铜与缓冲剂Bicine及芳香氮碱三元混配配合物的稳定性研究

用pH电位滴定法测定了HL的酸常数（L＝苯并咪唑，吡啶，3，4－二甲基吡啶，异喹啉）以及二元配合物CuL2＋和三元混配配合物Cu（Bic）L＋（Bic-＝Bicine的单电荷阴离子）的稳定常数．三元混配配合物相对于二元配合物的稳定性用△lgKCu＝lgKCu(Bic)Cu(Bic)L-lgKCuCuL来表示．结果表明由于δ-π协同效应和疏水作用。

Bicine单电荷阴离子与芳香氮碱形成的三元金属离子混配配合物的稳定性研究

用 pH电位滴定法首次研究了水溶液中三元混配配合物M(Bic)L+(M2 +=Ni2 +或Zn2 +,L =苯并咪唑、吡啶、3,4-二甲基吡啶、异喹啉 ,Bic- =N ,N -双 (羟乙基 )甘氨酸的单电荷阴离子 )的稳定性 .三元混配配合物相对于二元配合物的稳定性差值用ΔlgKM=lgKM(Bic)M(Bic)L-lgKMML来表示 .结果表明这些三元混配配合物比统计规律所估计的要稳定得多 ,且ΔlgKZn大于ΔlgKNi.三元混配配合物稳定性增大可归因于πA-πB 协同作用和Zn2 +配位构型的转变 .

Calculation of the pH of Buffer Solution of 2-[<i>N</i>-Morpholino]ethanesulfonic Acid (MES) from 5°C to 55°C

This paper reports the results for the pH of three buffer solutions free of chloride ion. The remaining six buffer solutions have saline media of the ionic strength I = 0.16 mol.kg-1, matching closely to that of the physiological sample. Conventional paH values for the three buffer solutions without the chloride ion and six buffer solutions with the chloride ion at I = 0.16 mol.kg-1 from 5°C to 55°C have been calculated. The operational pH values for five buffer solutions at 5°C and 55°C have been determined based on the difference in the values of the liquid junction potentials between the blood phosphate standard and the experimental buffer solutions. Five of these buffers are recommended as standards for the physiological pH range 7.5 to 8.5.

The ternary metal mixed ligand complexes formed by benzimidazole and N, N-bis (2-hydroxyethyl) glycine

The stability constants of the ternary M（Bic）（Bzim）+ complexes, where M2+=Cu2+, Ni2+ or Zn2+, Bic-=the anion of N, N-bis（2-hydroxyethyl） glycine and Bzim = benzimidazole, were determined by potentiometric pH titration in aqueous solution. One of them (M2+ = Cu2+) was also separately determined by spectrophotometry. The results show that these ternary complexes are stabler than expected on statistical grounds. The enhanced stability of the ternary M（Bic） （Bzim）+ complexes is attributed to the πA-πB cooperative effect between Bic- and benzimidazole. Besides, compared with Cu（Bic） （Bzim）+ and Ni（Bic） （Bzim）+, the ternary Zn（Bic）（Bzim）+ complex has relatively high stability. The crystal structure of [Cu（Bic）（Bzim）]ClO4 was determined by single crystal X-ray diffraction techniques. The copper atom has a trigonal-bipyramidal geometry, the basal plane is formed by an oxygen atom of the carboxylato group and two hydroxyl oxygen atoms, the apical position is occupied by a nitrogen