Benzophenone complexes

One of the best tests of purity of dioxane is the formation of the purple disodium benzophenone complex during reflux and its persistence on cooling. (Benzophenone is better than fluorenone for this purpose, and for the storing of the solvent.) [Carter, McClelland and Warhurst Trans Faraday Soc 56 343 I 960], TOXIC. 

Cyclohexane (Phillips 99+ mole %) was purified by stirring over H SO then distilled from a sodium dispersion. Tetrahydrofuran (Fisher) was distilled from a sodium/benzophenone complex. 

A benzophenone-based ruthenium complex (15) afforded high enantioselectivity in the catalytic asymmetric ketone hydrogenation (up to 99% ee, >99% yield). It was found that chirality of benzophenone complexes can be controlled even in the solution phase.332... 

Tetrahydrofuran (THE) was distilled over sodium-benzophenone complex and transferred to the reaction flask by applying a positive pressure of argon. N,N-Dimethyl formamide (DMF) was distilled over calcium hydride directly into the reaction flask. Styrene was distilled over calcium hydride and collected... 

The guest molecules are disordered as they usually are in clathrates, and we could not provide a conformation model of the guest molecules. However, the contents of the channels appeared different in the two structures. In the benzophenone complex, the analysis of the electron density revealed that the guest is completely included in the B Cyd torus and that the carbonyl occupies two positions near the level of the 04 a-toms of the glucose rings. In the biphenyl complex on the other hand, this fact cannot be ascertained. 

Chaudret and coworkers synthesized an ortho-ruthenated acetophenone complex (26) having axial tricyclohexylphosphine ligands. Complex 26 showed almost no catalytic activity, and on the basis of this observation and the activity of 22, they proposed that the binding of the CO Hgand to the ruthenium suppresses the catalytic activity of the ruthenium complex. Fogg and coworkers prepared ortho-ruthenated benzophenone complex 27, which showed only low catalytic activity and was proposed to be a catalytic sink in the alkylation of aromatic ketones. Weber and coworkers synthesized a unique zero-valent ruthenium complex (23), which was effective for the alkylation of aromatic ketones. Subsequently, Whittlesey and coworkers synthesized complex 25, which did not catalyze the hydroarylation. However, the authors stated it was highly Hkely that alternative isomers of 25 could be involved in the catalytic pathways. Further hints toward this end came with the characterization of the two N,0-coordinated acetylpyrrolyl complexes 24 and 28. Complex 24 was found to be an active catalyst of the reaction but was shown to isomerize to its inactive isomer 28 at 80 °C. 

Among the many organic compounds recently proposed for the photostabilization of polymers, derivatives of benzophenone, complex esters of salicyclic acid, derivatives of benzotriazole, various organic tin compounds, thlazolidones, etc. are finding use. The last two classes of compounds are not considered in this chapter, since the methods of synthesis, properties, and use of organic tin compounds [1, 2] and thiazo-lidones [3, 4] have been rather fully treated in the literature. 

Anhydrous magnesium chloride (1.5% HjO) and titanium tetrachloride (99.9%) were obtained from Aldrich. Alkylmagnesium compounds were obtained from LITHCO (in hexane) and from Texas Alkyls (in heptane). Samples of silica were obtained from W. R. Grace (290 m /g) imd from PQ Corporation (330 m /g), and they were pretreated up to 600 C, where necessary, under Nj before use. Solvents were distilled fresh from CaHj or from K-benzophenone complex (THF), and were stored over sodium wire where... 

The rhodium bisolefm complex Cp Rh( -C2H3SiMe3)2 was found to be a catalyst for the selective addition of olefins to the ortho-position of aromatic ketones. In the presence of excess ketone, the formation of a benzophenone complex, (Cp Rh)2-7 -7 -C6HsC(0)Ph 361, was observed. In this complex, the arene is 77 -coordinated to one Rh atom and 77 -coordinated to the other one." ... 

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