New applications of crown ethers. Part 8. Complexation of bis(monoazacrown ether)s with alkali-metal cations
作者:Gong-Xin He、Kiyoshi Kikukawa、Toshihiko Ikeda、Fumio Wada、Tsutomu Matsuda
DOI:10.1039/p29880000719
日期:——
The complexation behaviour of bis(monoazacrown ether)s (BCA15C5, BCA18C6, BOA15C5, BOA18C6) with alkali-metal cations was studied by means of solvent extraction, stability constants in homogeneous solution, and 13C n.m.r. spectroscopy. Bis(monoaza-18-crown-6)s, BCA18C6 and BOA18C6, cannot form an intramolecular sandwich complex with K+, probably because of the stability of the macrorings in pseudo-D3d
通过溶剂萃取,均相溶液中的稳定性常数和13 C nmr光谱研究了双(单氮杂row醚)(BCA15C5,BCA18C6,BOA15C5,BOA18C6)与碱金属阳离子的络合行为。Bis(monoaza-18-crown-6)s,BCA18C6和BOA18C6无法与K +形成分子内三明治复合物,这可能是因为大环在假D 3 d构象中具有稳定性,并且还优先提供了氧气BOA18C6的桥接链中的原子,如'lariat ethers'。对于bis(monoaza-15-crown-5),尤其是BOA15C5,在Na +和K +中均发现了分子内夹心结构的存在。复合体。据推测,更具柔韧性的单氮杂15冠环不受夹心结构形成的限制,桥链中的氧原子不仅增加了链的柔韧性,而且还可以与之直接配位。保持在三明治腔中的阳离子。