Model Investigations for Vanadium-Protein Interactions. Synthetic, Structural, and Physical Studies of Vanadium(III) and Oxovanadium(IV/V) Complexes with Amidate Ligands
Date
1996Author
Keramidas, Anastasios D.Papaioannou, Agelos B.
Vlahos, Antonis T.
Kabanos, Themistoklis A.
Bonas, George
Makriyannis, Alexandros M.
Raptopoulou, Catherine P.
Terzis, Aris
Source
Inorganic chemistryVolume
35Issue
2Pages
357-367Google Scholar check
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3, C19H13N3O2SV, Mr = 398.34, monoclinic, P21/n, a = 12.1108(10) Å, b = 19.4439(18) Å, c = 7.2351(7) Å, β = 103.012(3)°, V = 1660.0(4) Å3, Z = 4, R = 0.0355, and Rw = 0.0376 4·CH3CN, C19H12N3O4VNa·CH 3CN, Mr = 461.31, monoclinic, P21/c, a = 11.528(1) Å, b = 11.209(1) Å, c = 16.512(2) Å, β = 103.928(4)°, V = 2071.0(5) Å3, Z = 4, R = 0.0649, and Rw = 0.0806 5·2CH3OH, C20H10N2O5VNa 2·2CH3OH, Mr = 519.31, triclinic, P1, a = 12.839(1) Å, b = 8.334(1) Å, c = 12.201(1) Å, α = 106.492(2)°, β = 105.408(2)°, γ = 73.465(2)°, V = 1175.6(3) Å3, Z = 2, R = 0.0894, and Rw = 0.1043 Reaction of the amide ligand N-[2·((2-pyridylmethylene)amino)phenyl]pyridine-2-carboxamide (Hcapca) with VCl3 affords the compound trans·[VCl2(capca)] (1), the first example of a vanadium(III) complex containing a vanadium-deprotonated amide nitrogen bond, while reaction of bis(pentane-2,4-dionato)oxovanadium(IV) with the related ligands N-[2-((2-phenolylmethylene)amino)phenyl]pyridine-2-carboxamide (H2phepca), 1-(2-hydroxybenzamido)-2-(2-pyridinecarboxamido)benzene (H3hypyb), and 1,2-bis(2-hydroxybenzamido)benzene (H4hybeb) yields the complexes [VO(phepca)] (2), Na[VO(hypyb)]·2CH3OH (4·2CH3OH), and Na2[VO(hybeb)]·3CH3OH (5·3CH3OH) respectively. The preparation of the complex {N-[2-((2-thiophenoylmethylene)amino)phenyl]pyridine2-carboxamido} oxovanadium(IV) (3) has been achieved by reaction of N-(2-aminophenyl)pyridine-2-carboxamide and 2-mercaptobenzaldehyde with [VO(CH3COO)2]x. Oxidation of complex 5·3CH3OH with silver nitrate gives its vanadium(V) analogue (8·CH3OH), which is readily converted to its corresponding tetraethylammonium salt (10·CH2Cl2) by a reaction with Et4NCl. The crystal structures of the octahedral 1·CH3CN, and the square-pyramidal complexes 3, 4·CH3CN, 5·2CH3OH, and 10 were demonstrated by X-ray diffraction analysis. Crystal data are as follows: 1·CH3CN, C18H13Cl2N4OV·CH 3CN Mr = 464.23, monoclinic, P21/n, a = 10.5991(7) Å, b = 13.9981(7) Å, c = 14.4021(7) Å, β= 98.649(2)°, V = 2112.5(3) Å3, Z = 4, R = 0.0323, and Rw 0.0335 10, C28H32N3O5V Mr = 541.52, monoclinic, P21/c, a = 11.711(3) Å, b = 18.554(5) Å, c = 12.335(3) Å, β = 95.947(9)°, V = 2666(2) Å3, Z = 4, R = 0.0904, and Rw = 0.0879. In addition to the synthesis and crystallographic studies, we report the optical, infrared, magnetic, and electrochemical properties of these complexes. Electron paramagnetic resonance [of oxovanadium(IV) species] and 1H, 13C{1H}, and 51V nuclear magnetic resonance [of oxovanadium(V) complex] properties are reported as well. This study represents the first systematic study of vanadium(III), VIVO2+, and VVO3+ species containing a vanadium-deprotonated amide nitrogen bond.