Synthesis, Crystal Structures, and Magnetic Properties of Three New Iron Complexes Derived from 3,5‐Bis(pyridin‐2‐yl)‐1,2,4‐triazole

Abstract

Two new iron(III) complexes and one iron(II) complex have been synthesized from the solvothermal reactions of FeCl3·6H2O with 3,5‐bis(pyridin‐2‐yl)‐1,2,4‐triazole (Hbpt) in methanol or acetonitrile. KSCN acted as the reducing agent in the synthesis of iron(II) complex of 3. [FeCl3(Hbpt)(H2O)]·H2O (1) crystallizes in the triclinic space group $P{\bar 1}$ with a = 7.475(1), b = 9.468(2), c = 12.309(2) Å, α = 73.880(2), β = 74.746(2), γ = 81.849(2)°, V = 805.2(2) Å3, Z = 2. [Fe2(bpt)2Cl4] (2): orthorhombic space group Pnnm with a = 9.895(2), b = 10.632(2), c = 13.195(2) Å, V = 1388.1(4) Å3, Z = 2. [Fe2(bpt)2(MeOH)2Cl2] (3): orthorhombic space group Pbca with a = 14.4204(16), b = 9.8737(11), c = 19.792(2) Å, V = 2818.1(5) Å3, Z = 4. 1 features the first structurally characterized metal complex of the neutral Hbpt ligand in which the Hbpt ligand adopts an unprecedented zwitterionic form. 2 shows a neutral dinuclear iron(III) complex and the [Fe2(bpt)2]4+ unit is ideally planar. The two iron(III) ions separated by a distance of 4.408(2) Å are doubly triazolate‐bridged. Each dimeric unit is connected with six other dimeric ones via the bifurcated C‐H···Cl hydrogen bonds, these connections extend the dimeric moieties into a three‐dimensional molecular architecture. 3 is a neutral centrosymmetric dinuclear FeII complex, in which intermolecular moderate O‐H···N hydrogen bonding interactions between the methanol molecules and 4‐position nitrogen atoms of the triazolato groups extend the dinuclear species into a two‐dimensional supramolecular architecture of (4,4) topology. Magnetic studies indicate there exists an antiferromagnetic spin coupling in FeIII2 and FeII2 units via the double triazolate bridges in 2 and 3.

Construction of Cd/Zn(II)-1,2,4-Triazolate Coordination Complexes via Changing Substituents and Anions

“…The dihedral angle between the coordinated pyridyl group and the triazolate ring is 9.5(5)°, whereas that between the noncoordinated pyridyl group and the triazolate ring is 15.3(5)°. It is worth noting that although a variety of coordinated complexes based on anionic 2-pytrz ligands have been reported, only one example containing the neutral 2-pytrz was structurally characterized more recently 1 ORTEP diagram showing the coordination environments for (a) the binuclear structure of complex 1 and (b) three-dimensional supramolecular structure generated by four types (I−IV) of hydrogen bonds.…”

A new homobimetallic cobalt(II) complex based on the tetradentate 3,5-bis(2-pyridyl)-1H-1,2,4-triazole ligand: Synthesis, crystal structure, Hirshfeld analysis, spectroscopic characterization, magnetic properties and antimicrobial activities

“…This laster can be often deprotonated to form an anionic 3,5-bis(2pyridyl)-1,2,4-triazolate (bpt) in the formation process of complexes. However, only few mono or dinuclear transition metal complexes as well as tetranuclear or even polymeric complexes containing anionic bpt ligand were characterized by X-ray diffraction [4,6,7,[12][13][14][15][16][17][18][19][20], which indicate that these coordination compounds have relatively poor crystallization behaviour.…”

Di- and Tri-nuclear VIII and CrIII Complexes of Dipyridyltriazoles: Ligand Rearrangements, Mixed Valency and Ferromagnetic Coupling

“…The literature complexes of adpt are almost solely mono-or dinuclear (Klingele and Brooker, 2003), with the exception of some tetranuclear (White and Brooker, 2013), octanuclear (White and Brooker, 2013), and polymeric (Dupouy et al, 2009) systems. The next most commonly studied ligand of this general type is dpt − with the resulting complexes showing a far richer variety in nuclearity from monometallic through to polymetallic clusters and polymers (Zhang et al, 2005;Chen et al, 2006a;Keene et al, 2006;White et al, 2012).…”