1.3- Diphenyl phenanthroline oxidation

Photoinduced oxidation of 1,4-dimethoxybenzene (DMB) and tetrahydrofuran (THF) by [Au(C N N-dpp)Cl]+ in acetonitrile upon UV/Vis irradiation have been observed. The time-resolved absorption spectrum recorded 12 (xs after excitation of [Au(C N N-dpp)Cl] with a laser pulse at 35 5 nm showed the absorption band of the DMB radical cation at 460nm, whereas upon excitation at 406 nm in the presence of THF, a broad emission characteristic of the protonated salt of 2,9-diphenyl-l,10-phenanthroline (Hdpp ) developed at 500 nm. 

Oxidation of l,3-diphenyl[4,7]phenanthroline with potassium permanganate in alkaline medium resulted in transformation of the 4,7-phenanthroline ring system into 1,8-diazafluorenone. Oxidation of 12-aryl-9,9-dimethyl-8,9,10,12-tetrahydro-7H-benzo[i ][4,7]phenanthrolin-11-ones, resulting from the condensation of 6-arylmethyleneaminoquino-lines and 1 with sodium nitrite in acetic acid led to 12-aryl-9,10-dihydro-8H-benzo[frJ[4,7Jphenanthrolin-ll-ones (04RJOC1322) (Scheme 83). 

Tocopherol carries six methyl groups three on the hydroquinone ring and three on the side chain. The three chiral centers are all of R configuration (2-R, 4 -R, 8 -R). The most significant chiral center at C2 is as stable to oxidative cleavage as the remote centers at C4 and C8, but it disappears, of course, upon oxidation to the quinone (see Scheme 7.2.1). The UV spectrum shows a maximum at 284 nm (e = 30,000) in petrol ether and at 292 nm in ethanol. Quantitative determination in food occurs by extraction with ether, HPLC, and reduction of Fe(III) ions to Fe(II). The iron(II) concentration is then determined colorimet-rically with 2,2 -dipyridyl = 520 nm) or 4,7-diphenyl-1,10-phenanthrolin. Solutions of free tocopherol fluoresce in the UV( ), whereas neither tocopherol acetate nor the quinone shows any fluorescence (Lang, 1974 Isler and Bmbacker, 1982). This phenomenon is not understood. 

Since tetrathiafulvene (TTF) is well known to be a good electron donor (reversibly oxidized at 0.30 V vs SCE) as well as the inherent chemical stability of its cation radical, it was incorporated into a macrocycle possessing the 2,9-diphenyl-1,10-phenanthroline subunit, previously described by Sauvage and his coworkers the Cu(I) [2]-catenate was synthesized and characterized <94TL4339>. 

For phase-modulation measurements we have chosen tiis(4,7-diphenyl-1,10-phenanthroline)ruthenium(II) perchlorate ([Ru(Ph2phn)3] ), which is highly sensitive to oxygen. This complex in silicon is also rather specific. The physiologically and medically important gases, CO2, nitrous oxide, cyclopropane,... 

The synthesis of isoindolinones (128) from IV-tosylbenzamides (129) and t-butyl acrylate was achieved in high yields using O2 as oxidant and Pd(OAc)2 as catalyst in the presence of 4,7-diphenyl-l,10-phenanthroline and toluene. Aliphatic alkenes with electron-rich and electron-deficient alkenes or conjugated alkenes could also be... 

As in 4,5-disubstituted phenanthrenes, substitutions at the sterically most hindered Cl and CIO positions of 4,7-phenanthroline as depicted in 49 (Fig. 15) cause helical twist of the aromatic structure [54]. The first example of such derivatives, 1,10-dicarboxy-3,8-diphenyl-4,7-phenanthroline (50), was reported in 1932 (Scheme 9) [55]. Condensation of p-phenylenediamine with benzaldehyde and then with pyruvic acid followed by cyclization produced 50. Oxidation of 50 to tetracarbox-ydipyridyl 51 provided the supporting evidence for the formation of 50. 

The excited state of the complex Pt(4,7-diphenyl-1,10-phenanthroline)( 1,2-dicyano-l,2-ethylenethiolate) (Pt(dpphen)(mnt)) is oxidatively quenched by o-nitrobenzaldehyde [Eq. (3.46)], and reductively quenched by dimethylaniline [Eq. (3.47)], showing that excited state photoredox chemistry can be carried out with this series of platinum complexes " ... 

Suitable mechanisms have been proposed following determination of the kinetic and activation parameters for oxidation of 2-naphthol and cyclic ketones by nicotinium dichromate some a-amino acids by tripropylammonium fluorochromate " distyryl ketone by quinaldinium fluorochromate methanol by benzyltriethylammonium chlorochromate catalysed by 1,10-phenanthroline substituted benzyl alcohols by tetraethylammonium bromochromate L-cysteine by pyridinium bromochromate lactic acid and 3,5-dimethyl-2,6-diaryl piperidin-4-one oximes by pyridinium chlorochromate allyl alcohol by IDC benzophenoxime by bispyridine silver(I) dichromate and alkyl phenyl sulfides by cetyltrimethylammonium dichromate. A non-linear Hammett plot obtained for the oxidation of substituted benzyl alcohols by IDC has been attributed to the operation of substituent effect on two steps of the proposed mechanism. " Kinetic and activation parameters for oxidation of o-toluidine and of A-methyl-2,6-diphenyl piperidin-4-one oxime and its 3-alkyl derivatives by sodium dichromate have been determined and suitable mechanisms have been suggested. Micellar catalysis in the 1,10-phenanthroline-promoted chromic acid oxidation of propanol... 

Fig. 4. Lewis bases that form adducts with rare-earth tris / -diketonates. Abbreviations bipy = 2,2 -bipyridine phen = 1,10-phenanthroline terpy = 2,2, 6, 2"-terpyridyl bath = bathophenanthroline or 4,7-diphenyl-l,10-phe-nanthroline Hpbm = 2-(2-pyridyl)benziraidazole tppo = triphenylphosphine oxide tbpo = tri-n-butylphosphine oxide topo = tri-n-octylphosphine oxide tbp = tributylphosphate dmso = dimethylsulfoxide.

---