Synthesis, characterization, and structure of a new N-nitrosamine of cyclam (1,4,8,11-tetraazacyclotetradecane)

A novel N-nitrosamine of cyclam has been synthesized. The N–N bond lengths values, as determined from the X-ray crystal structure, fall in the 1.318(2) and 1.320(2) Å range, smaller than the ones expected for the N–N single bond. The N–NO bond angles are in the 115.0(1)° and 114.8(1)° range. The νNO, νNN, and δN–NO vibrational modes were observed in the infrared spectrum at 1454, 1139, and 555 cm−1, respectively. The photolysis of the cyclam(NO)4 compound gives rise to the nitrosyl release through an heterolytic cleavage of the N–NO bonds, as indicated by the appearance of the νNO+ band at 2228 cm−1 at the expense of decreasing the νNO, νNN, and δN–NO bands.