Thionitrosyl and Selenonitrosyl Complexes

The NS molecule is stabilized by coordination to a transition metal and a large number of complexes, primarily with metals from groups 6-9, are known.62,78 The most common preparative routes are reactions of (a) nitride complexes with a sulfur source, e.g., S8, propylene sulfide or sulfur halides, (b) (NSC1)3 with transition-metal complexes, and (c) [SN]+ salts with transition-metal complexes. 

2 and 7.3, respectively. The second method was employed to generate the first thionitrosyl complex. Halide abstraction from complexes of thiazyl halides has also been used in a few cases. Surprisingly, the use of 

S4N4 as a source thionitxosyl-metal complexes is limited to a single example. The first selenonitrosyl-metal complex TpOs(NSe)Cl2 (Tp = hydrotris(l-pyrazolyl)borate) was prepared recently by method (a).  

The nitrogen atom in the (almost) linear metal-thionitrosyl complexes is 5p-hybridized and the NS ligand behaves as a three-electron donor. The N-S bond distances in metal complexes vary between 1.45 

---