Factors influencing the nitrogen vs oxygen bonding mode of amides bound to pentaamminecobalt(III) and the kinetics and mechanism of rearrangement

Donor-acceptor electronic coupling as a function of bridging group: mixed-valence diruthenium(II,III) complexes bridged by isonicotinato and isonicotinamido ligands

“…For the µ-isonicotinato complex, the sensitivity of the pyridineattached metal center to donor number (28.5 mV/DN) is somewhat greater than that of the carboxylato-attached center (24 mV/DN) so that (=£py -£oco) decreases slightly with donor number. Interaction of the ammine hydrogen atoms with the solvent increases with solvent donor number and, since the Ru(III) N-H bonds are more acidic than those of Ru(II), the stabilization of the Ru(III) complex increases with solvent donor number and the Ru(II)/(III) couple becomes more reducing as donor number increases.…”

“…The analogous isonicotinamide-based system is potentially more complicated, however, since amides may coordinate a metal center either through oxygen or nitrogen. 32 Recent studies indicate that the deprotonated amide (RC(O)NH') ligand binds preferentially through nitrogen, while protonation favors rearrangement to the oxygen-bonded isomer (eq 14).16• 24 The rates for such linkage…”

Modular N,O‐Chelating Ligands: Group‐4 Amidate Complexes for Catalytic Hydroamination

“…In general, coordination occurs through the more basic oxygen with "hard" metals (1), [29] but through the nitrogen to "soft" metals (2). [30,31] Most examples are reported as either type i or type ii, without reference to isomerism between the two. Furthermore, if the amide is in its neutral form, typically the ligand coordinates through the oxygen to the metal center (eg.…”

Acetamide Coordination in a Nickel(I) Macrocyclic Complex: Synthesis, Properties, and X-ray Crystal Structure of a Five-Coordinate Nickel(I) Iminol Complex of 1,3,6,8,12,15-Hexaazatricyclo[13.3.1.18,12]icosane

“…The nitrile hydration and the coordination chemistry of the metal−amide linkage are of interest also in their own rights and in the context of metal ion−peptide chemistry. − The coordination mode of amide has been known to depend on the acidity of the medium and the type and oxidation state of the metal ion. The complexes of O-bonded amide, − anionic N-bonded amidate, − N-bonded amide, − and N-bonded iminol 43,44 have been reported.…”