Diastereomeric discrimination in 1,4,7-tris((S )-2-hydroxypropyl)-1,4,7-triazacyclononane and its lithium(I), sodium(I) and zinc(II) complexes
作者:Jennifer M. Weeks、Mark A. Buntine、Stephen F. Lincoln、Edward R. T. Tiekink、Kevin P. Wainwright
DOI:10.1039/b008687h
日期:——
In methanol, interchange between equivalent forms of a single diastereomer of 1,4,7-tris((S)-2-hydroxypropyl)-1,4,7-triazacyclononanelithium(I), [Li(S-thpc9)]+, and a similar interchange in [Na(S-thpc9)]+ have been characterised by variable temperature 13C1H} NMR spectroscopy. The respective kinetic parameters are: k = 33.5 ± 0.8 and 3030 ± 80 s−1 at 298.2 K, ΔH‡ = 50.6 ± 1.0 and 50.9 ± 1.3 kJ mol−1, and ΔS‡ = −46.1 ± 3.4 and −7.6 ± 4.7 J K−1 mol−1, with the corresponding log(K/dm3 mol−1) = 3.39 ± 0.05 and 2.50 ± 0.05 at 298.2 K and I = 0.05 mol dm−3 (NEt4ClO4), where K is the complex stability constant. In N,N-dimethylformamide (DMF), log(K/dm3 mol−1) = 3.29, 2.29, 2.28, 2.27, 2.29 and 7.59 (all ± 0.05) for [M(S-thpc9)]+ where M+ = Li+, Na+, K+, Rb+, Cs+ and Ag+, respectively. For the interchange between equivalent forms of a single diastereomer of 1,4,7-tris((S)-2-hydroxy-2-phenylethyl)-1,4,7-triazacyclononanelithium(I), [Li(S-thpec9)]+, and a similar interchange in [Na(S-thpec9)]+, the kinetic parameters obtained in DMF are: k = 20.5 ± 0.8 and k = 8600 ± 200 s−1 at 298.2 K, ΔH‡ = 32.8 ± 1.8 and 54.7 ± 1.2 kJ mol−1, and ΔS‡ = −110 ± 3.2 and 13.8 ± 4.2 J K−1 mol−1, respectively. In DMF, log(K/dm3 mol−1) = 3.64, 2.03, 1.91, 1.91, 1.62 and 7.59 (all ± 0.05) for [M(S-thpc9)]+ where M+ = Li+, Na+, K+, Rb+, Cs+ and Ag+, respectively. Gas phase ab initio modelling shows S-thpc9, S-thpec9 and their Li+, Na+ and Zn(II) complexes to assume single distorted trigonal prismatic diastereomeric conformations, as do X-ray crystallographic, abinitio modelling and 13C1H} NMR spectroscopic solution studies of [Zn(S-thpc9)]+.
F中,1,4,7-三((S)-2-羟基-2-苯乙基)-1,4,7-三氮杂环壬基锂(I)的单个非对映异构体的等效形式之间的互换,[Li(S-thpc9)]+,以及[Na(S-thpc9)]+中的类似互换,其动力学参数为:在298.2 K时,k = 33.5 ± 0.8和3030 ± 80 s−1,ΔH‡ = 50.6 ± 1.0和50.9 ± 1.3 kJ mol−1,以及ΔS‡ = −46.1 ± 3.4和−7.6 ± 4.7 J K−1 mol−1,相应的log(K/dm3 mol−1) = 3.39 ± 0.05和2.50 ± 0.05,I = 0.05 mol dm−3 (NEt4ClO4),其中K是复合稳定性常数。在N,N-二甲基甲酰胺(DMF)中,log(K/dm3 mol−1) = 3.29、2.29、2.28、2.27、2.29