Kinetic study of the Ce(III)‐, Mn(II)‐ or Fe(phen)32+‐catalyzed Belousov‐Zhabotinsky reaction with 2‐ketoglutaric acid

The Belousov‐Zhabotinsky (BZ) reaction of bromate ion with 2‐ketoglutaric acid (KGA) in aqueous sulfuric acid catalyzed by Ce(III), Mn(II), or Fe(phen)₃²⁺ ion exhibits sustained barely damped oscillations under aerobic conditions. In general, the reaction oscillates without an induction period. Fe(phen)₃²⁺ ion behaves differently from Ce(III) and Mn(II) ions in catalyzing this oscillating system. The gem‐diol form of KGA exhibits different behavior from that of the keto form of KGA in the BZ reaction. The kinetics and mechanism of the reaction of KGA with Ce(IV), Mn(III), or Fe(phen)₃³⁺ ion was investigated. The order of relative reactivities of metal ions toward reaction with KGA is Mn(III) > Ce(IV) ≫ Fe(phen)₃³⁺. Experimental results are rationalized. © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 33: 101–107, 2001     

Kinetic study of the Ce(III)‐, Mn(II)‐, or ferroin‐catalyzed Belousov‐Zhabotinsky reaction with pyruvic acid

The Ce(III)‐, Mn(II)‐, or ferroin (Fe(phen)₃²⁺)‐catalyzed reaction of bromate ion and pyruvic acid (PA) or its dimer exhibits oscillatory behavior. Both the open‐chain dimer (parapyruvic acid, γ‐methyl‐γ‐hydroxyl‐α‐keto‐glutaric acid, DPA1) and the cyclic‐form dimer (α‐keto‐γ‐valerolactone‐γ‐carboxylic acid, DPA2) show more sustained oscillations than PA monomer. Ferroin behaves differently from Ce(III) or Mn(II) ion in catalyzing these oscillating systems. The kinetics of reactions of PA, 3‐brompyruvic acid (BrPA), DPA1, or DPA2 with Ce(IV), Mn(III), Fe(phen)₃³⁺ ion were investigated. The order of relative reactivity of pyruvic acids toward reaction with Ce(IV), Mn(III), or Fe(phen)₃³⁺ ion is DPA2 > DPA1 > BrPA > PA and that of metal ions toward reaction with pyruvic acids is Mn(III) > Ce(IV) > Fe(phen)₃³⁺. The rates of bromination reactions of pyruvic acids are independent of the concentration of bromine and the order of reactivity toward bromination is (DPA1, DPA2) > BrPA > PA. Experimental results are rationalized. © 2000 John Wiley & Sons, Inc. Int J Chem Kinet 32: 408–418, 2000     

Kinetic Study of the Ce(III)‐, Mn(II)‐, or Ferroin‐Catalyzed Belousov‐Zhabotinsky Reaction with Allylmalonic Acid

In a stirred batch experiment and under aerobic conditions, ferroin (Fe(phen)₃²⁺) behaves differently from Ce(III) or Mn(II) ion as a catalyst for the Belousov‐Zhabotinsky (BZ) reaction with allylmalonic acid (AMA). The effects of bromate ion, AMA, metal‐ion catalyst, and sulfuric acid on the oscillating pattern were investigated. The kinetics of the reaction of AMA with Ce(IV), Mn(III), or Fe(phen)₃³⁺ ion was studied under aerobic or anaerobic conditions. The order of reactivity of metal ions toward reaction with AMA is Fe(phen)₃³⁺ > Mn(III) > Ce(IV) under aerobic conditions whereas it is Mn(III) > Ce(IV) > Fe(phen)₃³⁺ under anaerobic conditions. Under aerobic or anaerobic conditions, the order of reactivity of RCH(CO₂H)₂ (R = H (MA), Me (MeMA), Et (EtMA), allyl (AMA), n‐Bu (BuMA), Ph (PhMA), and Br (BrMA)) is PhMA > MA > BrMA > AMA > MeMA > EtMA > BuMA toward reaction with Ce(IV) ion and it is MA > PhMA > BrMA > MeMA > AMA > EtMA > BuMA toward reaction with Mn(III) ion. Under aerobic conditions, the order of reactivity of RCH(CO₂H)₂ toward reaction with Fe(phen)₃³⁺ ion is PhMA > BrMA > (MeMA, AMA) > (BuMA, EtMA) > MA. The experiment results are rationalized.     

