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•The first un-barbed osseous projectile point in Europe directly dated to the early Lateglacial Interstadial GI-1e.•The Upper Magdalenian tradition of double-bevelled points was carried over into the Final Palaeolithic.•The swift Lateglacial faunal turnover in the Central European low mountain range required a shift from reindeer antler as raw material to bone from other large cervid species.

In the present Feature Article, a kinetic strategy for controlling the microstructure of synthetic polymer chains prepared via a radical chain‐growth polymerization process is presented. This approach was recently developed in our laboratory and relies on the controlled kinetic addition of ultrareactive N‐substituted maleimides during the atom transfer radical polymerization of styrene. This method is experimentally straightforward and can be applied to a broad library of functional N‐substituted maleimides. Thus, this platform allows synthesis of unprecedented polymer materials such as 1D macromolecular arrays. The basic kinetic requirements, the experimental conditions, and the synthetic scope of this approach are discussed in details herein.

A series of functional initiators for atom transfer radical polymerization ATRP was prepared. These structures contain an ATRP initiating site, a labile palkoxybenzyl ester Wang linker and a functional endgroup i.e., COOH, N3, OH, CCH, or NHFmoc. These novel initiators can be utilized for synthesizing welldefined soluble polymer supports. For instance, the azide, alcohol, alkyne, and NHFmoc derivatives were tested as initiators for the bulk ATRP of styrene. SEC, MALDITOFMS, and NMR measurements indicated that welldefined polystyrene samples with defined endgroups have been synthesized in this process. Moreover, it was demonstrated that the labile Wang linkers could be easily cleaved with a mild trifluoroacetic acid treatment.

The adsorption of the heterocycles cyclopentane, tetrahydrothiophene, tetrahydrofuran, and pyrrolidine on five adsorbents (one zeolite, two activated carbons, and two silica–alumina gels) was studied with a sensor gas calorimeter at 25 °C. Systematic data on simultaneously measured adsorption isotherms and load-dependent heats of adsorption are given. The adsorption isotherms show that the maximum loading is arranged according to the molar volume of the adsorptives. Having the lowest molar volume, tetrahydrofuran reaches the highest saturation loading on all adsorbents. Based on the measured data, the prevailing interactions and their strength are analyzed. Depending on the functionalities, dispersion, induction, and dipole interactions as well as hydrogen bonds can be formed between the adsorptives and the adsorbents’ surfaces. Since pyrrolidine can act as a donor and an acceptor in hydrogen bonding, it achieves the highest heat of adsorption in all measurements. As pyrrolidine shows a stepwise decrease in the heat of adsorption on the silica–alumina gels, it represents a promising sample molecule for an accurate energetic characterization of silica–alumina gels.

A novel kinetic process was investigated for functionalizing “on‐demand” local regions of well‐defined linear polystyrene chains. This concept relies on the atom transfer radical copolymerization (ATRP) of functional N‐substituted maleimides with styrene. This copolymerization is a controlled radical process, which combines two unique kinetic features: i) all the polymers chains are growing simultaneously and ii) the cross‐propagation of the comonomers is highly‐favored as compared to homopolymerization. Thus, discrete amounts of N‐substituted maleimides (e.g., 1 equiv as compared to initiator) are consumed extremely fast in the copolymerization process and are therefore locally incorporated in narrow regions of the growing polystyrene chains. MALDI‐TOF analysis of model copolymers indicated that this kinetic concept is efficient. Although a sequence distribution is observed, well‐defined polymer chains having only one or two functional maleimide units per chain were found to be the most abundant species. Furthermore, the position of the functional groups in the polystyrene chains can be kinetically‐controlled by adding the N‐substituted maleimides at desired times during the course of the polymerization. This method is very versatile and can be applied to a wide variety of N‐substituted maleimides. Herein, a library of 20 different maleimides bearing various functional groups (e.g., aromatic moieties, fluorinated groups, hydroxy functions, protected esters, protected amines, light‐responsive moieties, fluorophores and biorelevant functions such as short poly(ethylene glycol) segments or biotin moieties) was investigated. In most cases, the functional N‐substituted maleimides could be efficiently incorporated in the polystyrene chains.

Well-defined surfactants, composed of a hydrophobic cholesterol moiety and a hydrophilic polymer segment, were synthesized via the atom transfer radical copolymerization of various oligo(ethylene glycol) (meth)acrylates initiated by Cholesteryl-2-Bromoisobutyrate (CBI). After polymerization, the bromine ω-end-groups of the surfactants were transformed into an azide function by nucleophilic substitution. Depending on their hydrophilic-hydrophobic balance, these novel surfactants lead to different types of structures in pure deionized water. For instance, surfactants with a hydrophilic block based on Oligo(Ethylene Glycol) Methyl Ether Acrylate (OEGA) repeat units were found to be molecularly soluble in pure water, even for very short hydrophilic segments. On the other hand, surfactants based on copolymers of OEGA with the more hydrophobic monomer 2-(2-Ethoxyethoxy)Ethyl Acrylate (EEO2A) formed defined micellar aggregates (Dh∼100 4;nm) in aqueous solution. These aggregates were found to be thermoresponsive and exhibited a lower critical solution temperature in water at approximately 45 °C. Moreover, the outer-corona of these micellar assemblies could be successfully functionalized in situ using the copper-catalyzed “click” cycloaddition of azides and alkynes. For instance, the azide functions of the surfactants could be efficiently “clicked” to propargyl alcohol at room temperature and in dilute aqueous solutions. FTIR and 1H NMR measurements indicated that the yield of click cycloaddition was in most cases above 95%.

The self-organization of random copolymers composed of a nucleobase monomer (either 1-(4-vinylbenzyl)thymine or 9-(4-vinylbenzyl)adenine) and dodecyl methacrylate (DMA) was studied in dilute chloroform solutions. The balance between the molar fractions of the nucleobase monomer (leading to intermolecular H-bonding) and DMA (soluble moiety in chloroform) in the polymer chains was found to be the parameter that principally influences the self-organization. DMA-rich copolymers are molecularly soluble in chloroform, whereas nucleobase-rich copolymers are insoluble in this solvent. Copolymers possessing an equimolar comonomer composition self-assemble into micrometer-sized particles physically cross-linked by intermolecular H-bonds (either thymine−thymine or adenine−adenine interactions, depending on the studied copolymer). Nevertheless, when mixed together, thymine- and adenine-based colloids fuse into thermodynamically stable microspheres cross linked by adenine−thymine interactions.

Ohne Zusammenfassung:

Ohne Zusammenfassung:

A complete libraryof N‐substituted maleimides is introduced by J.‐F. Lutz and S. Pfeifer in their Full Paper on p. 10949 ff.The atom transfer radical copolymerization of these fascinating monomers with styrene allows the design of well‐defined macromolecules with tailor‐made comonomer sequences. Background painting: nature morte aux livresby Ozias Leduc, 1892. Oil on canvas 32×40 cm. Collection: Musée national des beaux‐arts du Québec, n° 98.07. © Musée national des beaux‐arts du Québec.