Catalytic chain growth Suzuki−Miyaura polymerization of an AB-fluorene monomer using isolated (Ini1) or in situ generated (Ini2) Phos-Ph-Pd( t Bu 3 P)Br as an initiator afforded well-defined heterodifunctional polyfluorenes featuring a phosphonate group (initiating chain end) and a radically polymerizable (Phos-PF8-Sty) or atom transfer radical polymerization (ATRP)-initiating (Phos-PF8-AlkylBr) group (terminating chain end). The resulting Phos-PF8-AlkylBr polymer was directly employed for the growth of a second nonconjugated block by controlled activators regenerated by electron transfer ATRP without the need for further intermediate conversion steps. The PF8 macroinitiator was found to be a viable initiator for the generation of narrowly distributed diblock copolymers with a controlled block length of PF8 and polystyrene, poly(methyl methacrylate), or poly(2-ethylhexyl methacrylate), respectively. Novel conjugated nonconjugated comb polymers were generated by controlled radical copolymerization of PF8 macromonomers, bearing a styrene end group, with styrene or methacrylates. Thereby, it was possible to tune the number of phosphonate moieties per chain between 2 and 15.

Hybrid particles consisting of II−VI semiconductor quantum dots and conjugated polymers are increasingly relevant, but access is limited by the usual stepgrowth nature of polymer formation. We report on a graftingfrom approach by controlled Pd(II)-mediated polymerization to yield CdSe/CdS nanocrystals with a defined number of polyfluorene chains grown from their surface, as concluded from MALDI-TOF analysis and quantitative end-capping. Further studies underline the importance of matching the monomers' and the surface-bound initiators' reactivity.H ybrid nanoparticles consisting of II−VI semiconductor nanocrystals and organic semiconducting polymers are fundamentally and practically relevant. A decisive feature is the possibility for charge or energy transfer between the organic and inorganic part, combined with their colloidal nature. Possible fields of application are photovoltaics and light emitting devices 1−3 or bioimaging. 4,5 For the synthesis of hybrid particles with a well-defined shell of polymer chains attached to the core's surface, grafting-from approaches are generally the method of choice. They allow for a covalent attachment of polymers with defined chain length and high graft densities. 6 Grafting-from techniques are, however, incompatible with step growth polymerizations, the common mechanism for conjugated polymer syntheses. Thus, to date only a grafting-through approach has been reported for II-VIinorganic/organic semiconductor hybrid nanoparticles, by which Emrick et al. 7 obtained CdSe nanoparticles functionalized with oligo(phenylene vinylene) tri-and tetramers and by which Holder et al. 8 yielded CdSe nanocrystals functionalized with polyfluorene.We now report on a controlled grafting-from polymerization approach to yield CdSe/CdS nanocrystals with polyarylene chains grown from their surface (Scheme 1).Chain growth type polymerizations are possible by advanced Suzuki-Miyaura-and Kumada-coupling polymerization protocols. 9−11 The palladium-catalyzed Suzuki-Miyaura polymerization is compatible with a larger scope of functional groups 12,13 and, in particular, solvents, as it does not require organo-metallic monomers as the Kumada coupling polymerization. As a further consequence, no magnesium salts are left behind in the final product, which appears beneficial for optoelectronic properties. 6 High quality CdSe/CdS quantum dots (QDs) with a mean size of 8 nm were obtained by a modified previously reported synthesis, 14 resulting in QDs with 47% quantum yield with a maximum intensity at 636 nm and a narrow full width at halfmaximum of 30 nm. During the CdS shell synthesis, the major ligand present is the L-type ligand oleyl amine, which allows for an effective displacement by the X-type ligand (4-halophenyl)-phosphonic acid. The amount of ligand that can bind to the QDs was determined by 31 P NMR. Nanoparticle-bound species give rise to broad 31 P NMR signals, whereas nonbound species result in sharp signals. Successive portions of (4-halophenyl)-phosphonic acid were added to the QDs until a s...

Allylboration is a versatile and robust tool for the one-pot, catalyst free post-polymerization functionalization of novel borylated 1,4-cis-poly(butadiene) from insertion copolymerization.

A robust algorithm based on cross-correlations and lucky imaging reliably allows the correction of spectrally diffused datasets. This step enables the resolution-limited analysis of the emission fine structure of semiconductor quantum dots (QDs). Bright and dark excitonic transitions are resolved with optimum signal-to-noise ratio, allowing for a precise determination of the angular direction of linear polarization of the different lines. The angular phases between polarization directions are intrinsically connected to the orientations of emission dipoles. This fact provides a tool for accurate numerical computation of the azimuth ϕ and polar angle θ of the QD with respect to the optical axis. Our in-situ characterization of QD fine structure and orientation represents a precise and non-invasive method without requiring specialized equipment beyond a standard luminescence setup. In this way, important information is provided whenever efficient coupling of a quantum emitter to the electromagnetic field is targeted by various nano-and micro-optic strategies.

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