornene and 5-norbornene-2-carboxylic acid methyl ester (exo/endo = 1/4 or 2/3) containing between 15 and 20 mol-% ester units. The copolymerization of norbornene and 2-methyl-5-norbornene-2-carboxylic acid methyl ester (exo/endo = 7/3) was faster than the copolymerization mentioned before. In contrast the homopolymerization of 2-methyl-5-norbornene-2-carboxylic acid methyl ester was 10 times slower than that of 5-norbornene-2-carboxylic acid methyl ester (exo/endo = 1/4).

A new class of homogeneous chromium(III)-based catalysts of the type [Cp*CrMeCl]2/MAO with different kinds of Cp ligands has been synthesized. The influence of the electronic nature and the sterical demand of the catalysts were explored with regard to the vinylic polymerization of norbornene. The catalyst activity could be increased by intensifying the electron-donating character of the Cp ligand, whereas the sterical demand of the Cp ligand affects the crystallinity of the obtained polynorbornene. In order to improve their processability, copolymers of norbornene with ethene were made using the [Cp*CrMeCl]2/MAO catalyst, which led to copolymers with a high α-olefin content. Furthermore, highly linear, ultra-high molecular weight polyethylene was obtained using the new class of chromium(III)-based catalysts.

Poly(phenyleneethynylene)s prepared by Pd/Cu-catalyzed synthesis contain diine defect structures. Diines are formed by reaction of Pd(II) species with ethynylides. The side reaction can be avoided by a low stationary state concentration of ethynylides. This can be achieved by a one pot reaction where removing of the trimethylsilyl groups and the polycondensation is simultaneously carried out. Deprotection is becoming the rate determining step, and thus the stationary state concentration of ethynyl compounds is low. A Cufree Pd catalyst is used. The absence of diines is shown in model reactions. An ester-containing poly(phenyleneethynylene) is prepared using the new technique. The polymer is amorphous, thermotropic, and lyotropic with a Tg of 41°C. It can be hydrolyzed to a polyelectrolyte with a rigid polymer backbone.

The synthesis of star-shaped adamantane multipodes with rigid branches based on p-hydroxybenzoic acid is reported. These multipodes are able to crystallize but can also be obtained in the glassy state. They are soluble in various low molar mass organic solvents, in fact, much better than linear rigid molecules of similar length, and they are miscible in polymer matrices up to concentrations of 30 wt%. The multipodes were found to influence the dielectric and mechanical properties of the polymers significantly.

The anionic polymerization of butyl acrylate initiated with a system consisting of the P-4-tert-butyl base and isobutyric acid methyl ester was investigated. The major fraction of the polymer contains a butoxy endgroup. The role of the non-coordinated butanolate in initiating the polymerization reaction, its probable formation, and consequences effecting the polymerization are discussed. NMR investigation reveals that 5% of the isobutyric acid methyl ester are deprotonated by the P-4-tert-butyl base in the equilibrium state at -50 degrees C whereas 11% of the acetic acid ethyl ester are deprotonated. The formation of block copolymers is observed on sequential addition of butyl acrylate and methyl methacrylate.

The vinylic polymerization of bicyclo[2.2.1]hept-2-ene (norbornene) with Co(II) compounds, such as Co(II) stearate, substituted bis(1,3-diketo)cobalt(II), Co(dppe)Cl2, and the metallocene [η5-(C5Me5)Co-η2-Cl]2, in chlorobenzene activated with methylaluminoxane (MAO) is reported. MAO* synthesized by the hydrolysis of trimethylaluminium in chlorobenzene instead of toluene increases the catalytical activity strongly, and a turn over of 2.7 tons of poly(2,3-bicyclo[2.2.1]hept-2-ene) per mol cobalt per hour was achieved. The polymers obtained are amorphous (WAXS). They show weight-average molecular weights up to M̄w = 1.5 · 106 and are soluble in chlorobenzene, 1,2-dichlorobenzene, cyclohexane, and decahydronaphthalene.

The polymerization of bicyclo[2.2.1]hept-2-ene (norbornene) with the catalysts bis(benzoylacetonato)cobalt(II) and bis-(trifluoroacetylacetonato)cobalt(II) activated with methylalumoxane in toluene (MAO) or in chlorobenzene (MAO*) in the presence of ethene was investigated. MAO* results in catalysts with much higher activity than with MAO. The reaction results in low molecular weight poly(2,3-bicyclo[2.2.1]hept-2-ene) macromonomers terminated with a vinylic end group due to β-hydride elimination after insertion of an ethene monomer unit. No copolymers were formed. The molecular weight (Mn = 1100—6000 g/mol) and the glass transition temperature (Tg = 75—2608C) of the macromonomers depend on the ethene pressure.

