Sulphamide structure

The bond energy of ionic states of individual bonds is strengthened if alternate positive and negative charges arise on adjacent atoms. As an example, we shall consider first, sulphamide S02(NH2)2> for which the valence bond structure... 

H2NS02NWC14 (312) has been synthesized from WC16 and sulphamide and it forms adducts with pyridine and acetonitrile. The crystal structure of the acetonitrile adduct has a S-N-W angle of 169.3° and the nitrogen tungsten bond appears to be a double bond312. 

The variation of colour in silver compounds including sulphamides has been correlated with structure. The colour changes go from colourless to red, depending on the number of silver(I) atoms coordinating the donor atoms of the bases used318. Ag(I) sulphamides show different colours depending on the stoichiometry, disilver sulphamides are colourless, trisilver sulphamides are deep red. 

The chemistry of the S -oxides of all four isomeric thiadiazoles has been reviewed in detail. The properties of these compounds are best accounted for by regarding their structures as cyclic sulphonylhydrazines (1), a- and /3-aniinosulphonamides (2), sulphamides (3), and hydrazinosulphones (4). 

The condensation of sulphamide and diethyl oxalate produces 3,4-dihydroxy-1,2,5-thiadiazole 1,1-dioxide as the dipotassium salt in high yield. The free acid (177) is an excellent precursor for the preparation of other functional derivatives, and for building up fused ring systems incorporating the 1,2,5-thiadiazole 1,1-dioxide structure (see below). The two isomeric benzothiadiazole acetoximes (178) and (179) undergo the Beckmann reaction, resulting in the fission of their carbocyclic ring. This provides an effective synthesis of novel ajS-unsaturated 1,2,5-thiadiazoles (180 X = COaH, Y = CR=CHCN X =... 

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