Spectroscopic and computational studies of an end-on bound superoxo-Cu(II) complex: geometric and electronic factors that determine the ground state.
A variety of techniques including absorption, magnetic circular dichroism (MCD), variable-temperature, variable-field MCD (VTVH-MCD), and resonance Raman (rR) spectroscopies are combined with density functional theory (DFT) calculations to elucidate the electronic structure of the end-on (η(1)) bound superoxo-Cu(II) complex [TMG(3)trenCuO(2)](+) (where TMG(3)tren is 1,1,1-tris[2-[N(2)-(1,1,3,3-tetramethylguanidino)]ethyl]amine). The spectral features of [TMG(3)trenCuO(2)](+) are assigned, including the first definitive assignment of a superoxo intraligand transition in a metal-superoxo complex, and a detailed description of end-on superoxo-Cu(II) bonding is developed. The lack of overlap between the two magnetic orbitals of [TMG(3)trenCuO(2)](+) eliminates antiferromagnetic coupling between the copper(II) and the superoxide, while the significant superoxo π*(σ) character of the copper dz(2) orbital leads to its ferromagnetically coupled, triplet, ground state.
Woertink
Julia S
JS
Department of Chemistry, Stanford University, Stanford, California 94305, USA.
Tian
Li
L
Maiti
Debabrata
D
Lucas
Heather R
HR
Himes
Richard A
RA
Karlin
Kenneth D
KD
Neese
Frank
F
Würtele
Christian
C
Holthausen
Max C
MC
Bill
Eckhard
E
Sundermeyer
Jörg
J
Schindler
Siegfried
S
Solomon
Edward I
EI
D000042:Absorption; D003300:Copper / Q000737:chemistry*; D004579:Electron Transport; D004583:Electrons; D008024:Ligands; D008280:Magnetics; D008958:Models, Molecular; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000737:chemistry*; D011789:Quantum Theory; D013057:Spectrum Analysis
D008024:Ligands; D009942:Organometallic Compounds; D003300:Copper