“Cubism” on the Nanoscale: From Squaric Acid to Porous Carbon Cubes

Abstract

3D cube-shaped composites and carbon microparticles with hierarchically porous structure are prepared by a facile template-free synthesis route. Via the coordination of zinc acetate dihydrate and squaric acid, porous 3D cubic crystalline particles of zinc squarate can be obtained. These are easily transformed into the respective zinc oxide carbon composites under preservation of the macromorphology by heat treatment. Washing of the composite materials results in hierarchically porous carbons with high surface areas (1295 m(2) g(-1) ) and large pore volumes (1.5 cm(3) g(-1) ) under full retention of the cube-like architecture of the initial crystals. The materials are shown to be promising electrode materials for supercapacitor applications with a specific capacitance of 133 F g(-1) in H2 SO4 at a scan rate of 5 mV s(-1) , while 67% of this specific capacitance is retained, when increasing the scan rate to 200 mV s(-1) .

A High‐Throughput Composite Catalyst based on Nickel Carbon Cubes for the Hydrogenation of 5‐Hydroxymethylfurfural to 2,5‐Dimethylfuran

“…SA tends to form stable metal‐oxocarbon complexes on co‐ordination to metal ions . Inspired by this, we recently synthesized crystals with some unique 3D cube morphologies based on a squaric acid–zinc complex (SAZn) . Heat treatment of SAZn at 900 °C in a nitrogen (N 2 ) atmosphere and subsequent washing in an acid solution yields a porous carbon (PC) material (SAZn_PC), which possesses a hierarchical pore structure under retention of the cube morphology with inner cavities of fractal‐like structure.…”

“…Recently, we reported a synthesis strategy for the preparation of hierarchically porous carbon materials derived from the crystals of the coordination complex of zinc (Zn) ions and squaric acid (SA) . These primary crystals determine the structural properties of the final carbon already before the conversion to carbon, providing a porous carbon material with a unique 3D‐cube morphology, an inner hierarchical pore system, and a high specific surface area.…”

Rational Design of Carbon Nitride Materials by Supramolecular Preorganization of Monomers

“…As shown before, a careful selection of the monomer sequence is crucial for the rational tailoring of the final material; the preorganization or small C‐rich molecules with a lower N content than melamine or cyanuric acid results in different C 2 N or N‐doped carbons after calcination. For example, a complex of zinc squarate forming porous crystalline particles yields a cubic carbon composite upon pyrolysis at 900 °C . The use of the same squaric acid complexed with an N‐containing monomer, namely urea, yields nanostructured C 2 N frameworks upon carbonization .…”

Squaryl Molecular Metaphors – Application to Rational Drug Design and Imaging Agents

“…Molecular metaphors can have a broad range of applications, from synthetic organic chemistry to nanotechnology platforms [36] and including biomaterials [37]. Consequently, this review provides a valuable contribution to the interest of drug discovery and molecular imaging groups.…”

“…Admittedly, it is hard to stay on top of a still rapidly developing synthetic methodology and move to systems of biological complexity at the same time. Some opinions signify that we have a complete array of methods available with which to probe and investigate living systems, for example the use of computational methods applied to rational drug design [35].Molecular metaphors can have a broad range of applications, from synthetic organic chemistry to nanotechnology platforms [36] and including biomaterials [37]. Consequently, this review provides a valuable contribution to the interest of drug discovery and molecular imaging groups.…”