Kinetic study of the Ce(iii)- or Mn(ii)-catalyzed Belousov–Zhabotinsky reactions with mixed organic acid/ketone substrates

In a stirred batch reactor, the Ce(III)- or Mn(II)-catalyzed Belousov–Zhabotinsky reaction with mixed organic acid/ketone substrates exhibits oscillatory behavior. The organic acids studied here are: dl-mandelic acid (MDA), dl-4-bromomandelic acid (BMDA), and dl-4-hydroxymandelic acid (HMDA), and the ketones are: acetone (Me₂CO), methyl ethyl ketone (MeCOEt), diethyl ketone (Et₂CO), acetophenone (MeCOPh), and cyclohexanone ((CH₂)₅CO). The effects of bromate ion, organic acid, ketone, metal-ion catalyst, and sulfuric acid concentrations on the oscillatory patterns are investigated. Both conventional and stopped-flow methods are applied to study the kinetics of the oxidation reactions of the above organic acids by Ce(IV) or Mn(III) ion. The order of relative reactivities of the oxidation reactions of organic acids in 1 M H₂SO₄ is Mn(III)(SINGLEBOND)HMDA reaction>Ce(IV)(SINGLEBOND)HMDA reaction>Mn(III)(SINGLEBOND)BMDA, reaction>Mn(III)(SINGLEBOND)MDA reaction>Ce(IV)(SINGLEBOND)BMDA reaction>Ce(IV)(SINGLEBOND)MDA reaction. Spectrophotometric study of the bromination reactions of the above ketones shows that these reactions are zero-order with respect to bromine and first-order with respect to ketone and that ketone enolization is the rate-determining step. The order of relative rates of bromination or enolization reactions of ketones in 1 M H₂SO₄ is (CH₂)₅CO≫(MeCOEt, Et₂CO, Me₂CO)>MeCOPh. © 1998 John Wiley & Sons, Inc. Int J Chem Kinet:30: 595–604, 1998     

Belousov–Zhabotinskii type oscillations with amino acids or peptides as organic substrates in the presence of Mn2+ and Fe(phen)32+ as coupled catalysts

Nine amino acids, aspartic acid, glycine, serine, tyrosine, alanine, glutamic acid, threonine, cystine, phenylalanine, and two peptides, and two peptides, glycine-glycine peptide, glutamic acid-cystine-glycine peptide, give rise to damped oscillations of the Belousov–Zhabotinskii(BZ) type in a batch reactor. Both Mn²⁺ and Fe(phen)₃² are essential for most of those oscillations; and the oscillations in [Mn³⁺] and [Fe(phen)₃³⁺] are also observed. The role of two metallic ions played in the oscillations are analyzed, showing that Mn²⁺ catalyzes the oxidation of the amino acids or peptides by BrO₃⁻ to produce some intermediates which effectively reduce Br₂ to Br⁻ catalyzed by Fe(phen)₃²⁺. © 1998 John Wiley & Sons, Inc. Int. J. Chem Kinet 30: 243–247, 1998.     

Fe(phen)32+‐Modified Zeolite Particles and Their Energetic Studies

Chemically modified zeolite Y (NaY) particles and their resulting modified electrodes were prepared with acridinium (AcH+), iron(II) and 1,10‐phenanthroline (phen) for energetic studies. According to diffuse reflectance absorption spectroscopy and cyclic voltammetry, AcH⁺ and Fe(phen)₃²⁺ were successfully entrapped in the zeolite particles. Transient emission spectra measurements showed that the life time of AcH+* in the zeolite particles (to 35 ns; λ_ex 365 nm; λ_em 500 nm) was greatly reduced upon incorporating Fe(phen)₃²⁺ and Fe²⁺. The fast de cay of AcH+*(NaY) suggested that a reductive quench was likely to take place in the zeolite particle. Probably due to a size‐exclusion effect, the bulky electron donor, N, N‐diethyl‐2‐methyl‐1,4‐phenylenediamine (DEPD), revealed a difficulty in reaching the photosensitizer, AcH⁺, in side the zeolite particle. As a consequence, the in significant photocurrent for the oxidation of DEPD was from the NaY|AcH⁺ electrode. However, if Fe²⁺ and Fe(phen)₃²⁺ were incorporated, the photocurrent would become more significant. Closer examinations, in addition, showed that the photooxidaton of DEPD occurred more rapidly on the NaY|AcH⁺|Fe(phen)₃²⁺ electrode, compared to the NaY|AcH⁺|Fe²⁺ electrode. This difference apparently results from a greater gap in energetics between DEPD and Fe(phen)₃³⁺_(NaY) than that between DEPD and Fe³⁺_(NaY). Due to this effect, a greater amount of indophenol blue, derived from the coupling reaction of the oxidized DEPD with 1‐naphthol, was formed and de posited on the NaY|AcH⁺|Fe(phen)₃²⁺modified electrode. Thanks to this photo‐induced charge‐transfer reaction, the NaY|AcH⁺|Fe(phen)₃²⁺ particle showed an application potential in image recording.     

