Mechanism of Nitrogen-Containing Cyclic Polymerization

Abstract

The comprehensive polymerization mechanism of the nitrogen-containing cycles 1-azobicyclo (3,1,0)-hexane (ABH), conidine, quinuclidine, and triethylenediamine under the action of quaternary ammonium salts, ammonium salts, and BF₃ complex with conidine is studied. Polymerization is of the living polymers type, and the active centers of monomer polymerization are ions and ion pairs: the activity of the latter is comparable to and exceeds that of the free ions. The effects of the nature of the counterion, cation, and medium polarity on the reaction rate are investigated. The polymerization rate is found to depend on the nature of the counterion in the polymerization of ion pairs, but not to depend on the counterion in the polymerization of free ions. The reaction rate is proportional to the counterion size in the polymerization of ion pairs. In the case of conidine K₊ = 0.2, K_±(Cl^?) = 0.28, K_±(Br^?) = 0.36, K_±(I^?) = 0.51, and K_±(ClO₄ ^?) = 0.62 (liter)/(mole)(min). The heats of nitrogen-cyclic polymerization are measured and correlated with the activation energy.     

Radiation-Induced Polymerization of Urea Canal Complex. Part 4. Radiation-Induced Polymerization of Acrylonitrile in Urea-Ethylene Glycol Supercooled Liquid System

Abstract

Using elementary analysis, NMR on ^{3 1}P and ¹H nuclei, and electroconductivity methods, the acrylonitrile, methacrylonitrile, formaldehyde, and β-propiolactone anionic polymerization in the presence of triethylphosphine is shown to follow the macrozwitterion mechanism: quartary phosphonium being on one end of a polymer chain and the growing anion on the other. The number of covalent bonds through the whole polymer chain between charges forming the active center increases with the propagation reaction. The active centers stationary concentration in the system is low when connected with both the slow initiation reaction and with the fast active centers termination reaction. Thus the ion interaction of different growing polymer chains can be ignored. The active centers parts occurring in the form of ion pairs (the ends are near and form the “cyclic”) and of free ions (the ends are separated) are determined by the monomolecular equilibrium, and its constant depends upon the macro-zwitterion polymerization degree K_d ⁽ⁿ⁾ = K_d ^(I)n^3/2. Such constant depends upon the chain length affords the macrozwitterion self-accelerated propagation with its length, as the free ion reactivity is more than that of ion pairs. The self-accelerated chain propagation effect shows up as an increase of polymerization initial rate order and polymer molecular weight in the monomer concentration. This effect can be avoided by the introduction of electrolyte into the system, which dissociates into ions and transforms all cyclic ion pairs into the linear form, the latter dissociating independently of chain length. The strict mathematical analysis of stationary and nonstationary polymerization kinetics made it possible to determine all the elementary constants separately: K_i = 5.6 × 10^?4 liters/ (mole) (min); K_- = 2.5 × 10⁴ liter/ (mole) (min); K_± = 2.0 liters/ (mole) (min); K_t = 0.84/min; K_t ¹ = 4/min; K_d ^(I) = 10^?4; K₃ = 0.07 × 10^?4 mole/liter.     

Photoinitiated free radical polymerization of vinyl compounds in aqueous solution

A new method for the photochemical initiation of polymerization of vinyl compounds in aqueous solution is described. The photochemically active species is an ion pair complex of the formula Fe³⁺X⁻(X⁻ = OH⁻, CI⁻, N⁻₃, etc.). The light absorption by the ion pair leads to an electron transfer causing reduction of the cation and oxidation of the anion to an atom or free radical X. The latter leads to the initiation of polymerization in accordance with X + CH₂CHR→XCH₂ CHR . The kinetics of the reaction were studied by the measurement of: (a) ferrous ion formed (colorimetrically), (b) monomer disappearance (by titration and by weighting the polymer), (c) the chain length of the polymer (in the case of methyl methacrylate). The dependence of the quantum yield on the light intensity, light absorption fraction, and the concentration of vinyl monomer and ferrous ion added initially was investigated. A complete mechanism, both with regard to the formation of free radicals and the polymerization reaction, was put forward involving: (1) light absorption, (2) a primary dark back reaction, (3) dissociation of the primary product, (4) a secondary dark back reaction, (5) initiation of polymerization by free radicals, (6) propagation of polymerization, and (7) termination by recombination of active polymer endings. The mechanism was verified by the experimental results and some constant ratios were estimated quantitatively.     

