Intramolecular donor–acceptor structures prepared by covalently binding conjugated octylphenanthrenyl‐imidazole moieties onto the side chains of regioregular poly(3‐hexylthiophene)s exhibit lowered bandgaps and enhanced electron transfer compared to the parent polymer, e.g., conjugation of 90 mol% octylphenanthrenyl‐imidazole moieties onto poly(3‐hexylthiophene) chains reduces the optical bandgap from 1.91 to 1.80 eV, and the electron transfer probability is at least twice as high as that of pure poly(3‐hexylthiophene) when blended with [6,6]‐phenyl‐C61‐butyric acid methyl ester. The lowered bandgap and the fast charge transfer both contribute to much higher external quantum efficiencies, thus much higher short‐circuit current densities for copolymers presenting octylphenanthrenyl‐imidazole moieties, relative to those of pure poly(3‐hexylthiophene)s. The short‐circuit current density of a device prepared from a copolymer presenting 90 mol% octylphenanthrenyl‐imidazole moieties is 13.7 mA · cm−2 which is an increase of 65% compared to the 8.3 mA · cm−2 observable for a device containing pure poly(3‐hexylthiophene). The maximum power conversion efficiency of this particular copolymer is 3.45% which suggest that such copolymers are promising polymeric photovoltaic materials.

A hyperbranched aromatic poly(amide-imide) was prepared by the copolymerization of 4-(3,5-dicarboxyphenoxy)phthalic anhydride, a B′B2 type monomer, and 1,4-phenylenediamine, an A2 type monomer. The rapid reaction between the anhydride and amino group led to the formation of the dominant imide intermediate which can be regarded as a new AB 2 type of monomer. The intermediate, without isolation, was subjected to further polymerization in the presence of TPP/pyridine, as condensing agents, to give the hyperbranched poly(amide-imide), containing carboxylic acid chain ends. In comparison, the AB 2 monomer was prepared separately, and the conventional self-polymerization of this monomer was also studied. The structures of the obtained polymers were characterized by FTIR and 1 H NMR spectroscopy. The spectral data showed that these two polymers, prepared from two different synthetic approaches, have nearly identical structures. The degree of branching of the hyperbranched poly(amideimide)s was estimated to be 60-61%. The terminal carboxylic acid groups were modified by reaction with a variety of aromatic amines to give the corresponding amide derivatives. The nature of the chain ends was shown to have a significant effect on the solubility and T g of the hyperbranched poly(amideimide)s. Experimental SectionGeneral Directions. N-Methyl-2-pyrrolidinone (NMP) and N,N-dimethylformamide (DMF) were distilled over CaH2 under reduced pressure. Pyridine was dried by distillation after being refluxed with KOH. 1,4-Phenylenediamine was recrystallized from MeOH. Triphenyl phosphite (TPP) was purified by distillation under reduced pressure. (2,3-Dihydro-2-thioxo-3-benzoxazolyl)phosphonic acid diphenyl ester (DBOP) was used as received. All other reagents and solvents were used as received from commercial sources unless otherwise stated. 1 H and 13 C NMR spectra were recorded on a Varian Unity 300 MHz or a Bruker-DRX 300 MHz spectrometer. IR spectra were obtained on a Nicolet 360 FT-IR spectrometer. Mass spectra were obtained on a JEOL JMS-SX 102A mass spectrometer. Size exclusion chromatography (SEC) was carried out on a Waters chromatography unit, interfaced with a Waters 410 differential refractometer. Three 5 µm Waters styragel columns (300 × 7.8 mm), connected in series of decreasing order of pore size (10 5 , 10 4 , and 10 3 Å), were used with DMF as the eluent. Standard samples of PMMA were

New dendritic poly(ether imide)s were synthesized by the convergent growth approach, using 1-(4-aminophenyl)-1,1-bis(4-hydroxyphenyl)ethane, as the building block. The aromatic nucleophilic substitution of the building block with 3-nitro-N-phenylphthalimide led to the first-generation dendron with aminophenyl group at the focal point, which was subsequently reacted with 3-nitrophthalic anhydride to yield the dendritic wedge containing an activated nitro group. The resulting nitro functionality was allowed to react with the building block to give the second-generation dendron, which was then condensed with 3-nitrophthalic anhydride, followed by ring closure to re-form the phthalimide ring and restore a reactive nitro group. Through an aromatic nucleophilic substitution, the dendritic wedges with an activated nitro group were coupled to the polyfunctional core to form the dendritic macromolecules. Structures of the ether−imide dendrimers were fully characterized by use of a combination of techniques including 1H NMR, 13C NMR, IR, and mass spectrometry. The glass transition temperature of the dendrimers increased with molecular weight, and the variation was consistent with theoretical calculations. These dendritic poly(ether imide)s are soluble in various organic solvents and had a thermal stability comparable to linear poly(aryl ether imide)s.