Exogenous bridge and tautomer effects on magnetic interaction of binuclear copper(II) complexes of μ-phenolato Schiff bases

Four enol-form binuclear copper complexes with different exogenous bridges, [Cu2(L)(μ-Cl)] (1), [Cu(L)(μ-N3)]· DMF (2), [Cu2(L)(μ-OCH3)] (3) and [Cu2(L)(μ-C3H3N2)]· 1/2C2H5OH (4), where L is the trivalence anion of binucleating ligand 2,6-diformyl-4-methylphenol di(tenzoylhydrazone), have been synthesized and characterized. Crystal data for complex (3) are as follows: space group P1- , a=0.8294(1), 6=0.9333(3), c= 1.473 6(6) nm, α=79.51(3)°, β=80.93(2)°,γ=81.32(2)°, Z=1. The magnetic measurements indicated that the effect of exogenous bridging ligands on magnetic interaction is corresponding to that in spectrochemical series. The effect of enol- and keto-form tautomer on magnetic interaction was explained from the point of view of structural factors and electron effects by using molecular mechanks and quantum chemistry calculations.     

Synthesis and Properties of u-Oxamido Heterobinuclear Cu(Ⅱ)-Co(Ⅱ) Complexes

Three heterobinuclear complexes were synthesized, namely [Cu (oxpn) Co (L)2] (ClO4)2·xH2O(L= 2,2'-bipyridyl(bpy), 1,10-phenanthroline(phen) , and 5-nitro-1, 10-phenanthroline (NO2-phen)), where oxpn represents N, N'-bis(3-aminopropyl) oxam-ido. Based on 1R, elemental analysis, conductivity measurement and electronic spectra, these complexes were characterized by an extended oxamido-bridged structure with Cu(Ⅱ) in a planar environment and Co(Ⅱ) in a octahedral environment. The symmetry of the cation is very close to C2v.The complexes were also characterized with variable temperature (4~300K) magnetic susceptibility, and the data were fit for the susceptibility equation derived from spin Hamilton, H= -2JS1.S2-DSx12 by least square strategy. The exchange integral, J, was found to be -22.36 cm-1 (for bpy);-15.45 cm-1 (for phen); -19. 10cm-1(for NO2-phen), indicating that there is a weak antiferromagnetic spin-exchange interaction between the metal ions.     

Synthesis and magnetic properties of binuclear cobalt(Ⅱ), nickel(Ⅱ) and copper(Ⅱ) complexes bridged by oxamidate group

Four binuclear Co(Ⅱ), Ni(Ⅱ) and Cu(Ⅱ) complexes bridged by oxamidate (oxd) group have been synthesized, namely Co2(byp)2(oxd)(ClO4)2 (1), Co2(Me2bpy)2(oxd)(ClO4)2.H2O (2), Ni2(bpy)2(oxd)(ClO4)2.2H2O (3) and Cu2(Me2bpy)2(oxd)(NO3)2 (4). (bpy=2,2'-bipyridyl, Me2-bpy=4,4'-dimethylbipyridyl, oxd=oxamidate) The complexes are characterized by IR, UV spectra, EPR and variable-temperature magnetic susceptibility (4-300 K). The susceptibility data for. complexes 1 and 3 were least-squares fit to the susceptibility equation derived from the spin Hamiltonian H=-2J . S1 . S2. The exchange integral, J, was found to be equal to -3.62 cm-1 in 1 and -1.82 cm-1 in 3. This indicates a weak antiferromagnetic spin exchange interaction between the metal ions.     

铜(Ⅱ)离子导向的自组装研究

A few copper(Ⅱ) ions or groups have been designed and investigated for metal-assisted self assembly. Reactions of these metal units with a number of linear bridging ligands have led to the production of some dinuclear copper(Ⅱ) complexes and coordination polymers in which metal centers are all five-coordinate in the configuration of a square pyramid or a triangular bipyramid.     