Synthesis and characterization of novel neutral nickel complexes bearing fluorinated salicylaldiminato ligands and their catalytic behavior for vinylic polymerization of norbornene

A series of salicylaldimine‐based neutral Ni(II) complexes (3a–j) [ArN = CH(C₆H₄O)]Ni(PPh₃)Ph [3a, Ar = C₆H₅; 3b, Ar = C₆H₄F(o); 3c, Ar = C₆H₄F(m); 3d, Ar = C₆H₄F(p); 3e, Ar = C₆H₃F₂(2,4); 3f, Ar = C₆H₃F₂(2,5); 3g, Ar = C₆H₃F₂(2,6); 3h, Ar = C₆H₃F₂(3,5); 3i, Ar = C₆H₂F₃(3,4,5); 3j, Ar = C₆F₅] have been synthesized in good yield, and the structures of complexes 3a and 3i have been confirmed by X‐ray crystallographic analysis. Using modified methylaluminoxane as a cocatalyst, these neutral Ni(II) complexes exhibited high catalytic activities for the vinylic polymerization of norbornene. It was observed that the strong electron‐withdrawing effect of the fluorinated salicylaldiminato ligand was able to significantly increase the catalyst activity for vinylic polymerization of norbornenes. In addition, catalyst activity, polymer yield and polymer molecular weight can also be controlled over a wide range by the variation of reaction parameters such as Al:Ni ratio, norbornene:catalyst ratio, monomer concentration, polymerization temperature and time. Copyright © 2008 John Wiley & Sons, Ltd.     

Cationic polymerization of 1,4,6-trioxaspiro [4,4]-nonane

Cationic polymerization of 1,4,6-trioxaspiro [4,4]-nonane ( 1 ) with (CH₃)₃O⁺SbF₆^?(2) and CH₃OSO₂CF₃(3) initiators has been investigated. Although the observed rates of initiation and propagation are relatively slow, they consist of rapid reversible elementary reactions. In ¹H-NMR spectra, a broadening of the monomer signal was observed, indicating a fast exchange between “free” monomer and monomer engaged in the active species. The variety of orthoester bonds were observed in the polymer formed at the early stages of monomer conversion. The final polymer has, however, structure of a linear poly(ester–ether) including two subsequent ester or ether linkages. To account for these new facts, the mechanism of polymerization was proposed, consisting of a rapid reversible opening of one of the rings in the monomer molecule involved in the growing species, followed by the slower opening of the second ring with formation of the ester linkages. It appears that the rings originally present in the chains rearrange into the linear units intramolecularly.     

Equilibrium anionic polymerization of the isopropenyl monomers containing aromatic heterocycles

The anionic polymerization of three monomers, 2-isopropenyl-4,5-dimethyloxazole(I), 2-isopropenylthiazole(II), and 2-isopropenylpyridine(III), was studied in THF. These monomers produced red-colored living polymers on addition of sodium naphthalene or living α-methylstyrene tetramer as an initiator. It was observed that a considerable amount of monomer remained in the respective living polymer–monomer system, indicating that an equilibrium between the polymer and the monomer existed as in the case of α-methylstyrene. At lower temperatures, the conversion of the monomer to the polymer increased. The equilibrium monomer concentrations [M_e] were determined at different temperatures, and the heats (ΔH) and the entropies (ΔS°) of polymerization were obtained by plotting In(1/[M_e]) against 1/T as ΔH = ?9.4, ?6.8, and ?6.2 kcal/mole, ΔS°S = ?22.9, ?16.5, and ?16.6, eu for I, II, and III, respectively.     

