Crown-Annelated 9,10-Bis(1,3-dithiol-2-ylidene)-9,10-dihydroanthracene Derivatives as Cation Sensors:Synthesis,X-ray Crystal Structures,Voltammetric and Spectroscopic Monitoring of Metal Complexation

摘要

The synthesis of O_4S_2-crown annelated derivatives of 9,10-bis(1,3-dithiol-2-ylidene)-9,10-dihydroanthracene using the novel Horner-Wadsworth-Emmons reagent 7 is reported.The bis-and mono-crown systems 9 and 12 function as efficient ligands inteh viltammetric and UV/Vis spectroscopic recognition of Na~+ and Ag~+.Solution electrochemical studies reveal that metal complexation to the crown unit(s) leads to a significant positive shift inthe potential of the first,two-electron oxidation wave of 9 and 12 [maximum shift E_1~(ox) velence 115mV for 9 in the presence of Ag~+ (ca.10 molar equivalents)].Considerably smaller shifts(<30mV) were observed for complexation of Li~+,K~+ and Ba~2.UV/Vis spectrophotometric studies of metal binding (Na~+ and Ag~+) to 9 are consistent with the simultaneous formation of 1:1 and 1:2 complexes.The X-ray crystal structures of compouns 10 and 12 centre dotCH_2Cl_2 are reported.The anthracenediylidene moiety of 12 is U-shaped due to the boat conformation of teh central (quinodimethane) ring and folding of both 1,3-dithiole rings,providing an overall saddle conformation.The folding in 10 is reduced as steric crowding is relieved by removal of one of the 1,3-dithiole units.