Inclusion of quinolines by binaphthol: structures and selectivity.
The enclathration selectivity of the host compound 2,2'-dihydroxyl-1,1'-binaphthyl, BINAP, towards the guests quinoline (Q), 2-methylquinoline (2MeQ), 6-methylquinoline (6MeQ) and 8-methylquinoline (8MeQ) were established by competition experiments as: BINAP.2(2MeQ) > BINAP.2Q > BINAP.2(8MeQ) > BINAP.2.5(6MeQ). The crystal structures of the inclusion compounds were elucidated and are all stabilised by (host)O-H...N(guest) hydrogen bonds. Thermal analysis yields the same sequence with respect to the relative stabilities. pH Control was employed to dramatically modify the selectivity profile of the pair of 2-methylquinoline (2MeQ) and 8-methylquinoline (8MeQ).
Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa.
Mino R
MR
Caira
Y
Y
Paul Chang
Luigi R
LR
Nassimbeni
Hong
H
Su