화학공학소재연구정보센터
Electrochimica Acta, Vol.89, 784-791, 2013
pi-Donor layer coverage onto glassy carbon by electrochemical means. Reduction of omega-iodoalkyl-tetrathiafulvalenes
Organic pi-donors such as tetrathiafulvalenes (IT F) substituted by primary alkyl iodides (RI) may react in contact with polarized glassy carbon at potentials more negative than - 1 V vs. Ag/AgCl. Accordingly, useful heterogeneous layers are formed which are directly attached to a conducting surface. The present work focuses on the grafting of TTfs possessing polyethylene links ended with an iodine atom (TTF-(CH2)(n)-I). Two different methods are proposed: (i) via the carbon charge considered as a polynucleophile (at carbon surface polarized at E<-1.7 V) and (ii) via the catalytic coverage of carbon by Pd (at about -1 V), using aprotic polar solvents such as acetonitrile, N,N-dimethylformamide, and propylene carbonate containing tetraalkylammonium salts. At very negative potentials, the cathodic charge of carbon is expected to generate nucleophiles while the use of palladium (used at an average surface concentration of 4 x 10(-10) atom cm(-2)) may favour the formation of transient alkyl radicals. TTF layers are easily generated by these two methods and superficial concentrations were found to be high, up to 10 x 10(-9) mol cm(-2). A similar grafting of TTFs was successfully achieved onto graphite. (C) 2012 Elsevier Ltd. All rights reserved.