Jozef Hodyl PhD Thesis - Theses - Flinders University

60 in 0.5% DMSO-MeCN (v/v). 82 The terminal pyridyl groups are presumed also toaccept hydrogen bonds from dihydrogen phosphate adding to the binding strengthand hence selectivity.A set of cyclic anion receptors 14 and 15 containing amide and amine moieties aspart of their backbone was reported by Hossain et al. in 2003. 83 These receptors weredesigned to bind tetrahedral anions, for instance sulfate and phosphate, selectively. 83H 3 C CH 3ONHCH 3NNHOONHNNHOXXXXONHNCH 3HNOONHNHNOH 3 C CH 314, X = CH15, X = N16, X = CH17, X = NThese receptors contain four amide NH hydrogen bond donor groups and twotertiary amine moieties that can be methylated to give quaternarised ammoniumreceptors 16 and 17, in effect furnishing the receptor with two additional sites forbinding anions. 83 Binding of anions such as H 2 PO - 4 is strengthened in receptors 16and 17 where the logK values are 4.06 and 5.32, respectively, whereas receptors 14and 15 give logK values of 2.92 and 4.04, respectively, as determined from 1 H NMRmonitored titration experiments in CD 3 OD.The "catalogue" for anion receptors bearing the amide moiety is vast due to theefficacy of the amide group in binding anionic species in a range of both polar andnon-polar solvents. 84-881.3.4 Alcohol based anion receptorsConsidering that hydroxy groups are excellent hydrogen bonding donor groups it can15