Metal–selenium interactions. Crystal structure of binuclear [(1eta-iodo)-(2eta-mu-iodo) (triphenyl selenophosphorane– Se)mercury(II)]2 complex

Reaction of mercury(II) diiodide with triphenyl selenophosphorane–Se (1:1 mole ratio) in acetone followed by recrystallisation of the product from chloroform formed crystals of stoichiometry {HgI2(Ph3PSe)}(1). Compound 1 exists as a centrosymmetric homobimetallic dimer, {Hg(m-I)I(Ph3PSe)}2, as monoclinic crystals of space group P21/n. The dimer comprises two m2-iodo atoms that form unequal Hg–I bonds {2,823(10), 3,1135(9) Å} and two equal terminal Hg–I bonds {2,6524(10) Å}. The Se atom of Ph3PSe forms terminal Hg–Se bond {2,5914(11)Å} and thus the geometry about each Hg centre is distorted tetrahedral and the range of tetrahedral bond angles is 92,97(2) to 130,85(3)o, the largest being that of Se(1)– Hg(1)–I(1) and the shortest, I(2)–Hg(1)–I(2)*. Hg–Hg and I–I separations of {4,0930(11)Å} and {4,3097(15)Å} are more than the sums of their respective van der Waal radii {3,00 Å and 4,24 Å}.