32785-44-7Relevant academic research and scientific papers
Detection of Cyclo-N5?in THF Solution
Bazanov, Boris,Geiger, Uzi,Carmieli, Raanan,Grinstein, Dan,Welner, Shmuel,Haas, Yehuda
, p. 13233 - 13235 (2016)
Compelling evidence has been found for the formation and direct detection of the cyclopentazole anion (cyclo-N5?) in solution. The anion was prepared from phenylpentazole in two steps: reduction by an alkali metal to form the phenylpentazole radical anion, followed by thermal dissociation to yield cyclo-N5?. The reaction solution was analyzed by HPLC coupled with negative mode mass spectrometry. A signal with m/z 70 was eluted about 2.1 min after injection of the sample. Its identification as N5was supported by single and double labeling with15N, which yielded signals at m/z=71 and 72, respectively, with identical retention times in the HPLC column. MS/MS analysis of the m/z=70 signal revealed a dissociation product with m/z=42, which can be assigned to N3?. To our knowledge this is the first preparation of cyclo-N5?in the bulk. The compound is indefinitely stable at temperatures below ?40 °C, and has a half-life of a few minutes at room temperature.
N5- in Solution: Isotopic Labeling and Further Details of Its Synthesis by Phenyl Pentazole Reduction
Bazanov, Boris,Geiger, Uzi,Grinstein, Dan,Welner, Shmuel,Haas, Yehuda
, p. 6727 - 6731 (2017/09/20)
The cyclopentazolate anion, N5-, has been researched extensively over the years and detected in the gas phase more than a decade ago, but was only recently measured in solution. The process whereby aryl pentazole reduction leads to the production of N5- is still not fully understood. Here, the production of N5- in solution was investigated using isotopic labeling techniques while implementing changes to the synthesis methodologies. 15N labeled phenyl pentazole produced appropriately labeled phenyl pentazole radical anions and N5- which, upon collision induced dissociation, produced the expected N3- signals. Changing to higher purity solvent and less coated Na metal allowed for a much more rapid pace, with experiments taking less time. However, the best yields were obtained with heavily coated metal and much longer reaction times. Utilization of a vacuum line and ultrapure solvents led to no products being detected, indicating the importance of a sodium passivation layer in this reaction and the possibility that sodium is too strong a reducer. These findings can lead to better production methods of N5- and also explain past failures in implementing aryl pentazole reduction techniques. (Chemical Equation Presented).
