Complexation of Methyl Orange and Tropaeolin 000 No. 2 by β-cyclodextrin dimers
作者:Carolyn A. Haskard、Bruce L. May、Tomas Kurucsev、Stephen F. Lincoln、Christopher J. Easton
DOI:10.1039/a603638d
日期:——
Spectrophotometric studies of the complexation of Methyl Orange
(MO
-
) and Tropaeolin 000 No. 2 (TR
-
) anions by
dimeric
N,Nâ²-bis(6
A
-deoxy-6
A
-β-cyclodextrin)urea (βCD)
2
ur and its oxalamide
and succinamide analogues, (βCD)
2
ox and
(βCD)
2
su, respectively, are consistent with the
predominant formation of complexes of the general formulae
(βCD)
2
x·MO
-
characterized by
stability constants
K
1
=(1.05±0.04)Ã10
5
,
(1.92±0.04)Ã10
5
and
(2.50±0.02)Ã10
4
dm3
mol
-1
and (βCD)
2
x·TR
-
characterized by
K
1
=(1.39±0.03)Ã10
4
,
(7.4±0.1)Ã10
3
and
(4.60±0.05)Ã10
3
dm3
mol
-1
, in aqueous phosphate buffer at pH 9.0 and 5.5 and
298.2 K. These values are significantly greater than
K
1
=2160 and 710 dm3
mol
-1
for the β-cyclodextrin complexes,
βCD·MO
-
and βCD·TR
-
and
are indicative of cooperative binding in
(βCD)
2
x·MO
-
and
(βCD)
2
x·TR
-
. The factors affecting
complex stability are discussed and comparisons are made with related
systems.
分光光度法研究甲基橙(MO - )和托帕啉 000 No.2 (TR - ) 阴离子与二聚 N,Nâ²-双(6 A -脱氧-6 A -δ²-环糊精)脲 (δ²CD)2ur及其草酰胺和琥珀酰胺类似物 (δ²CD) 2 ox 和 (δ²CD) 2 su(分别为 (δ²CD) 2 xÂ-MO - 和 (δ²CD) 2 su)的络合研究结果一致,主要形成了通式为 (δ²CD) 2 xÂ-MO - 的络合物,其特征为稳定常数 K 1 =(1.05±0.04)Ã10 5 , (1.92±0.04)Ã10 5 和 (2. 50±0.02)Ã10 5。50±0.02)Ã10 4 dm3 mol -1 和 (βCD) 2 xÂ-TR - 其特征为 K 1 =(1.39±0.03)Ã10 4, (7.4±0.1)Ã10 3 和 (4.60±0.05)Ã10 3 dm3 mol -1 ,在 pH 值为 9.0 和 5.5 以及 298.2 K 的磷酸盐缓冲水溶液中。这些值明显大于δ-环糊精复合物、δ²CDÂ-MO -和δ²CDÂ-TR -的K 1 =2160和710 dm3 mol-1,表明(δ²CD) 2 xÂ-MO -和(δ²CD) 2 xÂ-TR -中存在协同结合。讨论了影响复合物稳定性的因素,并与相关系统进行了比较。