Two Different Pathways in the Reduction of [(S=)PCl(μ-NtBu)]2 with Na.

Reduction of the cyclodiphosphazane [(S=)ClP(μ-NtBu)]2 (1) with sodium metal in refluxing toluene proceeds via two different pathways. One is a Wurtz-type pathway involving elimination of NaCl from 1 followed by head-to-tail cyclization to give the hexameric macrocycle [(μ-S)P(μ-NtBu)2 P(=S)]6 (2). The other pathway involves reduction of the P=S bonds of 1 to generate colorless singlet biradicaloid dianion trans-[S-P(Cl)(μ-NtBu)]2 (2-) , which is observed in the polymeric structures of three-dimensional [{(S-)ClP(μ-NtBu)2 PCl(S)}Na(Na⋅THF2 )]n (3) and two dimensional [{(S-)ClP(μ-NtBu)2 PCl(S)} (Na⋅THF)2 ]n (4).