We have developed a new method, i.e., XLOGP3, for logP computation. XLOGP3 predicts the logP value of a query compound by using the known logP value of a reference compound as a starting point. The difference in the logP values of the query compound and the reference compound is then estimated by an additive model. The additive model implemented in XLOGP3 uses a total of 87 atom/group types and two correction factors as descriptors. It is calibrated on a training set of 8199 organic compounds with reliable logP data through a multivariate linear regression analysis. For a given query compound, the compound showing the highest structural similarity in the training set will be selected as the reference compound. Structural similarity is quantified based on topological torsion descriptors. XLOGP3 has been tested along with its predecessor, i.e., XLOGP2, as well as several popular logP methods on two independent test sets: one contains 406 small-molecule drugs approved by the FDA and the other contains 219 oligopeptides. On both test sets, XLOGP3 produces more accurate predictions than most of the other methods with average unsigned errors of 0.24-0.51 units. Compared to conventional additive methods, XLOGP3 does not rely on an extensive classification of fragments and correction factors in order to improve accuracy. It is also able to utilize the ever-increasing experimentally measured logP data more effectively.

It has been established that sodium dodecyl sulfate (SDS) binds to the micelles and monomers of the block copolymer F127. SDS binds to the monomeric unassociated F127 in the form of polymer/bound SDS micellar complexes. SDS binds to F127 micelles first forming mixed micelles, which dissociate into smaller mixed aggregates and then to single F127 unassociated monomers. A third interaction of SDS, which involves promotion of F127 micelles at concentrations up to 3 °C below the critical micellar temperature of pure F127, was identified and is investigated in the present work. The formation of such SDS-induced mixed micelles was monitored using differential scanning calorimetry, light scattering, isothermal titration calorimetry, and a SDS selective electrode for electromotive force measurements. These investigations have shown how the different binding and aggregation processes between SDS and F127 involving induced micellization, growth of mixed micelles, breakdown of mixed micelles, and binding of SDS to monomeric F127 can be identified and characterized.

The binding of both an anionic surfactant, sodium dodecyl sulfate (SDS), and a cationic surfactant, tetradecyltrimethylammonium bromide (TTAB), to various water soluble copolymers containing equal amounts of the monomers of methyl vinyl imidazole (MVI) and vinyl pyrrolidone (VP) and various amounts of a third monomer, vinyl acrylic acid(AA), have been studied using surfactant selective electrodes and isothermal titration microcalorimetry (ITC). The change in the binding behavior of both surfactants has been investigated as the charge and content of the acrylic acid monomer has been systematically altered. The data clearly show how surfactant binding can be both moderated and enhanced. In the presence of salt there is almost no binding of the MVI/VP/AA polymer in its anionic form with TTAB, whereas the binding with SDS is somewhat reduced in comparison with the data for no salt. The ITC measurements have also been used to investigate the binding of various forms of the polymer with a commercial sample of sodium dodecylbenzenesulfonate. The binding data are very well defined and clearly show similar trends to those observed for SDS.

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In spite of an ongoing advancement, current popular EES systems including Li-ion batteries (LIBs), supercapacitors (SCs), and redox flow cells (RFCs) are limited by severe performance challenges of electrode materials in terms of low energy and power density as well as short durability. To mitigate the issues, carbon nanomaterials could be introduced to these EES systems, taking advantage of their unique geometry, excellent conductivity, large surface area, and intrinsic flexibility. Numerous carbon nanomaterial based EES systems, where carbon nanomaterials are adopted as either conducting additive or active electrode, have been developed and demonstrated appealing energy and power features. With the capability to enhance the structural and electrochemical properties of electrodes, carbon nanomaterials and their derivatives offer a wide range of possibilities to design advanced EES devices that can meet our growing energy and power demands in the future.A number of reviews have been published in the past few years on the application of carbon nanomaterials in EES. [5][6][7][8] However, this area is so active and new works accumulate very quickly. Therefore, it is helpful to update the new designs and outcomes. This progress report will summarize the most exciting recent (from the year 2010 onwards) advances in the application of carbon nanomaterials with different dimensions, i.e., 0D fullerene, 1D CNT, 2D graphene, and 3D assemblies of CNT and graphene, in EES systems, and highlight the new trends in the field. Besides the repetitively reviewed LIBs and SCs, this work will also deal with another important system, the RFC, which has been rejuvenated recently and is becoming increasingly vital for large scale energy storage. The recent EES applications of carbon nanomaterials will be discussed based on their dimensions. Structure and Properties of Various Nanostructured CarbonFullerenes, CNTs, and graphene all present conjugated π electron systems. The unique electronic configuration combined with geometric structure endows them with extraordinary properties, which make them superior to their competitors for specific applications such as EES. 0D FullerenesFullerene normally has a hollow sphere or ellipsoid shape. Specifically, C 60 has a cage-like fused-ring structure (truncated Carbon nanomaterials including fullerenes, carbon nanotubes, graphene, and their assemblies represent a unique type of materials in diverse formats and dimensions. They feature a large surface area, superior conductivity, fast charge transport, and intrinsic stability, which are essentially required for vari ous electrochemical energy storage (EES) systems such as Li-ion batteries, supercapacitors, and redox flow cells. The scaled-up and reliable production and assembly of carbon nanomaterials is a prerequisite for the development of carbon nanomaterial-based EES devices. In this progress report, the preparation of carbon nanostructures and the state-of-the-art applications of carbon nanomaterials with different dimensions in versatile EES...

