Bis mono-aza crown ethers. The formation of intramolecular complexes with dications
作者:Martin R. Johnson、Ian O. Sutherland、Roger F. Newton
DOI:10.1039/c39790000306
日期:——
The host molecules (4a–d), containing two crownether ring systems, form 1 : 1 complexes (8) with the bis primary alkylammonium salt (7); in the cases of the host (4a) and (4b) guest–host fit is so good that only the intramolecularcomplex is formed, but for the other host molecules (4c) and (4d) the complex (8) is probably accompanied by the polymeric complex (9).
The complexation behaviour of bis(monoazacrownether)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。
JOHNSON M. R.; SUTHERLAND I. O.; NEWTON R. F., J. CHEM. SOC. PERKIN TRANS., PART 1, 1980, NO 2, 586-600