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

Abstract

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 P, 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.