1,1′,4,5-Tetra­hydro­tri­spiro­[1,3,2-di­aza­phosphole-2,2′-[1,3,5,2,4,6]tri­aza­triphosphinine-4′,6′′-dibenzo[d,f][1,3,2]dioxaphosphepine-6′,6′′′-dibenzo[d,f][1,3,2]dioxaphosphepine] acetone monosolvate

The title compound, C(26)H(22)N(5)O(4)P(3)·C(3)H(6)O, has been achieved in a two-step synthesis that does not require chromatography. This mol­ecule contains a seven-membered spiro­cyclic ring at two P-atom positions and a five-membered ring containing new P—N bonds at the other P-atom position. Endocyclic torsion angles about the central biphenyl C—C bonds are −41.5 (3) and −44.4 (3)°, and P—N bonds of the central P(3)N(3) ring are within the range 1.5665 (17)–1.6171 (17) Å, while the P—O distances are in the range 1.5940 (14)–1.6041 (14) Å. One N—H group makes an inter­molecular N—H⋯N hydrogen bond, forming centrosymmetric dimers, while the other N—H group makes an N—H⋯O hydrogen bond to the acetone solvent mol­ecule. The crystal was a two-component non-merohedral twin with ratio 0.811/0.189.