Electronic Structures of Tris(Dioxolene)Chromium And Tris(Dithiolene)Chromium Complexes of the Electron-Transfer Series [Cr(Dioxolene)(3)]**Z And [Cr(Diothiolene)(3)]**Z (Z = 0, 1-, 2-, 3-). a Combined Experimental And DensityFunctional Theoretical Stud

Journal Article · Mon Jun 01 04:00:00 EDT 2009 · Inorg. Chem. 46:7827,2007

OSTI ID:953999

Kapre, R R; Bothe, E; Weyhermuller, T; George, S DeBeer; Muresan, N; Wieghardt, K

From the reaction mixture of 3,6-di-tert-butylcatechol, H{sub 2}[{sup 3,6}L{sub cat}], [CrCl{sub 3}(thf){sub 3}], and NEt{sub 3} in CH{sub 3}CN in the presence of air, the neutral complex [Cr{sup III}({sup 3,6}L{sup {sm_bullet}}{sub sq}){sub 3}] (S = 0) (1) was isolated. Reduction of 1 with [Co(Cp){sub 2}] in CH{sub 2}Cl{sub 2} yielded microcrystals of [Co(Cp){sub 2}][Cr{sup III}({sup 3,6}L{sup {sm_bullet}}{sub sq}){sub 2}({sup 3,6}L{sub cat})] (S = {1/2}) (2) where ({sup 3,6}L{sup {sm_bullet}}{sub sq}){sup 1-} is the {pi}-radical monoanionic o-semiquinonate of the catecholate dianion ({sup 3,6}L{sub cat}){sup 2-}. Electrochemistry demonstrated that both species are members of the electron-transfer series [Cr({sup 3,6}L{sub o,o})]{sup z} (z = 0, 1-, 2-, 3-). The corresponding tris(benzo-1,2-dithiolato)chromium complex [N(n-Bu){sub 4}][Cr{sup III}({sup 3,5}L{sup {sm_bullet}}{sub s,s}){sub 2}({sup 3,5}L{sub s,s})] (S = 1/2) (3) has also been isolated; ({sup 3,5}L{sub s,s}){sup 2-} represents the closed-shell dianion 3,5-di-tert-butylbenzene-1,2-dithiolate(2-), and ({sup 3,5}L{sup {sm_bullet}}{sub s,s}){sup 1-} is its monoanionic {pi} radical. Complex 3 is a member of the electron-transfer series [Cr({sup 3,5}L{sub s,s}){sub 3}]{sup z} (z = 0, 1-, 2-, 3-). It is shown by Cr K-edge and S K-edge X-ray absorption, UV-vis, and EPR spectroscopies, as well as X-ray crystallography, of 1 and 3 that the oxidation state of the central Cr ion in each member of both electron-transfer series remains the same (+III) and that all redox processes are ligand-based. These experimental results have been corroborated by broken symmetry density functional theoretical calculations by using the B3LYP functional.

• Research Organization: Stanford Linear Accelerator Center (SLAC)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-76SF00515
• OSTI ID: 953999
• Report Number(s): SLAC-REPRINT-2009-393
• Journal Information: Inorg. Chem. 46:7827,2007, Journal Name: Inorg. Chem. 46:7827,2007 Journal Issue: 19 Vol. 46; ISSN 0020-1669; ISSN INOCAJ
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ABSORPTION SPECTROSCOPY
AIR
COMPLEXES
CRYSTALLOGRAPHY
DENSITY FUNCTIONAL METHOD
ELECTROCHEMISTRY
ELECTRON SPIN RESONANCE
ELECTRON TRANSFER
ELECTRONIC STRUCTURE
FUNCTIONALS
IONS
MIXTURES
Other
OTHER
CHEM
REDUCTION
SYMMETRY
VALENCE