SELF-ASSEMBLED MONOLAYERS WITH CHARGE-TRANSFER FUNCTIONAL-GROUPS - IMMOBILIZATION OF THE ELECTRON-DONOR TMPD AND THE ELECTRON-ACCEPTOR TCNQ

Spontaneously adsorbed molecular films containing derivatives of the e lectron donor tetramethylphenylenediamine (TMPD) or the electron accep tor tetracyanoquinodimethane (TCNQ) are formed by exposure of polycrys talline Au to 1 mM solutions of an alkanethiol TMPD reagent or an alky l disulfide TCNQ species, respectively. Characterization of these redo x-active films by cyclic voltammetry establishes the presence of (3.3 +/- 0.3) x 10(-10) mol/cm(2) of redox-active TMPD groups in the case o f TMPD films and (2.4 +/- 0.5) x 10(-10) mol/cm(2) of redox-active TCN Q groups in the case of the TCNQ films. These films readily undergo ch arge-transfer reactions with complementary electron accepters and dono rs as verified by reflection-absorption infrared spectroscopy and lase r desorption mass spectrometry. These films provide convenient approac hes for exploiting well-known charge-transfer chemistry in interfacial adhesion measurements and for tailoring the electronic structure of m etal-organic interfaces.