Fourier-transform infrared study of short-lived highly reduced dithiolene complexes by potential-modulation spectroelectrochemical techniques

The reduction of [M(mnt)(3)(3-) (M = V, Mo or Re; mnt = maleonitriledithiolate) has been examined by potential-modulation spectroelectrochemical techniques. Despite the highly reducing potentials required to effect the reductions (-1.57 to -2 V) and the highly unstable character of the reduction products the values of nu(CN) have been obtained for [M(mnt)(3)](4-) (M = V, Re or Mo) (2164, 2133 and 2134 cm(-1) respectively). The sensitivity of the nu(CN) values to the identity of the metal for CM(mnt)(3)](4-) is greater than that found for the corresponding trianions suggesting an increased metal contribution to the frontier orbitals. The application of potential-modulation techniques to the examination of bulk solution species Is described and shown to offer significant advantages for highly reactive electrochemically generated species.