Lanthanide Complexes of the Klaui Metalloligand, CpCo(P=O(OR)2)3: An Examination of Ligand Exchange Kinetics between Isotopomers by Electrospray Mass Spectrometry
Lanthanide Complexes of the Klaui Metalloligand, CpCo(P=O(OR)2)3: An Examination of Ligand Exchange Kinetics between Isotopomers by Electrospray Mass Spectrometry
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DOI：
10.1021/ic301830u
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发表时间：
2012-11-19
影响因子：
4.6
通讯作者：
Twamley, Brendan
中科院分区：
文献类型：
--
作者：
Allen, Kevin J. H.;Nicholls-Allison, Emma C.;Twamley, Brendan
合成了一系列含两个钴金属配体的稀土配合物{[CpCo（P=O（OR）（2））（3）]（2）Ln（H2O）（x）}Cl-+（-）（Ln = Nd，3; Eu，4; Tb，5; Y B，6; R = Et，a; R = Ph，B）。电喷雾质谱和热重分析表明，阳离子是无溶剂或含有非常弱的结合水分子。对相关配合物{[CpCo（P=O（OPh）（2））（3）]（2）Yb）（+）[CoCl 3（THF）]（-）7进行了晶体学表征，证实了这种情况下的阳离子是6-配位和无溶剂的。通过电喷雾质谱法测定了3a-6a和5 b的d（0）-和d（60）-同位素异构体之间的配体交换速率。发现在乙腈中，从最小离子（Yb，6a，k = 0.3 M-1 s（-1））到最大离子（Nd，3a，>2500 M-1 s（-1）），配体交换速率增加近4个数量级。此外，随着水浓度从纯乙腈中的30 M-1 s（-1）增加到50：50（v/v）乙腈/水中的268 M-1 s（-1），5a（Tb）的配体交换速率迅速增加。改变亚磷酸酯取代基对5 b（R = Ph）相对于5a（R = Et）的配体交换速率没有显著影响。
A series of lanthanide complexes, {[CpCo(P=O(OR)(2))(3)](2)Ln(H2O)(x)}Cl-+(-) (Ln = Nd, 3; Eu, 4; Tb, 5; 'Yb, 6; R = Et, a; R = Ph, b) bearing two cobalt metalloligands were prepared. Electrospray mass spectrometry and thermogravimetric analysis suggest that the cations are either solvent free or contain very weakly bound water molecules. The related complex {[CpCo(P=O(OPh)(2))(3)](2)Yb)(+) [CoCl3(THF)](-), 7, was crystallographically characterized, and the cation in this case was confirmed to be 6-coordinate and solvent free Ligand exchange rates between the d(0)- and d(60)-isotopomers of 3a-6a and 5b were determined in acetonitrile by electrospray mass spectrometry. The ligand exchange rate was found to increase by almost 4 orders of magnitude from the smallest (Yb, 6a, k = 0.3 M-1 s(-1)) to largest ion (Nd, 3a, >2500 M-1 s(-1)) in acetonitrile. Additionally, the ligand exchange rate increased rapidly for 5a (Tb) with increasing water concentration from 30 M-1 s(-1) in pure acetonitrile to 268 M-1 s(-1) in 50:50 (v/v) acetonitrile/water. Changing the phosphite substituent had no significant impact on the rate of ligand exchange for 5b (R = Ph) relative to 5a (R = Et).