Nitro derivatives of pyrrole, furan and 1H-tetrazole: ring or nitro bases?

摘要: The gas-phase basicity of pyrrole, furan, 1H-tetrazole and their nitro derivatives has been analyzed by means high level ab initio DFT calculations. 2-nitrofuran was also determined FT-ICR mass spectrometry. Our results indicate that although pyrrole furan behave as carbon bases in the gas phase, protonate preferentially on group. Conversely, both its 5-nitro derivative ring, because intrinsic group is significantly dampened when attached to a tetrazolic ring. For 5-nitro-1H-tetrazole most stable protonated species corresponds an open structure formed protonation N1, which followed N1–N2 bond cleavage. This non-cyclic entropically favored therefore it should be one observed ICR measurements.