4.9- diazapyrenes

A six-membered ring is formed in the reduction of 2-nitrobiphenyl-2 -carboxylic acid68 or 6,6 -dinitrobiphenyl-2,2 -dicarboxylic acid.69 In the former case a phenanthridine is formed, in the latter a 4,9-diazapyrene. Similarly, a seven-membered ring is obtained when 2-nitro-2 -isothiocyano-biphenyl (15) is reduced in acidic solution with the formation of 6-mercapto-dibenzo[d/]-l,3-diazepine 3-oxide (16)70 [Eq. (28)]. 

Pyrimidine 1 is the lUPAC accepted name for 1,3-diazabenzene, while quinazoline 2 is the accepted name for benzo[r lpyrimidine or 1,3-diazanaphthalene. Perimidine 3 is the lUPAC accepted name for l//-benzo[r/ ]quinazoline or H -naphtho[l,8-r/i ]pyrimidine, while benzo. 4]perimidine 4 is also known as 1,3-diazapyrene. 

Coverage of perimidine chemistry can be found in two review articles <1981RCR816, 1995AQ151>, while benzo[g/5]perimidine chemistry is discussed in a review of diazapyrenes <2003CHE1417>. 

The question of whether 1 Ob, 1 Oc-diazapyrene (101) is capable of a finite existence has been the subject of theoretical considerations. According to HMO calculations, 100 was suggested to be the more stable valence tautomer."7 [2,2](2,6)Pyridinophane (99) was prepared in different reaction sequences by Baker et al. Their intention was to synthesize 100 however, owing to lack of material, it was impossible to investigate possible routes for converting 99 into 100.118... 

The outer-sphere electron transfer reaction between [Fe(CN)6] and [Co(NH3)5H20] has been studied as a function of temperature and pressure in a variety of water-glycerol solvent mixtures. While AV remains essentially constant at 28 cm moP both A/f and A5 increase with an increase in the viscosity of the solvent. The intramolecular electron transfer processes in (NH3)5CoLFe(CN)5 complexes, where L is 3,3 -dimethyl-4,4 -bipyridine, 4,4 -bipyridylacetylene, 2,7-diazapyrene, and 3,8-phenathroline, have been studied. The activation free energies display an inverse dependence on the Fe-Co distance and, when corrected for solvent reorganization energies, are relatively constant at 14.0 0.5 kcal moP. ... 

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