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Carbon is anything but a new material, yet ubiquitously applicable for many catalytic transformations in modern organic chemistry. It is highly versatile, as it occurs as modifications abundantly available as 1–3D carbonaceous materials due to technical progress. In addition, materials such as activated charcoal, ordered mesoporous carbon (OMC), graphite and graphene (oxide), carbon nanotubes (CNTs), nanospheres (nano-onions, fullerenes), and many others are no “innocent” supports, as demonstrated by many recent publications within the revitalized field of “carbocatalysis”. By nature, carbon scaffolds offer a perfect link between nanoscaled matter and organic molecules, which makes them an ideal cornerstone for molecular catalysts. Apart from this inherent chemical significance, the physical properties (e.g., different conductivity) are equally important for the performance of heterogeneous or immobilized homogeneous catalysts. Careful selection of the carbon scaffold enables control of reactivity by tuni...

Concentrating dilute streams is a key operation in numerous industries. The work presented here investigates the use of magnetic nanoparticles as transport reagents to mechanically move specific compounds against concentration gradients. Using a model system (arsenate), a cyclic, two-step process for concentrating solutes can be realized, based on a reversible, pH dependent adsorption equilibrium and two stirred tanks: adsorption of the model ion As(V) from a dilute aqueous stream (large tank) onto chemically functionalized magnetic nanoparticles allows water purification at the mg per liter level. Magnetic separation thereby results in an energy efficient removal of the noxious ion from a large water volume (no pumping, magnetic sedimentation/flocculation) and transfer into a much smaller, separate volume (small tank). Changing the acidity (pH) within the much smaller tank allows desorption of the collected ion As(V) into a small volume and thereby permits efficient enrichment. This process scheme, therefore, splits a highly dilute stream into a purified stream (A) and a concentrate stream (B) by using a true moving bed. Long time recycling of the functional magnetic nanoparticles mainly depends on the efficiency of magnetic filtration, under the conditions of reversible adsorption and by using stable magnetic nanoparticles (carbon-coated metal nanoparticles).

A novel organic/inorganic hybrid material comprising carboncoated cobalt nanoparticles and a poly(benzylchloride)styrene shell is the first magnetic support that complies with important requirements for immobilized reagents and scavengers, that is, stability under harsh conditions (e.g., acids), sufficient loading (up to 2 mmol g(-1)), and satisfying magnetization. The durability of the scaffold was demonstrated by immobilization of a trialkylsilane reagent, which served as a "magnetic" protecting group for a number of primary and secondary alcohols. Importantly, the scaffold could be efficiently separated, recycled, and reused after alcohol cleavage (HF·pyridine) via regeneration of the silyl chloride moiety with BCl(3).

Carbon is anything but a new material, yet ubiquitously applicable for many catalytic transformations in modern organic chemistry. It is highly versatile, as it occurs as modifications abundantly available as 1–3D carbonaceous materials due to technical progress. In addition, materials such as activated charcoal, ordered mesoporous carbon (OMC), graphite and graphene (oxide), carbon nanotubes (CNTs), nanospheres (nano-onions, fullerenes), and many others are no “innocent” supports, as demonstrated by many recent publications within the revitalized field of “carbocatalysis”. By nature, carbon scaffolds offer a perfect link between nanoscaled matter and organic molecules, which makes them an ideal cornerstone for molecular catalysts. Apart from this inherent chemical significance, the physical properties (e.g., different conductivity) are equally important for the performance of heterogeneous or immobilized homogeneous catalysts. Careful selection of the carbon scaffold enables control of reactivity by tuni...

(a nanoparticulate support for magnetic separation in organic synthesis) Physical Data: ferromagnetic cobalt (fcc) nanoparticles (average diameter: 190 °C). Can be separated from liquid dispersion utilizing an external magnetic field with field gradient (e.g., solid-state neodymium magnet). Ultrasonic dispersion is optimal, mechanical, orbital, or vortex stirring is advisable, magnetic stirring is possible.

A mussel-inspired synthetic adhesive based on dopamine containing methacrylate copolymers was developed to bond polymers to metal surfaces at an adhesion strength of up to 20 MPa for bulk samples.

Magnetic nanoparticle dispersions are traditionally made from superparamagnetic materials since the absence of magnetic particle–particle attraction under normal conditions (no external field) easily allows preparation of stable dispersions. For inductive heating in medicinal chemistry or material science, however, the much higher magnetization of ferromagnetic metals over the currently used oxides is attractive. Traditional attempts to prepare stable dispersions of ferromagnetic particles, however, failed since the strong magnetic particle–particle attraction usually overcomes repulsive effects from surfactants or steric stabilizers (typically polymers). In the present work, we demonstrate how the direct, covalent attachment of highly charged polymers can circumvent stabilizer detachment and loss, and permits preparation of stable dispersions of ferromagnetic particles. More specifically, carbon-coated metal nanoparticles were covalently functionalized with positively charged polymer brushes via surface initiated atom transfer radical polymerization (SI-ATRP). Particle size distributions with an average diameter of 24 nm provided a ferromagnetic liquid with unprecedented stability in water over several months. The stability was discussed by comparison of the potentials of non-functionalized and modified nanomagnets within a modified Derjaguin–Landau–Verwey–Overbeek (DLVO) theory. Measurements for inductive heating at different frequencies and various field strengths showed an average specific absorption rate of 360 W g−1. Altogether, this suggests that efficiently stabilized dispersions of ferromagnetic nanoparticles could be an alternative to superparamagnetic iron oxide particles in a number of applications.