Molecular structure in the solid state (X-ray crystallography) and in solution (1H and13C nuclear magnetic resonance spectroscopy) of 1,3-diazetidines and pentasubstituted biguanides. X-Ray molecular structure of 2,4-bis-(6-methyl-3-methylthio-5-oxo-4,5-dihydro-1,2,4-triazin-4-yl)-5,5-pentamethylene-1,3-diphenylbig anide and 1,3-bis-(p-chlorophenyl)-5-dimethylamino-2,4-bis-(6-methyl-3-methylthio-5-oxo-4,5-dihydro-1,2,4-triazin-4-yl)biguanide