Intrinsic Dynamic and Static Nature of Halogen Bonding in Neutral Polybromine Clusters,with the Structural Feature Elucidated by QTAIM Dual-Functional Analysis and MO Calculations

The intrinsic dynamic and static nature of noncovalent Br-∗-Br interactions in neutral polybromine clusters is elucidated for Br₄–Br₁₂, applying QTAIM dual-functional analysis (QTAIM-DFA). The asterisk (∗) emphasizes the existence of the bond critical point (BCP) on the interaction in question. Data from the fully optimized structures correspond to the static nature of the interactions. The intrinsic dynamic nature originates from those of the perturbed structures generated using the coordinates derived from the compliance constants for the interactions and the fully optimized structures. The noncovalent Br-∗-Br interactions in the L-shaped clusters of the C_s symmetry are predicted to have the typical hydrogen bond nature without covalency, although the first ones in the sequences have the vdW nature. The L-shaped clusters are stabilized by the n(Br)→σ*(Br–Br) interactions. The compliance constants for the corresponding noncovalent interactions are strongly correlated to the E(2) values based on NBO. Indeed, the MO energies seem not to contribute to stabilizing Br₄ (C_2h) and Br₄ (D_2d), but the core potentials stabilize them, relative to the case of 2Br₂; this is possibly due to the reduced nuclear–electron distances, on average, for the dimers.     

An unpaired electron-based hole-transporting molecule: triarylamine-combined nitroxide radicals

A durable nitroxide radical combined with a triarylamine moiety exhibited a hole-drift mobility of 6 x 10(-3) cm(2) V(-1) s(-1), to which the aminophenyl nitroxide structure contributed.     

Polymeric cobalt-schiff-base and -porphyrin complexes as a dioxygen device

New functions of polymeric cobalt complexes were examined using their oxygen-binding reactions in the solid state. An oxygen-releasing device was prepared by compositing the oxygen-binding but electrically insulating cobalt-Schiff-base or -porphyrin complex with a conductive carbon powder. The device quickly released the absorbed oxygen in response to an applied voltage. A polymer film containing the cobalt-Schiff-base complex reversibly stretched in response to the atmospheric oxygen concentration. The driving force of the stretching of the film was attributed to the crystal structure change of the complex before and after the oxygen-binding.     

Market selection: hungry misers and bloated bankrupts

The Market Selection Hypothesis is a principle which (informally) proposes that ‘less knowledgeable’ agents are eventually eliminated from the market. This elimination may take the form of starvation (the proportion of output consumed drops to zero), or may take the form of going broke (the proportion of asset held drops to zero), and these are not the same thing. Starvation may result from several causes, diverse beliefs being only one. We firstly identify and exclude these other possible causes, and then prove that starvation is equivalent to inferior belief, under suitable technical conditions. On the other hand, going broke cannot be characterized solely in terms of beliefs, as we show. We next present a remarkable example with two agents with different beliefs, in which one agent starves yet amasses all the capital, and the other goes broke yet consumes all the output—the hungry miser and the bloated bankrupt. This example also serves to show that although an agent may starve, he may have long-term impact on the prices. This relates to the notion of price impact introduced by Kogan et al. (Market selection, working paper, 2009), which we correct in the final section, and then use to characterize situations where asymptotically equivalent pricing holds.     

Polymerization of lactic <Emphasis Type="Italic">O</Emphasis>-carboxylic anhydride using organometallic catalysts

The ring-opening polymerization of 5-methyl-1,3-dioxolane-2,4-dione(lactic O-carboxylic anhydride,LacOCA) using organometallic complexes,including Co(Ⅲ) complexes with Schiff base ligands,Tin(Ⅱ) alphatates and Al(Ⅲ) complexes with Schiff base ligands,was explored.The polymerization was carried out by treatment of the organometallic complexes with LacOCA in toluene under mild conditions.The corresponding poly(lactic acid) was characterized by spectroscopy and thermal analyses,which revealed insight into the structure of the effective catalyst for the polymerization of LacOCA.     

Discovery of surfactants for metal/semiconductor separation of single-wall carbon nanotubes via high-throughput screening

We report novel surfactants that can be used for the separation of metallic (M) and semiconducting (S) single-wall carbon nanotubes (SWCNTs). Among the M/S separation methods using surfactants in an aqueous solution, sodium dodecyl sulfate plays a key role in density gradient ultracentrifugation (DGU) and agarose gel separations. In this study, we screened 100 surfactants for M/S separation using a high-throughput screening system. We identified five surfactants, which could be used for both DGU and agarose gel separations, suggesting that the basic principle of these separations is common. These surfactants have relatively low dispersibilities, which is likely due to their common structural features, i.e., straight alkyl tails and charged head groups, and appeared to enable M- and S-SWCNTs to be distinguished and separated. These surfactants should stimulate research in this field and extend the application of electrically homogeneous SWCNTs not only for electronics but also for biology and medicine.