Sadakane M, Dickman M H, Pope M T
Department of Chemistry, Georgetown University, Washington, DC 20057-1227, USA.
Inorg Chem. 2001 Jun 4;40(12):2715-9. doi: 10.1021/ic0014383.
The ammonium salt of the 1:1complex (1) of Ce(III) with alpha(1)-P(2)W(17)O(61)(-) was prepared and characterized by elemental analysis, vibrational and NMR spectroscopy ((31)P, (183)W), cyclic voltammetry, and single-crystal X-ray analysis (P1; a = 15.8523(9) A, b = 17.4382(10) A, c = 29.3322(16) A, alpha = 99.617(1) degrees, beta = 105.450 (1) degrees, gamma = 101.132(1) degrees, V = 7460.9(7) A(3), Z = 2). The anion consists of a centrosymmetric head-to-head dimer, [Ce(H(2)O)(4)(P(2)W(17)O(61))],(14-) with each 9-coordinate Ce cation linked to four oxygens of one tungstophosphate anion and to one oxygen of the other anion. On the basis of P NMR spectroscopy, a monomer-dimer equilibrium exists in solution with K = 20 +/- 4 M(-1) at 22 degrees C. Addition of chiral amino acids to aqueous solutions of 1 results in splitting of the (31)P NMR signals as a result of diastereomer formation. No such splitting is observed with glycine or DL-proline, or when chiral amino acids are added to the corresponding complex of the achiral alpha(2)-isomer of P(2)W(17)O(61)(-). From analysis of the (31)P NMR spectra, formation constants of the two diastereomeric adducts of 1 with L-proline are 7.3 +/- 1.3 and 9.8 +/- 1.4 M(-1).
制备了铈（III）与α(1)-P(2)W(17)O(61)(-)的1:1配合物（1）的铵盐，并通过元素分析、振动光谱和核磁共振光谱（(31)P、(183)W）、循环伏安法以及单晶X射线分析（P1；a = 15.8523(9) Å，b = 17.4382(10) Å，c = 29.3322(16) Å，α = 99.617(1)°，β = 105.450 (1)°，γ = 101.132(1)°，V = 7460.9(7) Å(3)，Z = 2）对其进行了表征。阴离子由一个中心对称的头对头二聚体[Ce(H(2)O)(4)(P(2)W(17)O(61))]，(14-)组成，每个九配位的Ce阳离子与一个钨磷酸盐阴离子的四个氧原子以及另一个阴离子的一个氧原子相连。基于(31)P核磁共振光谱，在22℃时溶液中存在单体 - 二聚体平衡，K = 20 ± 4 M(-1)。向1的水溶液中加入手性氨基酸会由于非对映异构体的形成导致(31)P核磁共振信号分裂。用甘氨酸或DL - 脯氨酸时未观察到这种分裂，或者当手性氨基酸加入到P(2)W(17)O(61)(-)的非手性α(2)-异构体的相应配合物中时也未观察到这种分裂。通过对(31)P核磁共振光谱的分析，1与L - 脯氨酸的两种非对映异构加合物的形成常数分别为7.3 ± 1.3和9.8 ± 1.4 M(-1)。
