The heteroditopic receptors 1 and 2 firmly include an AgI ion into the NS2O2 crown and establish selective H-bond interactions with anions at the covalently linked urea/thiourea (U/T) subunit. Studies in MeCN solution showed that the metal center induces a 103-106-fold enhancement of the anion association constant, due to a coordinative interaction with the O/S atom of the U/T moiety. In the presence of F-, the Ag-O interaction promotes the release of a proton from one of the urea N-H fragments. AgI coordination to the S atom of the thiourea derivative 2 promotes the formation of unusually stable H-bond complexes with Cl- and Br-.
Metal-Enhanced H-Bond Donor Tendencies of Urea and Thiourea toward Anions: Ditopic Receptors for Silver(I) Salts
AMENDOLA, VALERIA;FABBRIZZI, LUIGI;LICCHELLI, MAURIZIO;MONZANI, ENRICO;
2005-01-01
Abstract
The heteroditopic receptors 1 and 2 firmly include an AgI ion into the NS2O2 crown and establish selective H-bond interactions with anions at the covalently linked urea/thiourea (U/T) subunit. Studies in MeCN solution showed that the metal center induces a 103-106-fold enhancement of the anion association constant, due to a coordinative interaction with the O/S atom of the U/T moiety. In the presence of F-, the Ag-O interaction promotes the release of a proton from one of the urea N-H fragments. AgI coordination to the S atom of the thiourea derivative 2 promotes the formation of unusually stable H-bond complexes with Cl- and Br-.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.