Electronic tuning

Along these lines, imidazoline [68, 69] rather than oxazoline coordination sites better fitted into a modular concept in order to understand how the electronic properties should ideally be, since electron density can be readily adjusted by the choice of the N substituent [70]. The Cp ligand C5R5 in 47 permits steric and electronic tuning. With the electron-withdrawing effect of five Ph groups R, the... 

Electronic Tuning of the Lability of Inert Co(HI) and Pt(II) Complexes Rudi Van Eldik... 

Intermolecular [4+2]-cycloaddition of vinylallenes with alkynes is efficiently mediated by means of an electronically tuned rhodium catalyst (Scheme 16.81) [91]. A five-membered rhodacycle is formed from the vinylallene. Coordination followed by insertion of an alkyne to the rhodacycle generates a seven-membered rhodacycle, from which rhodium(I) is eliminated reductively to produce a cyclohexatriene, leading to the aromatic compound. 

Verma M, Chaudhry AF, Morgan MT et al (2010) Electronically tuned 1,3,5-triarylpyrazo-lines as Cu(I)-selective fluorescent probes. Org Biomol Chem 8 363-370... 

Electron impact ionization is the method of choice for the generation of molecular ions to be analyzed in a mass spectrometer [55, 56]. This method is based on essentially the same principle as radiolytical generation, but it is used at considerably lower pressures, typically 10 6 torr. High energy electrons, tuned to energies between 10 and 70 eV, are ejected from a heated filament and impact on molecules contained in an evacuated ionization chamber. In the collision, energy is transferred to the substrate causing ionization. 

Still further distortions can take place. In NiP, the chains of Ni and P atoms discernible in the MnP structure break up into Ni2 and P2 pairs. For phosphides, it is experimentally clear that the number of available electrons tunes the transition from one structural type to another. Nine or 10 valence electrons favor the NiAs structure (for phosphides), 11-14 the MnP, and a greater number of electrons the NiP alternative. For the arsenides this trend is less clear. 

With more, admittedly tedious, work, every aspect of these spaghetti diagrams can be understood. And, much more interestingly, so can the electronic tuning of the NiAs - MnP -> NiP displacive transition.75 Now let s return to some simpler matters, concerning surfaces. 

There are a very large number of different ester protecting groups available and we have selected only five of the more common representatives which exemplify the breadth of graduated hydrolytic lability that is available by simple steric or electronic tuning. Thus pivalate esters, with their greater steric hin-... 

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