Palladium-catalyzed Polycondensation Research Articles

Regiocontrolled synthesis of ester-functionalized polythiophenes via direct arylation polycondensation

A series of ester-functionalized polythiophenes (P3OETs) with precisely controlled head-to-tail (HT) ratios was synthesized via palladium-catalyzed direct arylation polycondensation (DArP). The ionization potentials and optical bandgaps of P3OETs decreased as their HT ratios increased because of the increased backbone coplanarity and extensive π-electron delocalization. The method of precisely controlling the regioregularity and HT ratio can contribute to the design of new polythiophene derivatives with enhanced electronic functionality. A series of ester-functionalized polythiophenes (P3OETs) with precisely controlled head-to-tail (HT) ratios was synthesized via palladium-catalyzed direct arylation polycondensation (DArP). The ionization potentials and optical bandgaps of P3OETs decreased as their HT ratios increased because of the increased backbone coplanarity and extensive π-electron delocalization. The method of precisely controlling the regioregularity and HT ratio can contribute to the design of new polythiophene derivatives with enhanced electronic functionality.

Synthesis and characterization of novel soluble poly(arylene ether amide triphenylphosphine oxide)s by heterogeneous palladium-catalyzed carbonylation polymerization

A new aromatic diiodide monomer, bis(4-(3-iodophenoxy)phenyl)phenylphosphine oxide (BIPPO), was prepared by condensation of bis(4-fluorophenyl)phenylphosphine oxide with 3-iodophenol. A series of poly(arylene ether amide triphenylphosphine oxide)s were synthesized via heterogeneous palladium-catalyzed carbonylative polycondensation of BIPPO, aromatic diamines, and carbon monoxide. Polymerization reaction proceeded smoothly in N,N-dimethylacetamide (DMAc) at 120 °C with 1,8-diazabicyclo[5,4,0]-7-undecene (DBU) as the base by using the bidentate phosphino-modified magnetic nanoparticles-anchored palladium complex [2P-Fe3O4@SiO2-PdCl2] as a recyclable catalyst under 1 bar of CO, producing new poly(arylene ether amide triphenylphosphine oxide)s with inherent viscosities ranging from 0.69 to 0.76 dl/g. All the polymers obtained were easily soluble in strong polar aprotic organic solvents and even in less polar pyridine at room temperature, and provided transparent, flexible and tough films by casting from their DMAc solutions. These polymers displayed good thermal stability with the glass transition temperatures ranging from 196 to 249 °C, the temperatures at 5% weight loss ranging from 441 to 490 °C in nitrogen. All the polymers were amorphous and their films showed good mechanical behavior with tensile strengths of 78.5–91.6 MPa, tensile moduli of 2.15–2.69 GPa, and elongations at break of 9.8–14.6%.

Synthesis of high-performance triphenylamine-based polyfluorenes via C–N coupling reaction: thermal and photoelectric properties

Aromatic high-performance triphenylamine-based polyfluorenes (PTPAFs) have been successfully constructed by palladium-catalyzed polycondensation reaction. The chemical structures of the resulting PTPAFs are confirmed by means of Fourier-transform infrared spectroscopy and nuclear magnetic resonance, and the testing results showed a good agreement with the proposed structures. The resulted polymers show excellent solubility, high thermal stability with the decomposition temperatures (Td5%) over 320 °C and the glass transition temperatures (Tg) over 305 °C. The PTPAF1 and the PTPAF2 exhibit the enhanced high occupied molecular orbital (HOMO) energy levels (− 3.93 eV, − 4.00 eV, respectively) and the depressed low unoccupied molecular orbital (LUMO) energy levels (− 0.99 eV, − 1.41 eV, respectively). Owing to their special structures, PTPAFs showed encouraging photonic luminescence and good electroactivity and could be used as a potential light source in the blue region.

