Premium
Density Functional Theory Study of trans ‐Dioxo Complexes of Iron, Ruthenium, and Osmium with Saturated Amine Ligands, trans‐ [M(O) 2 (NH 3 ) 2 (NMeH 2 ) 2 ] 2+ (M=Fe, Ru, Os), and Detection of [Fe(qpy)(O) 2 ] n + ( n =1, 2) by High‐Resolution ESI Mass Spectrometry
Author(s) -
Tong Glenna So Ming,
Wong Ella LaiMing,
Che ChiMing
Publication year - 2008
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200701563
Subject(s) - density functional theory , chemistry , antibonding molecular orbital , osmium , singlet state , transition metal , ground state , crystallography , ruthenium , ligand (biochemistry) , atomic orbital , computational chemistry , catalysis , electron , excited state , organic chemistry , atomic physics , biochemistry , physics , receptor , quantum mechanics
Density functional theory (DFT) calculations on trans ‐dioxo metal complexes containing saturated amine ligands, trans ‐[M(O) 2 (NH 3 ) 2 (NMeH 2 ) 2 ] 2+ (M=Fe, Ru, Os), were performed with different types of density functionals (DFs): 1) pure generalized gradient approximations (pure GGAs): PW91, BP86, and OLYP; 2) meta‐GGAs: VSXC and HCTH407; and 3) hybrid DFs: B3LYP and PBE1PBE. With pure GGAs and meta‐GGAs, a singlet d 2 ground state for trans ‐[Fe(O) 2 (NH 3 ) 2 (NMeH 2 ) 2 ] 2+ was obtained, but a quintet ground state was predicted by the hybrid DFs B3LYP and PBE1PBE. The lowest transition energies in water were calculated to be at λ ≈509 and 515 nm in the respective ground‐state geometries from PW91 and B3LYP calculations. The nature of this transition is dependent on the DFs used: a ligand‐to‐metal charge‐transfer (LMCT) transition with PW91, but a π(FeO)→π*(FeO) transition with B3LYP, in which π and π* are the bonding and antibonding combinations between the d π (Fe) and p π (O 2− ) orbitals. The Fe VI/V reduction potential of trans ‐[Fe(O) 2 (NH 3 ) 2 (NMeH 2 ) 2 ] 2+ was estimated to be +1.30 V versus NHE based on PW91 results. The [Fe(qpy)(O) 2 ] n + (qpy=2,2′:6′,2′′:6′′,2′′′:6′′′,2′′′′‐quinquepyridine; n =1 and 2) ions, tentatively assigned to dioxo iron(V) and dioxo iron(VI), respectively, were detected in the gas phase by high‐resolution ESI‐MS spectroscopy.