Gas-phase thermolysis of pyrazolines. 4. Electronic structure and gas-phase thermolysis of 4-substituted 3,3,5,5-tetramethyl-3,5-dihydro-4H-pyrazoles studied by photoelectron spectroscopy. First evidence for an alkylideneselenirane.
The electronic structures of the tetramethyldihydropyrazoles [(I; R=Se,S:O, NNH2, NN:CMe2) and II] have been studied by photoelectron spectroscopy and interpreted with the aid of semi-empirical SCF MO calcns. (PM3). Gas-phase pyrolyzes of I and II have been carried out and analyzed by photoelectron spectroscopy. Both I(R =Se, S:O) and in part I(R=NNH2) eliminate mol. nitrogen to form reactive species which cyclize to three-membered rings, i.e. the novel alkylideneselenirane III, the alkylidenethiirane S-oxide IV, and the cyclopropanone hydrazone V, resp., which decomp. at higher temps. The elusive alkylideneselenirane III was studied by IR spectroscopy in an argon matrix at 10 K.
Dieser Eintrag ist freigegeben.