4‐Iodo‐1,3,5,7‐tetramethyl‐1,3,5,7‐tetraaza‐4λ 5 ‐phosphaspiro[3.3]heptane‐2,6‐dione: Synthesis and Crystal Structure of the First Iodophosphorane

A trigonal‐bipyramidally coordinated P atom is the characteristic structural element of the title compound 2 , which can be synthesized from the readily available 1 by Cl/I exchange. The crystals of 2 are pale yellow at −30°C, but at room temperature light brown; they decompose above 50°C. The P‐I bond, which is without precedent, is 245.8(3) pm long.