TY - JOUR
T1 - A combined spectroscopic and computational study of a high-spin S = 7/2 diiron complex with a short iron-iron bond
AU - Zall, Christopher M.
AU - Zherebetskyy, Danylo
AU - Dzubak, Allison L.
AU - Bill, Eckhard
AU - Gagliardi, Laura
AU - Lu, Connie C.
PY - 2012/1/2
Y1 - 2012/1/2
N2 - The nature of the iron-iron bond in the mixed-valent diiron tris(diphenylforamidinate) complex Fe 2(DPhF) 3, which was first reported by Cotton, Murillo et al. (Inorg. Chim. Acta 1994, 219, 7-10), has been examined using additional spectroscopic and theoretical methods. It is shown that the coupling between the two iron centers is strongly ferromagnetic, giving rise to an octet spin ground state. On the basis of Mössbauer spectroscopy, the two iron centers, formally mixed-valent Fe(II)Fe(I), are completely equivalent with an isomer shift δ = 0.65 mm s -1 and quadrupole splitting δE Q = +0.32 mm s -1. A large, positive zero-field splitting D 7/2 = 8.2 cm -1 has been determined from magnetic susceptibility measurements. Multiconfigurational quantum studies of the complete molecule Fe 2(DPhF) 3 found one dominant configuration (σ) 2(π) 4(π*) 2(σ *) 1(δ) 2(δ *) 2, which accounts for 73% of the ground-state wave function. By considering all the configurations, an estimated metal-metal bond order of 1.15 has been calculated. Finally, Fe 2(DPhF) 3 exhibits weak electronic absorptions in the visible and near-infrared regions, which are assigned as d-d transitions from the doubly occupied metal-metal π molecular orbital to half-occupied π *, δ, and δ* orbitals.
AB - The nature of the iron-iron bond in the mixed-valent diiron tris(diphenylforamidinate) complex Fe 2(DPhF) 3, which was first reported by Cotton, Murillo et al. (Inorg. Chim. Acta 1994, 219, 7-10), has been examined using additional spectroscopic and theoretical methods. It is shown that the coupling between the two iron centers is strongly ferromagnetic, giving rise to an octet spin ground state. On the basis of Mössbauer spectroscopy, the two iron centers, formally mixed-valent Fe(II)Fe(I), are completely equivalent with an isomer shift δ = 0.65 mm s -1 and quadrupole splitting δE Q = +0.32 mm s -1. A large, positive zero-field splitting D 7/2 = 8.2 cm -1 has been determined from magnetic susceptibility measurements. Multiconfigurational quantum studies of the complete molecule Fe 2(DPhF) 3 found one dominant configuration (σ) 2(π) 4(π*) 2(σ *) 1(δ) 2(δ *) 2, which accounts for 73% of the ground-state wave function. By considering all the configurations, an estimated metal-metal bond order of 1.15 has been calculated. Finally, Fe 2(DPhF) 3 exhibits weak electronic absorptions in the visible and near-infrared regions, which are assigned as d-d transitions from the doubly occupied metal-metal π molecular orbital to half-occupied π *, δ, and δ* orbitals.
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U2 - 10.1021/ic202384b
DO - 10.1021/ic202384b
M3 - Article
C2 - 22148181
AN - SCOPUS:84855365644
SN - 0020-1669
VL - 51
SP - 728
EP - 736
JO - Inorganic chemistry
JF - Inorganic chemistry
IS - 1
ER -