Synthesis and characterization of several lumazine derivative complexes of Co(II), Ni(II), Cu(II), Cd(II), Pd(II) and Pt(II). X-ray structures of a mononuclear copper complex and a dinuclear cadmium complex

Redox mechanism of lumazine at a glassy carbon electrode

“…A large number of LMZ-metal complexes [14,17,18] has been studied to mimic the environment and reactivity of the metal site of the enzymes. Some of these complexes have been characterized by X-ray crystallography [18] and their biological activity evaluated [7]. Although only a few of these compounds have been the subject of more detailed studies, generally it has been shown that the target for these inhibitors has to be carefully selected in order to avoid unwanted effects.…”

Metal complexes with the ligand derived from 6-acetyl-1,3,7-trimethyllumazine and benzohydrazide. Molecular structures of two new Co(II) and Rh(III) complexes and analysis of in vitro antitumor activity

“…Nevertheless, the bond Co-O4 (2.364(3) Å), also in equatorial plane, is significantly longer than the Co-O distances for O63 and O1W atoms (2.149(3) and 2.142(3) Å), this fact can be justified by the weak basic nature of O4 atom [28,29] and the steric hindrances produced by the tetradentate coordination. So the coordination number for the metallic center it could be defined as [6+1] and the coordination may be best described as a distorted capped octahedron [30] with the O4 atom capping the O1W-N5 edge and opening the O1W-Co-N5 angle (144.13(1)°).…”

Synthesis and chemical characterization of some transition metal complexes with a 6-acetyl-1,3,7-trimetyllumazine ligand

“…In the infrared spectrum of compounds, the bands about 3450 and 3330 cm -1 can be assigned to the vibration ν(N-H) of N62 hydrazonic [28,29]. Two sharp and intense bands must be assigned to the combination of the stretching vibrations of both exocyclic carbonyl groups, the first one assignable to the vibration ν(C2=O), while the second corresponds to the ν(C4=O) [28,29].…”

“…In the infrared spectrum of compounds, the bands about 3450 and 3330 cm -1 can be assigned to the vibration ν(N-H) of N62 hydrazonic [28,29]. Two sharp and intense bands must be assigned to the combination of the stretching vibrations of both exocyclic carbonyl groups, the first one assignable to the vibration ν(C2=O), while the second corresponds to the ν(C4=O) [28,29]. In general, the ν(C63=O) mode can not be observed in the spectra of the complexes, because of the involvement in the coordination enlarges the bond shifting, consequently, the band to a lower wave-number region in which may be hidden by other lumazine vibrations; however the compounds Cd(NO 3 ) 2 (PZLMH) and Gd(NO 3 ) 2 (PZLMH) show a latter vibration (ν(C63=O)) displaced to 1644 and 1650 cm -1 , respectively, which appearing as become a shoulder in the ν(C4=O) bands [30,31].…”