Recyclable heterogeneous palladium-catalyzed Heck coupling polycondensation of bis(acrylamide)s with aromatic diiodides towards polycinnamamides

A new and practical method for the preparation of high molecular weight polycinnamamides has been developed through a heterogeneous palladium-catalyzed Heck coupling polycondensation of bis(acrylamide)s with aromatic diiodides. The polymerization proceeded smoothly in DMF at 100 °C in the presence of a magnetic nanoparticles-anchored bidentate phosphine-palladium(II) acetate complex [Fe3O4@SiO2-2P-Pd(OAc)2] and tributylamine, yielding a series of polycinnamamides with inherent viscosities up to 0.89 dL/g and a low level of palladium residue (below 10 ppm). The polycinnamamides obtained were quite soluble in dipolar aprotic solvents and had glass transition temperatures ranging from 221 to 269 °C and 10% weight loss temperatures ranging from 437 to 458 °C in nitrogen. These polymers could afford transparent and tough films by solution-casting with tensile strengths of 59.6–82.8 MPa, tensile moduli of 1.78–2.12 GPa, and elongations at break of 7.5–12.5%. The Fe3O4@SiO2-2P-Pd(OAc)2 catalyst can be conveniently separated from the polymer and recovered by simply using an external magnetic field, and recycled at least eight times without apparent decrease in catalytic efficiency.

Synthesis of cardo poly(arylene ether ketone amide)s by heterogeneous palladium-catalyzed polycondensation of aromatic diiodides, aromatic diamines containing cardo groups and CO

New cardo poly(arylene ether ketone amide)s were synthesized by heterogeneous palladium-catalyzed carbonylative polycondensation of aromatic diiodides with ether–ketone linkages, aromatic diamines bearing cardo groups, and carbon monoxide. Polymerizations were conducted in N,N-dimethylacetamide (DMAc) at 120 °C in the presence of a bidentate phosphino-functionalized magnetic nanoparticles-immobilized palladium complex [Fe3O4@SiO2-2P-PdCl2] and 1,8-diazabicyclo[5,4,0]-7-undecene (DBU), yielding a series of cardo poly(arylene ether ketone amide)s with inherent viscosities up to 0.77 dL/g. All the polymers were readily soluble in various dipolar aprotic solvents at room temperature. These polymers showed good thermal stability with the glass transition temperature of 223–289 °C, the temperature at 5% weight loss of 441–464 °C in nitrogen. These cardo poly(arylene ether ketone amide)s could afford transparent, flexible, and strong films by solution-casting with good tensile properties. These polymer films exhibited lower dielectric constants, lower water uptakes, and higher optical transparency. Furthermore, this heterogeneous palladium catalyst can facilely be separated from the reaction mixture by simply applying an external magnet and recycled at least eight times with almost consistent activity.

Novel preparation of poly(arylene ether sulfone amide)s via supported palladium-catalyzed carbonylative polymerization

Two new aromatic diiodides with ether–sulfone linkages were synthesized via a one-step procedure. A series of poly(arylene ether sulfone amide)s were synthesized by a supported palladium-catalyzed polycondensation of aromatic diiodides having ether–sulfone linkages, aromatic diamines, and CO. Polycondensation reactions were conducted in N,N-dimethylacetamide using a magnetic nanoparticles-bound palladium(II) complex [Fe3O4@SiO2-2P-PdCl2] as the catalyst and 1,8-diazabicycle[5,4,0]-7-undecene as the base at 120 °C, yielding poly(arylene ether sulfone amide)s having inherent viscosities of 0.43–0.77 dL/g. The resulting polymers were soluble in polar aprotic solvents and showed glass transition temperatures in the 204–265 °C range, with 10% weight losses occurring at temperatures above 456 °C in nitrogen. Most of the polymers afforded transparent and tough films by solution-casting with tensile strengths of 71.8–82.2 MPa, Young’s moduli of 1.77–2.35 GPa, and elongations at break of 9.3–13.4%. More importantly, this supported palladium catalyst can facilely be separated from the product by simply using an external magnetic field and reused at least seven times with almost consistent activity.

Synthesis of poly(ether ketone amide)s by a heterogeneous palladium-catalyzed polycondensation of aromatic diiodides, diamines, and carbon monoxide

A series of novel aromatic poly(ether ketone amide)s (PEKAs) were synthesized by the heterogeneous palladium-catalyzed carbonylative polycondensation of aromatic diiodides with ether ketone units, aromatic diamines, and carbon monoxide in N, N-dimethylacetamide (DMAc) at 120°C using 6 mol% of a magnetic nanoparticles–supported bidentate phosphine palladium complex (Fe3O4@SiO2-2P-PdCl2) as catalyst and 1,8-diazabicyclo[5,4,0]-7-undecene as base. The PEKAs had inherent viscosities ranging from 0.61 dl g−1 to 0.75 dl g−1. All the PEKAs were soluble in strong dipolar organic solvents. These PEKAs showed glass transition temperatures between 178°C and 232°C and 10% weight loss temperatures ranging from 443°C to 496°C in nitrogen. These PEKAs could be cast into transparent, flexible, and strong films from DMAc solutions with tensile strengths of 72.8–82.6 MPa, tensile moduli of 2.19–2.84 GPa, and elongations at break of 5.4–7.5%. Importantly, the heterogeneous palladium catalyst can be conveniently recovered from the reaction mixture by simply applying an external magnet and recycled up to eight times without significant loss of activity.

