On the nature of spin- and orbital-resolved Cu+–NO charge transfer in the gas phase and at Cu(I) sites in zeolites
| Autor: | Ewa Broclawik, Paweł Kozyra, Mariusz Radoń, Jerzy Datka |
|---|---|
| Jazyk: | angličtina |
| Předmět: |
Valence (chemistry)
Spins charge transfer chemistry.chemical_element Antibonding molecular orbital Condensed Matter Physics donation and backdonation Copper natural orbitals for chemical valence Gas phase Cu(I) sites NO activation Electron transfer Crystallography chemistry Atomic orbital Unpaired electron Atomic physics Physical and Theoretical Chemistry |
| Zdroj: | Structural Chemistry. 23(5):1349-1356 |
| ISSN: | 1040-0400 |
| DOI: | 10.1007/s11224-012-0050-y |
| Popis: | Electronic factors essential for NO activation by Cu(I) sites in zeolites are investigated within spin-resolved analysis of electron transfer channels (natural orbitals for chemical valence). NOCV analysis is performed for three DFT-optimized models of Cu(I)–NO site in ZSM-5: [CuNO]+, (T1)CuNO, and (M7)CuNO. NO as a non-innocent, open-shell ligand reveals significant differences between independent deformation density components for α and β spins. Four distinct components are identified: (i) unpaired electron donation from NO π‖* antibonding orbital to Cus,d; (ii) backdonation from copper d yz to π⊥* antibonding orbital; (iii) donation from occupied π‖ and Cu d xz to bonding region, and (iv) donation from nitrogen lone-pair to Cus,d. Channel (i), corresponding to one-electron bond, shows-up solely for spin majority and is effective only in the interaction of NO with naked Cu+. Channel (ii) dominates for models b and c: it strongly activates NO bond by populating antibonding π* orbital and weakens the N–O bond in contrast to channel (i), depopulating the antibonding orbital and strengthening N–O bond. This picture perfectly agrees with IR experiment: interaction with naked Cu+ imposes small blue-shift of NO stretching frequency while it becomes strongly red-shifted for Cu(I) site in ZSM-5 due to enhanced backdonation. |
| Databáze: | OpenAIRE |
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