
%0 Journal Article
%A Donati, Donato 
%A Roelens, Stefano 
%A Torriti, Riccardo 
%A Valle, Giovanni 
%T Structure and Binding Properties of Four New Oligomeric Cyclophane Esters: 1,4-Xylylene 1,4-Phenylene Diacetates and Dipropionates
%J Australian Journal of Chemistry
%D 1998/05/20
%V 51
%N 5
%P 361-370
%K 
%R https://doi.org/10.1071/C97215
%U https://www.publish.csiro.au/paper/C97215 
%X The X-ray crystal structure determinations of four new oligomeric cyclophane esters are reported. They are: (3a) monomeric 1,4-xylylene (1,4-phenylene)diacetate, P21/n (No. 14), a 5&#183;959(5), b 15&#183;795(5), c 8&#183;094(5) &#197;, &#946; 108&#183;060(5)&#176;, V 724&#183;3(8) &#197;3 , Z 2, R1(2&#963;) 0&#183;0522, wR2 0&#183;125; (3b) monomeric 1,4-xylylene (1,4-phenylene)dipropionate, P21/c (No. 14), a 5&#183;878(1), b 14&#183;642(2), c 18&#183;909(2) &#197;, &#946; 96&#183;00(10)&#176;, V 1618&#183;5(4) &#197;3 , Z 4, R1(2&#963;) 0&#183;053, wR2 0&#183;165; (3c) dimeric 1,4-xylylene (1,4-phenylene)diacetate, P-1 (No. 2), a 14&#183;633(2), b 17&#183;529(2), c 5&#183;736(1) &#197;, &#945; 98&#183;30(10), &#946; 90&#183;60(10), &#947; 95&#183;40(10)&#176;, V 1449&#183;0(4) &#197;3, Z 2, R1(2&#963;) 0&#183;057, wR2 0&#183;158; (3d) dimeric 1,4-xylylene (1,4-phenylene)dipropionate, P21/a (No. 14), a 8&#183;145(1), b 11&#183;379(2), c 17&#183;401(2) &#197;, &#946; 101&#183;40(10)&#176;, V 1580&#183;9(4) &#197;3, Z 4, R1(2&#963;) 0&#183;034, wR2 0&#183;095. Monomeric cyclophanes (3a,b) exhibit a well defined cleft, while dimeric (3c,d) adopt a flat conformation devoid of cavities. Binding properties were determined by 1H n.m.r. titrations in CDCl3 at T = 296 K. Complexation experiments with quaternary ammonium salts revealed that host (3c) possesses appreciable binding ability toward N-methylpyridinium (&#8211;&#916;G&#176; = 5&#183;9 kJ mol-1), tetramethylammonium (&#8211;&#916;G&#176; = 8&#183;8 kJ mol-1) and acetylcholine (&#8211;&#916;G&#176; = 7&#183;5 kJ mol-1) cations, despite its lack of a preorganized cavity. 
