Preparation, structural characterization and physical properties of palladium(II) and platinum(II) complexes of the biheteroaromatic ligand 2-(2′-pyridyl)quinoxaline (L)

Synthesis, characterization, DFT studies and DNA binding of mixed platinum (II) complexes containing quinoxaline and 1,2-dithiolate ligands

“…2-(2 0 -pyridyl)quinoxaline [31,34], and Pt(pq)Cl 2 [35] were prepared according to the literature procedures. All reactions and manipulations were conducted under a pure argon atmosphere using standard Schlenk techniques.…”

“…The capillary voltage was optimum at about 3.3 kV for the positive ions. The focus and skimmer lenses voltages were 40 and 45 V, respectively [35,37]. Photolysis experiments were carried out with a 1000 W Xenon lamp in an Oriel, mod 68820, Universal Arc.…”

“…Thus, the elucidated by DFT means structure of 2 was compared with the Pd(pq)Cl 2 [35] which is isomorphous to 1. The molecular structure of 2 is shown in Fig.…”

Mixed ligand complexes with 2-piperidine-carboxylic acid as primary ligand and ethylene diamine, 2,2′-bipyridyl, 1,10-phenanthroline and 2(2′-pyridyl)quinoxaline as secondary ligands: preparation, characterization and biological activity

“…The spectra of the pyq complexes (6, 8, and 10) are similar to those of the complexes in which pyq behaves as a bidentate ligand [10,[26][27][28]. The characteristic in-plane and out-of-plane 2¢-pyridyl ring deformation bands appear at 620 and 401 cm )1 , respectively, in the free pyq, are shifted to higher frequencies in the complexes indicating the involvement of the pyridyl nitrogen atom (N1¢) in coordination [10] (Scheme 2).…”

“…the pyridine nitrogen and the nearest quinoxaline nitrogen are located on the opposite side to the carbon-carbon bond which connects the pyridine and quinoxaline rings; the reverse has been observed in complexation [26,27]. However, the electron density on the 2¢-pyridyl ring of pyq (Scheme 2) diminished upon coordination to Pd (II) (6), Ag (I) (8)and UO 2 (II) (10), including a downfield shift of H 6 0 resonance, which appears near d 9.35 p.p.m.…”