5-COORDINATE IRON CARBONYL COMPLEXES WITH FLUOROCARBON-BRIDGED LIGANDS

The fluorocarbon-bridged di(tertiary phosphines) ffos and f6fos react with iron pentacarbonyl to yield the compounds ffosFe(CO)3, ffosFe(CO)4, and f6fosFe(CO)3. A related di(tertiary arsine) gives ffarsFe(CO)4 and ffarsFe2(CO)8. The Fe(CO)3 compounds have C2v symmetry and the structures are probably based on a distorted trigonal bipyramid with equatorial-equatorial substitution. The ligands act, respectively, as monodentate and bridging groups in the Fe(CO)4 and Fe2(CO)8 compounds. The Müssbauer spectra of these and related compounds show little variation in isomer shift. However it seems that the Mossbauer quadrupole splittings can be used to distinguish between cis- and trans-disubstituted derivatives of a trigonal-bipyramidal iron(O) complex. Other spectroscopic data for these compounds are given. In particular the carbonyl infrared spectra show some interesting features. © 1969, American Chemical Society. All rights reserved.