The tetrameric macrocycle [{P(μ-N-tBu)}2NH]4

The 1:1 reaction of the symmetrical dimers [ClP(mu -(NBu)-Bu-t)](2) 1 and [H2NP(mu -(NBu)-Bu-t)](2) 2 in thf-Et3N gives the tetrameric macrocycle [{P(mu -(NBu)-Bu-t)}(2)NH](4) 3 (67%); consisting of four P-2(mu -(NBu)-Bu-t)(2) rings linked by endo N-H groups.