Electrochemistry and spectroelectrochemistry (EPR, UV-vis-near-IR) of platinum(II) 2,2[prime]-bipyridine and ring-metalated bipyridine complexes: Pt[sup II](L[sup [minus]]) and Pt[sup I](L[sup [minus]]) but not Pt[sup I](L)
- Univ. of North Texas, Denton (United States)
- Universiti Brunei Darussalam (Germany)
- Universitaet Stuttgart (Germany)
- The University, Glasgow (United Kingdom)
The Pt(II) complexes [Pt(bpy)(py)[sub 2]][sup 2+] (I), [Pt(bpy)(Me[sub 2]N-py)[sub 2]][sup 2+] (II), [Pt(Me[sub 2]-bpy)(py)[sub 2]][sup 2+] (III), [Pt(bpy)(en)][sup 2+] (IV), [Pt(Mebpy-H)(py)[sub 2]][sup 2+] (V), [Pt(Mebpy-H)(bpy)][sup 2+] (VI), [Pt(phen)(py)[sub 2]][sup 2+] (VII), and [Pt(py)[sub 4]][sup 2+] (VIII) (bpy, 2,2[prime]-bipyridine; py, pyridine; Mebpy-H, N-methyl-2,2[prime]-bipyridinyl-C(3),N[prime]; Me[sub 2]-bpy, 4,4[prime]-dimethyl-2,2[prime]-bipyridine; Me[sub 2]N-py, 4-(dimethylamino)pyridine; en, 1,2-diaminoethane; phen, 1,10-phenanthroline) have been investigated by cyclic voltammetry and where possible by EPR spectroelectrochemistry and by UV-vis-near-IR spectroelectrochemistry. All complexes except VIII show at least two reversible reductive one-electron processes; VI shows three, and VIII shows one chemically irreversible process. In all cases, the doubly reduced species showed the characteristic [pi][sup *] [yields] [pi][sup *] UV-vis-near-IR absorptions of the ligand anion radicals. For the singly reduced species, EPR spectra show the added electron to be localized on the bipyridine-type ligand. However, the UV-vis-near-IR spectra of these species are not typical of ligand-based reduction products, and the potentials are less negative than expected for such a process. The authors conclude that the singly reduced species are best formulated as containing Pt(II), with the semioccupied and/or the lowest unoccupied ligand orbitals (corresponding to the LUMO and SLUMO of the unreduced parent species) being perturbed by the presence of metal orbitals. The doubly reduced species, however, are straightforward anion radical complexes of Pt(I).
- OSTI ID:
- 6900319
- Journal Information:
- Inorganic Chemistry; (United States), Journal Name: Inorganic Chemistry; (United States) Vol. 31:24; ISSN 0020-1669; ISSN INOCAJ
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400400* -- Electrochemistry
ABSORPTION SPECTROSCOPY
AZINES
BIPYRIDINES
CHEMISTRY
COMPLEXES
DATA
ELECTROCHEMISTRY
ELECTRON SPIN RESONANCE
EXPERIMENTAL DATA
HETEROCYCLIC COMPOUNDS
INFORMATION
INFRARED SPECTRA
MAGNETIC RESONANCE
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PLATINUM COMPLEXES
PYRIDINES
RESONANCE
SPECTRA
SPECTROSCOPY
TRANSITION ELEMENT COMPLEXES
ULTRAVIOLET SPECTRA
VISIBLE SPECTRA