Sigma donor and pi acceptor characteristics of certain NN-bidentate ligands: a DFT Study

Phenanthroline—A Versatile Ligand for Advanced Functional Polymeric Materials

“…Upon formation of the Fe II ‐SCNPs , the solution instantaneously turned bright red. The low energy π*‐orbitals of phen enable strong metal‐to‐ligand charge‐transfer absorption in the visible and UV‐region, which often causes characteristic bands for the corresponding transition metal phen complexes. Compared to a solution of the molecular iron(II) complex [Fe(phen) 3 ]SO 4 , depicting a characteristic three shouldered trace with a maximum at 507 nm, the trace of Fe II ‐SCNPs exhibits a similar shape with a maximum resonance at 512 nm (Figure ).…”

“…Upon formation of the Fe II -SCNPs,t he solutioninstantaneously turned bright red. The low energy p*-orbitals of phen [58] enables trong metal-to-ligand charge-transfer absorption in the visible and UV-region, which often causes characteristic bands for the corresponding transition metal phen complexes.C ompared to as olutiono ft he molecular iron(II) complex [Fe(phen) 3 ]SO 4 ,d epicting ac haracteristic three shouldered trace with am aximum at 507 nm, the trace of Fe II -SCNPs exhibits as imilars hape with am aximum resonance at 512 nm ( Figure 2). Similar trace shape and literature references [59,60] validate the assumption of a3:1 ligand to metal ratio complex formation as the resultingf olding unit of the Fe II -SCNPs.I nc omparison, [Ni(phen) 3 ]SO 4 does not exhibit an intense color.T hus, very high concentrations are necessary to obtain ac haracteristica bsorption in the UV/Vis spectrum, however,s uch concentrationsc ouldn ot be obtained for the Ni II -SCNPs.T herefore, ac omparison with the molecular complex was not feasible.…”

PtII‐Catalyzed Hydroxylation of Terminal Aliphatic C(sp3)−H Bonds with Molecular Oxygen

“…In particular, previous studies, for example, on the Periana-Catalytica system for methane oxidation with SO 3 , [35,36] have revealed the potential of bidentate N-heteroaromatic ligands in stabilizing related Pt II complexes, based on the strong s-donor and p-acceptor interactions of these ligandswith electron rich low oxidation state metals. [37] As shown in Ta ble 4, no metallic platinum wasd etected in the reactionv ial after 6h when 1mol %o f2 ,2'-bipyridine was initially included in the substrate solution (entry 2). As imilar improvement of the catalysts tabilityw as, however, achieved with 1mol %o fp yridine (entry 3), demonstrating that am onodentate ligand gives comparable stabilization as ab identate, chelating ligand.M oreover,an egative impact on the activity was observed for both ligands, which provedt ob em ore severe for 2,2'-bipyridine.…”

Structural and spectroscopic characterization and DFT studies of 2-amino-1,10-phenanthrolin-1-ium chloride

“…We have an ongoing interest in the synthesis of azabridged bis-1,10-phenanthroline derivatives [10][11][12], mainly due to their significant biological activity of the corresponding metal complexes in which the planar and also rigid structure of 1,10-phenanthroline (phen) can either intercalate or bind to the grooves of DNA or RNA [13][14][15][16][17][18][19][20]. Therefore, the design and synthesis of new derivatives of phen with extended properties have gained a significant attention by many researchers [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36]. We have previously reported an alternative strategy to synthesize a series of phen derivatives [37].…”