Haromy T P, Linck C F, Cleland W W, Sundaralingam M
Department of Biochemistry, College of Agricultural and Life Sciences, University of Wisconsin-Madison 53706.
Acta Crystallogr C. 1990 Jun 15;46 ( Pt 6):951-7. doi: 10.1107/s0108270189008401.
The meridional and facial isomers of triamminechromium pyrophosphate were separated by chromatography on Dowex-50-H+, and crystallized as isoionic species. The meridional isomer crystallized as a monomer [Cr(HP2O7)(NH3)3(H2O)].2H2O but the facial isomer crystallized as a centrosymmetric dimer of [Cr(HP2O7)(NH3)3]. 2H2O, in which the remaining water in the coordination sphere of each chromium is replaced by a phosphate oxygen from the other monomer unit. Meridional isomer: monoaquatriammine(pyrophosphato)chromium(III) dihydrate, Mr = 332.1, monoclinic, P21/c, a = 7.825 (2), b = 10.107 (3), c = 15.322 (5) A, beta = 103.92 (5) degrees, V = 1176 (1) A 3, Z = 4, Dx = 1.875 g cm-3 lambda(Mo K alpha) = 0.71073 A, mu = 12.6 cm-1, F(000) = 684, final R = 0.050 for 1828 reflections. The most notable difference between this compound and the corresponding tetraammine complex reported previously is a significant shortening of the metal-ligand bond lengths not only for the water ligand but also for the ammonia ligands. The dimer: mu-(pyrophosphato-O,O',O")-bis[triamminechromium(III)] dihydrate, Mr = 314.0, monoclinic, P21/c, a = 8.695 (2), b = 10.327 (3), c = 11.913 (4) A, beta = 97.81 (5) degrees, V = 1060 (1) A3, Z = 4, Dx = 1.969 g cm-3, lambda(Cu K alpha) = 1.5418 A, mu = 125.7 cm-1, F(000) = 644, final R = 0.047 for 1389 reflections. This structure, which sits on a center of inversion, forms a tricyclic complex involving two Cr atoms. The structure is characterized by reciprocal coordination between the metal ions and anionic O atoms of the pyrophosphate moieties.(ABSTRACT TRUNCATED AT 250 WORDS)
焦磷酸三氨合铬的经式和面式异构体通过在Dowex - 50 - H⁺上进行色谱分离，并结晶为等离子体物种。经式异构体结晶为单体[Cr(HP₂O₇)(NH₃)₃(H₂O)]·2H₂O，但面式异构体结晶为[Cr(HP₂O₇)(NH₃)₃]·2H₂O的中心对称二聚体，其中每个铬配位球中的剩余水被来自另一个单体单元的磷酸氧取代。经式异构体：一水合三氨（焦磷酸根）铬(III)二水合物，Mr = 332.1，单斜晶系，P21/c，a = 7.825(2)，b = 10.107(3)，c = 15.322(5) Å，β = 103.92(5)°，V = 1176(1) ų，Z = 4，Dx = 1.875 g cm⁻³，λ(Mo Kα) = 0.71073 Å，μ = 12.6 cm⁻¹，F(000) = 684，对1828个反射的最终R = 0.050。该化合物与先前报道的相应四氨配合物之间最显著的差异是，不仅水配体，而且氨配体的金属 - 配体键长都显著缩短。二聚体：μ -（焦磷酸根 - O,O',O"）- 双[三氨合铬(III)]二水合物，Mr = 314.0，单斜晶系，P21/c，a = 8.695(2)，b = 10.327(3)，c = 11.913(4) Å，β = 97.81(5)°，V = 1060(1) ų，Z = 4，Dx = 1.969 g cm⁻³，λ(Cu Kα) = 1.5418 Å，μ = 125.7 cm⁻¹，F(000) = 644，对1389个反射的最终R = 0.047。这个位于反演中心的结构形成了一个涉及两个Cr原子的三环配合物。该结构的特征是金属离子与焦磷酸部分的阴离子O原子之间的相互配位。（摘要截断于250字）
