Crystal and Molecular Structure of 1,11-bis(Tropolone)-3,6,9-trioxaundecane · RbI
Abstract The complex between the polyether ligand 1,11-bis(tropolone)-3,6,9-trioxaundecane and RbI crystallizes in space group P21/c with cell dimensions a = 11.383(4), b = 14.493(5), c = 16.122(6) Å and β = 111.02(5)° with Z = 4. The structure was solved on the basis of 3734 X-ray reflections measured on a diffractometer with CuKα-radiation and refined to an R of 0.101. The polyether wraps around the Rb+ in a circular structure. One of the tropolone rings is elevated in order to avoid collision. Rb+ is located 1.224(6) Å above the plane formed by five oxygen atoms of the ligand, it is coordinated to I -(3.666(2)Å) and to all oxygens. The Rb+ ··· O distances of the least electronegative “ester oxygens”, 3.14(1) Å and 3.18(1) Å are significantly longer compared to the other Rb+···O distances in the range 2.81(1) Å to 3.08(1) Å. The conformation about the C-C and C-O bonds of the ligand are gauche and trans as generally found in such molecules. The two tropolone seven-membered rings are slightly non-planar and display an envelope-type structure.