Macromolecular Rapid Communications

Front Cover: For the first time, thin-film libraries of zinc(II) bis-2,2′:6′,2″-terpyridine metallopolymers are prepared by inkjet printing to study structure–property relationships and their possible usage for organic photovoltaic (OPV) or polymer light-emitting diode (PLED) applications. Using a combinatorial approach, various important parameters, including solvent system, dot spacing, and substrate temperature, as well as UV–vis absorption and emission properties, can be screened in a materials-efficient and reproducible manner. Further details can be found in the article by C. Friebe, A. Wild, J. Perelaer, and U. S. Schubert* on page 503.

Front Cover: Two-photon absorption (TPA) is of interest for optical power limiting, data storage, two-photon microscopy, microfabrication, frequency up-conversion lasing, and many other applications. Highly efficient inorganic TPA molecules are now reported. Ruthenium alkynyl den-drimers up to second generation in size have been prepared by a divergent route and exploiting Sonogashira coupling. These compounds display an NLO dendrimer effect – their cubic nonlinearities and two-photon absorption cross-sections increase nonlinearly on increasing dendrimer generation. Further details can be found in the article by K. A. Green, P. V. Simpson, T. C. Corkery, M. P. Cifuentes, M. Samoc, and M. G. Humphrey* on page 573.

Polystannanes are a unique type of polymer and their main chain is composed of covalently bound metal atoms. Polystannanes have attracted much interest in polymer science. Information on various aspects of these polymers, including their synthesis, properties, processing, orientation, degradation, and stabilization is provided.

Polymers containing transition-metal complexes, one of the most excellent optoelectronic materials, have attracted more and more research interest in recent years. They exhibit excellent optoelectronic properties, combining the advantages of both polymers and metal complexes. New research trends in the optical and electronic applications of polymers containing transition-metal complexes are summarized.

Investigation of photoinduced dynamics in terpyridine systems presents a cornerstone in the guided design toward innovative photoactive materials. This contribution features recent work dissecting the complex photoinduced processes in terpyridine-based coordination complexes and polymers into dynamics associated with the individual molecular building blocks.

The fabrication of dye-doped cross-linked rubbery nanoparticles that exhibit upconversion even at relatively low power densities is reported here. Successful loading of an upconverting dye pair into the nanoparticles following surfactant-free emulsion polymerization is reported. In addition to optical properties, the nanoparticles were characterized by electron microscopy and dynamic light scattering.

Thin-film libraries of zinc(II) bis-2,2′:6′,2″- terpyridine metallopolymers were prepared by inkjet printing to study structure–property relationships between the synthesized polymers and their possible usage for organic photovoltaic (OPV) or polymer light-emitting diode (PLED) applications. Several processing parameters, including dot spacing, solvent system, substrate temperature, and UV-vis absorption/emission, were studied, for the first time, in a combinatorial approach using inkjet printing.

Cationic cobaltocenium-containing block copolymers are prepared by ring-opening metathesis polymerization. These block copolymers exhibit counterion-dependent self-assembly in solutions. The stability of the self-assembled micelles is dictated by ion exchange between the two different segments. These micelles are further used as templates to prepare oxidized cobalt nanoparticles, which show a magnetic response.

A new, fast, and efficient method for the synthesis of ruthenium(II) bis terpyridine metallopolymers is presented. The homoleptic Ru^II complex of 4′-(perfluorophenyl)-2,2′:6′,2″-terpyridine is a versatile monomer for a thiol -para- fluorine click reaction and can easily be converted with π-conjugated dithiols resulting in metallopolymers in a fast and efficient manner.

An innovative polymer built upon charged iridium(III), [Ir], and neutral platinum(II) units, [Pt], exhibiting charge transfer excited states [Pt]→[Ir], has been prepared. The absorption and emission spectra exhibit features reminiscent of both chromophores, and the emission lifetimes and quantum yields are intermediate between those for the isolated units, indicating a unique case of formation of hybrid excited states.

Zn^II and Ru^II metallo-copolymers composed of donor- and acceptor-substituted bis-terpyridyl ligands were synthesized and their electo-optical properties were investigated. Compared with the other conjugated polyelectrolytes, the PVC device with a configuration of ITO/PEDOT:PSS/P4:PC₆₁BM (1:1, w/w)/Ca/Al yielded the highest PCE value of 0.90% with V_oc = 0.70 V, J_sc = 3.50 mA cm⁻², and FF = 0.37.

Aqueous micelles have been prepared from poly(N-isopropylacrylamide)-block-polystyrene copolymers functionalized at the extremity of their poly(N-isopropylacrylamide) coronal chains by terpyridine ligands. The effect of temperature and of the addition of Zn(II) ions on those micelles has been then studied.