Synthesis of π-Extended Dithienobenzodithiophene-Containing Medium Bandgap Copolymers and Their Photovoltaic Application

Two medium bandgap alternating conjugated copolymers, namely, poly{5,10-di(2-hexyldecyloxy)dithieno[2,3-d:2′,3′-d′]benzo[1,2-b:4,5-b′]dithiophene-2,7-diyl-alt-thiophene-2,5-di-yl} (P1) and poly{5,10-di(2-hexyldecyloxy)dithieno[2,3-d:2′,3′-d′]benzo[1,2-b:4,5-b′]dithiophene-2,7-di-yl-alt-thieno[3,2-b]thiophene-2,5-diyl} (P2), were prepared by the palladium-catalyzed Stille polycondensation and characterized by gel permeation chromatography (GPC), UV-Vis absorption and photoluminescence (PL) spectra, thermal gravimetric analysis (TGA), cyclic voltammetry (CV) etc. The resultant copolymers show moderate solubility in common organic solvents and enough stabilities for photovoltaic application. And both copolymers absorb the solar light from 300–600 nm, with the optical band gaps () calculated from the onset of absorption in the solid film of ca. 2.1 eV. The highest occupied molecular orbital (HOMO) levels of two copolymers determined by CV were at about −5.35 eV. Photovoltaic propertites of the polymers were investigated by using the polymers as donor and [6,6]-phenyl-C71 butyric acid methyl ester (PC71BM) as acceptor with a weight ratio of polymer:PC71BM of 1:2. The power conversion efficiencies (PCEs) of polymer solar cells based on PDTBTT-TT reached 2.50%, with an open-circuit voltage (Voc) of 0.70 V, a short-circuit current density (Jsc) of 6.89 mA cm−2, and a fill factor (FF) of 52%, under the illumination of AM1.5, 100 mW cm−2. These results indicate that dithieno[2,3-d:2′,3′-d′]benzo[1,2-b:4,5-b′]dithiophene (DTBDT) is a promising building block for the high-performance organic electronic materials.

Synthesis and characterization of new thermally stable polymers as new high-performance engineering plastics

A series of new poly(imino ether)s (PIEs) have been synthesized via palladium-catalyzed polycondensation of 4,4′-dibromodiphenyl ether with various aromatic diamines. All PIEs were fully characterized by Fourier transform infrared spectroscopy, elemental analyses, differential scanning calorimetry, thermogravimetric analysis, gel permeation chromatography, and x-ray diffraction. These polymers show high thermal stability and high decomposition temperatures. A model compound was synthesized and characterized by standard spectroscopic methods in order to confirm the proposed structure and to assist in the structure proof of the polymer.

Deeply Colored Polymers Containing 1,3,4,6-Tetraarylpyrrolo[3,2-b]pyrrole-2,5-dione (IsoDPP) Units in the Main Chain

