2,2 ,6,6 -tetraphenyl- -1,1-dioxide

Diphenyl-4//-thiopyran (9) was oxidized to its S,S-dioxide 141g with Ru04 (82CJC574). 2,4,4,6-Tetraphenyl-4//-thiopyran-S-oxide (143) was obtained from 56 (R = Ph) with H202-Ac0H under mild conditions [92JCS(P2) 1301 ]. 

Crystal and molecular structures of 2,4,4,6-tetraphenyl-4//-thiopyran-1-oxide (143) and the corresponding 1,1-dioxide 141a were investigated to show the boat conformations of the heterocycles as well as an interesting... 

Reduction of both nickel porphyrins and thiaporphyrins to Ni1 species has been studied by EPR and 2H NMR spectroscopy.179, 2 58 The Ni1 complex of 5,10,15,20-tetraphenyl-21-thiaporphyrin has been isolated and characterized. Reaction of this complex with sulfur dioxide produced a paramagnetic five-coordinated Ni1 S02 adduct, while reaction with nitrogenous base ligands (amines, pyridines, imidazoles) yielded five- and six-coordinate complexes. In addition, the crystal structure of Ni1 diphenyldi-p-tolyl-21-thiaporphyrin has been determined. The coordination geometry about the nickel center is essentially square planar with extremely short Ni—N and Ni—S bonds (Ni—N = 2.015(2) A, 2.014(12) A, and 1.910(14) A and Ni—S = 2.143(6) A).2359... 

The photocatalyzed reduction of carbon dioxide at elevated pressure was also investigated. Porous glass beads were used to obtain efficient gas-liquid contact. With isopropanol as the solvent and 2-propyl formate as the reducing agent,the reaction products were carbon monoxide and hydrogen. The catalyst, chloro(tetraphenyl-porphinato)rhodium(III), was irradiated with visible light /21/. 

Diphenylacetic acid has been obtained by the reduction of benzilic acid with hydriodic acid and red phosphorus 1 by the treatment of phenylbromoacetic acid with benzene and zinc dust,2 or with benzene and aluminum chloride 3 by the hydrolysis of diphenylacetonitrile 4 by heating a-diphenyldichloroethyl-ene with alcoholic sodium ethylate 5 by heating benzilic acid 6 from diphenylmethane, mercury diethyl, sodium and carbon dioxide 7 by the oxidation of a,a,5,S-tetraphenyl- 8-butine 8 by the decomposition of some complex derivatives obtained from diphenylketene 9 by the hydrolysis of diphenyl-5,5-hydan-toin 10 by the treatment of diphenylbromoacetic acid with copper 11 by the oxidation of dichlorodiphenylcrotonic acid.12... 

Chromium tetraphenyl hydrogen carbonate, (C6H5)4Cr.HC03. 2HaO.—An aqueous solution of the tetraphenyl base is saturated with carbon dioxide and concentrated over sulphuric acid in vacuo. The residue is treated with alcohol and the product precipitated by ether. Orange crystals separate, M.pt. 110° to 1110 C., prolonged desiccation over phosphorus pentoxide causing decomposition and formation of diphenyl. 

In 1978, Inoue reported the first example of a single-site catalyst, a tetraphenyl-porphyrin aluminium chloride complex (Fig. 18a), which was used with EtPh3PBr as a co-catalyst [109, 110]. The complex was used to copolymerize PO and carbon dioxide it was very slow (taking up to 23 days) but did produce PPC of low molecular weight and narrow PDI. Later, in 2003, the manganese(III) acetate analogue of this complex was the first example of a catalyst capable of copolymerizing CHO and C02 under 1 atm pressure. 

Fig. 15.17. Current in milliamperes cm-2 for CO production from C02 using C02+ tetraphenyl porphyrins modified with various pyridyl derivatives. (Reprinted with permission from T. Atoguchi, A. Aramata, and M. Engo, C02 Reduction by Macrocyclic Transition Metal Complex-Modified Electrodes," in Proc. International Symposium on Chemical Fixation of Carbon Dioxide, p. 338, Fig. 5,1991.)...

Depending on the substituents in (61) and on the concentration of the catalyst, however, other products may also subsequently be formed. In some cases, SbCl5-complexed primary intermediates of type (65) could even be isolated and characterized by NMR spectroscopy as well as by well-defined chemical reactions (81JA1789). Treatment of tetraphenyl-1,2,4-trioxolane (67) with antimony pentachloride or liquid sulfur dioxide, a mild Lewis acid, gave benzophenone and phenyl benzoate in a molar ratio of 1 1 (80JA288). The formation of the ester corresponds to that of the carboxylic acid from (61) via path A or path B. 

Selenophene 1,1-dioxides have been found to be more thermally labile than the corresponding thiophene 1,1-dioxides. While dimerization is often observed in the thermal decomposition of the latter, the neat thermolysis of selenophene 1,1-dioxides leads primarily to ring-opened products. For example, thermolysis of 2,3,4,5-tetraphenyl-selenophene 1,1-dioxide 5 gave a variety of a ring-opened products (Equation 1) <1998H(48)61>, whereas thermolysis of compound 5 in toluene leads to the formation of 2,3,4,5-tetraphenylfuran. 

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. 

Phenyl Arsines. When diphenyl chloroarsine is treated with (mono)phenyl arsine in an atmosphere of nitrogen or carbon dioxide, arsenobenzene and tetraphenyl diarsine are formed ... 

Tin triphenyl bromide has more recently been ])repared by treating tin tetraphenyl in boiling chloroform with iodine, when tin triphenyl iodide is produced. This is then changed to the hydroxide by 30 per cent, sodium hydroxide, and the solution shaken with concentrated hydrobromic acid. Yield 50 per cent. This method obviates the cooling in solid carbon dioxide adopted by Krause. It crystallises in millimetre-long pyramids or octahedra, and from dilute solution in fern-like masses. It melts at 120-5° C., and boils at 249 C. at 13 5 mm. 

Sulphamide reacts with bis (diphenylphosphino) methane (459) in the presence of diethylazodicarboxylate to give 69% yield of [(sulphamidodiphenylphospha-25-azeno)methyl] diphenylphosphine oxide (460)412 and 6% of the cyclic compound 3,3,5,5-tetraphenyl-4//-l,2,6,3,A5,525-thiadiazadiphosphorin-l,l-dioxide (461). 

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