Thionylimide anion

Transition-metal complexes of the thionylimide anion exhibit characteristic vibrations in the regions 1260-1120, 1090-1010 and 630-515 cm , which are assigned to Oas(NSO), Os(NSO) and <5(NSO), respectively. X-ray structural data for several M-NSO complexes reveal N-S and S-O bond lengths of ca. 1.46 0.04 A indicative of double bond character in both of these bonds. 

The SN2 ion is isoelectronic with the thionylimide anion, NSO , and with sulfur dioxide, SO2. The frequencies of the three fundamental vibrations are 1198, 1001, and 528 cm . The salt K2[SN2] is an important reagent for the preparation of other sulfur diimide derivatives when Mes SiNSNSiMes is not sufficiently reactive. For example, both acyclic and cyclic arsenic(III) compounds, t-Bu2AsNSNAs-t-Bu2 and t-BuAs(NSN)2As-t-Bu, have been obtained in this way. 

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