Monomere und polymere Dimethylaminothioquadratato‐Komplexe: Die Kristallstrukturen von Nickel(II)‐, Cobalt(II)‐, Silber(I)‐, Platin(II)‐, Gold(I)‐, Quecksilber(II)‐ und Blei(II)‐Dimethylaminothioquadrataten

Monomeric and Polymeric Dimethylaminothiosquarato Complexes: The Crystal Structures of Nickel(II), Cobalt(II), Silver(I), Platinum(II), Gold(I), Mercury(II) and Lead(II) Dimethylaminothiosquarates The ligand 2‐dimethylamino‐3, 4‐dioxo‐cyclobut‐1‐en‐thiolate, Me₂N‐C₄O₂S⁻ (L) forms neutral and anionic complexes with nickel(II), cobalt(II)‐, silver(I)‐, platinum(II)‐, gold(I)‐, mercury(II)‐ and lead(II). According to the crystal structures of seven complexes the ligand is O, S‐chelating in [Ni(L)₂(H₂O)₂]·2 H₂O, [Co(L)₂(CH₃OH)₂] and (with limitations) in [Pb(L)₂·DMF]. In the remaining compounds the ligand behaves essentially as a thiolate ligand. The platinum, gold and mercury complexes [TMA]₂[Pt(L)₄], [TMA] [Au(L)₂] and [Hg(L)₂] are monomeric. In [TMA][Ag₂(L)₃]·5.5 H₂O a chain‐like structure was found. In the asymmetric unit of this structure eight silver ions, with mutual distances in the range 2.8949(4) to 3.1660(3)Å, are coordinated by twelve thiosquarato ligands. [Pb(L)₂·DMF] has also a polymeric structure. It contains a core of edge‐bridged, irregular PbS₄ polyhedra. TMA[Au(H₂NC₄O₂S)₂] has also been prepared and its structure elucidated.     

Kinetic study of ruthenium(VI)‐catalyzed oxidation of 2‐butanol by alkaline hexacyanoferrate(III)

The oxidation kinetics of 2‐butanol by alkaline hexacyanoferrate(III) catalyzed by sodium ruthenate has been studied spectrophotometrically. The initial rates method was used for kinetic analysis. The reaction rate shows a fractional‐order in [hexacyanoferrate(III)] and [substrate] and a first‐order dependence on [Ru(VI)]. The dependence on [OH⁻] is rather more complicated. The kinetic data suggest a reaction mechanism involving two active catalytic species. Each one of these species forms an intermediate complex with the substrate. The attack of these complexes by hexacyanoferrate(III), in a slow step, produces ruthenium(V) complexes which are oxidized in subsequent steps to regenerate the catalyst species. © 1999 John Wiley & Sons, Inc. Int J Chem Kinet 31: 1–9, 1999     

Salen-Mn（Ⅲ）-Complex-Catalyzed Oxidations of Secondary Alcohols

Secondary alcohols were catalytically oxidized with diace-toxyiodobenzene as oxidant in the presence of salen-Mn(Ⅲ)complex to aiTord the eorrespoltding ketones, in up to 99% yield, using CH2Cl2 or water as reaction media.     

