TY - JOUR
T1 - Oxidation states "naturally"
T2 - A Natural Bond Orbital method for determining transition metal oxidation states
AU - Webster, Albert J.
AU - Mueller, Chelsea M.
AU - Foegen, Neil P.
AU - Sit, Patrick H.-L.
AU - Speetzen, Erin D.
AU - Cunningham, Drew W.
AU - D'Acchioli, Jason S.
PY - 2016/8/16
Y1 - 2016/8/16
N2 - The oxidation state (OS) concept is arguably one of the most useful formalisms in chemistry. OSs are used to explain a variety of phenomena at transition metal centers, from chemical reactivity to spectroscopic properties. Attempting to define a theoretical method of evaluating this construct, however, has resulted in a broad debate among chemists, particularly inorganic chemists. With this in mind we propose a simple method for determining the oxidation states of transition metal centers using Natural Bond Orbital (NBO) theory. A description of the wavefunction (or electron density in the case of density functional theory, as presented in this investigation) is obtained from quantum chemical calculations. The 5 × 5 d-orbital Natural Atomic Orbital (NAO) occupation matrix is then obtained, and diagonalized. The resulting eigenvalues deliver the d-orbital occupations, from which the oxidation states can be inferred. The NBO-driven method also allowed us to probe "ambiguous" cases where a strong π-acid is involved in bonding (in our case, CO). The scope of the method is described, along with promising future applications.
AB - The oxidation state (OS) concept is arguably one of the most useful formalisms in chemistry. OSs are used to explain a variety of phenomena at transition metal centers, from chemical reactivity to spectroscopic properties. Attempting to define a theoretical method of evaluating this construct, however, has resulted in a broad debate among chemists, particularly inorganic chemists. With this in mind we propose a simple method for determining the oxidation states of transition metal centers using Natural Bond Orbital (NBO) theory. A description of the wavefunction (or electron density in the case of density functional theory, as presented in this investigation) is obtained from quantum chemical calculations. The 5 × 5 d-orbital Natural Atomic Orbital (NAO) occupation matrix is then obtained, and diagonalized. The resulting eigenvalues deliver the d-orbital occupations, from which the oxidation states can be inferred. The NBO-driven method also allowed us to probe "ambiguous" cases where a strong π-acid is involved in bonding (in our case, CO). The scope of the method is described, along with promising future applications.
KW - Density functional theory
KW - Dewar-Chatt-Duncanson model
KW - Natural Bond Orbital (NBO) theory
KW - Oxidation states
KW - Transition metals
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UR - https://www.scopus.com/record/pubmetrics.uri?eid=2-s2.0-84949446854&origin=recordpage
U2 - 10.1016/j.poly.2015.11.018
DO - 10.1016/j.poly.2015.11.018
M3 - RGC 21 - Publication in refereed journal
SN - 0277-5387
VL - 114
SP - 128
EP - 132
JO - Polyhedron
JF - Polyhedron
ER -