Molecular Design and Characterization of Multidentate Ligand

多齿配体的分子设计和表征

• 批准号: 10650802
• 负责人: ODASHIMA Tsugikatsu
• 金额: $ 2.24万
• 依托单位: Ichinoseki National College of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10650802/
• 关键词: Multidentate Ligand; Hydrazone; Copper (II); Extraction Equilibrium; Adduct Complex; Synergistic Effect; 含硫黄ヒドラゾン; 酸解離定数; 抽出吸光試薬; 銅(II)錯体

A multidentate ligand, 2-mercaptobenzaldehyde 5-nitro-2-pyridylhydrazone (MBNPH), derived from benzaldehyde-2-pyridylhydrazone(BPH) was designed and synthesized. Its properties, reactivities with metal ions and extractabilities of the complexes have been investigated. It has been found that (1) the introduction of an electron - withdrawing group to the 5-position of the pyridine ring brings about increases in molar absorptivities (ε) of the metal complexes, (2) the introduction of a mercapto group to the 2-position of the phenyl ring of BHP brings about increases in selectivity for Cu (II), especially, and (3) the introduction of both nitro and mercapto groups to BPH lowers the values of the acid dissociation constants (pKa), pKaィイD21ィエD2=7.26 (SH group) and pKaィイD22ィエD2=10.80 (NH group). In benzene, Cu (II) reacts with MBNPH to form a 1:2 yellow complex (λィイD2maxィエD2 = 483nm, ε= 34,000 MィイD1-1ィエD1 cmィイD1-1ィエD1) and an adduct complex (λィイD2maxィエD2 = 474 nm, ε= 54,000 MィイD1-1ィエD1 cmィイD1-1ィエD1) by the synergistic effect of pyridine base when it is present. The ratio of three components in the adduct complex is estimated to be Cu (II) : MBNH : pyridine = 1 : 2 : 2. Furthermore, the equilibrium constants of the Cu (II) complex were determined ; the extraction constant (log KィイD2exィエD2), the distribution constant (log KィイD2DCィエD2) and the stability constants (logβィイD21ィエD2, logβィイD22ィエD2) were found to be 2.19, 2.10, 5.79 and 17.6, respectively.

以苯甲醛-2-吡啶腙（BPH）为原料，设计合成了一种多齿配体2-巯基苯甲醛-5-硝基-2-吡啶腙（MBNPH）。研究了配合物的性质、与金属离子的反应性和萃取性能。结果表明：（1）在吡啶环的5位引入吸电子基团，使配合物的摩尔吸光系数（ε）增大;（2）在BHP苯环的2位引入巯基，使Cu（Ⅱ）的选择性增大，（3）引入硝基和巯基后，BPH的酸离解常数（pKa）降低，pKa =7.26（SH基）和pKa =10.80（NH基）。在苯中，Cu（Ⅱ）与MBNPH反应生成1：2的黄色配合物（λ max = 483 nm，ε= 34，000 M H2O D1 - 1 cm H2O D1 - 1 cm H2O D1）和加合物（λ max = 474 nm，ε= 54，000 M H2O D1 - 1 cm H2O D1 - 1 cm H2O D1）。加合物中三种组分的比例估计为Cu（II）：MBNH：吡啶= 1：2：2。此外，还测定了Cu（II）配合物的平衡常数，萃取常数（log K_（？）D_2 ex_（？）D_2）、分配常数（log K_（？）D_2 DC_（？）D_2）和稳定常数（logβ_（？）D_