Protonation of Ferrocene: A Low‐Temperature X‐ray Diffraction Study of [Cp₂FeH](PF₆) Reveals an Iron‐Bound Hydrido Ligand

Abstract

Ferrocene, Cp Fe, is quantitatively protonated in a mixture of liquid HF/PF to yield [Cp FeH](PF ), which was characterized by H/ C NMR and Fe Mössbauer spectroscopy as well as single-crystal X-ray diffraction analysis. X-ray diffraction analysis at 100 K revealed a disordered, iron-coordinated hydrido ligand, which was unambiguously located by aspherical atom refinement at 100 K, and by analyzing the non-disordered crystal structure at 30 K, revealing a non-agostic structure.

Quantum Crystallography: Current Developments and Future Perspectives

“…[108,109] More recently,t he bond distance of hydrogen in the vicinity of am etal atom was characterized. [110] The power of the multipole modeli sa lso illustrated by research that aims at understanding interactions in macromolecular complexes of biological importance.H ere the model provides fast access to electrostatic potential, electrostatic energies and the topology of 1 r ðÞ , [111,112] while still maintaining the accuracy of quantum mechanical computations. [113,114] …”

Protonation of Ferrocene: A Low‐Temperature X‐ray Diffraction Study of [Cp2FeH](PF6) Reveals an Iron‐Bound Hydrido Ligand

“…[33,34] As expected for the formally tetravalent Fe ion of [Cp 2 FeH] + ,t he isomer shift, d,o f0 .40(1) mm s À1 is [7] In comparison, for the parent, tetravalent, paramagnetic [Cp* 2 Fe] 2+ (S = 1) complex, significantly more positive isomer shifts of 0.59(1) mm s À1 and smaller quadrupole splittings were reported for the SbF 6 À (Cp* tilt angle: 16.568 8, DE Q = 1.89(1) mm s À1 )a nd the Sb 2 F 11 À salt with parallel Cp* rings (DE Q = 2.00(1) mm s À1 ). [35] In summary,m ore than 50 years after the discovery of ferrocene,l ow-temperature X-ray diffraction studies with single crystals of [Cp 2 FeH](PF 6 ) [36] enabled the determination of the molecular structure of protonated ferrocene.T he hydride ligand is unambiguously bonded to the iron atom and shows no agostic interactions.The identity of [Cp 2 FeH](PF 6 ), which is formed after addition of PF 5 to ferrocene in HF solution, has additionally been confirmed by 1 Hand 13 CNMR as well as zero-field 57 Fe Mçssbauer spectroscopy.…”

A meso‐Tetraaryl‐21‐carbaporphyrin: Incorporation of a Cyclopentadiene Unit into a Porphyrin Architecture

“…During chromatography fractions containing 7-Few ere also separated. [30,31] In both processes the fundamental ferrocene entity is preserved. Thep resence of 7-Few as confirmed by ac haracteristic paramagnetically shifted 1 HNMR spectrum (see Figure S40).…”