Formal azobenzene

Structure determinations of the formally o-tellurated azobenzenes (6a)-(8a) reveal the presence of N to Te bonding and give evidence of electron delocalization in the heteroatom moiety. Selected bond lengths (A) and bond angles (°) are given in Table 2. The 1-substituted lA ,2,3-benzo-telluradiazole structures (6b)-(8b) make an important contribution to the molecular structure <79JCR(S)145, 85JOM(293)219>. 

The 1,2,3-diazasilacyclopentane (229) is formed in a photochemical reaction between trans azobenzene and hexamethylsilacyclopropane (Equation (18)) <840M579>. 1,3,4-Diazasilacyclopentane (230) is formed in a formally analogous manner (Scheme 24) in high yields <930M529>. The much... 

Recently Rouike has reported a series of cyclopalladated imine complexes with either acetylacetonate or cyclopentadienyl as the other ligand, as in Figure 8 [29]. Unlike Ghedini s azobenzene complexes these are isomerically pure but still display mesophases at similar temperatures. The square planar 16e acetylacetonate complexes display both nematic and Sa phases with extended mesophase ranges compared to the free ligands. Not surprisingly, the formally trigonal bipyramidal 18e cyclopentadienyl complexes show a nematic phase at much lower temperatures and tend to decompose above c. 180°C. 

The assumption of two linear independent partial reactions was controlled by an EDQ-diagram for both reactions. These are plotted in combination in Fig. 5.24. The photoreaction of the tra 5-azobenzene was evaluated according to the method of formal integration using the following equations ... 

Additional information is provided in the Appendix. Using the various sections of the book and the examples of the azobenzene and of the trans-stilbene photoreaction, the process of photokinetic analysis is demonstrated step by step. References to useful software and programs are provided in many literature citations, therefore these are not included in the Appendix. However, it proved helpful to use spreadsheets for simple evaluations. For this reason a Macro for formal integration is included. Its use is demonstrated by means of a simple reaction. 

In some of the preceding examples a molecule of CO (a one-carbon unit) has formally inserted into the M-C other examples of this type of reaction, which affords heterocycles, have been described, using, for example, palladium complexes (Takahashi and Tsuji, 1967) or octacarbonyl dicobalt as a catalyst and azobenzenes, Schiff bases, oximes, phenylhydrazones, semicarbazones, or azines as substrates (Mura-... 

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