Synthesis and characteristic properties of polymers P1–P4 containing 1,3,4,6-tetraarylated pyrrolo[3,2-b]pyrrole-2,5-dione (isoDPP) units in the main chain are described. P1 and P2 were prepared upon palladium-catalyzed polycondensation of 3,6-bis(4-bromophenyl)-1,4-bis(4-tert-butylphenyl)pyrrolo[3,2-b]pyrrole-2,5-dione (M1) or 1,4-bis(4-bromophenyl)-3,6-bis(4-tert-butylphenyl)pyrrolo[3,2-b]pyrrole-2,5-dione (M2) and 2,2′-(9,9-dihexyl-9H-fluoren-2,7-diyl)bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolane) (M4), while P3 and P4 were synthesized upon polycondensation of 3,6-bis(5-bromothien-2-yl)-1,4-bis(4-dodecylphenyl)pyrrolo[3,2-b]pyrrole-2,5-dione (M3) and 2,5-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)thiophene (M5) or 9-(2-ethylhexyl)-2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)carbazole (M6). Deeply colored polymers with molecular weights between 3.5 and 22 kDa were obtained. The polymers were soluble in common organic solvents such as dichloromethane, chloroform, and tetrahydrofuran. All polymers exhibit broad absorption bands with high extinction coefficients (ϵ > 2 × 104 L mol–1 cm–1) but weak fluorescence, the quantum yields being below 1%. Although P1 and P2 are isomers, their optical properties are rather different. P1 with polyconjugated backbone exhibits an absorption maximum at 409 nm, while P2 has a maximum at 360 nm due to interruption of π-conjugation at the lactam N atoms. The presence of thienyl-isoDPP units in the backbone causes a red-shift of the absorption to 489 nm (P3) and 435 nm (P4). All polymers exhibit nearly irreversible oxidation and reduction behavior. Bandgaps of the polymers with phenyl-substituted isoDPP units (P1 and P2) are at about 2 eV, while those of polymers with thienyl-substituted isoDPP (P3 and P4) are at about 1.5 eV.

Synthesis of End‐capped Regioregular Poly(3‐hexylthiophene)s via Direct Arylation

The synthesis of regioregular head-to-tail poly(3-hexylthiophene)s capped with aryl groups (Ar-HT-P3HTs) has been accomplished by palladium-catalyzed polycondensation of 2-bromo-3-hexylthiophene (1) via direct arylation. A variety of aryl groups are installed at the initiated end in 86%-98% selectivity using aryl bromides and iodides as capping agents. The polymerization proceeds via a two-stage process. Before monomer 1 is consumed, the competitive formation of end-capped and non-capped HT-P3HTs is operative, where the molecular weight increases linearly with monomer conversion. After 1 is consumed, the resulting polymers are coupled with each other to afford highly end-capped HT-P3HTs.

Synthesis of Carbazoled Poly(<i>Arylene Imino</i>)

The carbazoled poly(arylene imino)s (c-PAI) have been synthesized via palladium-catalyzed polycondensation of 3,6-diamino-N-(2-ethylhexyl)carbazole with different aromatic dibromides. The structure of c-PAI were characterized by means of FT-IR, 1H NMR spectroscopy and elemental analysis, the results show an agreement with the proposed structure. The thermal properties of c-PAI were detected by DSC and TG. The result show that the polymers possess high glass transition temperature (Tg＞250°C ), good thermal stability with high decomposition temperatures (TD＞410°C), In addition to the thermal properties, the optical properties were studied, including Uv-vis absorption, photoluminescence and time of flight (TOF).

π-Conjugated Poly(aryleneethynylene)s Consisting of Salophen and Ni−Salophen Units in the π-Conjugated Main Chain: Preparation and Chemical Properties

π-Conjugated poly(aryleneethynylene)s consisting of N,N′-bis(salicylidene)-1,2-phenylenediamine (salophen) units (Poly-1−Poly-3) and salophen−nickel complex units (Poly-1−Ni) were prepared in high yields by the palladium-catalyzed polycondensation of H−≡−Ar−≡−H (Ar = fluorene or 2,5-dialkoxy-p-phenylene) with dibromo compounds of salophen (Br2−Salophen) and its nickel complex (Br2−Salophen−Ni), respectively. The Ni-free polymers (Poly-1−Poly-3) showed good solubility in CHCl3 and THF, had high thermal stability, and exhibited number-average molecular weights (Mn) of 9200−14000 in GPC analysis. The UV−vis spectra of the polymers showed π−π* transition peaks at about 420 nm, which was comparable to those of poly(p-phenyleneethynylene)s. The UV−vis spectrum of Poly-1−Ni exhibited additional intermediate and small peaks at about 480 and 600 nm, which were assigned to a charge-transfer (CT) electronic transition and a d−d transition, respectively. The complexation of Poly-1 with Ni2+ proceeded clearly and quan...

Synthesis and properties of poly(arylene imino) containing fluorenone group (PIKF)

AbstractA series of novel poly(arylene imino) containing fluorenone group (PIKF) have been synthesized via palladium-catalyzed polycondensation. The thermal properties of PIKF are detected by thermal behavior (TG) and differential scanning calorimetry (DSC). UV-vis absorption spectra, photoluminescence are investigated. PIKF exhibit good thermal stability and high Tgs(>200 °C ). The optical properties of PIKF show that PIKF are interesting materials for further investigations to be presented as possible candidates for use as an electron transport layer (n-type) in multilayer LEDs.

