1202525-40-3Relevant academic research and scientific papers
Synthesis, characterization, and ligand exchange reactivity of a series of first row divalent metal 3-hydroxyflavonolate complexes
Grubel, Katarzyna,Rudzka, Katarzyna,Arif, Atta M.,Klotz, Katie L.,Halfen, Jason A.,Berreau, Lisa M.
, p. 82 - 96 (2010)
A series of divalent metal flavonolate complexes of the general formula [(6-Ph2TPA)M(3-Hfl)]X (1 -5-X; X = OTf or CIO4 -; 6-Ph2TPA = N,N-bis((6-phenyl-2-pyridyl)methyl)-A/-((2- pyridyl)methyl)amine; M = Mn(II), Co(II), Ni(II), Cu(II), Zn(II); 3-HfI = 3-hydroxyflavonolate) were prepared and characterized by X-ray crystallography, elemental analysis, FTIR, UV-vis, 1H NMR or EPR, and cyclic voltammetry. All of the complexes have a bidentate coordinated flavonolate ligand. The difference in M-O distances (△M-o) involving this ligand varies through the series, with the asymmetry of flavonolate coordination increasing in the order Mn(II) ～ Ni(II) 1H NMR studies indicate that the 3-HfI complexes of Co(II), Ni(II), and Zn(II) exhibit a pseudo-octahedral geometry in solution. EPR studies suggest that the Mn(II) complex 1-OTf may form binuclear structures in solution. The mononuclear Cu(II) complex 4-OTf has a distorted square pyramidal geometry. The oxidation potential of the flavonolate ligand depends on the metal ion present and/or the solution structure of the complex, with the Mn(II) complex 1-OTf exhibiting the lowest potential, followed by the pseudo-octahedral Ni(II) and Zn(II) 3-HfI complexes, and the distorted square pyramidal Cu(II) complex 4-0Tf. The Mn(II) complex [(6Ph2TPA)Mn(3-HfI)]OTf (1 -OTf) is unique in the series in undergoing ligand exchange reactions in the presence of M(CIO4) 2-6H2O (M = CO, Ni, Zn) in CD3CN to produce [(6-Ph2TPA)M(CD3CN)n](X)2, [Mn(3-Hfl)2-0.5H2O], and MnX2 (X = OTf or CIO4 -). Under similar conditions, the 3-HfI complexes of Co(II), Ni(II), and Cu(II) undergo flavonolate ligand exchange to produce [(6-Ph2TPA)M(CD3CN)n](X)2 (M = Co, Ni, Cu; n = 1 or 2) and [Zn(3HfI)2 ? 2H2O]. An Fe(II) complex of 3-HfI, [(6-Ph2TPA)Fe(3-Hfl)]ClO4 (8), was isolated and characterized by elemental analysis, FTIR, UV-vis, 1H NMR, cyclic voltammetry, and a magnetic moment measurement. This complex reacts with O2 to produce the diiron(lll)μ-oxo compound [(6-Ph 2TPAFe(3Hfl))2(μ-O)](ClO4)2 (6).
