Structural studies in metal-purpurate complexes. Part 5. Crystal structure of di-μ-aqua-tetrakis(purpurato)distrontium tridecahydrate

The crystal structure of the title compound [Sr₂L₄]·15H₂O (L = purpurate) has been determined at 295 K by X-ray diffraction and refined by least squares to R 0.082 (2 839 'observed' reflections). Crystals are triclinic space group P1, a = 17.342(5), b = 15.337(5), c = 10.553(4) Å, α = 86.20(2), β = 91.64(2), γ = 107.71(2)°, Z = 2. Each strontium atom is nine-co-ordinated by a tridentate purpurate species [Sr-N, 2.69(1), 2.75(1); Sr-O, 2.56(1)-2.63(1) Å], with two further contacts to adjacent purpurates [Sr-O, 2.68(1)-3.18(1) Å], two water molecules [Sr-O, 2.61(1)-2.72(1) Å], and two further water molecules which bridge adjacent pairs of nine-co-ordinate strontium atoms [Sr-O, 2.64(1)-2.75(1) Å; Sr-O-Sr, 107.9(4), 107.7(5)°]. Dimeric units are thus formed which are linked polymerically by purpurate species.