Synthesis and characterisation of cyclopentadienylcobalt and pentamethylcyclopentadienylcobalt diselenolenes
作者:Christopher P. Morley、Richard R. Vaughan
DOI:10.1039/dt9930000703
日期:——
Reaction of [Co(C5R15)(CO)2] (R1 = H or Me) with 1,2,3-selenadiazoles in toluene under reflux in the presence of an excess of elemental selenium leads in moderate yield to the diselenolenes [Co(C5R15)SeC(R2)=C(R3)Se}] [R2-R3=(CH2)6, CH=CH(CH2), or CH=CH(CH2)2CH=CH; R2=Ph, R3=H; R2=R3=Ph]. In particular this procedure provides access to novel compounds without electron-withdrawing substituents. The products have been characterised by H-1 NMR, IR, UV/VIS and mass spectroscopy, microanalysis and cyclic voltammetry. Each diselenolene undergoes a fully reversible one-electron reduction, and exhibits a low-energy electronic transition at ca. 800 nm. Of the substituents (R1,R2,R3), R1 has the greatest influence on the spectroscopic and electrochemical properties. For structurally similar compounds there is a linear correlation between the half-wave potential for the reduction and the energy of the first electronic absorption band.