A macromolecule composed of an indefinite number of Zn-salphen complexes fused into a unique conjugated system is synthesized. The repeating molecular structure is spectroscopically examined by comparison with its analogous oligomers, including a newly synthesized tetranuclear complex. The XRD pattern suggests that the molecular assembly is highly ordered in the solid state by virtue of various intermolecular interactions.

Reactions of regioregular organometallic polymers possessing titanacyclopentadiene-2,5-diyl units to give polymers containing thiophene or selenophene units are described. The transformation of the main chain structure of the organotitanium polymer takes place smoothly by reactions with S₂Cl₂ or Se₂Cl₂ to give fully π-conjugated polymers with high HOMO energy levels.

An aminoquinoline-borafluorene complex is successfully incorporated into a main-chain of poly(arylene-ethynylene)s. This moiety restricts two aromatic planes, aminoquinoline and borafluorene, orthogonally, and extends the π-conjugation of the main-chain. The aminoquinolate moiety acts as a moderate electron acceptor so that the side-chains of the polymers regulate the fluorescence quantum yields by electron transfer.

The post-modification reaction of poly(pentafluorostyrene) allows the effective grafting of supramolecular binding motifs onto the linear polymer backbone. A metallo-supramolecular gel was obtained after the addition of iron ions as well as a phoshorescent iridium-containing polymer by grafting amine-functionalized metal complexes to the polymer.

Commonly referred to as “scorpionates”, poly(1-pyrazolyl)borate (Tp) ligands possess powerful coordination chemistry toward transition metals. In this paper, we introduce a new class of telechelic polymers that are functionalized with Tp ligands and explore their self-assembly into supramolecular structures via coordination to Fe(II). Successful formation of supramolecular polymers was confirmed through NMR, GPC, DSC, CV, and UV–vis analyses.

Soluble, high molecular weight poly(arylene ethynylene)s are constructed in high yields from silole and tetraphenylethene building blocks. The polymers are thermally stable and light emissive. They exhibit high refractive indices and can generate negative photoresist patterns upon UV irradiation.

Ruthenium alkynyl dendrimers incorporating 1,2-bis(diphenylphosphino)ethane co-ligands have been synthesized in a divergent manner, utilizing Pd-catalyzed coupling at organometallic fragments. These compounds display an NLO dendrimer effect – their cubic nonlinearities and two-photon absorption cross-sections increase nonlinearly on increasing dendrimer generation.

An efficient assembly strategy of light-active complexes into polymers is essential for future energy conversion materials. The scope of positional control of suitable metal complexes is investigated by functional initiators and post-modification of poly(ϵ-caprolactone). The prepared dye-labeled polymers display blue or red emission at ambient conditions.

Conjugated polymers incorporated with heteroleptic ruthenium complexes were synthesized by palladium-catalyzed reaction. The electronic absorption of the polymer main chain was strongly dependent on the ligand on the metal center, which showed a significant red shift compared with the metal-free polymers. The potentials of using these polymers for photosensitizers in organic photovoltaic devices were demonstrated.

The reaction between poly(ferrocenyldimethylsilane) (PFDMS) and Schlosser's base (t-BuLi/KOt-Bu pair) in THF at low temperature results in the lithiation of the Cp rings. Further reaction with trimethylsilyl chloride or D₂O afforded Cp-substituted PFDMSs with up to 1.8 new substituents per repeating unit. NMR spectroscopic analyses of these products suggest regioselective lithiation at the β position of the Cp ligands.

Linear-rigid ruthenium(II) metallo-supramolecular polymers featuring a π-conjugated spacer and tridentate ligands with clicked-on solubilizing groups were synthesized and studied by size exclusion chromatography and analytical ultracentrifugation as well as atomic force and transmission electron microscopy revealing a photoredoxactive polymer that allows for the preparation of solution-processed films.

Two platinum-acetylide polymers functionalized with the electron-deficient thiazolothiazole spacer are synthesized that exhibit p-channel field-effect charge transport characteristics with an impressive peak field-effect charge-carrier mobility of (2.1–2.8) × 10⁻² cm² V⁻¹ s⁻¹ and an on/off ratio of (0.8–1.0) × 10⁵ for the holes. The high hole mobility value is among the highest reported for metallopolyynes to date.

Palladium nanoparticle (NP)/conducting polymer hybrid composites have been prepared by seeded growth and demonstrate electrocatalytic activity toward oxygen reduction, an important process in fuel cells. The metal center directly embedded in the conducting metallopolymer backbone serves as a seed point for size-controlled palladium NP growth.