Amphiphilic poly(ethyleneimine)s prepared by modification with long-chain alkyl halides are described. The amphiphilic range of the polymers can be influenced directly by the degree of alkylation, the n-alkyl chain length and the molecular weight of the poly(ethyleneimine) and indirectly by using additives. The wide range of stabilization properties of the alkylated poly(ethyleneimine)s was demonstrated by microemulsion polymerization of styrene and preparing gold colloids.

Oxidative addition to a metal in a low valent state produces catalysts that allow reporter or functional groups to be introduced to a polymer chain end. Substituted allyltrifluoroacetates were added to Ni(0)(COD)(2). The resulting pi-allyl-Ni trifluoroacetates are dimeric in the solid state as well as in solution. The crystal structure of bis[(eta(3)-2-phenylallyl)(trifluoroacetato)-nickel(II)], bis[(eta(3)-2-trimethylsilylallyl)(trifluoroacetato)nickel(II)], and bis[(eta(3)-3-phenylallyl)(trifluoroacetato)nickel(II)] are given and correlated with the reactivity as polymerization catalysts. Butadiene, styrene, and norbornene are used as monomers. The substituent of the allyl group is found quantitatively to be the end group of each macromolecule. Thus it Is demonstrated that no chain transfer occurs.

Considered are chain molecules characterized by rotational potentials with a set of low energy states separated by large energy barriers. The expectation is that such chain molecules should exhibit unique properties. Polynorbornene and laterally substituted polynorbornenes are characteristic examples. Simulations based on ab initio methods, semiempirical quantum mechanical methods, and force field methods are employed in order to derive information on the chain conformation and dynamics of the polynorbornenes. The finding is that they display a random rigid coil with a characteristic ratio of the order of 10, that they are not able to collapse even in poor solvents, and that isolated chains are rigid up to temperatures well above room temperature. Details of the rotational potential can be controlled by a proper selection of lateral substituents.

The regioselectivity of Pd-catalyzed coupling reactions of functionalized benzenes and olefins with respect to the ratio of 1.2-product/1.1-product was monitored by model reactions. The coupling of halobenzenes, benzene triflate, and aryldiazonium salts was studied under various reaction conditions. In order to simulate corresponding polyreactions, special focus was on the coupling of ortho-substituted functionalized benzenes with ethylene or styrene in order to evaluate the input of mono- and disubstituted aryl monomers and the choice of the olefin on the regioselectivity of polyreactions. The results of the model reactions were transferred to the polyreactions. The polymers were characterized by NMR, absorption and photoluminescence spectroscopy as well as electroluminescence.

Colloidal dispersions of nanometer sized palladium colloids with very high stability were prepared in block copolymer micelles of polystyrene-b-poly-4-vinylpyridine and analyzed by electron microscopy and X-ray analysis. The resulting polymer/metal hybrids can easily be dissolved and handled in standard organic solvents such as toluene, tetrahydrofuran, and cyclohexane. They were successfully used for the Pd-catalyzed carbon(-) carbon coupling of aryl halides with alkenes (Heck reaction). Such block copolymer stabilized palladium colloids exhibit about the same reactivity as low molecular weight Pd complexes classically used for the Heck reaction, but show a much higher stability: in most reactions, the hybrids remain catalytically active even after 50000 turn-over cycles, Reaction rates were significantly controlled by the reactivity of the educts, but also respond to micelle architecture and dispersity of the palladium. Other advantages of the block copolymer stabilizer are that they are more simple and readily accessible than the phosphor-containing chelates, and that they dissolve even in ''simple'' solvents such as toluene (instead of amidic solvents).

Bilayer light-emitting diodes have been fabricated by combining hole-transporting tri-stilbeneamine or poly[(2,5-bis((2-ethylhexyl)oxy)-1,4-phenylene)vinylene] (EH-PPV) with new electron-transporting polystyrene copolymer carrying tert-butyl or CF3-substituted quaterphenyl substituents as charge-transporting moieties. The latter are resistent against recrystallization and favor internal charge accumulation by virtue of low-lying HOMO and LUMO positions. When LEDs with interfacial electron barriers greater than or equal to 0.5 eV are addressed by a rectangular voltage pulse, a step-function-like onset of the electroluminescence is observed after an extended delay time that depends on the time period between successive voltage pulses. It reflects the commencement of electron tunneling once the interfacial charge density has reached a critical value. The experimental results are in accordance with model calculations.

The vinylic polymerization of 5-norbornene-2-carboxylic esters with different palladium catalysts to polymers of high molecular weights is reported. Computer simulations based on a force field approach show that these polymers display a rigid statistical chain conformation and are thus a further example of rotationally strongly constrained polymers. The polymers are soluble in a variety of solvents despite their rigidity, they are amorphous, possess glass transition temperatures well above 250 degrees C, and have a high packing density. The dipoles located in the lateral groups perform a secondary relaxation process similar to the case of flexible or rigid rod-like polymers containing ester groups.