RESUMO
The iridium dihydride [Ir(H)2 (HPNP)](+) (PNP=N(CH2 CH2 PtBu2 )2 ) reacts with O2 to give the unusual, square-planar iridium(III) hydroxide [Ir(OH)(PNP)](+) and water. Regeneration of the dihydride with H2 closes a quasi-catalytic synthetic oxygen-reduction reaction (ORR) cycle that can be run several times. Experimental and computational examinations are in agreement with an oxygenation mechanism via rate-limiting O2 coordination followed by H-transfer at a single metal site, facilitated by the cooperating pincer ligand. Hence, the four electrons required for the ORR are stored within the two covalent MH bonds of a mononuclear metal complex.
RESUMO
Squaring the circle: the novel dienamido pincer ligand N(CHCHPtBu(2))(2)(-) affords the isolation of the unusual square-planar iridium(II) and iridium(III) amido complexes [IrCl{N(CHCHPtBu(2))(2)}](n) (n=0 (1), +1 (2)). In contrast, the corresponding iridium(I) complex of the redox series (n=-1) is surprisingly unstable. The diamagnetism of 2 is attributed to strong NâIr π donation.
RESUMO
Potassium N-isopropyl-2-(isopropylamino)troponiminate, K{(iPr)2ATI}, and potassium N-cyclohexyl-2-(cyclohexylamino)troponiminate, K{(Cy)2ATI}, were synthesized by treatment of the neutral ligands with an excess of KH in THF. Reaction of the potassium reagents with [AuClPPh3] resulted in the gold complexes [Au{(iPr)2ATI}PPh3] and [Au{(Cy)2ATI}PPh3]. The solid-state structures of both compounds, in which the ligands are arranged in plane, show distorted trigonal planar coordinated gold atoms. Potassium 2-(isopropylamino)troponate (K(iPrAT)) and the cyclohexyl analogue (K(CyAT)) were obtained by deprotonation of corresponding aminotropones with KH. In an analogous fashion the gold complexes of composition [Au(iPrAT)PPh3] and [Au(CyAT)PPh3] were prepared by reaction of K(iPrAT) and K(CyAT) with [AuClPPh3], respectively.