|
Showing 1 - 6 of
6 matches in All Departments
The functionalization of surfaces on the nanoscale is one of the
most fascinating and at the same time challenging topics in
science. It is the key to tailoring catalysts, sensors, or devices
for solar energy conversion, whose functional principle is based on
the interaction of an active solid surface with another (liquid or
gaseous) phase. As an example, planar transition metal complexes
adsorbed on solid supports are promising candidates for novel
heterogeneous catalysts. An important feature of these catalysts,
compared to supported metal clusters, is the fact that the active
sites, i. e. , the coordinated metal centers with their vacant
axial coordination sites, are well de?ned and uniform.
Metalloporphyrinoids are particularly suitable in this respect
because they combine a structure forming element-the rigid
molecular frame, which often induces long range order-with an
active site, the coordinated metal ion. Its planar coordination
environment leaves two axial coordination sites available for
additional ligands. If adsorbed on a surface, one of these axial
sites is occupied by the underlying substrate. The resulting
electronic interaction with the surface can be used to tailor the
electronic structure and thereby the reactivity of the metal
center. The remaining site is free for the attachment of molecules
(sensor functionality) and/or operates as a reaction center
(single-site catalysis). Prototype examples are omnipresent in
nature, where in particular metallo-tetrapyrrols play a decisive
role in important biological processes, with the most prominent
examples being iron porphyrins in heme, magnesium porphyrins in
chlorophyll, and cobalt corrin in vitamin B12.
The functionalization of surfaces on the nanoscale is one of the
most fascinating and at the same time challenging topics in
science. It is the key to tailoring catalysts, sensors, or devices
for solar energy conversion, whose functional principle is based on
the interaction of an active solid surface with another (liquid or
gaseous) phase. As an example, planar transition metal complexes
adsorbed on solid supports are promising candidates for novel
heterogeneous catalysts. An important feature of these catalysts,
compared to supported metal clusters, is the fact that the active
sites, i. e. , the coordinated metal centers with their vacant
axial coordination sites, are well de?ned and uniform.
Metalloporphyrinoids are particularly suitable in this respect
because they combine a structure forming element-the rigid
molecular frame, which often induces long range order-with an
active site, the coordinated metal ion. Its planar coordination
environment leaves two axial coordination sites available for
additional ligands. If adsorbed on a surface, one of these axial
sites is occupied by the underlying substrate. The resulting
electronic interaction with the surface can be used to tailor the
electronic structure and thereby the reactivity of the metal
center. The remaining site is free for the attachment of molecules
(sensor functionality) and/or operates as a reaction center
(single-site catalysis). Prototype examples are omnipresent in
nature, where in particular metallo-tetrapyrrols play a decisive
role in important biological processes, with the most prominent
examples being iron porphyrins in heme, magnesium porphyrins in
chlorophyll, and cobalt corrin in vitamin B12.
Die Autoren stellen in diesem essential einen
herausforderungsbasierten und studierendenzentrierten Ansatz der
Hochschuldidaktik vor, mit dem Studierende neben fachlichen
Inhalten gleichzeitig auch Problemloesungsfahigkeiten, analytische
und soziale Kompetenzen sowie die Fahigkeit zur Selbstreflexion und
-entwicklung erwerben und anwenden koennen. Basierend auf aktuellen
Erkenntnissen der Motivations-, Lern- und Neurowissenschaften wird
ein praxisorientiertes Lehr- und Lernmodell prasentiert, in dem
Herausforderungen, aktives Handeln, Feedback und Reflexion im
Zentrum stehen. Studierende sollen dabei zu selbststandigem
kritischem Denken motiviert werden. Das essential enthalt
zahlreiche Tipps fur eine die Studierenden aktivierende und
motivierende Form des Lehrens und Lernens sowie konkrete
Anwendungsbeispiele aus der Lehrpraxis.
|
You may like...
Booth
Karen Joy Fowler
Paperback
R463
R366
Discovery Miles 3 660
The Butler
Danielle Steel
Paperback
R383
Discovery Miles 3 830
The Survivors
Jane Harper
Paperback
R493
R455
Discovery Miles 4 550
Southern Man
Greg Iles
Paperback
R420
R280
Discovery Miles 2 800
|