Metal-selenium interactions. Synthesis and crystal structure of [diiodo{1,1 '-methylene-bis (diphenyl phosphine selenide)}] zinc(II)

Reaction of 1,1 ' -methylenebis(diphenylphosphine selenide) {Ph2P(Se)-CH2-P (Se)Ph-2, dpmSe(2)} with zinc(II) diiodide in dry diethylether-denzene mixt ure formed ZnI2(dpmSe(2)) (1), which has been characterised with the help o f analytical data, IR spectroscopy and single crystal X-ray crystallography . Zinc(II) is bonded to two iodine atoms {Zn-I, 2.5732(9), 2.5584(7) Angstr om} and two selenium atoms {Zn-Se, 2.5135(8), 2.4906(10) Angstrom}. The ang les about Zn vary from 104.57(3) and 114.69(3) Angstrom respectively. Thus dpmSe(2) chelates to Zn(II) forming a distorted 103.56(3) to 114.69(3) Angs trom with Se(1)-Zn-Se(2) and I(1)-Zn-I(2) bond angles being tetrahedral geo metry about the metal centre. In the six membered metallacyclic ring formed by Zn(1), Se(1), P(1), C(13), P(2) and Se(2) atoms, the angles at Se atoms , namely, Zn(1)-Se(1)-P(1) and Zn(1)-Se(2)-P(2) {96.86(4) and 100.67(5)degr ees, respectively} are the lowest. This reveals higher angular flexibility at Se atom vis-a-vis angles at P or C atoms. Complex 1 is the first example of a complex of zinc(II) with a tertiary phosphine selenide ligand, whose structure has been solved.