Evidence of Unusually Long Metal–Aqua Interaction: The Crystal Structure of Tetraphenylphosponium Rhenium(V)aquatetracyanonitrido Monohydrate Tri-terpyridine

Abstract

The rhenium(V)aquatetracyanonitrido complex with 2,2′,2″-terpyridine (trpy) as adduct has been isolated and characterized with IR and X-ray crystallography. The title compound crystallizes in the monoclinic space group P21/n with unit cell parameters: a = 16.6829(2), b = 25.7198(10), c = 19.7098(3)A, β = 94.3860(10)°, V = 8432.3(2) A3, Z = 4. The rhenium in the anion has a distorted octahedral geometry with the Re(V) atom surrounded by the terminal nitrido ligand, four carbon atoms of the cyanide ligands and water molecule trans (171.33(4)°) to the nitride group. The water molecule is situated between the rhenium atom and one of the trpy nitrogen ligands with an exceptionally long metal aqua interaction equal to 2.658(3)A and with a distance equal to 2.804(5)A between the oxygen atom and the trpy nitrogen atom. Principal dimensions for this compound are; Re ≡ N = 1.655(3), Re-C1 = 2.100(4), Re-C2 = 2.094(5), Re-C3 = 2.094(4), Re-C4 = 2.113(4)A. The water molecule is situated between the rhenium atom and one of the trpy nitrogen ligands with an exceptionally long metal aqua interaction equal to 2.658(3)A and with a distance equal to 2.804(5)A between the aqua group and the nitrogen atom.