ABSTRACT
Thiocarbonyl dithiocyanate (1) and chlorothiocarbonyl thiocyanate (2) were synthesized from thiophosgene and ammonium or silver thiocyanate, respectivley. Their crystal structures show syn-anti (1) and syn (2) conformations, which were confirmed in the bulk phases by powder X-ray diffraction, vibrational spectroscopy and DFT calculations. Further calculations explain the isolation of the kintetic reaction products by a lower transition stateas opposed to the thermodynamic reaction products. Reaction of 1 with ethanol gave a dithiobiuret derivative (3). In a proof-ofprinciple study we show that it in turn can be used for the complexation of Ni2+ (4).
ABSTRACT
The reactivity of carbonyl diisocyanate, CO(NCO)2 , and carbonyl diisothiocyanate, CO(NCS)2 with nucleophiles shows different patterns: Whereas carbonyl diisocyanate adds two equivalents of nucleophile forming carbonyl bis(carbamoylhalides), carbonyl diisothiocyanate only adds one equivalent and undergoes intramolecular ring closure, resulting in the formation of substituted thiadiazines. In this study we have reacted both carbonyl diisocyanate and carbonyl diisothiocyanate with the full series of hydrogen halides HF to HI, isolating carbonyl bis(carbamoylfluoride) (1), -chloride (2), -bromide (3), and -iodide (4) as well as (6-chloro-2,3-dihydro-2-thioxo-4H-1,3,5-thiadiazin-4-one (5), and 6-bromo-2,3-dihydro-2-thioxo-4H-1,3,5-thiadiazin-4-one (6). The compounds were analysed by single-crystal X-ray diffraction, NMR spectroscopy, IR and Raman spectroscopy, and elemental analysis. Quantum mechanical calculations show thermodynamic reasons for the differences in reactivity.
