The effects of auxiliary ligands on the synthesis, crystal structures and properties of three complexes with a substituted pyridazine ligand

Abstract

Three new complexes, [Co(L) 2 (SCN) 2 ] (1), [Co 2 (L) 4 (l-N 3 ) 2 ](ClO 4 ) 2 (H 2 O) 1.5 (2), and [Ni(L) 3 ](ClO 4 ) 2 -(CH 3 OH) 2 (3), have been synthesized and structurally characterized, where L is 3-(3 0 ,5 0 -dimethyl-pyrazole)-6-Clpyridazine. Single crystal X-ray analyses show that all three complexes crystallize in the monoclinic crystal system. In complex (1), the Co(II) atom is in a distorted octahedral environment consisting of four nitrogen atoms from two ligands and two nitrogen atoms of SCN -, which is further extended into a 1D chain by intermolecular hydrogen bonds. Two Co(II) atoms in complex (2) are linked by two azide anions in a l-1,1 mode to make a binuclear structure. Without any auxiliary ligand, the Ni(II) atom in complex (3) adopts a distorted octahedral geometry involving six nitrogen atoms from three ligands. The electronic absorption spectra of the title compounds are discussed as well. The effects of auxiliary ligands on the structures and properties of the title complexes have been studied and discussed.Electronic supplementary material The online version of this article (

Pyridazine- versus Pyridine-Based Tridentate Ligands in First-Row Transition Metal Complexes

“…Suitable synthetic pathways are available for symmetric substitution of 3,6-diformylpyridazine . Pyridazines with only one additional donor next to a ring-nitrogen atom leading to bi- or tridentate ligands are synthetically more challenging and thus have been significantly less investigated in coordination chemistry. − …”

Electronic and Photophysical Properties of ReI(CO)3Br Complexes Modulated by Pyrazolyl–Pyridazine Ligands

“…Their planarity and limited conformational flexibility disfavor the nonradiative deactivation paths. , From the synthetic point of view, they are also relatively easy to be prepared and modified. Examples of complexes with pyrazolyl–pyridazine ligands coordinated to metals belonging to any of the transition series have been previously described. − Compounds having pyrazolyl or the related triazolyl-pyridazine ligands chelate to Re I (CO) 3 X (X = Cl or Br), ,− and have shown the influence of the presence of substituents in the ligand on the compound properties, i.e., they can modulate their ability for being used as the photocatalyst. , This effect can also be used for the design of efficient light-emitting materials . In the present work, we describe the synthesis, electronic and photophysical properties of a series of monometallic Re I complexes (see Scheme ) based on the pyrazolyl–pyridazine moiety with different substituents to explore the tuning of the photophysical properties and their potential use as ligands with a second metal site.…”

New pyridazine-based binuclear nickel(ii), copper(ii) and zinc(ii) complexes as prospective anticancer agents

“…18 Pyridazine with only one additional donor next to a ring nitrogen atom leading to bi-or tri-dentate ligands have been less investigated in coordination chemistry. 19 Cancer is the second leading cause of human death after cardiovascular diseases. 20 Though chemotherapy is the mainstay of cancer treatment, the use of available chemotherapeutics still suffers from major limitations such as lack of selectivity of cancer tissues, causing unwanted side effects and the acquisition of multiple-drug resistance by cancer cells.…”