Syndiospecific living polymerization of 4-methylstyrene with (trimethyl)pentamethylcyclopentadienyltitanium/tris(pentafluorophenyl)borane/trioctylaluminium catalytic system

The polymerization of 4-methylstyrene with the (trimethyl)pentamethylcyclopentadienyltitanium (Cp*TiMe₃)/tris(pentafluorophenyl)borane (B(C₆F₅)₃)/trioctylaluminium (AlOct₃) catalytic system at –20°C was carried out. The number-average molecular weight (M_n) of the polymers increased linearly with increasing monomer conversion. The propagating chain ends were successfully reacted with tert-butyl isocyanate, and the M_n of the polymer determined by ¹H NMR was in good agreement with the M_n determined by GPC measurement. It is concluded that this catalytic system promoted the syndiospecific living polymerization of 4-methylstyrene.     

Electronic excitation in anionic polymerization of butadiene: Nonempirical calculations of reaction complexes

A new mechanism of anionic polymerization of butadiene is proposed. In the elementary chemical act, the “living” polymer–monomer complex is excited into the low‐lying triplet state. This state has the character of charge (electron) and cation (Li⁺ or Na⁺) transfer from the terminal unit of the active center to the monomer molecule. In the framework of this concept, the probability of chemical bond formation is determined by spin density on radical centers of reagent molecules. Semiempirical and ab initio 6‐31G** quantum‐chemical calculations showed stable interaction between components of the complex in the ground electronic state (9–11 kcal/mol) and low energy levels of triplet excited states (<14 kcal/mol). This new approach is shown to be useful in the analysis of polymerization kinetics and the microstructure of polybutadiene depending on the cation type and the ion pair state. The mechanism of cis‐trans isomerization in the terminal unit of the living polymer consists in concerted rotation about the C_β? C_γ bond and the migration of Li between C_α and C_γ atoms. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002     

Some aspects of plasma polymerization of fluorine-containing organic compounds. II. Comparison of ethylene and tetrafluoroethylene

Plasma polymerizations of ethylene and tetrafluoroethylene are compared. In the plasma polymerization of ethylene and of tetrafluoroethylene, glow characteristics play an important role. Glow characteristic is dependent on a combined factor of W/F_m, where W is discharge power and F_m is monomer flow rate. At higher flow rates, higher wattages are required to maintain “full glow.” In the plasma polymerization of tetrafluoroethylene, simultaneous decomposition of the monomer competes with plasma polymerization. Above a certain value of W/F_m, decomposition becomes the predominant reaction, and the polymer deposition rate decreases with increasing discharge power. ESCA results indicate that the plasma polymer of tetrafluoroethylene that is formed in an incomplete glow region (low W/F_m) is a hybrid of polymers of plasma polymerization and of plasma-induced polymerization of the monomer. Polymers formed under conditions of high W/F_m to produce “full glow” are similar, regardless of the extent of decomposition of the monomer. They contain carbons with different numbers of F(CF₃, ? CF₂? , >CF? , >C<) and carbons bonded to other more electronegative substituents.     

Living cationic polymerization of vinyl ethers with carboxylic acid/tin tetrahalide initiating systems. I. New initiating systems based on acetic acid and selection of Lewis acid and basic additive leading to living polymers with low polydispersity