Studies on oscillating chemical reaction in Cu(II)‐catalyzed thiocyanate–hydrogen peroxide–NaOH system using pulsating sensor

We present a novel measurement technique to study an oscillating chemical reaction using a new class of sensor, viz. a pulsating sensor developed in‐house. A halogen‐free oscillating chemical reaction in the Cu(II)‐catalyzed H₂O₂‐KSCN–NaOH system reported by Orban was chosen to examine the performance of this technique. Shift in potential during the oscillating reaction was captured online with high precision and excellent resolution using this simple but high‐performance pulsating potentiometric measurement technique. In this work, the influence of bath temperature and flow rate of reagents on the Cu(II)‐catalyzed H₂O₂–KSCN–NaOH oscillating chemical reaction is investigated to optimize the conditions for rapid oscillations. This, in turn, helps to evolve analyte pulse perturbation techniques for rapid assay of hydrazine, uranium(VI), and sodium thiosulfate in aqueous solutions using the above oscillating reaction. © 2012 Wiley Periodicals, Inc. Int J Chem Kinet 45: 19–29, 2013     

Kinetic study of the Ce(III)- or ferroin-catalyzed Belousov-Zhabotinsky reaction with ethyl- or butyl-malonic acid

In a stirred batch experiment, ferroin (Fe(phen)₃²⁺) behaves differently from Ce(III) as a catalyst for the Belousov-Zhabotinsky reaction with ethyl- or n-butyl-malonic acid (EtMA or BuMA) The effects of bromate ion, organic substrate, metal-ion catalyst, and sulfuric acid on the oscillating pattern were investigated. The kinetics of the reactions of methylmalonic acid (MeMA), bromomethyl-malonic acid (BrMeMA), EtMA, bromoethylmalonic acid (BrEtMA), BuMA, bromo(n-butyl)malonic acid (BrBuMA) with Ce(IV) or Fe(phen)₃³⁺ ion were studied. Under aerobic or anaerobic conditions, the order of reactivity toward Ce(IV) oxidation is MeMA > EtMA > BuMA > BrMeMA >> (BrEtMA, BrBuMA). Under aerobic conditions, the order of reactivity toward reacting with Fe(phen)₃³⁺ ion is MeMA > (BuMA, EtMA) >> (BrMeMA, BrEtMA, BrBuMA). The experimental results are rationalized. © 1996 John Wiley & Sons, Inc.     

Bi(III)‐catalyzed C―S cross‐coupling reaction

A direct synthetic route for the C―S coupling of aryl halides with thiophenols is described. This method is tolerant to electron‐withdrawing and electron‐donating functional groups and also to the presence of functional groups in the ortho position of the aryl iodide or thiophenol. Aryl iodides are coupled with thiophenols without affecting the other functionalities present in the aryl ring. These reactions follow second‐order kinetics. Copyright © 2012 John Wiley & Sons, Ltd.     

Polyethylene Glycol–Mediated Kinetic Study of Nitrodecarboxylation of α,β‐Unsaturated Acids by Blau's Fe(III) Bipy Complex

A kinetic and mechanistic study of nitro decarboxylation of α,β‐unsaturated acids (USA) has been taken up by Blau's yellow complex [Fe(III) nitrate–Bipy] in polyethylene glycol (PEG)–acetonitrile media. Kinetics of the reactions indicated a rate law: rate = ab[Fe (III)][Bipy][USA]/(1 + b [Bipy]), that represents the Michaelis–Menten type mechanism. Reaction rates are significantly influenced by the structural variation and concentration of PEG. The mechanism of PEG‐mediated reaction was explained through the formation of more active [PEG bound Fe(III) nitrate–Bipy species] than [Fe (III) nitrate–Bipy] itself. Formation of [PEG bound Fe(III) nitrate–Bipy species] could be due to the interaction of polyoxyethylene glycolate moiety with [Fe (III) nitrate–Bipy species] in the lines of nonionic micellar interactions.     

