Nature of Cr–NO Bonding from 15 N Solid-State NMR and X-ray Absorption Spectroscopic Signatures
Year: 2026
Type: article
Abstract: Transition metal nitrosyl species holds prime importance in chemistry; yet describing their electronic structure and bonding remain a great challenge. In this contribution, combination of spectroscopic techniques – IR, X-ray absorption spectroscopy (XAS) and 15N solid-state NMR spectroscopy, augmented by computational analysis, are applied to a family of low-valent Cr nitrosyl complexes focusing on their bonding environment. Cr K-edge XAS signature of such complexes point out the significant π-backdonation drawing parallel with related π-acceptor ligands such as CO or isocyanides. Orbital-level analysis on their electronic structure, tied with the 15N solid-state NMR signature, further highlight the formation of filled π(Cr-N) orbitals suggesting the potential Cr-N multiple bond character reminiscent of the “nitride-N-oxide” type resonance structure for Cr(NO)X3 with strongly σ-donating X ligands. In contrast, the related bis(nitrosyl) species exhibit double-bond character resembling what has been observed when comparing mono- and cis-bis(imido) species in d0 metal centers. Notably, the developed Cr-N multiple bond character inherently suggests the highly filled antibonding, π*(N-O) orbital, which is consistent with the known reactivity of Cr-nitrosyls species accompanying N-O bond cleavage, further implying their potential relevance to deNOx catalysis.
DOI: 10.1021/jacs.5c20748
Institutions: ETH Zurich, Southern Federal University
Language: English
Subfield: Organic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7166561174