Cationic polymerization of isobutyl vinyl ether (IBVE) with acetic acid (CH₃COOH)/tin tetrahalide (SnX₄: X = Cl, Br, I) initiating systems in toluene solvent at 0°C was investigated, and the reaction conditions for living polymerization of IBVE with the new initiating systems were established. Among these tin tetrahalides, SnBr₄ was found to be the most suitable Lewis acid to obtain living poly(IBVE) with a narrow molecular weight distribution (MWD). The polymerization with the CH₃COOH/SnBr₄ system, however, was accompanied with the formation of a small amount of another polymer fraction of very broad MWD, probably due to the occurrence of an uncontrolled initiation by SnBr₄ coupled with protonic impurity. Addition of 1,4-dioxane (1–1.25 vol %) or 2,6-di-tert-butylpyridine (0.1–0.6mM) to the polymerization mixture completely eliminated the uncontrolled polymer to give only the living polymer with very narrow MWD (M _w/M _n ≤ 1.1; M _w, weight-average molecular weight; M _n, number-average molecular weight). The M _n of the polymers increased in direct proportion to monomer conversion, continued to increase upon sequential addition of a fresh monomer feed, and was in good agreement with the calculated values assuming that one CH₃COOH molecule formed one polymer chain. Along with these results, kinetic study and direct ¹H-NMR observation of the living polymerization indicated that CH₃COOH and SnBr₄ act as so-called “initiator” and “activator”, respectively, and the living polymerization proceeds via an activation of the acetate dormant species. The basic additives such as 1,4-dioxane and 2,6-di-tert-butylpyridine would serve mainly as a “suppressor” of the uncontrolled initiation by SnBr₄. The polymers produced after quenching the living polymerization with methanol possessed the acetate dormant terminal and they induced living polymerization of IBVE in conjunction with SnBr₄ in the presence of 1,4-dioxane. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 3173–3185, 1998     

Synthesis of homopolymers and multiblock copolymers by the living ring‐opening metathesis polymerization of norbornenes containing acetyl‐protected carbohydrates with well‐defined ruthenium and molybdenum initiators

The ring‐opening metathesis polymerization (ROMP) of norbornenes containing acetyl‐protected glucose [2,3,4,6‐tetra‐O‐acetyl‐glucos‐1‐O‐yl 5‐norbornene‐2‐carboxylate ( 1 )] and maltose [2,3,6,2′,3′,4′,6′‐hepta‐O‐acetyl‐maltos‐1‐O‐yl 5‐norbornene‐2‐carboxylate ( 2 )] was explored in the presence of Mo(N‐2,6‐ⁱPr₂C₆H₃)(CHCMe₂Ph)(O^tBu)₂ ( A ), Ru(CHPh)(Cl)₂(PCy₃)₂ ( B ; Cy = cyclohexyl), and Ru(CHPh)(Cl)₂(IMesH₂)(PCy₃) ( C ; IMesH₂ = 1,3‐dimesityl‐4,5‐dihydromidazol‐2‐ylidene). The polymerizations promoted by B and A proceeded in a living fashion with exclusive initiation efficiency, and the resultant polymers possessed number‐average molecular weights that were very close to those calculated on the basis of the monomer/initiator molar ratios and narrow molecular weight distributions (weight‐average molecular weight/number‐average molecular weight < 1.18) in all cases. The observed catalytic activity of B was strongly dependent on both the initial monomer concentration and the solvent employed, whereas the polymerization initiated with A was completed efficiently even at low initial monomer concentrations. The polymerization with C also took place efficiently, and even the polymerization with 1000 equiv of 1 was completed within 2 h. First‐order relationships between the propagation rates and the monomer concentrations were observed for all the polymerization runs, and the estimated rate constants at 25 °C increased in the following order: A > C > B . On the basis of these results, we concluded that ROMP with A was more suitable than ROMP with B or C for the efficient and precise preparation of polymers containing carbohydrates. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4248–4265, 2004     

Living cationic polymerization of vinyl ethers by electrophile/lewis acid initiating systems. XII. Phosphoric and phosphinic acids/zinc chloride initiating systems for isobutyl vinyl ether

