Mercury(II) halide complex of cis-[(tBuNH)(Se)P(μ-NtBu)2P(Se)(NHtBu)]

Abstract

The mercury(II) halide complex [1,3-di-tert-butyl-2,4-bis(tert-butylamino)-1,3,2λ5,4λ5-diazadiphosphetidine-2,4-diselone-κ2Se,Se′]diiodidomercury(II) N,N-dimethylformamide monosolvate, [HgI2(C16H38N4P2Se2)]·C3H7NO or (1)HgI2, 2, containing cis-[(tBuNH)(Se)P(μ-NtBu)2P(Se)(NHtBu)] (1) was synthesized and structurally characterized. The crystal structure of 2 confirms the chelation of chalcogen donors to HgI2 with a natural bite angle of 112.95 (2)°. The coordination geometry around mercury is distorted tetrahedral as indicated by the τ4 geometry index parameter (τ4 = 0.90). In the mercury complex, the exocyclic tert-butylamido 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 interactions with the solvent N,N-dimethylformamide. These interactions may introduce geometrical distortion and deviation from an ideal geometry. An isostructural HgBr2 analogue containing cis-[(tBuNH)(S)P(μ-NtBu)2P(S)(NHtBu)] was also synthesized and structurally characterized, CIF data for the compound being presented as supporting information.

Keywords

• crystal structure
• cyclodiphosphazanes
• mercury(ii) halide
• tert-butylamido