N-(2-Pyridyl)acetamide complexes of palladium(II), cobalt(II), nickel(II), and copper(II)

Non Deprotonated Metal Complexes of the Bis-amide Tetradentate Ligand N,N′ -(Dipicolyl) -1,8-naphthylenediamine

“…On the other hand, if the amide-N atom coordinates, the amide I, II and III bands should shift in the opposite directions. Our experimental data are consistent with amide-0 coordination (Table III) [1,3,4,5,11]. The fact that the amide I, II and III bands shift to other frequencies and do not remain in the same positions, indicates that both of the amide groups of LH2 are coordinated to the metal ions [9,11,28].…”

“…The diffuse reflectance spectrum of Ni(LH2)Cl2 • 2 H20 is indicative of six-coordination [1,3,4,6,9,11,12,20]. The very broad and split character of the d-d transition bands suggests that the complex involves a low symmetry six-coordinated configuration [21].…”

“…The deprotonated system acts as a tetradentate, N4, ligand [10]. Since recently there has been some debate over the coordination site of neutral secondary non-deprotonated amides [9,11], it was very interesting to study the mode of coordination of the above ligand coordinated to bivalent transition metal ions without deprotonation. As a continuation of the interest of our laboratory in the study of the metal-amide interactions [10,12,13], the present paper deals with the preparation and characterization of the Mn(II), Ni(II) and Cu(II) cationic complexes with LH2.…”

Metal complexes of 3-thiophene carboxamides containing a pyridine ring

“…Compared to the free ligands, the amide I band is lowered about 40 cm −1 which is consistent with coordination by the carbonyl oxygen atom [16][17][18]. In 5, two amide I bands are observed, one for the unidentate ligand and the other for coordinated oxygen in the bidentate ligand.…”

“…Interestingly, the bonding occurs through only the amide carbonyl group and the nitrogen on the pyridine ring; no evidence for bonding through the amide nitrogen atom was observed to occur in neutral solution although there are many examples of this mode of bonding for deprotonated amides [16,[26][27][28][29]. Selected crystallographic data, bond distances, bond angles, and hydrogen bonds/contacts are presented in Tables 2-5.…”