Novel coordination behavior of a pteridine-benzoylhydrazone ligand (BZLMH): Theoretical calculations, XRD structures and luminescence studies

Structural Variety of Cobalt(II), Nickel(II), Zinc(II), and Cadmium(II) Complexes with 4,4′‐Azopyridine: Synthesis, Structure and Luminescence Properties

“…Metals such as Ni 2+ , Cu 2+ , and Co 2+ usually quench organic ligand luminescence; this is in contrast to the Zn 2+ and Cd 2+ ions, for which the effect is not present . As depicted in Figure , upon excitation at approximately λ =370 nm, two strong emission bands are observed at λ =466 and 494 nm with a weak emission band at λ =570 nm in azpy.…”

“…To analyze the nature of the observed emission bands, the photoluminescent properties of the azpy ligand were also explored. Metals such as Ni 2 + ,C u 2 + ,a nd Co 2 + usuallyq uench organic ligand luminescence; [28][29][30][31][32][33][34][35][36] this is in contrast to the Zn 2 + and Cd 2 + ions, for which the effect is not present. [37][38] As depicted in Figure 7, upon excitation at approximately l = 370 nm, two strong emission bands are observed at l = 466 and 494 nm with aw eake mission band at l = 570 nm in azpy.I rradiation of crystalline complexes 1-5 under similar conditions (l ex = 378 nm) resulted in broad unsymmetrical emissions,a sapair of bands at l = 468, 468, 463, 469, and 464 nm and correspondingly other bands at l = 492, 493, 486, 491 and 483 nm, respectively.T he profiles of the emissionb ands are quite similar to that of the metal-free ligand.T he similare missionso f1-5 can be assigned to intraligand emission of azpy,a sp reviously reported.…”

Heteropolyhedral silver compounds containing the polydentate ligandN,N,O-E-[6-(hydroxyimino)ethyl]-1,3,7-trimethyllumazine. Preparation, spectral and XRD structural study and AIM calculations

“…The bridging organic ligands play an important role in successful cluster synthesis and the exploration of the coordination properties of new ligands is necessary to tune and improve their biological and chemical properties. In previous papers, we reported the structural chemistry of metal complexes with 6-substituted-1,3,7-trimethyllumazine using as substituents acetyl, 23 thiosemicarbazones, 24 benzoylhydrazones 25 and azines with aromatic aldehydes 26 to functionalize the 6 position. Despite a lot of coordination compounds of these ligands being isolated with transition metal ions, the structural chemistry and reactivity of those of silver remains still quite unexplored.…”

“…Despite a lot of coordination compounds of these ligands being isolated with transition metal ions, the structural chemistry and reactivity of those of silver remains still quite unexplored. [23][24][25][26] In this context, 6-substituted lumazines containing one oxime arm could be versatile ligands in coordination chemistry due to their ability to generate polynuclear systems. Taking into account these considerations and with the aim to gain a better insight into the coordinative factors involved in the assembly of silver clusters using pteridine derivatives, we decided to use a lumazine-oxime ligand.…”

Synthesis and anti‐HIV activity of new 2‐thiolumazine and 2‐thiouracil metal complexes

“…It is known that pteridine and pterin act by inhibiting the xanthin oxidase, as a key enzyme in the biosynthesis of DNA precursors and a generator of free radicals [14,15]. The capability of pteridines and pterines for simulating the reactivity of metal sites in several enzymes [16][17][18][19] encouraged many laboratories to synthesize the metal complexes of these molecules [20,21].…”