Conjugated alternating copolymers containing both donor and acceptor moieties in the main chain

A straightforward synthesis toward two conjugated alternating copolymers consisting of 2,7-linked carbazole donor (2,7-Cz) and ladderized pentaphenylene with diketone bridge (LPPK) acceptor chromophores is reported: the copolymers differ by the repeat unit ratio between the 2,7-Cz and LPPK units within the backbone; energy and charge transfer properties and supramolecular organizations of donor-acceptor moieties in these copolymers have been studied via optical spectroscopy and two-dimensional wide-angle X-ray scattering (2D-WAXS); preliminary results such as the efficient energy and charge transfer and pi-stacking character in the solid state suggest that the copolymers are potentially useful for photovoltaic devices.     

A novel structural form of MIL-53 observed for the scandium analogue and its response to temperature variation and CO2 adsorption

The scandium analogue of the flexible terephthalate MIL-53 yields a novel closed pore structure upon removal of guest molecules which has unusual thermal behaviour and stepwise opening during CO(2) adsorption. By contrast, the nitro-functionalised MIL-53(Sc) cannot fully close and the structure possesses permanent porosity for CO(2).     

Tournament immersion and cutwidth

A (loopless) digraph H is strongly immersed in a digraph G if the vertices of H are mapped to distinct vertices of G, and the edges of H are mapped to directed paths joining the corresponding pairs of vertices of G, in such a way that the paths used are pairwise edge-disjoint, and do not pass through vertices of G that are images of vertices of H. A digraph has cutwidth at most k if its vertices can be ordered {v₁,…,vn} in such a way that for each j, there are at most k edges uv such that u∈{v₁,…,vj−1} and v∈{vj,…,vn}.We prove that for every set S of tournaments, the following are equivalent:

•

there is a digraph H such that H cannot be strongly immersed in any member of S,

•

there exists k such that every member of S has cutwidth at most k,

•

there exists k such that every vertex of every member of S belongs to at most k edge-disjoint directed cycles.

This is a key lemma towards two results that will be presented in later papers: first, that strong immersion is a well-quasi-order for tournaments, and second, that there is a polynomial time algorithm for the k edge-disjoint directed paths problem (for fixed k) in a tournament.     

Toward the peri‐Pentacene Framework

Based on modern pyrene chemistry, a new route toward the synthesis of the peri‐pentacene framework was developed. Firstly, the tetraketo form as stable precursor was targeted, because the fully aromatic peri‐pentacene is predicted to suffer from high instability and reactivity. Therefore, a recently developed 4,5,9,10‐tetrafunctionalization of pyrene was utilized to build up a planar and a dragonfly‐shaped derivative in five steps, which only differ in the two outer bonds between the peripheral benzene rings. The planar tetraketone could only be dissolved in strong acids upon protonation, which limited the use of analytical methods. In contrast, the dragonfly‐shaped form showed excellent organosolubility. In‐depth investigation by NMR spectroscopy revealed co‐existence of atropo‐isomers in solution. The optical and electronic properties were analyzed by UV/Vis spectroscopy and cyclic voltammetry. To approach aromatic conjugation, stepwise reduction in solution by using tetrabutylammonium borohydride was carried out. Reduced species were studied by ESR and UV/Vis spectroscopy, as well as by MALDI‐TOF MS, confirming the formation of the radical anion.     

Chiral recognition in solution and the gas phase. Experimental and theoretical studies of aromatic D- and L-amino acid–Cu(II)–chiragen complexes Jennifer L. Seymour František Tureček Andrei V. Malkov Pavel Kočovský Journal of Mass Spectrometry 2004; 39: 1044–1052

The original article to which this Erratum refers was published in Journal of Mass Spectrometry 2004; 39: 1044–1052.     

Untersuchungen an Stickstoff-Chlor-Verbindungen. VII. Neue N-Perchlorylverbindungen durch Ammono- und Aminolyse von Dichlorheptoxid

Studies on Nitrogen Chlorine Compounds. VII. New N-Perchloryl Compounds by Ammono- and Aminolysis of Dichlorine Heptoxide The reaction of dichlorine heptoxide with ammonia, primary and secondary amines leads to compounds belonging to the class of amides of perchloric acid. The remaining acidic hydrogen atoms on nitrogen could be replaced by metal cations. The compounds were characterized as far as possible by analysis, IR and ¹H-NMR spectroscopy. The changing of the bond character between nitrogen and chlorine depending on the substituents on nitrogen is discussed.