ORGANOMETALLIC THIAZENES - OXIDATIVE ADDITION OF S4N4 TO LOW-VALENT METALS - ELECTROCHEMISTRY AND N-15 NMR OF CPCOS2N2 AND CP-ASTERISK-COS2N2

The reactions of S4N4 with CpM(CO)x and Cp*M(CO)x (M = Mn, Fe, Co, Ni and Rh) result in tractable products only when M = Co. The electrochemical behaviour of the previously known complexes CPCoS2N2 and Cp*CoS2N2 has been investigated by DC and AC cyclic voltammetry. Each has a single one-electron reduction process occurring at -0.65 V (Cp) and -0.99 V (Cp*). vs. SCE, in CH2Cl2 solution. For the Cp complex, chemical reduction using cobaltocene has also been achieved. 15N NMR spectra were recorded for 99% N-15 enriched samples: 550 (broad singlet) and 431 (singlet) for Cp, 518 (broad singlet) and 404 ppm (singlet) for Cp*, referenced to liquid NH3. The electronic absorption spectra are also reported, and interpreted in the light of EHMO calculations.