Ruthenium half-sandwich complexes with tautomerized pyrazolyl-pyridazine ligands: Synthesis, spectroscopic and molecular structural studies

Preparation, characterization, crystal structures and catalytic oxidation activities of two transition metal complexes of an N-heterocyclic pincer ligand

“…It is interesting to note that when the bond angle of N pz* -M-N pz* is larger, the deviation of corresponding dihedral angle (tz-pz*) is also larger. Meanwhile, the bond lengths of Ni-N are all shorter than the equivalent Co-N bond lengths, while the N pz* -Ni-N pz* bond angles are larger than the N pz* -Co-N pz* bond angles, which are consistent with relevant literature in which the bond angle of N pz* -Ni-N pz* is 151.40 (14) and that of N pz* -Co-N pz* is 148.46(12) [27]. The composition of bulk samples of complexes 1 and 2 was confirmed by X-ray powder diffraction (PXRD) (Fig.…”

“…Triazine ligands have a rich coordination chemistry [13][14][15] and find potential applications in the fields of catalysis [16], magnetism [17], as well as biological activities [18]. Triazine-pyrazole derivatives can act as bidentate or tridentate ligands and are used as tripodal 'scorpionate' ligands for transition metals.…”

Mono and dinuclear half-sandwich platinum group metal complexes bearing pyrazolyl-pyrimidine ligands: Syntheses and structural studies

“…The ligand 4,6-bis(pyrazolyl)pyrimidine (L1) and its analogues, 4,6-bis(3-methyl-pyrazolyl)pyrimidine (L2) and 4,6-bis(3,5-dimethyl-pyrazolyl)pyrimidine (L3), are the subject of this investigation. They have a structural similarity to 3,6-bis(pyrazolyl)pyridazine (A) and 4,5-bis(pyrazolyl)quinoxaline (B) both of which have been previously studied [29,30]. In our previous work, we demonstrated that the ligand A does not yield dinuclear compounds with two half-sandwich platinum group metal atoms, since the steric nature of the ligand, resulted only in the formation of mononuclear complexes [29].…”

“…They have a structural similarity to 3,6-bis(pyrazolyl)pyridazine (A) and 4,5-bis(pyrazolyl)quinoxaline (B) both of which have been previously studied [29,30]. In our previous work, we demonstrated that the ligand A does not yield dinuclear compounds with two half-sandwich platinum group metal atoms, since the steric nature of the ligand, resulted only in the formation of mononuclear complexes [29]. However it is true in the case of more sterically free ligand B also, because it also yielded mononuclear complexes, since the pyrazole rings of the ligand tilted with respect to the central quinoxaline ring because of the steric collide between the R' groups of the pyrazole rings.…”

Syntheses and characterization of mono and dinuclear complexes of platinum group metals bearing benzene-linked bis(pyrazolyl)methane ligands

“…In recent years, we have been carrying out arene ruthenium and Cp* rhodium and iridium complexation reactions with a variety of nitrogen-based ligands [21][22][23][24][25][26][27] including pyrazolyl-pyrimidine, pyrazolyl-pyridazine and pyridyl-pyridazine ligands. All of these ligands after coordination with metal have given five membered chelating complexes; this is the first time that isolated six-membered chelating complexes with 1,4-bis{bis(pyrazolyl)-methyl}benzene (L1) or 1,4-bis{bis(3-methylpyrazolyl)methyl}benzene (L2) (Chart 1) ligands have been isolated with these metal complexes.…”