The Importance of Chemistry for Nanotechnology

The paradigm shift from uniform bulk materials towards nanostructured multifunctional materials is essential for future knowledge transfer from fundamental to applied sciences. In nanotechnology, two approaches are employed: “top-down” and “bottom-up”. In the top-down approach, larger assemblies are broken down to smaller units, while the bottom-up approach makes use of atomic or molecular building blocks to construct the desired nanostructures. Chemistry plays a major role in the bottom-up approach by providing progressive building blocks, such as “smart” molecules, that can be combined — preferentially by self-organisation — to create fundamentally new classes of materials. The ultimate goal is to create environmentally friendly, highly efficient, low-cost devices serving multifunctional purposes for a steadily more diversified modern societ

Facile synthesis of a nickel(0) phosphine complex at ambient temperature.

The reaction of the bis(methoxy)-2-pyridyl-phosphine (MeO)2P(2-py) (1) with [Ni(MeCN)6](BF4)2 leads to the unexpected single-step reduction of NiII and the formation of a tetrahedral nickel(0) complex [{(MeO)2P(2-py-H)}2{(MeO)2P(2-py)}2Ni](BF4)2 (2). The redox activity is probably induced by the decomposition of the tetrafluoroborate anion; NMR spectroscopic studies point towards a fluoride-assisted oxidation of the 2-pyridyl-phosphine ligand, with associated reduction of the metal

Conjugation in and Optical Properties of 1‑<i>R</i>‑1,2-Diphospholes and 1‑<i>R</i>‑Phospholes

The strength of conjugation between the diene moieties of 1-<i>R</i>-1,2-diphospholes and 1-<i>R</i>-phospholes and exocyclic phenyl groups of these P-heteroles has been quantitatively characterized by the use of Raman activities of the bands of the phenyl substituents. It is shown that conjugation in both types of phospholes is very similar to the conjugation of phenyl groups with the diene system of cyclopentadiene. Introduction of substituents (−OMe, −C­(O)­H, −NO₂, −NMe₂, and −CHCH₂) in the <i>para</i>-position of the phenyl groups of 1-<i>R</i>-1,2-diphospholes extends π-delocalization of exocyclic groups into the electronic system of the 1,2-diphosphole ring, producing bathochromic shifts of the absorption bands up to 63 nm. In contrast, hypsochromic shifts up to 40 nm can be achieved by introduction of SnMe₃ or SiMe₃ groups at the phosphorus­(III) atom of the 1,2-diphosphole and concomitant increase of aromaticity of the P-heterole. Conjugation shifts the “centre of gravity” of the whole electronic absorption spectrum, whereas positions of separate absorption bands are not simply dependent on conjugation lengths