Electronic and electrochemical properties of platinum(II) and platinum-mercury-carboxylato complexes containing 2-Me2NCH2C6H4, 2,6-(Me2NCH2)2C6H3- and 2-Me2NC6H4CH2 - ligands

Abstract

The organoplatinum(II) compounds [{2, 6-(Me{2}NCH{2}){2}C{6}H{3}}PtBr] and cis-[(C-N){2}Pt] (C-N = 2-Me{2}NCH{2}C{6}H{4}, 2-Me{2}NC{6}H{4}CH{2}) can be chemically irreversibly oxidized in the potential range 1.00 to 1.35 V vs. an Ag/AgCl electrode, whereas the organoplatinum@?mercury complexes [{2,6-Me{2}NCH{2}){2}C{6}H{3}}(RCO{2})PtHg(O{2}CR)Br] and [(C-N){2}@m-O,O'-RCO{2})PtHg(O{2}CR)] (R = Me) could only be reduced, in the potential range -0.20 to -0.70 V, resulting in deposition of metallic mercury on the electrode. Reoxidation of the mercury occurred in the potential range +1.00 to +1.20 V.Both the organoplatinum(II) and organoplatinum@?mercury complexes (R = i-Pr) showed strong U.V. absorptions below 320 nm, which are assigned to Metal-to-Ligand Charge Transfer transitions. The bis-benzly platinum@?mercury compound [(2Me{2}NC{6}H{4}CH{2}){2}(@m-O,O'-i-Pr)] Showed an additional strong absorption, assigned to a @s-@s}*{ transition, at 335 nm.The results have been interpreted as indicating the presence or the Pt@?Hg complexes of a metal@?metal bond, either covalent or donative, involving interaction of an initially filled, high energy orbital on Pt and empty orbital on Hg.