932703-85-0Relevant articles and documents
Acireductone dioxygenase- (ARD-) type reactivity of a Nickel(II) complex having monoanionic coordination of a model substrate: Product identification and comparisons to unreactive analogues
Szajna-Fuller, Ewa,Rudzka, Katarzyna,Arif, Atta M.,Berreau, Lisa M.
, p. 5499 - 5507 (2007)
A mononuclear Ni(II) complex ([(6-Ph2TPA)Ni(PhC(O)C(OH)C(O)Ph)] ClO4 (1)), supported by the 6-Ph2TPA chelate ligand (6-Ph2TPA = N,N-bis((6-phenyl-2-pyridyl)methyl)-N-((2-pyridyl)methyl) amine) and containing a cis-β-ketoenolate ligand having a C2 hydroxyl substituent, undergoes reaction with O2 to produce a Ni(II) monobenzoate complex ([(6-Ph2TPA)Ni(O2CPh)]ClO4 (3)), CO, benzil (PhC(O)C(O)Ph), benzoic acid, and other minor unidentified phenyl-containing products. Complex 3 has been identified through independent synthesis and was characterized by X-ray crystallography, 1H NMR, FAB-MS, FTIR, and elemental analysis. A series of cis-β-keto-enolate Ni(II) complexes supported by the 6-Ph2TPA ligand ([(6-Ph 2TPA)Ni(PhC(O)CHC(O)Ph)]ClO4 (4), [(6-Ph 2TPA)Ni(CH3C-(O)CHC(O)CH3)]ClO4 (5), and [(6-Ph2TPA)Ni(PhC(O)CHC(O)C(O)Ph) (6)) have been prepared and characterized. While these complexes exhibit structural and/or spectroscopic similarity to 1, all are unreactive with O2. The results of this study are discussed in terms of relevance to Ni(II)-containing acireductone dioxygenase enzymes, as well as in the context of recently reported cofactor-free, quercetin, and β-diketone dioxygenases.
O2-dependent aliphatic carbon-carbon bond cleavage reactivity in a Ni(II) enolate complex having a hydrogen bond donor microenvironment; comparison with a hydrophobic analogue
Grubel, Katarzyna,Fuller, Amy L.,Chambers, Bonnie M.,Arlf, Atta M.,Berreau, Lisa M.
experimental part, p. 1071 - 1081 (2010/05/15)
A mononuclear Ni(II) complex having an acireductone type ligand, and supported by the bnpapa (N,N-bis((6-neopentylamino-2-pyhdyl)methyl)-N-((2- pyridyl)methyl)amine) ligand, [(bnpapa)Ni(PhC(O)C(OH)C(O)Ph)]ClO4 (14), has been prepared and characterized by elemental analysis, 1H NMR, FTIR, and UV-vis. To gain insight into the1H NMR features of 14, the air stable analogue complexes [(bnpapa)Ni(CH3C(O)CHC(O)CH 3)]ClO4 (16) and [(bnpapa)Ni(ONHC(O)CH3)] ClO4 (17) were prepared and characterized by X-ray crystallography, 1H NMR, FTIR, UV - vis, mass spectrometry, and solution conductivity measurements. Compounds 16 and 17 are 1:1 electrolyte species in CH 3CN. 1H and 2H NMR studies of 14, 16, and 17 and deuterated analogues revealed that the complexes having six-membered chelate rings for the exogenous ligand (14 and 16) do not have a plane of symmetry within the solvated cation and thus exhibit more complicated 1H NMR spectra. Compound 17, as well as other simple Ni(II) complexes of the bnpapa ligand (e.g., [(bnpapa)Ni(ClO4)(CH3CN)]ClO4 (18) and [(bnpapaNi)2(μ-Cl)2](ClO4)2 (19)), exhibit 1H NMR spectra consistent with the presence of a plane of symmetry within the cation. Treatment of [(bnpapa)Ni(PhC(O)C(OH)C(O)Ph)] ClO4 (14) with O2 results in aliphatic carbon-carbon bond cleavage within the acireductone-type ligand and the formation of [(bnpapa)Ni(O2CPh)]ClO4 (9), benzoic acid, benzil, and CO. Use of 18O2 in the reaction gives high levels of incorporation (>80%) of one labeled oxygen atom into 9 and benzoic acid. The product mixture and level of 18O incorporation in this reaction is different than that exhibited by the analogue supported the hydrophobic 6-Ph2TPA ligand, [(6-Ph2TPA)Ni(PhC(O)C(OH)C(O)Ph)]ClO 4 (2). We propose that this difference is due to variations in the reactivity of bnpapa- and 6-Ph2TPA-ligated Ni(II) complexes with triketone and/or peroxide species produced in the reaction pathway.
