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首页> 外文期刊>Polyhedron: The International Journal for Inorganic and Organometallic Chemistry >COPPER(II), NICKEL(II) AND ZINC(II) COMPLEXES OF N,N',N'',N'''-TETRAKIS(2-HYDROXYPROPYL)-1,4,8,11-TETRA-AZACYCLOTETRADECANE - RATES OF FORMATION AND DISSOCIATION OF THE COPPER(II) COMPLEX
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COPPER(II), NICKEL(II) AND ZINC(II) COMPLEXES OF N,N',N'',N'''-TETRAKIS(2-HYDROXYPROPYL)-1,4,8,11-TETRA-AZACYCLOTETRADECANE - RATES OF FORMATION AND DISSOCIATION OF THE COPPER(II) COMPLEX

机译：N，N'，N''，N'''-四（2-羟基丙基）-1,4,8,11-四氮杂环丁烷的铜（II），镍（II）和锌（II）络合物-价格铜（II）络合物的形成与分解

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The preparation of the pendant arm macrocycle N,N',N'',N'''-tetrakis(2-hydroxypropyl)- 1,4,8,11-tetra-azacyclotetradecane (THPC = L) by reaction of propylene oxide with 1,4,8,11 -tetra-azacyclotetradecane (cyclam) is described. Copper(II), nickel(II) and zinc(II) complexes of the ligand have been prepared and characterized. The reaction of L with copper(II) in basic solution has been studied by stopped flow techniques L + [Cu(OH)(3)](-) --> [CuL](2+); k(1) L + [Cu(OH)(4)](2-) --> [CuL](2+); k(2) At 25 degrees C and I = 1.0 mol dm(-3), k(1) = 3.7 x 10(5) and k(2) = 2.1 x 10(4) dm(3) mol(-1) s(-1). These values may be compared with the constants obtained for cyclam, k(1) = 2.7 x 10(6) and k(2) = 3.8 x 10(4) dm(3) mol(-1) s(-1) at 25 degrees C. The mechanism of the reaction is discussed. The copper(II) complex [CuL](2+) dissociates readily in acidic solution. The kinetics of dissociation have been studied by stopped how methods in the acidity range 0.05-1.0 mol dm(-3) HClO4. Two reactions could be detected, the first reaction was complete within 20-30 ms at 25 degrees C and was attributed to a pre-equilibrium protonation step. The second reaction, associated-with an absorbance decrease was assigned to the acid dissociation step and was acid dependent at low acidities and acid independent at high acidities. In the acidity range used the dissociation can be fitted to the kinetic scheme [CuL](2+) + H+ reversible arrow [CULH](3+); K [CuLH](3+) --> Cu2+ + LH+; k and k(Obs) = kK[H+]/(1 + K[H+]), with k = 7.1 +/- 0.4 s(-1) and K = 1.3 +/- 0.1 dm(3) mol(-1) at I = 1.0 mol dm(-3) and 25 degrees C. The pK values of THPC determined by potentiometric titration are 9.08, 8.30, < 2 and < 2 at 25 degrees C. Studies of the solution equilibria of the ligand with copper(II) and nickel(II) by potentiometric methods indicate that with copper(II) the titration data can be fitted to the single equilibrium Cu2+ + L reversible arrow CuL2+ with log beta(110) = 15.54(3). In the case of nickel(II) deprotonation of the complex occurs with log beta(110) = 7.32(3), log beta(11-1) = - 1.71(3) and log beta(11-2) = - 12.62(4). Deprotonation of the pendant hydroxyl groups in the nickel(II) complex has been confirmed by visible spectral measurements. (C) 1997 Elsevier Science Ltd. [References: 12]
机译：环氧丙烷与环氧丙烷反应制备侧链大环N，N'，N''，N'''-四（2-羟丙基）-1,4,8,11-四氮杂环十四烷（THPC = L）描述了1,4,8,11-四氮杂环十四烷（cyclam）。已经制备并表征了配体的铜（II），镍（II）和锌（II）配合物。用停止流动技术L + [Cu（OH）（3）]（-）-> [CuL]（2+）研究了L与碱性溶液中铜（II）的反应。 k（1）L + [Cu（OH）（4）]（2-）-> [CuL]（2+）; k（2）在25摄氏度且I = 1.0 mol dm（-3）时，k（1）= 3.7 x 10（5）和k（2）= 2.1 x 10（4）dm（3）mol（-1 ）s（-1）。可以将这些值与为Cyclam获得的常数进行比较，其中k（1）= 2.7 x 10（6）和k（2）= 3.8 x 10（4）dm（3）mol（-1）s（-1） 25℃。讨论了反应机理。铜（II）络合物[CuL]（2+）在酸性溶液中容易解离。通过停止研究在酸度范围为0.05-1.0 mol dm（-3）HClO4中的方法，研究了解离动力学。可以检测到两个反应，第一个反应在25摄氏度下于20-30毫秒内完成，并归因于预平衡质子化步骤。与吸光度降低相关的第二个反应被分配给酸解离步骤，该反应依赖于低酸度的酸和依赖于高酸度的酸。在所用的酸度范围内，解离可适合动力学方案[CuL]（2+）+ H +可逆箭头[CULH]（3+）; K [CuLH]（3+）-> Cu2 + + LH +; k和k（Obs）= kK [H +] /（1 + K [H +]），其中k = 7.1 +/- 0.4 s（-1）和K = 1.3 +/- 0.1 dm（3）mol（-1 ）在I = 1.0 mol dm（-3）和25摄氏度下。通过电位滴定法测定的THPC的pK值在25摄氏度下为9.08、8.30，<2和<2。 （II）和镍（II）的电位法表明，对于铜（II），滴定数据可以拟合为单平衡Cu2 + + L可逆箭头CuL2 +，对数beta（110）= 15.54（3）。在镍（II）的情况下，配合物的去质子化以log beta（110）= 7.32（3），log beta（11-1）=-1.71（3）和log beta（11-2）=-12.62（ 4）。镍（II）络合物中侧链羟基的去质子化已通过可见光谱测量得到证实。 （C）1997 Elsevier Science Ltd. [参考：12]

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