Sn-NH2 complexes (lignates)

[Atropos]

If the reduction of an azide with SnCl2 were to form Sn-NH2 complexes, what would it entail to eliminate these complexes and free up the amine for extraction from the reaction mixture?

Here is what little I could find after sifting through several hundred posts:

In cases when the metal ion forms stable amine complexes  which make ? quantitative precipitation difficult, the precipitation may be carried out with ammonium acetate or tetramethylammonium hydroxide solutions (22). In addition to these agents and the various alkali metal hydroxides, active MgO and alkaline earth hydroxides may also be used as precipitants.

Sodium borohydride enables manufacturers to meet the most stringent effluent limits, and to precipitate metals in their elemental form (rather than metal complexes)

If you a royal-blue Zn-NHCH3 complex, the zinc ions must be reduced out of solution.
That is Zn+2 + 2e ==>> Zn (s)
This is done using Mg metal, or electrochemically.

So:  Is it possible to break up these complexes using Mg, though the post this came from is on the subject of methylamine? Or perhaps (doubtfully) NaBH4?

[Ritter]

Atropos,

The following reference is about using SnCl2 to reduce alkylazides to alkylamines:  Tetrahedron 1990, 46, 587

Check it out, it should answer all of your questions.

From memory I can tell you that aniline is synthesized industrially via reduction of nitrobenzene witn Sn/HCl.  The resulting Sn/amine complex is decomposed by addition of a very large amount of sodium hydroxide.

Hope this helps!  Check your PM's

[Rhodium]

A Fast Procedure for the Reduction of Azides and Nitro Compounds Based on the Reducing Ability of Sn(SR)₃^- Species
Martí Bartra, Pedro Romea, Fèlix Urpí, and Jaume Vilarrasa

Tetrahedron 46(2), 587-594 (1990)

(https://www.thevespiary.org/rhodium/Rhodium/pdf/nitro-azide.red.tin-thiolate.pdf)

Abstract
Tin(II) complexes prepared by treatment of SnCl₂ or Sn(SR)₂ with appropriate amounts of RSH and Et₃N appear to be the best reducing agents for azides (to amines) reported so far. These tin(II) complexes also reduce primary and secondary aliphatic nitro compounds to oximes, usually within minutes at r.t. or hours in the cold, and tertiary aliphatic as well as aromatic nitro compounds to afford the corresponding hydroxylamines. In general, azides react more rapidly than nitro substituents, whereas carbonyl groups, sulphoxides, sulphones, nitriles, and esters are practically unreactive under the same conditions. Some mechanistic details of the reaction of Sn(SPh)₃^- with azides and nitro compounds have also been elucidated.