“…Seemingly for the same reason, monosubstituted R-N=S=N-H derivatives have neither been isolated nor unambiguously characterised. 2,3 This work deals with the synthesis and X-ray structural characterization of first stable R-N=S=N-H sulfur diimide 1 (R = 2,4,6-Bu t 3 C 6 H 2 S).…”