Hydroxylamine-N, N-disulphonates and nitrosodisulphonates: preparations, characterizations, and magnetic and spectroscopic properties

Abstract

A series of hydroxylamine-N,N-disulphonate and nitrosodisulphonate salts with monovalent cations have been prepared and characterized. The salts of the hydroxylamine-N,N-disulphonate ion crystallize with either [(S03)2NOH]2- ions or {[ (S03)2N0]2H}5- groups. In general, salts with [(S03)2NOH]2- ions crystallized from basic aqueous solutions when the pH was less than 11.5 while those containing {[ (S03)2N0]2H}5- groups form on crystallization from more strongly basic aqueous solutions. Nitrosodisulphonate ions, in low concentration, can enter the crystal lattices of salts containing [(S03)2NOH]2- ions, presumably substitutionally for the [(S03)2NOH]2- ion. This was confirmed by e.p.r. measurements. Species with S=1 form on Co60 irradiation of the salts containing (S03)2N0]2H}5- groups. These species have zero-field splittings which suggest they arise from the net loss of a hydride ion from the (S03)2N0]2H}5- group. Two crystalline modifications of potassium nitrosodisulphonate and two crystalline modifications of rubidium nitrosodisulphonate were found to have thermally accessible triplet states. This was concluded from measurements of the zero-field splitting, the temperature dependence of the static magnetic susceptibility and the temperature dependence of the e.p.r. absorption area for powdered samples of each of these salts. Measurements of the temperature dependences of the line width and line separation of the e.p.r. signals arising from the S=1 species in each of the crystalline modifications of potassium nitrosodisulphonate suggest that these S=1 excitations are excitons. Measurements of the temperature dependences of the static magnetic susceptibility (100-300 K) of powdered samples of the other nitrosodisulphonate salts prepared show that these salts contain S=½ nitrosodisulphonate ions. The room temperature e.p.r. powder spectra of these salts are also reported. A catalog of the infrared spectra (in KBr) or the hydroxylamine-N,N-disulphonate and nitrosodisulphonate salts prepared is given, in addition to a catalog of the powder reflectance spectra of the nitrosodisulphonate salts.