Synthesis and structures of [S=(H)P(μ-NR)]2, potential building blocks for inorganic phosphorus-sulfur macrocycles.

The reactions of the chloro-phosph(iii)azane dimers [ClP(μ-NR)]2 with LiSH give the dimers [S[double bond, length as m-dash](H)P(μ-NR)]2 (), which are potential new building blocks for inorganic macrocycles of the type [{P(μ-NR)}2(μ-S)]n. NMR spectroscopic studies and DFT calculations show that the preference for the cis or trans isomers of is largely influenced by the steric demands of the R-group, with cis isomers being preferred for bulky substituents. This is an important factor in regard to applications in macrocycle synthesis since the cis arrangement is pre-organized for cyclisation.