ABSTRACT:Delamination is a key step to obtain individual layers from inorganic layered materials needed for fundamental studies and applications. For layered van-der-Waals materials like graphene the adhesion forces are small allowing for mechanical exfoliation, whereas for ionic layered materials like layered silicates the energy to separate adjacent layers is considerably higher. Quite counter intuitively, we show for a synthetic layered silicate (Na 0.5 -hectorite) that a scalable and quantitative delamination by simple hydration is possible for high and correlated. This is indicated by fulfilling the classical Hansen-Verlet and Lindeman criteria for melting. We provide insight into the requirements for layer separation and controlling the layer distances for a broad range of materials and outline an important pathway for the integration of layers into devices for advanced applications.
We report on the synthesis and physical chemical characterization of a class of heteroleptic mononuclear cyclometalated bis(phenylpyridine)iridium(III) complexes with tetrazolate chelate ligands, such as the deprotonated form of 2-(1 H-tetrazol-5-yl)pyridine ( PyTzH), 2-(1 H-tetrazol-5-yl)pyrazine ( PzTzH), and 5-bromo-2-(1 H-tetrazol-5-yl)pyridine ( BrPyTzH). The electrochemical and photophysical investigations of the resulting iridium(III) complexes revealed a rather wide span of redox and emission properties as a consequence of the nature of the ancillary tetrazolate ligand. In particular, within a series of the three neutral species, the emission observed changes from the blue-green of the pyridyltetrazolate complex to the red of that containing the pyrazinyltetrazolate ligand. The bromo-containing species, despite it displaying poor photophysical performances, is a synthetically attractive building block for the construction of polymetallic architectures. Moreover, the investigation of the reactivity toward electrophiles of one of the neutral mononuclear complexes, by methylation of the coordinated tetrazolate ligand, has also allowed further tuning of the electronic properties. In the latter case, the emission color tuning is also associated with a simple method for the conversion of a neutral species, a potentially triplet emitter for organic light-emitting devices, into the corresponding methylated cation, which might be used as a dopant for light-emitting electrochemical cell type devices or as a marker for biological labeling.
Killing with light: A multifunctional nanosized zeolite L uses amino groups, a luminescent dye, and a 1O2 producer to target, label, and kill pathogenic and antibiotic‐resistant bacteria.
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