Tetraphenyl compounds

At 100°C the tetraphenyl compound decomposes to triphenylbismuthine and metallic bismuth (68). 

The tetraphenyl compound 7 has a mass spectrum essentially the same as the 4H, but quite different from the IH isomer. ... 

Chromium triphenyl perchlorate, (C6H5)3CrC104, is prepared by the fractional precipitation of a solution of chromium triphenyl hydroxide with dilute perchloric acid. The salt is microcrystalline it is best preserved under a mixture of alcohol and ether in an ice-chest in the dry state it is more labile and explosive than the corresponding tetraphenyl compound. 

Some molecules are studied for their theoretical interest one being cyclopentadienone 16. But it turns out that this dimerises instantly by a Diels-Alder reaction and cannot be studied. The simplest cyclopentadienone that can be made is the tetraphenyl compound 17. Aldol disconnection gives 18 but we can now do a second aldol disconnection to reveal the two symmetrical starting materials 19 and 20. 

Thietanone 1,1-dioxides are unknown, although the tetraphenyl compound may be an intermediate in the oxidation of the 2-thietanone 308 with m-chloro-perbenzoic acid to the sulfinic-carboxylic acid anhydride 331. The methods discussed below apply to 3-thietanone 1,1-dioxides and derivatives. 

The behaviour of the 2,2 -biphenylylenediphenylselenurane (27) was closely similar to the tetraphenyl compound (24). It can be prepared by action of phenyllithium either on the biphenylyl phenylselenonium salt or on the selenoxide. However, the decomposition appeared to solvent-dependent. Due to the non-symmetry of the molecule, the ligand coupling can occur by two ways. (See section 2222) The favoured pathway takes place at room temperature to afford the phenyl orr/w-terphenyl selenide (28). In the presence of HMPA (hexamethylphosphoramide), a more complex mixture was formed. The usually favoured pathway gave only a minor amount of the product (28), whereas the major pathway led to the formation of dibenzoselenophene (29) and biphenyl (5) in equivalent amounts. (Scheme 8.6)... 

IS prepared by the interaction of tnphenylpliosplnne and chloro-p-tolylmethyl ketone. It crystallises in colourless needles, M.pt. 231 C., and IS more soluble in water than the preceding- tetraphenyl-compound. Thefyee betaine forms silky needles, M.pt. 181 C., the platinichloride, yellowish-red needles, decomposing at 211° C., the hydrobiomide melts at 261° C., the hyduodide melts at 265° C., and the nitrate gives slender, transparent needles, M.pt. 183° to 184° C,... 

The benzyl derivative has poor stability. The tetraphenyl compound forms dark green crystals with a metallic lustre. It was prepared by the reaction of sodium tetraphenyIcyclopentadienide with tropylium bromide to give a dihydrosesquifulvalene, which was dehydrogenated to the sesquifulvalene by the action of dichlorodicyanobenzoquinone [272]. Its spectra show that it is to be regarded principally as a polyene with little dipolar character. It can, however, be reduced by lithium aluminium hydride. 

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