13C NMR and FT-IR spectra of thiocyanogen, S2(CN)2, selenocyanogen, Se2(CN)2, and related compounds

The pseudohalogens thiocyanogen [(SCN)(2)], sulfur dicyanide [S(CN)(2)], selenocyanogen [(SeCN)(2)], selenium dicyanide [Se(CN)(2)] and selenium diselenocyanate [Se(SeCN)(2)] have been prepared and studied by C-13 NMR spectroscopy for the first time. The C-13 NMR results confirm the structure previously assigned to these compounds on the basis of vibrational spectroscopy. Thiocyanogen, sulfur dicyanide, selenocyanogen and selenium dicyanide have been also studied as liquid film on KBr plate in the solid state (KBr pellet) by FT-IR spectroscopy and the data collected have been compared and discussed with previous results recorded on solutions in organic solvents. Good agreement with early results has been obtained. It has been confirmed by solid state C-13 NMR-MAS that under mild conditions selenocyanogen disproportionates into selenium dicyanide and selenium diselenocyanate. By heating selenocyanogen above 180 degrees C it polymerizes irreversibly into a brown polymer known as paraselenocyanogen whose FT-IR spectrum is surprisingly very similar to that of parathiocyanogen or polythiocyanogen, the product of self-polymerization of thiocyanogen. (C) 2000 Elsevier Science Ltd All rights reserved.