Disassembly of diruthenium(II,III) tetraacetate with P-N donor ligands

作者：Essoun Ernest; Wang Ruiyao; Aquino Manuel A S^*

来源：Inorganica Chimica Acta, 2017, 454: 97-106.

DOI：10.1016/j.ica.2016.02.021

• Diruthenium(II,III) tetraacetate
• P-N donor ligands
• Synthetic methodology
• X-ray crystallography

Valent-averaged diruthenium(II,III) tetraacetate, [Ru-2(mu-O2CCH3)(4)(H2O)(2)](PF6), was reacted with various bidentate P-N donor ligands. These reactions led to the partial displacement of bridging carboxylate groups and concomitant cleavage of the Ru-Ru bond, producing novel complexes. Disassembly reactions with the aminophosphines; diphenyl-2-pyridylphosphine (dpppy) and 2-(diphenylphosphino)ethylamine (dppea), produced homoleptic tris-chelated species, fac-[Ru(dpppy-P,N)3](PF6)2 (III) and mer-[Ru(dppea-P,N)(3)](PF6)(2) (VI), respectively. Disassembly reactions with aromatic aminophosphines; 2-(diphenylphosphino)methylpyridine (dppmpy) and 2-(diphenylphosphino)ethylpyridine (dppepy), led to heteroleptic tris-chelated complexes cis,cis,trans-[Ru(dppmpy-P,N)(2)(eta(2)-O2CCH3)](PF6)center dot MeOH (IV) and cis,cis,trans-[Ru(dppepy-P,N)(2)(eta(2)-O2CCH3)](PF6) (V), respectively, whereas reaction with the non cyclic aminophosphine, 3-(diphenylphosphino)-1-propylamine (dpppa) and the non-cyclic iminophosphine, 2-(diphenylphosphino)benzylidinebenzylamine (dppbba), led to the heteroleptic tris-chelated complexes cis,cis,trans-[Ru(dpppa-P,N)(2)(eta(2)-O2CCH3)](PF6 center dot EtOH (VII) and cis,cis,trans-[Ru(dppbba-P, N)(2)(eta(2)-O2CCH3)](PF6)center dot 2MeOH center dot H2O (VIII), respectively. All complexes were fully characterized. Electrochemical studies (CV, OSWV) showed that the homoleptic tris-chelated complexes had higher oxidation potentials (E-pa) than the corresponding heteroleptic tris-chelated complexes, due to the weak it-acceptor ability of the acetate group. Complex (III) has the highest Epa as it contains the strongest combination of it-accepting groups. The E-pa values of the heteroleptic complexes were found to be in the order: dppbba (CH=N) > dppmpy, dppepy (py) > dpppa (NH2), since amines are much poorer n-acceptors than pyridyl and imino groups. Complexes (III), (VI) and (VII) showed irreversible oxidation waves, while complexes (IV), (V) and (VIII) displayed quasi-reversible one electron processes.

• 出版日期2017-1-1