Mercury(II) halide complex of cis-[( (t) BuNH)(Se)P(μ-N (t) Bu)(2)P(Se)(NH (t) Bu)].

The mercury(II) halide complex [1,3-di-tert-butyl-2,4-bis-(tert-butyl-amino)-1,3,2λ(5),4λ(5)-di-aza-diphosphetidine-2,4-diselone-κ(2) Se,Se']di-iodido-mercury(II)N,N-di-methyl-formamide monosolvate, [HgI(2)(C(16)H(38)N(4)P(2)Se(2))]·C(3)H(7)NO or (1)HgI(2), 2, containing cis-[( (t) BuNH)(Se)P(μ-N (t) Bu)(2)P(Se)(NH (t) Bu)] (1) was synthesized and structurally characterized. The crystal structure of 2 confirms the chelation of chalcogen donors to HgI(2) with a natural bite angle of 112.95†(2)°. The coordination geometry around mercury is distorted tetra-hedral as indicated by the τ(4) geometry index parameter (τ(4) = 0.90). In the mercury complex, the exocyclic tert-butyl-amido substituents are arranged in an (endo, endo) fashion, whereas in the free ligand (1), the exocyclic substituents are arranged in an (exo, endo) pattern. Compound 2 displays non-classical N-H⋯O hydrogen-bonding inter-actions with the solvent N,N-di-methyl-formamide. These inter-actions may introduce geometrical distortion and deviation from an ideal geometry. An isostructural HgBr(2) analogue containing cis-[( (t) BuNH)(S)P(μ-N (t) Bu)(2)P(S)(NH (t) Bu)] was also synthesized and structurally characterized, CIF data for the compound being presented as supporting information.