Heterodinukleare Cobalt(II)‐, Nickel(II)‐, Kupfer(II)‐, Zink(II)und Palladium(II)‐Komplexe mit einem makrocyclischen Liganden vom Schiff‐Basen‐Typ: Synthesen und Strukturen

Complexes with Macrocyclic Ligands. IV. Heterodinuclear Cobalt(II), Nickel(II), Copper(II), Zinc(II) and Palladium(II) Complexes with a Macrocyclic Ligand of Schiff‐Base Type: Syntheses and Structures The synthesis and properties of nickel(II), copper(II), and palladium(II) complexes, [ML^Ph] ( 3 ; L^Ph = N,N′‐phenylene‐bis(3‐formyl‐5‐tert.‐butyl‐salicylaldimine)), are described. These neutral mononuclear complexes react with metal(II) perchlorate and 1,3‐propylenediamine to form heterodinuclear, macrocyclic, cationic complexes of the type [MM′(L^Ph,3)]²⁺ ( 4 ; M = Ni, Cu, Pd; M′ = Co, Cu, Zn). The structures of the five new compounds [NiCo(L^Ph,3)](ClO₄)₂, [NiCu(L^Ph,3)](ClO₄)₂, [CuCu(L^Ph,3)](ClO₄)₂, [CuZn(L^Ph,3)](ClO₄)₂, and [PdCu(L^Ph,3)](ClO₄)₂ were determined by X‐ray diffraction.     

5‐n‐Butylpyridine‐2‐carboxylate–copper(II) and –iron(III) complexes

In trans‐bis(5‐n‐butyl­pyridine‐2‐carboxyl­ato‐κ²N,O)­bis­(methanol‐κO)copper(II), [Cu(C₁₀H₁₂NO₂)₂(CH₄O)₂], the Cu atom lies on a centre of symmetry and has a distorted octahedral coordination. The Cu—O(methanol) bond length in the axial direction is 2.596 (3) Å, which is much longer than the Cu—­O(carboxylate) and Cu—N distances in the equatorial plane [1.952 (2) and 1.977 (2) Å, respectively]. In mer‐tris(5‐n‐bu­tyl­pyridine‐2‐carboxyl­ato‐κ²N,O)­iron(III), [Fe(C₁₀H₁₂NO₂)₃], the Fe atom also has a distorted octahedral geometry, with Fe—O and Fe—N bond‐length ranges of 1.949 (4)–1.970 (4) and 2.116 (5)–2.161 (5) Å, respectively. Both crystals are stabilized by stacking interactions of the 5‐n‐butyl­pyridine‐2‐carboxyl­ate ligand, although hydrogen bonds also contribute to the stabilization of the copper(II) complex.     

Zweikernige Palladium(II)‐, Platin(II)‐ und Iridium(III)‐Komplexe von Bis[imidazol‐4‐yl]alkanen

Dinuclear Palladium(II), Platinum(II), and Iridium(III) Complexes of Bis[imidazol‐4‐yl]alkanes The reaction of bis(1,1′‐triphenylmethyl‐imidazol‐4‐yl) alkanes ((CH₂)_n bridged imidazoles L(CH₂)_nL, n = 3–6) with chloro bridged complexes [R₃P(Cl)M(μ‐Cl)M(Cl)PR₃] (M = Pd, Pt; R = Et, Pr, Bu) affords the dinuclear compounds [Cl₂(R₃P)M–L(CH₂)_nL–M(PR₃)Cl₂] 1 – 17 . The structures of [Cl₂(Et₃P)Pd–L(CH₂)₃L–Pd(PEt₃)Cl₂] ( 1 ), [Cl₂(Bu₃P)Pd–L(CH₂)₄L–Pd(PBu₃)Cl₂] ( 10 ), [Cl₂(Et₃P)Pd–L(CH₂)₅L–Pd(PEt₃)Cl₂] ( 3 ), [Cl₂(Et₃P)Pt–L(CH₂)₃L–Pt(PEt₃)Cl₂] ( 13 ) with trans Cl–M–Cl groups were determined by X‐ray diffraction. Similarly the complexes [Cl₂(Cp*)Ir–L(CH₂)_nL–Ir(Cp*)Cl₂] (n = 4–6) are obtained from [Cp*(Cl)Ir(μ‐Cl)₂Ir(Cl)Cp*] and the methylene bridged bis(imidazoles).     

