Preparation and Spectral Properties of Cobalt(III) Complexes with<i>S</i>,<i>S</i>′-Ethylenebis(L-homocysteinate) and<i>S</i>,<i>S</i>′-Trimethylenebis(L-homocysteinate)
作者:Mikako Kanesaka、Ken-ichi Okamoto、Jinsai Hidaka
DOI:10.1246/bcsj.59.1145
日期:1986.4
Three cobalt(III) complexes of [Co(sexidentate-N2,S2,O2)] and [Co(terdentate-N,S,O)2] types were prepared; where sexidentate-N2,S2,O2 denotes S,S′-ethylenebis(l-homocysteinate) (l,l-ebhc) and S,S′-trimethylenebis(l-homocysteinate) (l,l-tbhc), and terdentate-N,S,O denotes l-ethioninate (l-eth). Each of the l,l-ebhc and l,l-tbhc complexes was chromatographically separated into two isomers, trans(O) and trans(N), and the l-eth complex was separated into three isomers, trans(O), trans(N), and trans(S). These isomers were characterized by their electronic absorption, CD, and 13CNMR spectra. The stereoselectivity in the formation of each geometrical isomer for the l,l-ebhc and l,l-tbhc complexes is discussed in relation to the flexibilities of the S,S-bridged backbone chelate ring and the l-homocysteinate moiety.
制备了三种钴(III)配合物,分别为[Co(sexidentate-N2,S2,O2)]和[Co(terdentate-N,S,O)2]类型;其中sexidentate-N2,S2,O2表示S,S′-乙烯基双(l-高半胱氨酸)(l,l-ebhc)和S,S′-三甲基双(l-高半胱氨酸)(l,l-tbhc),terdentate-N,S,O表示l-乙硫氨酸(l-eth)。通过色谱法将l,l-ebhc和l,l-tbhc配合物分别分离为两种异构体,即反式(O)和反式(N),并将l-eth配合物分离为三种异构体,即反式(O)、反式(N)和反式(S)。通过电子吸收、CD和13CNMR光谱对这些异构体进行了表征。结合S,S-桥接主链螯合环和l-高半胱氨酸部分的柔性,讨论了l,l-ebhc和l,l-tbhc配合物形成每种几何异构体的立体选择性。