Structure and reactivity of M+[Fe(CO)3(NO)]-

Abstract

Supplementary Material Available: Anisotropic thermal parameters (Table IV) and observed and calculated structure amplitudes (Table V) (22 pages). Ordering information is given on any current masthead page.

The Electronic Ground State of [Fe(CO)3(NO)]−: A Spectroscopic and Theoretical Study

“…However, two of the reported spectroscopic properties are not in line with this assignment: a) a NÀO bond length of 1.212 , [9] and b) a NO signal in the IR spectrum at 1647 cm À1 . [10] These properties indicate the NO ligand may not be cationic but in a reduced form. However, in the majority of cases reduced NO ligands are expected to be bound in a nonlinear fashion.…”

“…We started our investigation with a validation of the unusual NÀO distance [9] and of the small IR NO signal [10] using DFT methods and additional spectroscopic measurements. The BP86 functional [11] with the def-TZVP basis set [12] and COSMO [13] (Mçssbauer parameters were used to generate calibration data using COSMO (e = 80)) proved to be the method of choice.…”

“…The IR frequencies of the complex anion with various cations were reported by Pannell. [10] Using the non-coordinating cation PPN + and crown-ether complexed cations (Na + and K + ) in a THF solution, two CO signals (1979, 1875 cm À1 ) and a characteristic NO signal (1647 cm À1 ) were observed. [10] The calculated IR frequencies are in good agreement with the experimental ones.…”

“…[10] Using the non-coordinating cation PPN + and crown-ether complexed cations (Na + and K + ) in a THF solution, two CO signals (1979, 1875 cm À1 ) and a characteristic NO signal (1647 cm À1 ) were observed. [10] The calculated IR frequencies are in good agreement with the experimental ones. The IR frequencies are shifted to lower wavenumbers with increasing polarity/dielectric constant of Abstract: During the past 10 years iron-catalyzed reactions have become established in the field of organic synthesis.…”

The Evolution of Fe‐catalyzed Nucleophilic Activation of Acceptor‐substituted Vinyl‐ and Arylcyclopropanes

“…The NO ligand of [Fe(CO) 3 (NO)] − is normally considered to be cationic, and the oxidation state of iron is therefore said to be −II. However, according to the literature, this N−O has a bond length of 1.212 Å, and the NO signal in the IR spectrum appears at 1647 cm −1 , while being bound to the metal center in an almost linear fashion. The deviation of the structural parameters from the values one would expect for a cationic NO ligand attracted our attention, and we performed a combined spectroscopic and quantum chemical investigation .…”