Synthesis and characterization of complexes imparting N-pyridyl bonded meso-pyridyl substituted dipyrromethanes

Synthesis and evaluation of new polynuclear organometallic Ru(ii), Rh(iii) and Ir(iii) pyridyl ester complexes as in vitro antiparasitic and antitumor agents

“…This trend has also been observed within the molecular structures of similar Cp*Ir(III) and Cp*Rh(III) pyridyl complexes. 16,30,34,44,45 Within the pyridyl ester ligands of both 4 and 5, the dihedral angles formed between the central phenyl ring and each ester functionality is close to 90°indicating that the pyridyl rings orientate themselves almost perpendicular to the phenyl spacer thereby minimizing electrostatic interactions within the complex molecules.…”

“…The proton NMR spectra for complexes 3-8 all show a downfield shift of the protons ortho to nitrogen compared to their corresponding free ligands, which is typical for monodentate 4-pyridyl ligands coordinated to Ru(II), Rh(III) or Ir(III) metal centers. 14,16,[30][31][32][33][34][35][36][37] This deshielding is expected upon metal coordination to the nitrogen as it leads to less electron density in the ortho carbon-hydrogen bond due to strong back-bonding between an empty π*-orbital of nitrogen and a filled d-orbital of the transition metal.…”

Dipyrrin based metal complexes: reactivity and catalysis

“…The group of Pandey has reported a series of organometallic Ru(II), Ir(III) and Rh(III) complexes incorporating dpm ligands focusing on their biological activity, supramolecular assembly as well as their catalytic activity. [129][130][131][132][133][134] In particular, Rh(III) complexes of type 63 (Fig. 19b) were shown to catalyze the transfer hydrogenation of terephthaldehyde leading to the mono-reduced derivative 4hydroxymethylbenzaldehyde with complete conversion.…”

“…A similar reactivity was observed for compounds where the metal center (Ru(II), Ir(III) or Rh(III)) is coordinated to a peripheral pyridyl unit of a dipyrromethene ligand rather than by the dpm chelate itself. 131…”

Current Advances in the Synthesis of Valuable Dipyrromethane Scaffolds: Classic and New Methods

“…The electronic properties of this ligand can be modified by substitution at the beta -carbons and at the meso positions, while the steric properties can be tuned by substitution at the alpha -carbons. Zirconium complexes have been applied in olefin hydroamination [18] and ruthenium, rhodium and iridium complexes used as hydrogen transfer catalysts under aqueous and aerobic conditions [19]. The synthesis of dipyrromethene complexes has also been achieved with Mn, Co, Zn, Ni [20,21,22] or Sn [23].…”