The oxidation reaction in x-irradiated bis(ethylenediamine)platinum(II) bis(hydrogen squarate): a single-crystal EPR study of a platinum(III) complex

• Published in: Inorganic chemistry Vol. 31; no. 24; pp. 5056 - 5060
• Main Authors: Geoffroy, Michel, Bernardinelli, Gerald, Castan, Paule, Chermette, Henry, Deguenon, Diane, Nour, Safouh, Weber, Jacques, Wermeille, Michel
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.11.1992
• Subjects: 400201 > Chemical & Physicochemical Properties; CATIONS; CHARGED PARTICLES; CHEMICAL RADIATION EFFECTS; CHEMICAL REACTIONS; COMPLEXES; Condensed matter: electronic structure, electrical, magnetic, and optical properties; DATA; DECOMPOSITION; ELECTROMAGNETIC RADIATION; Electron paramagnetic resonance and relaxation; ELECTRON SPIN RESONANCE; Exact sciences and technology; EXPERIMENTAL DATA; INFORMATION; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; IONIZING RADIATIONS; IONS; MAGNETIC RESONANCE; Magnetic resonances and relaxations in condensed matter, mössbauer effect; MATHEMATICAL MODELS; NUMERICAL DATA; OXIDATION; Physics; PLATINUM COMPLEXES; RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY; RADIATION EFFECTS; RADIATIONS; RADICALS; RADIOLYSIS; RESONANCE; THEORETICAL DATA; TRANSITION ELEMENT COMPLEXES 400600 > Radiation Chemistry; X RADIATION; Platinum Complexes; Irradiation; Oxidation; X ray; Transition metal Complexes; Electron paramagnetic resonance; Experimental study; Single crystal; Low temperature
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic00050a025

A large single crystal of bis(ethylenediamine)platinum bis(hydrogen squarate) ([Pt(en)[sub 2]](HSq)[sub 2]), has been X-irradiated at 77 K and studied by EPR. The g and [sup 195]Pt hyperfine tensors obtained from the angular dependence of the spectrum are consistent with the trapping of a Pt(III) complex containing the unpaired electron in a d[sub z[sup 2]] orbital. Comparison of the orientations of the eigenvectors with those of the crystallographic interatomic vectors together with the predictions of X[alpha] calculations on the model complex [Pt(NH[sub 3])[sub 4](OH)[sub 2]][sup +] leads to a mechanism whereby a radiogenic radical, formed by homolytic scission of the hydrogen squarate hydroxyl, oxidizes the Pt(en)[sub 2] dication and yields [Pt(en)[sub 2](Sq)](HSq).