The stable diiron (2.5) complex ion [(NC)_5Fe(#mu#-tz)Fe(CN)_5]~(5-),tz=1,2,4,5-tetrazine,and its neighboring oxidation states

摘要

The conceptually simple mixed-valent diiron compound (NEt_4)_5[(NC)_5Fe(#MU#-TZ)Fe(CN)_5] with the 1,2,34,5-tetracine (tz0 bridging ligand was obtained as thermally and air-stable material that displays large and highly variabe electrochemical comproportionation constants between about 10~8 (in water) and 10~(19.0) ( in acetonitrile).Strong metal-metal interaction is also evident from spectroscopic results obtained for the solid and for the disssolvede species.The rateractionis also evident from spectroscopic results obtained for the solid and for the dissolved species.The rather intense intervalenc e charge-transfer band occurs around 2400 nm; infrqred and Mossbauer spectra reveal the high spectroscopic symmetry of the system according to an (Fe~(2.5)_2 formulation.DFT calculations on the [(NC)_5Fe(#mu#-tz)Fe(CN)_5]~(6-) ion confirm the presence of very low-lying #pi#~* (tz) and high-lying d(Fe) orbitals.