Lattice forces in heavy metal picrates: Structural characterization of lead and mercury species

Structure determinations for the dimethylsulfoxide (dmso) solvate of lead(II) picrate (picrate = pic = 2,4,6-trinitrophenoxide), formally a centrosymmetric dimer, [Pb-2(dmso)(4)(pic)(4)], and for unsolvated mercury(I) picrate, a polymer of conventional mercurous dimers, [Hg-2(-pic)(2)] show that, despite considerable differences in the form of the metal unit, there are remarkable similarities in the mode of coordination of the bridging picrate ligands. In both lattices, parallel arrays of picrate rings can be discerned but appear to be associated with short N center dot center dot center dot O,O center dot center dot center dot O or O center dot center dot center dot C contacts rather than C center dot center dot center dot C. In the Pb compound, there is also evidence of intramolecular contacts to dmso-S.