Phosphoric and phosphinic acid derivatives (R¹R²PO₂H; R¹, R² = OPh, OPh; OnBu, OnBu; Ph, Ph; Ph, H) in conjunction with zinc chloride (ZnCl₂) led to living cationic polymerization of isobutyl vinyl ether (IBVE) in toluene below 0°C. The number-average molecular weights (M?_n) of the polymers (M?_n > 2 × 10⁴) were directly proportional to monomer conversion and in excellent agreement with the calculated values assuming that one polymer chain forms per R¹R²PO₂H molecule. Throughout the reaction, the molecular weight distributions (MWDs) stayed narrow (M?_w/M?_n ? 1.1). A dibasic acid, PhOP (O) (OH)₂, coupled with ZnCl₂, also induced living cationic polymerization of IBVE where one molecule of the acid generated two living polymer chains. The polymerization by (PhO)₂PO₂H/ZnCl₂ and its model reactions were directly analyzed by ³¹P and ¹H-NMR spectroscopy. The analysis showed that the acid initially forms the adduct [CH₃CH(OiBu)OP(O)(OPh)₂], the phosphate linkage of which is in turn activated by ZnCl₂ so as to initiate living propagation. The finding thus indicates that (PhO)₂PO₂H indeed acts as an initiator in the living polymerization. The NMR analysis also suggested that an exchange reaction occurs between the phosphate group at the polymer terminal and the chlorine in ZnCl₂. The occurrence of living IBVE polymerization with these various R¹R²PO₂H/ZnCl₂ systems shows that phosphoric and phosphinic acids are another general class of protonic acids which are effective initiators for the living cationic polymerization assisted by Lewis acids. © 1993 John Wiley & Sons, Inc.     

ROMP of t-butyl-substituted ferrocenophanes affords soluble conjugated polymers that contain ferrocene moieties in the backbone

A substituted ferrocenophane, 1,1′-((1-tert-butyl)-1,3-butadienylene)ferrocene, was synthesized and polymerized via ring-opening metathesis polymerization (ROMP) to give soluble high molecular weight polymers with ferrocenylene units in the backbone. The monomer readily underwent polymerization upon exposure to a tungsten-based metathesis initiator, W(CHC₆H₄-o-OMe)(NPh)[OCMe(CF₃)₂]₂ (THF), to give high molecular weight polymers (M_w=ca. 300,000). The molecular weights could be varied systematically by adjusting the monomer-to-catalyst ratio. UV/vis spectra revealed a bathochromic shift for the polymer, consistent with enhanced conjugation compared to the monomer. The polymer exhibited thermal properties similar to oligomeric poly(ferrocenylene). Cyclic voltammetry of the polymer suggested that the iron centers are coupled electronically. Upon doping with I₂ vapor, the polymers displayed semiconducting properties (σ=10⁻⁵ S cm⁻¹). Theoretical calculations were used to evaluate the nature of the bonding in these and related polymers.     

Emulsifier-free emulsion polymerization of tetrafluoroethylene by radiation. II. Effects of reaction conditions on polymer particle size and number

The size, distribution, and number of PTFE particles formed by radiation-induced emulsifier-free polymerization were measured by electron microscope and automatic particle analyzer (centrifugation method). From the electron micrographs we found that the particles are formed within 5 min. The change in the number of polymer particles (n_p) with reaction time (t) depends on the relative concentration of growing polymer chains to stabilizing species produced by the radiolysis of water and monomer; that is, it was governed by TFE pressure/dose rate ratio and classified into three cases: case I, dn_p/dt = 0 (e.g., at 3 × 10⁴ rad/hr and 20 kg/cm²); case II, dn_p/dt < 0 (e.g., at dose rate below 1.9 × 10⁴ rad/hr and 20 kg/cm²); case III, dn_p/dt > 0 (e.g., at 3 × 10⁴ rad/hr and 2 kg/cm²). The polymer molecular weight above 10⁶ is almost independent of the particle size. The polymerization loci are mainly on the surface of polymer particles dispersed in the aqueous phase in cases I and II except in the initial stage. In case III new particles are formed successively during polymerization. Therefore the polymerization loci are mainly in the aqueous phase. Especially in case I, we concluded that after the generation of particles the propagation proceeds mainly on the surface of polymer particles like the core shell model proposed by Granico and Williams.     

