Redox-active heterobinuclear triazenide-bridged complexes; ancillary ligand control of electron distribution in a three-electron metal–metal bond

Abstract

Neutral heterobinuclear triazenide-bridged complexes are oxidised to paramagnetic monocations; the electron distribution in the s* metal-metal orbital of rhodium-iridium complexes may be controlled by the ancillary ligands at the two metals.

Paramagnetic (Alkene)Rh and (Alkene)Ir Complexes: Metal or Ligand Radicals?

“…+ , the M(cod) fragment contains most of the unpaired electron density (80 % and 75 %, respectively). [16] This is even more drastic in case of [I 2 Rh(µ-RNNNR) 2 Pd(η 3 -C 3 H 5 )] -, which has 90 % of the unpaired electron spin density located at the rhodium atom, with only 10 % at palladium. [17] The steric bulk of these species likely protects these cod species from decomposing via allylic C-H activation (vide infra).…”

What can we learn from two‐center three‐electron bonding with the topological analysis of ELF?

“…The competitive formation of σ (i.e., 2c-3e)-type or π-type bonding has also been evidenced in the photochemical oneelectron oxidation of aromatic sulfides [40] and has been shown to be sensitive to the steric and electronic influence of substituents. Finally, although it is formally out of the scope of heteroatom chemistry, 3e bonds involving metal atoms exist: the ferryl group Fe O in di-iron enzymes core models [41], the Al І N or the Al І C bonds that are formed spontaneously after insertion of the Al atom into alkyl ethers [42] or into the NH 3 molecule [43], and the Rh І Rh bond [44] or Rh І Ir bond [45] in bridged complexes, which have been evidenced by X-ray structural studies.…”

M⋯HNR interactions in imino-bound diaryltriazene complexes: structure and fluxionality

“…10 min), the solution was filtered, evaporated to low volume in vacuo, and then treated with n-hexane to give a yellow precipitate of the product. The iridium analogue of 2, namely [IrCl(CO) 2 (p-MeC 6 H 4 NNNHC 6 H 4 Me-p)] 5, was prepared as before, 2 by reacting [{Ir(l-Cl)(g 4 -cod)} 2 ] (cod = cycloocta- 3 -C 3 H 5 ) 2 }], [{Pt(l-Cl)Cl(PPh 3 )} 2 ] and [{Pd(l-Cl)Cl(PPh 3 )} 2 ], respectively.…”

“…5 cm 3 ) in vacuo. n-Hexane (10 cm 3 ) was added to precipitate a yellow powder which was washed with n-hexane (2 × 20 cm 3 ) and dried in vacuo, yield 182 mg (81%).…”

“…Our previous studies of the synthesis of redox-active, triazenidebridged binuclear complexes of Rh 1 and Ir 2 involved the deprotonation of metal triazene complexes preformed in situ. However, in order to synthesise analogous heterobimetallic species 3 it proved advantageous to isolate the mononuclear triazene intermediates before use. We therefore give details of the synthesis and characterisation of square-planar triazene complexes of Rh, Ir, Pd and Pt, their structural characterisation, which has revealed an additional MH-N axial interaction, and variable-temperature NMR spectroscopic studies which revealed a fluxional process involving interchange of the two aryl groups, R, of the triazene ligand RNNNHR.…”