One-electron oxidation of [(Me(n)tpa)Ir(I)(ethene)]+ complexes (Me(3)tpa = N,N,N-tri(6-methyl-2-pyridylmethyl)amine; Me(2)tpa = N-(2-pyridylmethyl)-N,N,-di[(6-methyl-2-pyridyl)methyl]-amine) results in relatively stable, five-coordinate Ir(II)-olefin species [(Me(n)tpa)Ir(II)(ethene)](2+) (1(2+): n = 3; 2(2+): n = 2). These contain a "vacant site" at iridium and a "non-innocent" ethene fragment, allowing radical type addition reactions at both the metal and the ethene ligand. The balance between metal- and ligand-centered radical behavior is influenced by the donor capacity of the solvent. In weakly coordinating solvents, 1(2+) and 2(2+) behave as moderately reactive metallo-radicals. Radical coupling of 1(2+) with NO in acetone occurs at the metal, resulting in dissociation of ethene and formation of the stable nitrosyl complex [(Me(3)tpa)Ir(NO)](2+) (6(2+)). In the coordinating solvent MeCN, 1(2+) generates more reactive radicals; [(Me(3)tpa)Ir(MeCN)(ethene)](2+) (9(2+)) by MeCN coordination, and [(Me(3)tpa)Ir(II)(MeCN)](2+) (10(2+)) by substitution of MeCN for ethene. Complex 10(2+) is a metallo-radical, like 1(2+) but more reactive. DFT calculations indicate that 9(2+) is intermediate between the slipped-olefin Ir(II)(CH(2)=CH(2)) and ethyl radical Ir(III)-CH(2)-CH(2). resonance structures, of which the latter prevails. The ethyl radical character of 9(2+) allows radical type addition reactions at the ethene ligand. Complex 2(2+) behaves similarly in MeCN. In the absence of further reagents, 1(2+) and 2(2+) convert to the ethylene bridged species [(Me(n)tpa)(MeCN)Ir(III)(mu(2)-C(2)H(4))Ir(III)(MeCN)(Me(3)tpa)](4+) (n = 3: 3(4+); n = 2: 4(4+)) in MeCN. In the presence of TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxo), formation of 3(4+) from 1(2+) in MeCN is completely suppressed and only [(Me(3)tpa)Ir(III)(TEMPO(-))(MeCN)](2+) (7(2+)) is formed. This is thought to proceed via radical coupling of TEMPO at the metal center of 10(2+). In the presence of water, hydrolysis of the coordinated acetonitrile fragment of 7(2+) results in the acetamido complex [(Me(3)tpa)Ir(III)(NHC(O)CH(3)))(TEMPOH)](2+) (8(2+)).

Oxidation induces oxygenation: The first IrII–ethene complex ever (2) was obtained by one‐electron oxidation of the corresponding IrI–ethene complex 1. Whereas 1 reacts with dioxygen to give an IrIII–peroxo‐ethene complex, the IrII–ethene complex 2 activates dioxygen towards CO bond formation and gives the IrIII–formylmethyl complex 3.

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New cationic, five-coordinate bis(ethene)iridium(i) complexes [(κ 3 -Me 3 -tpa)Ir I (ethene) 2 ] + (12 + ) and [(κ 3 -Me 2 -dpaMe)Ir I (ethene) 2 ] + (13 + ) have been prepared {Me 3 -tpa = N,N,N-tris[(6-methyl-2-pyridyl)Complexes 12 + and 13 + lose one ethene fragment in solution, yielding the five-coordinate mono(ethene) complex [(κ 4 -Me 3 -tpa)Ir I (ethene)] + (14 + ) and the four-coordinate mono-(ethene) complex [(κ 3 -Me 2 -dpa-Me)Ir I (ethene)] + (15 + ), respectively. [(κ 4 -Me 3 -tpa)Rh I (ethene)] + (11 + ), the rhodium analogue of 14 + , was also prepared. Whereas rhodium complex 11 + is stable in acetonitrile at room temperature, the iridium analogue 14 + converts to the cyclometallated (acetonitrile)(hydrido) complex 16 + within 72 h by dissociation of the

The dissociation of molecular oxygen at the clean surface of silver nanowires is studied in a mechanically controllable break junction (MCBJ) operating in organic liquids. From conductance histogram measurements, it can be concluded that the breaking of the nanowires exposes clean surfaces at which dissociation of dissolved oxygen molecules takes place, followed by chemisorption of the oxygen atoms at the nanowire surface. Subsequent characteristic changes in the appearance of individual conductance curves in the tunneling regime point to the mechano-catalytic oxidation of the solvent cyclohexane to cyclohexanol, and it is proposed that the oxygen atoms adsorbed at the nanowires are activated for this reaction, with the MCBJ acting as the mechano-catalyst.