Acid–Base Behavior of Substituted Hydrazone Complexes Controlled by the Coordination Geometry
Acid–Base Behavior of Substituted Hydrazone Complexes Controlled by the Coordination Geometry
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DOI：
10.1246/bcsj.20100065
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发表时间：
2010-07
影响因子：
4
通讯作者：
Mee Chang;Hiroyuki Horiki;K. Nakajima;A. Kobayashi;Ho‐Chol Chang;Masako Kato
中科院分区：
文献类型：
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作者：
Mee Chang;Hiroyuki Horiki;K. Nakajima;A. Kobayashi;Ho‐Chol Chang;Masako Kato
合成并表征了一系列新的取代腙配合物[Cu（Hpbph）I]（1），[Cu（Hpbph）PPh 3] PF 6（2-PF 6），[NiCl-（Hpbph）]Cl（3-Cl），[PtCl（Hpbph）]ClO 4（4-ClO 4），[PtCl（Hpbph）]（4 b）（Hpbph = 2-（二苯基膦基）苯甲醛2-吡啶腙）. X射线晶体学显示，铜（I）配合物采用伪四面体几何形状，而镍（II）和铂（II）配合物提供正方形平面形式。所有的配合物表现出不同的颜色变化的基础上的配体上的去质子化/质子化，虽然它们的酸/碱行为有很大的不同。在甲醇中的酸度常数（pKa）分别为11.4（1）、12.5（2）、7.7（3）和6.7（4）。结果表明，配体上质子的解离强烈依赖于配合物配位几何控制的配体变形，辅助配体也对酸性有一定影响。
A new series of substituted hydrazone complexes, [Cu(Hpbph)I] (1), [Cu(Hpbph)PPh 3] PF 6 (2-PF 6 ), [NiCl-(Hpbph)]Cl (3-Cl), [PtCl(Hpbph)]ClO 4 (4-ClO 4 ), and [PtCl(pbph)] (4b) (Hpbph = 2-(diphenylphosphino)benzaldehyde 2-pyridylhydrazone) have been synthesized and characterized. X-ray crystallography revealed that the copper(I) complexes adopt pseudo-tetrahedral geometry, while the nickel(II) and platinum(II) complexes provide square-planar forms. All the complexes exhibit distinct color changes on the basis of the deprotonation/protonation on the ligand although their acid/base behaviors are largely different. The acidity constants (pK a ) in methanol were determined to be 11.4 (1), 12.5 (2), 7.7 (3), and 6.7 (4). The results indicate that the dissociation of the proton on the ligand strongly depends on the ligand deformation controlled by the coordination geometry of the complexes and ancillary ligands also somewhat affect the acidity.