Ag emini-type amphiphilic molecule,c onstituted of two V-shaped polyaromatic amphiphiles linked by al inear acetylene spacer,w as synthesized.T he gemini amphiphile assembles into aw ell-defined aromatic micelle (ca. 2nmi n core diameter), providing higher stability in water even at low concentration (0.09 mm)a nd high temperature (> 130 8 8C). Unlike common gemini amphiphiles with aliphatic chains,the present amphiphile and its micellar assembly emit green and orange fluorescence (F F = 33 and 9%), respectively.D espite strong and multiple p-stacks of the polyaromatic panels of the amphiphiles,t he water-soluble gemini aromatic micelle incorporates medium-size to large hydrophobic compounds into the frameworks.I nterestingly,t he guest binding capability toward large planar molecules was enhanced by more than two times through the pre-encapsulation of spherical molecules in the cavity.
Carbonates are ubiquitous minerals carrying important information on aqueous environments where they precipitated on the Earth and space. While their ideal chemical formulae are denoted as simple as MCO3 or M1M2(CO3)2 (M: metal cations), natural carbonates generally form solid-solution series and their compositions deviate from the ideal formulae. Since their cation composition due to the substitution provides a sensitive indicator for chemical and thermodynamic environments of aqueous solutions where they precipitated, their composition analysis has been widely carried out from the environmental/geochemical/astrochemical aspects. However, in widely used back-scattered electron and energy dispersion X-Ray analyses, samples should be generally sliced and/or their surface be polished prior to the measurements. For analyzing rare samples with small sizes, such as ones sampled from deep-sea and/or meteorites and asteroids, a non-destructive method without any pretreatments has been strongly desired. Here, a novel analytical method for discriminating various carbonates with Raman micro-spectroscopy is demonstrated, showing that the biaxial plot of the peak frequencies of their lattice modes linearly moves upon partial substitution of the cations. The cation substitution leads to linear movement in the biaxial map, and the slopes of the movement were different for Mg2+-Fe2+ and Mn2+-Fe2+ substitutions. This finding suggests that the micro-Raman analysis would be a non-destructive analytical method for evaluating the relative amount of Mg2+, Fe2+, and Mn2+ in dolomite-ankerite-kutnohorite solid-solution series, as well as Mg2+/Fe2+ ratio for magnesite-breunnerite-siderite. It would be helpful for analyzing the present and past terrestrial and cosmochemical environments.
Graphical abstract
We herein report the quantitative formation of a new aromatic micelle from bent pentacene-based amphiphiles in water. Upon encapsulation, perylene bisimide dyes form a parallel stacked dimer and graphene nanosheets comprise few layer sheets with small lateral size.
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