Stereocontrolled Synthesis and Photoisomerization Behavior of All-Cis and All-Trans Poly(m-phenylenevinylene)s

All-cis and all-trans isomers of poly[(arylenevinylene)-alt-(5-octyloxy-1,3-phenylenevinylene)]s having three kinds of arylene groups (PmPVs: arylene = m-phenylene (1a), p-phenylene (1b), 4,4′-biphenylene (1c)) have been synthesized in almost perfect stereoregularity by two types of palladium-catalyzed polycondensation reactions, respectively. Suzuki−Miyaura-type polycondensation of (Z,Z)-bis(2-bromoethenyl)arenes with 5-octyloxy-1,3-benzenediboronic acid pinacolate affords all-cis 1a−c, whereas Hiyama-type polycondensation of (E,E)-bis(2-silylethenyl)arenes with 5-octyloxy-1,3-diiodobenzene forms all-trans 1a−c. The resulting polymers with relatively short effective π-conjugation lengths interrupted by m-phenylene units undergo two-way photoisomerization to give PmPVs containing cis- and trans-vinylene groups in nearly 1:1 ratios irrespective of the arylene groups of staring polymers.

Two-dimensionally extended organic high-spin poly(aminium cationic radical)s and their magnetic force microscopic images

Purely organic high-spin poly(aminium cationic radical)s of two-dimensionally extended soluble aromatic polyamines P1 and P2 were prepared by the palladium-catalyzed polycondensation of two multifunctional monomers, followed by chemical or electrochemical oxidations. The chemical structures of the precursor polyamines were fully characterized by 1H- and 13C nuclear magnetic resonance (NMR), infrared and MALDI-TOF mass spectra (MS). The aminium radical sites of N,N,N′,N′-tetraaryl-p-phenylenediamines were connected through the m-phenylene ferromagnetic coupler, which satisfies the non-Kekulé-type molecular design. Oxidation of radical sites was facilitated by electron-donating methoxy substituents. The first oxidation potential (Eo′(1)) of P2 with methoxy substituents, evaluated from the cyclic voltammograms in CH2Cl2, was 0.69 V (vs Ag/Ag+), whereas the Eo′(1) of P1 without electron-donating substituents was 0.78 V. This result was further verified by spectroelectrochemistry measurements. The electrochemically oxidized P2 displayed a more intense low-energy band at ca. 800 nm ascribed to aminium cationic radicals and bications. Chemical oxidation of P1 and P2 with NOPF6 solubilized with 18-crown-6 in CH2Cl2 gave the corresponding poly(aminium cationic radical)s. The high-spin ground states were confirmed by the temperature dependence of forbidden electron spin resonance (ESR) transition peak intensities, and the average spin quantum number (S) determined by the magnetic curves reached 8.4/2 at low temperatures. Remarkably, when a small amount of trifluoroacetic acid was added, the half-life of polyradicals reached ca. 1 week at room temperature (RT). This result prompted us to observe the single polymer-based molecular and magnetic images by atomic force microscopy and magnetic force microscopy, respectively. The precursor polyamine P1 showed globular-shaped polymer particles with an average vertical distance of 1.43 nm. After chemical oxidation, the vertical distance of P1 definitely decreased, reflecting the improved p-type character of the nitrogen atoms. Moreover, the detection of weak MFM images supported the presence of magnetic spins in the single polymers.

A Highly Selective Catalytic System for the Cross-Coupling of (E)-Styryl Bromide with Benzeneboronic Acid: Application to the Synthesis of All-Trans Poly(arylenevinylene)s