Kinetic study on the living/controlled cationic polymerization of p‐methoxystyrene coinitiated by tris(pentafluorophenyl)borane

A kinetic study of the living cationic polymerization of p‐methoxystyrene using 1‐(4‐methoxyphenyl)ethanol ( 1 )/B(C₆F₅)₃ initiating system in a mixture of CH₃CN with CH₂Cl₂ 1:1 (v/v) at room temperature was carried out utilizing a wide variety of conditions. The polymerization proceeded in a living fashion even in the presence of a large amount of water ([H₂O]/[B(C₆F₅)₃] ratio up to 20) to afford polymers whose M_n increased in direct proportion to monomer conversion with fairly narrow MWDs (M_w/M_n ≤ 1.3). The investigation revealed that the rate of polymerization was first‐order in B(C₆F₅)₃ concentration, while a negative order in H₂O concentration close to ?2 was obtained. It was also found that the rate of polymerization decreased with lowering temperature, which could be attributed to a decreased concentration in free Lewis acid, the true coinitiator of polymerization. A mechanistic scheme to explain the kinetic behavior of living p‐methoxystyrene polymerization is proposed, which has been validated by PREDICI simulation on multiple‐data curves obtained by ¹H NMR in situ polymerization experiment. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6928–6939, 2008     

SYNTHESIS AND POLYMERIZATION OF ALIPHATIC TERTIARY AMINO-GROUP N-SUBSTITUTED ACRYLAMIDES

Aliphatic tertiary amino-group N-substituted acrylamides, N-acryl-N′-methylpiperazine (AMP)and N-methacryl-N′-methylpiperazine (MAMP) were synthesized directly from N-methylpiperazinewith corresponding acryloyl chlorides and characterized by elementary analysis of their picrates,~1H-NMR, IR and MS. AMP did not polymerize with benzoyl peroxide (BPO), but could poly-merize with lauroyl peroxide (LPO). The rate equation of the polymerization was given as R_P=K_P [AMP]~(1.5)[LPO]~(0.5) and the overall activation energy of this polymerization system was 10.8Kcal/mol. The redox nature of LPO with the monomer itself was suggested. Even though AMP and MAMP hardly proceed the polymerization initiated with BPO, butunder lower concentration would form redox system with BPO to initiate the polymerization of MMAreadily. The rate equation of the polymerization of MMA initiated with MAMP-BPO systemwas given as R_P=K_P [MMA] [MAMP}~(0.5) [BPO]~(0.5) and the overall activation energy was 10.2Kcal/mol. The analysis of the obtained polymers confirmed that MAMP not only initiated the poly-merization of MMA by combining with BPO, but also took part in the polymer chains impartingthem with better biocompatibility.     

Dynamic analysis of branching in radical polymerization

A method for the theoretical analysis of branching in radical polymerization is presented which includes the dynamics of the process. In particular, the method is applied to a polymerization that occurs by decomposition of initiator, propagation, termination by radical combination, and chain transfer with polymer. By a numerical solution of the kinetic equations (suitably transformed), the time dependence of the number-average degree of polymerization (DP), the weight-average DP, the mean number of branches, and the monomer conversion are obtained. The parameters of the process, that is the rate coefficients and initial concentrations, have the following effects: (1) An increase in the chain transfer coefficient increases the ratio of weight-average to number-average X_w/X_n and the mean number of branches X_b, but does not change the number-average X_n. (2) For a given value of the chain transfer coefficient, a change in the parameters of the process such that X_n increases, causes X_w/X_n and X_b to increase also. (3) Chain transfer with polymer seems to produce relatively few polymer molecules having many branches and a large number of smaller polymer molecules having no branches; consequently, the polymer size (or molecular weight) distribution broadens.     

