Preparation of 1,1-diphenylthionitrosamine and X-ray crystal structures of two thionitrosamine complexes

The reaction of 1,1-diphenylhydrazine with S2Cl2 in the presence of triethylamine leads to 1,1-diphenylthionitrosamine. The chromium pentacarbonyl derivative was isolated and characterised by X-ray structure determination; [Cr(SNNPh2)(CO)5](2) crystallises in the space group P21/c with a= 786.5(1), b= 2 236.5(2), c= 1 054.6(1) pm, β= 89.44(8)°, and Z= 4; [Cr(SNNMe2)(CO)5](3) also crystallises in P21/c, with a= 1 042.2(3), b= 1 250.7(4), c= 954.6(3) pm, β= 110.21(3)°, and Z= 4. The structures were refined to R= 0.079 for 1 573 diffractometer data with F > 3σ(F), and R= 0.049 for 2 388 data with F > 3σ(F) respectively. The structures are similar, with CrSNNC2 planes approximately eclipsed to the carbonyls. One of the phenyl groups in (2) can take part in π interaction with the nitrogen atoms, which is associated with longer N–N and shorter S–N and Cr–S bonds in (2) than in (3).