Kinetic study of the ruthenium(VI)‐catalyzed oxidation of benzyl alcohol by alkaline hexacyanoferrate(III)

The kinetics of the Ru(VI)‐catalyzed oxidation of benzyl alcohol by hexacyanoferrate(III), in an alkaline medium, has been studied using a spectrophotometric technique. The initial rates method was used for the kinetic analysis. The reaction is first order in [Ru(VI)], while the order changes from one to zero for both hexacyanoferrate(III) and benzyl alcohol upon increasing their concentrations. The rate data suggest a reaction mechanism based on a catalytic cycle in which ruthenate oxidizes the substrate through formation of an intermediate complex. This complex decomposes in a reversible step to produce ruthenium(IV), which is reoxidized by hexacyanoferrate(III) in a slow step. The theoretical rate law obtained is in complete agreement with all the experimental observations. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 34: 421–429, 2002     

Form III of 2,2′,4,4′,6,6′‐hexanitro­azobenzene (HNAB‐III)

The crystal structure of form III of the title compound, HNAB [systematic name: bis(2,4,6‐trinitro­phenyl)diazene], C₁₂H₄N₈O₁₂, has finally been solved as a pseudo‐merohedral twin (monoclinic space group P2₁, rather than the ortho­rhombic space group C222₁ suggested by diffraction symmetry) using a dual space recycling method. The significant differences in the room‐temperature densities of the three crystalline forms allow examination of molecular differences due to packing arrangements. An interesting relationship with the stilbene analog, HNS, is discussed. Interatomic separations are compared with other explosives and/or nitro‐containing compounds.     

Kinetic study of copper(I)‐catalyzed click chemistry step‐growth polymerization

Oligomers and polymers containing triazole units were synthesized by the copper(I)‐catalyzed 1,3‐dipolar cycloaddition step‐growth polymerization of four difunctional azides and alkynes. In a first part, monofunctional benzyl azide was used as a chain terminator for the polyaddition of 1,6‐diazidohexane and α,ω‐bis(O‐propargyl)diethylene glycol, leading to polytriazole oligomers of controlled average degree of polymerization (DP_n = 3–20), to perform kinetic studies on low‐viscosity compounds. The monitoring of the step‐growth click polymerization by ¹H NMR at 25, 45, and 60 °C allowed the determination of the activation energy of this click chemistry promoted polyaddition process, that is, E_a = 45 ± 5 kJ/mol. The influence of the catalyst content (0.1–5 mol % of Cu(PPh₃)₃Br according to azide or alkyne functionalities) was also examined for polymerization kinetics performed at 60 °C. In a second part, four high molar mass polytriazoles were synthesized from stoichiometric combinations of diazide and dialkyne monomers above with p‐xylylene diazide and α,ω‐bis(O‐propargyl)bisphenol A. The resulting polymers were characterized by DSC, TGA, SEC, and ¹H NMR. Solubility and thermal properties of the resulting polytriazoles were discussed based on the monomers chemical structure and thermal analyses. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5506–5517, 2008     

Greenish‐yellow‐, yellow‐, and orange‐light‐emitting iridium(III) polypyridyl complexes with poly(ε‐caprolactone)–bipyridine macroligands

A set of novel greenish‐yellow‐, yellow‐, and orange‐light‐emitting polymeric iridium(III) complexes were synthesized with the bridge‐splitting method. The respective dimeric precursor complexes, [Ir(ppy)₂‐μ‐Cl]₂ (ppy = 2‐phenylpyridine) and [Ir(ppy? CHO)₂‐μ‐Cl]₂ [ppy? CHO = 4‐(2‐pyridyl)benzaldehyde], were coordinated to 2,2′‐bipyridine carrying poly(ε‐caprolactone) tails. The resulting emissive polymers were characterized with one‐dimensional (¹H) and two‐dimensional (¹H? ¹H correlation spectroscopy) nuclear magnetic resonance and infrared spectroscopy, gel permeation chromatography, and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry, and the successful coordination of the iridium(III) centers to the 2,2′‐bipyridine macroligand was revealed. The thermal behavior was studied with differential scanning calorimetry and correlated with atomic force microscopy. Furthermore, the quantitative coordination was verified by both the photophysical and electrochemical properties of the mononuclear iridium(III) compounds. The photoluminescence spectra showed strong emissions at 535 and 570 nm. The color shifts depended on the substituents of the cyclometallating ligands. Cyclic voltammetry gave oxidation potentials of 1.23 V and 1.46 V. Upon the excitation of the films at 365 nm, yellow light was observed, and this could allow potential applications in light‐emitting devices. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2765–2776, 2005