Abstract A highly selective system for palladium-catalyzed polycondensation of (E,E)-1,4-bis(2-bromoethenyl)benzene ((E,E)-1) with 2,5-dioctyloxybenzene-1,4-diboronic acid (2a) to give all-trans poly[( p-phenylenevinylene)-alt-(2,5-dioctyloxy-1,4-phenylenevinylene)] (all-trans 3) has been investigated using (E)-styryl bromide ((E)-4) and 2,5-dioctyloxybenzeneboronic acid (5a) as model compounds of (E,E)-1 and 2a, respectively. The reaction of (E)-4 and 5a in toluene in the presence of Pd(PPh3)4 catalyst and aqueous K2CO3 base affords considerable amounts of homocoupling products (i.e., 1,4-diphenylbutadiene (13%) and 2,2′,5,5′-tetraoctyloxybiphenyl (22%)), together with (E)-2,5-dioctyloxystilbene ((E)-6a) as the cross-coupling product (30%). The use of aqueous NaOH as a strong base and Bu4NBr as a phase-transfer catalyst notably reduces the homocoupling products, and the use of Pd(PBut3)2 instead of Pd(PPh3)4 results in almost perfect selectivity of the cross-coupling product (E)-6a. Under optimized catalytic conditions, the desired all-trans 3 has been successfully prepared without notable defects in the polymer chain.

Preparation and properties of poly(arylene) containing Si unit-bridged diphenylamine

Si (monosilane, disilane, and disiloxane) unit-bridged diphenylamine-containing poly(arylene) PARs were prepared and properties of PARs were compared with the relative Si unit-bridged diphenylamine homopolymers. PARs were prepared by palladium-catalyzed polycondensation between Si unit-bridged diphenylamine and distannyl- or diboryl-aromatic compound. PAR with disiloxane unit-bridged diphenylamine was also prepared by oxidation of PAR with disilane unit-bridged diphenylamine. Optical properties and electrochemical properties of PAR depended on not only bridging Si unit but also introduced arylene unit.

Intramolecular Through-Space Antiferromagnetic Interactions of Cross-Conjugated Aromatic Polyaminium Radical Gels

Highly networked, cross-conjugated aromatic polyamine gels were prepared by palladium-catalyzed polycondensation. The gels were characterized by the cross-polarization magic angle spinning (CP-MAS) 13C NMR and IR spectroscopies, thermogravimetric analysis, and X-ray diffraction. The data confirm that the polymerization proceeded without any side reactions and that the gels possessing the significant thermal stability are composed of the mixtures of polycrystalline and amorphous moieties. Chemical oxidation of the gels with NOPF6 solubilized with 18-crown-6 in CH2Cl2 gave the corresponding aminium polyradicals. Appearance of the ESR signals at g = 2.003 and the new IR peaks supported the aminium radical generation. The p-methoxy-substituted aromatic polyaminium radical, the polyradical of poly(2), realized the higher spin concentration of 65% and the enhanced chemical stability than the polyradical of poly(1) without any protecting groups. However, the magnetic measurements of the polyradical of poly(2) did not show any intramolecular ferromagnetic interactions, but indicated very strong intramolecular through-space antiferromagnetic interactions.

Synthesis of Carbazole-Based Polymers with 1,3,4-Oxadiazole Pendant Group and Their Application in Organic Light-Emitting Diodes

Structurally well-defined copolymers with high solubility were prepared via palladium-catalyzed polycondensation of N-(2-ethylhexyl)-3,6-dibromocarbazole with 2-aryl-5-(4-aminophenyl)-1,3,4-oxadiazole (aryl = phenyl, p-methylphenyl, p-methoxyphenyl). Copolymers consisted of alkylcarbazole groups in the main chain and 1,3,4-oxadiazole pendants in the side chain. The influence of their aryl substituents on physical, optical, band gaps and electroluminescent characteristics of the copolymers was investigated. Both UV-Visible absorption and photoluminescence emission peaks of the copolymers were similar to each other. The band gap energy of the polymers was measured in the range of 2.84 to approximately 2.88 eV, and HOMO energy in the range of -5.13 to approximately -5.18 eV. These copolymers were used as hole-transporting layers (HTL) in the light-emitting diodes with Alq3 as an emitting layer. Compared to devices with P-H and P-OCH3 used as HTL, it should be noted that device with P-CH3 used as HTL showed higher luminescence. Maximum luminescence of devices was measured to be 276 cd/m2 at 14 V with P-H, 625 cd/m2 at 15 V with P-CH3, and 471 cd/m2 at 14 V with P-OCH3. This might be due to effect of subtle changes in HOMO energy level of polymers with changing substituent groups. Phosphorescent polymer light emitting diodes were also fabricated with an emitting layer consisting of P-CH3 matrix and a red phosphorescent dopant (lr-PIQCH).