Imidazolium salicylaldimine frameworks for the preparation of tridentate N-heterocyclic carbene ligands

Bimetallic Co–Ni based complex catalyst for hydrogen production by catalytic hydrolysis of sodium borohydride with an alternative approach

“…The free ligand showed strong peaks at 1602e1619 cm À1 , which is characteristic of the azomethine (C]N) group [33]. In the case of the complexes, these bands were shifted to the lower or higher frequencies, indicating that the nitrogen atoms of the azomethine groups are coordinated to the Co or Ni as expected [34]. Azomethine groups are a useful tool for the fabrication of the new CoeNi metal complexes with specific electronic and structural properties, which probably due to to both the p / p *, n / p * and ded transitions of C]N and chargeetransfer transition arising from p electron interactions between the metal and ligand, which involves either a metal-to-ligand or ligand-to metal electron transfer.…”

Conversion of carbon dioxide to cyclic carbonates using diimine Ru(II) complexes as catalysts

“…The coordination of Schiff bases to Ru(II) through the nitrogen atom was expected to lower the (C N) frequency (1610-1626). [18,19] The 1 H NMR spectra of the Schiff bases show signals for the proton attached to the imine group and the protons from the aryl rings and proton signals at ca 1-2 ppm, indicating the presence of the methyl substituents on the aryl rings of the imine. The characteristic signals of imines (CH N) at 8.64 ppm for 1e and for1f as singlets were also observed.…”

“…This shift is indicative of coordination, with the transfer of electron density from the imine to the metal center. [18] …”

Mono- and dinuclear Pd(II) complexes of different salicylaldimine ligands as catalysts of transfer hydrogenation of nitrobenzene with cyclohexene and Suzuki–Miyaura coupling reactions

“…The free ligands showed strong peaks at 1602-1619 cm À1 , which are characteristic of the azomethine m(C@N) group [33]. In the case of the complexes, these bands were shifted to the lower or higher frequencies, indicating that the nitrogen atoms of the azomethine groups are coordinated to the palladium ion as expected [34]. In the IR spectra of the dinuclear Pd(II) complexes, a strong peak observed at 1646-1645 cm À1 was assigned to acetate m(COO) stretching.…”