TY - JOUR
T1 - Macrocyclic Receptor Molecules for Guanidinium Cations. Preparation, X-Ray Structures, and Kinetic Stabilities of 1:1 Complexes of Guanidinium Perchlorate with Benzo-27-crown-9, Dibenzo-27-crown-9, and Dibenzo-30-crown-10
AU - De Boer, Jan A. A.
AU - Uiterwijk, Jos W. H. M.
AU - Geevers, Jan
AU - Harkema, Sybolt
AU - Reinhoudt, David N.
PY - 1983/12
Y1 - 1983/12
N2 - The complexation of guanidinium perchlorate (I) with 18-33 ring atom crown ethers and with different subunits (e.g., catechol and 1,3-xylyl moieties) in examd. by 2-phase extns. The 18-crown ethers are able to form perching complexes; crown ethers with >=27 ring atoms have a ring size capable of forming encapsulated complexes with I. Arom., catechol, and esp. 1,3-xylyl moieties have a destabilizing effect on complex formation. The crystal and the mol. structures of the 1:1 complexes of I with benzo-27-crown-9, dibenzo-27-crown-9, and dibenzo-30-crown-10, are detd. by x-ray crystallog. In these encapsulated complexes all H atoms of the guanidinium cation are used in H-bonds to the macrocyclic host. The 27-crown ethers show an optimal fit between cation and the macrocyclic host with a complementary binding scheme. Dynamic 500-MHz 1H NMR gave the kinetic stabilities of these complexes with Delta Gd.thermod. values of 11.5, 11.2, and 12.0 kcal mol-1 for the complexes with benzo-27-crown-9, dibenzo-27-crown-9, and dibenzo-30-crown-10, resp.
AB - The complexation of guanidinium perchlorate (I) with 18-33 ring atom crown ethers and with different subunits (e.g., catechol and 1,3-xylyl moieties) in examd. by 2-phase extns. The 18-crown ethers are able to form perching complexes; crown ethers with >=27 ring atoms have a ring size capable of forming encapsulated complexes with I. Arom., catechol, and esp. 1,3-xylyl moieties have a destabilizing effect on complex formation. The crystal and the mol. structures of the 1:1 complexes of I with benzo-27-crown-9, dibenzo-27-crown-9, and dibenzo-30-crown-10, are detd. by x-ray crystallog. In these encapsulated complexes all H atoms of the guanidinium cation are used in H-bonds to the macrocyclic host. The 27-crown ethers show an optimal fit between cation and the macrocyclic host with a complementary binding scheme. Dynamic 500-MHz 1H NMR gave the kinetic stabilities of these complexes with Delta Gd.thermod. values of 11.5, 11.2, and 12.0 kcal mol-1 for the complexes with benzo-27-crown-9, dibenzo-27-crown-9, and dibenzo-30-crown-10, resp.
U2 - 10.1021/jo00173a008
DO - 10.1021/jo00173a008
M3 - Article
SN - 0022-3263
VL - 48
SP - 4821
EP - 4830
JO - Journal of Organic Chemistry
JF - Journal of Organic Chemistry
ER -