Chirality amplification refers to the ability of a small chiral bias to fully control the main chain helicity of polymers and assemblies. Further implementation of functional chirally-amplified helices as switchable asymmetric catalysts, chiral sensors and circularly-polarized light emitters will require a greater control of the energetics governing these chirality amplification effects. In this work, we report on the counterintuitive ability of an achiral molecule to suppress conformational defects in supramolecular helices thus leading to the emergence of homochirality in a system containing a very small chiral bias. We focus our investigation on supramolecular helices composed of an achiral benzene-1,3,5-tricarboxamide (BTA) ligand, coordinated to copper, and an enantiopure BTA co-monomer. Amplification of chirality as probed by varying the amount (sergeants-and-soldiers effect) or the optical purity (diluted majority-rules effect) of the enantiopure co-monomer, are modest in this initial system. However, both effects are hugely enhanced upon addition of a second achiral BTA monomer leading to a perfect control of the helicity either by means of a remarkably low amount of sergeants (0.5%) or a small bias from a racemic mixture of enantiopure co-monomers (10% e.e.). Such an enhancement in the amplification of chirality is only achieved by mixing the three components, i.e. the two achiral and the enantiopure co-monomers, highlighting a synergistic effect upon co-assembly of the three monomers. Investigation of the role of the achiral additive by multifarious analytical techniques supports its ability to stabilize the helical co-assemblies and suppress helix reversals i.e. conformational defects. Implementation of these helical copper precatalysts in the hydrosilylation of 1-(4-nitrophenyl)ethanone confirms that the effect of the achiral BTA additive is also operative under the conditions of the catalytic experiment. A highly enantioenriched product (90% e.e.) is produced by a supramolecular catalyst operating with ppm levels of chiral species. Scheme 1 Schematic representation of the concept. Supramolecular stacks are composed of a first soldier (green) and a low amount of sergeants (blue) (I) or a mixture of enantiopure monomers slightly biased from the racemic mixture (II). The stacks consist of a nearly equal amount of left and right-handed helical parts. Upon addition of a second soldier (orange), these helices become homochiral (III and IV). This soldier acts as a "rigidifier" by stabilizing the helical co-assemblies and removing helix reversals as indicated by the helix reversal penalty (HRP) values. This concept also applies for the construction of helical catalysts in which the first soldier bears a catalytic site. Scheme 2 Left: chemical structures of the BTA monomers used in this study. Right: representation of the helical co-assemblies, preferentially right-handed, formed by mixing l1-BTA, [Cu(OAc)2•H2O], (S)-BTA and a-BTA (S&S type mixture). For a tentative molecular representation of the concept sho...

Compared with carbon nanotubes and graphene, graphene oxide (GO) exhibits excellent water solubility and biocompatibility in addition to the characteristic G band in Raman spectra. Therefore GO might be able to act as a flexible Raman probe to image cells or tissues through Raman mapping. However, the weak intensity of the G band restricts such applications of GO. Here we decorated GO with Au nanoparticles and found that the Raman intensity of GO in aqueous dispersions were remarkably enhanced by the surface enhancement effect. Therefore, rapid Raman imaging for Hela 229 cells was realized using Au/GO hybrids as Raman probes. The cell internalization mechanism of GO and Au/GO hybrids were also studied using Raman imaging. An endocytosis pathway was proposed from the results. In addition, the aqueous dispersions of Au/GO hybrids are stable for several weeks. Therefore, relying on the surface enhancement effect of Au nanoparticles, GO exhibits great potential as a general Raman imaging tool for biosystems.

Direct growth of single-walled carbon nanotubes (SWNTs) on flat substrates by chemical vapor deposition (CVD) is very important for the application of SWNTs in nanodevices. In the growth process, catalysts play an important role in controlling the structure of SWNTs. Over the years, we have systematically studied the size-controlled synthesis of Fe-based nanoparticles and the CVD growth of SWNTs, especially the horizontally aligned SWNTs, catalyzed by these produced nanoparticles. Some new catalysts were also developed. Among them, Cu is shown to be a superior catalyst for growing SWNT arrays on both silicon and quartz substrates and Pb is a unique catalyst from which one can obtain SWNTs without any metallic contaminant. SWNTs prepared with both Cu and Pb are very suitable for building high-performance nanodevices. These studies are also very helpful for further understanding the growth mechanism of SWNTs.