Electroreductive polymerization of trans-[RuCl 2(vpy) 4] on Nd-Fe-B magnets: electrochemical impedance spectroscopy interpretation, Raman spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscopy analysis

The electropolymerization of trans-[RuCl₂(vpy)₄] (vpy=4-vinylpyridine) monomer on Nd-Fe-B magnets was studied by electrochemical impedance spectroscopy (EIS). Impedance diagrams obtained during the polymerization process were used to monitor film formation. The EIS results gave insight into the electrochemical phenomena occurring at the magnet surface as the polymerization process progressed. The film structure and morphology were also studied by X-ray photoelectron spectroscopy, scanning electron microscopy and Raman spectroscopy. The Raman spectroscopy results showed that the polymerization takes place at the vinyl groups of the monomer and also that the redox polymer structure is very similar to that of the monomer. The ratio of the intensity of the XPS peaks for fluorine (from the electrolyte PF₆ ^–) and ruthenium present in the film showed that the polymer on Nd-Fe-B contained an equal proportion of Ru²⁺ and Ru³⁺, indicating that part of the film is positively charged, i.e. {[RuCl₂(vpy)₄]⁺} _n .     

Living radical polymerization. II. Improved atom transfer radical polymerization of acrylamide in aqueous glycerol media with a novel pentamethyldiethylenetriamine‐based soluble copper(I) complex catalyst system

An improved atom transfer radical polymerization (ATRP) of acrylamide was achieved in a glycerol/water (1:1 v/v) medium with 2‐halopropionamide initiators, CuX (X = Cl or Br) as catalysts, pentamethyldiethylenetriamine (PMDETA) as a ligand, and CuX₂ (≥20 mol % CuX) and excess alkali halide (ca. 1 mol/dm³) as additives. The first‐order kinetic plots for the disappearance of the monomer at 130 °C were linear; this was a significant improvement over the results obtained earlier with the bipyridine ligand. However, even under such improved situations, about 7 mol % of the polymer chains were estimated to be formed dead. The polydispersity index was approximately 1.5. At a lower temperature (ca. 90 °C), a lower polydispersity index (1.24) was obtained for the bromide‐based initiating system. Chain‐extension experiments proved the living nature of the polymers. The presence of both extra halide ions and the monomer was necessary to take the CuX–PMDETA complex into solution. It was suggested that the soluble Cu(I) complex was formed with one PMDETA molecule acting as a monodentate ligand and with two halide ions and one acrylamide molecule occupying the other three coordination sites. Some support for the involvement of all three ligands (X^?, PMDETA, and acrylamide) in the complex formation was obtained from ultraviolet–visible spectroscopy studies. The better ATRP with the PMDETA ligand was attributed to the better stability and lesser hydrolysis of the 1:1 Cu⁺²/PMDETA complex with respect the corresponding bipyridine complex. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2483–2494, 2004     

Preparation and characterization of solution processable phthalocyanine‐containing polymers via a combination of RAFT polymerization and post‐polymerization modification techniques

In this work, a benzenedinitrile functionalized monomer, 2‐methyl‐acrylic acid 6‐(3,4‐dicyano‐phenoxy)‐hexyl ester, was successfully polymerized via the reversible addition‐fragmentation chain transfer method. The polymerization behavior conveyed the characteristics of “living”/controlled radical polymerization: the first‐order kinetics, linear increase of number‐average molecular weight with monomer conversion, narrow molecular weight distribution, and successful chain‐extension experiment. The soluble Zn(II) phthalocyanine (Pc)‐containing (ZnPc) polymers were achieved by post‐polymerization modification of the obtained polymers. The Zn(II) phthalocyanine‐functionalized polymer was characterized by FTIR, UV–vis, fluorescence, atomic absorption spectroscopy, and thermogravimetric analysis. The potential application of above ZnPc‐functionalized polymer as electron donor material in bulk heterojunction organic solar cell was studied. The device with ITO/PEDOT:PSS/ZnPc‐Polymer/PC₆₁BM/LiF/Al structure provided a power conversion efficiency of 0.014%, fill factor of 0.24, open circuit voltage (V_oc) of 0.21 V, and short‐circuit current (J_sc) of 0.28 mA/cm². © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 691–698