I was doing a reaxys substructure search for the compound shown on the left below, with the 3 amines on 1 carbon. However, the closest I found were all trinitro compounds like on the right. I would have thought the nitro compounds would be less stable and likely to explode. But given the lack of triamine compounds, they must be hard to make. All I can figure is that when all three amines are protonated you end up packing a lot of postive charge in a small place.
Now that I look at that nitro structure I'm pretty sure I got the charges wrong. Just ignore that.