Electrospray ionization tandem mass spectrometric studies to probe the interaction of Cu(II) with amoxicillin简

This study describes the application of electrospray ionization mass spectrometry(ESI-MS) to investigate copper ion interaction with amoxicillin. ESI mass spectra of Cu–amoxicillin complexes show complex ions at m/z 828, 792, 753, 731, 428, 388 and 366 corresponding to [63Cu+(2A-H)+2H2 O]+, [63Cu+(2A-H)]+, [2A+Na]+, [2A+H]+, [63Cu+(A-H)]+, [A+Na]+and [A+H]+(where A = amoxicillin). Based on the observed m/z values of Cu–amoxicillin complex ions, it is found that the Cu–amoxicillin ratios are 1:1 and 1:2, and the copper ions exhibited three feasible coordination numbers(2, 4 and 6) with amoxicillin complexes. The structures and coordination numbers of copper–amoxicillin complex ions were probed from their collisionally activated dissociation(CAD) spectra. Based on these results, it is confirmed that the copper ions could form stable tetrahedral and octahedral complexes with amoxicillin. This study validates the applicability of ESI-MS for probing copper–amoxicillin complex ions.     

SYNTHESIS AND MAGNETISM OF BINUCLEAR COPPER(Ⅱ) COMPLEXES CONTAINING SALUCYLAMIDATOCUPRATE(Ⅱ)

New binuclear copper(Ⅱ) complexes, [Cu(samen)Cu(NO_2-phen)]·H_2O and [Cu(sampn)-Cu(NO_2-phen)]·2H_2O have been synthesized, where samen~(4-), sampn~(4-) and NO_2-phen denote N, N′-ethylenedisalicylamidate anion, N, N′-1, 2-propanedisalicylamidate anion and 5-nitro-1, 10-phenanthroline respectively. 3ased on IR, elemental analyses and electronic spectra, the complexes are proposed to have a phenoxy-bridged structure and to consist of the Cu(Ⅱ)ion in distorted planar environment. The complexes have been characterized with varlable-temperature magnetic susceptibility (4—300 K) and the observed data were fit to those from a modified Bleaney-Bowers equation by least-squares method, giving the exchange integral J=-63.0 cm~(-1) (samen) and J=-46.5cm~(-1) (sampn). This indicates the existence of antiferromagnetic spin exchange interaction among the metal ions.     

Synthesis and characterization of μ-oxamido copper(Ⅱ)-iron(Ⅱ) heterobinuclear complexes with an antiferromagnetic exchange interaction

Four new u-oxamido heterobinuclear complexes have been synthesized and identified as [Cu(oxap)Fe(L)2]SO4, where oxap denotes the N, N'-bis(2-aminopropyl)oxamido dianion and L represents diaminoethane (en); 1,3-diaminopropane (pn); 1,2-diaminopropane (ap) and 2,9-dimethyl-1,10-phenanthroline (Me2-phen). Based on the elemental analyses, spectroscopic studies, magnetic moments (at room temperature) and molar conductivity measurements, extended oxamido-bridged structures consisting of a copper(Ⅱ) and an iron(Ⅱ) ions, which have a square planar environment and an octahedral environment, respectively, are proposed for these complexes. Complexes [Cu(oxap)Fe(en)2]SO4 (1) and [Cu(oxap)Fe(pn)2]SO4 (2) have been characterized by variable temperature magnetic susceptibility (4.2~300 K) and the observed data were least-squares fitted to the susceptibility equation derived from the spin Hamiltonian including single-ion zero-field interaction for the iron(Ⅱ) ion, H=-2JS1.S2-DSzl2, giving the exchange integrals J=-2     

Synthesis and Crystal Structures of Two Di-Cu(Ⅱ) Complexes Based on an Asymmetric Dinucleating Ligand

Two new dicopper(II) complexes [Cu2L(OAc)2](ClO4)·H2O(1) and [Cu2L(BPP)2]-(ClO4)(2) using an asymmetric dinucleating ligand HL and auxiliary ligands such as acetate(OAc) and bisphenyl phosphate(BPP) have been synthesized and characterized by elemental analysis, IR and single-crystal X-ray diffraction. Complex 1 crystallizes as blue single crystals that belong to the triclinic crystal system and P1 space group, while complex 2 crystallizes in a monoclinic P21/c space group. Single-crystal X-ray diffraction analysis reveals that the two copper ions in complexes 1 and 2 reside within the adjacent ligand compartments and are bridged by the endogenous phenoxo-O from ligand L and the introduction of two desired exogenous carboxylates or phosphates in the bidentate μ-1,3-bridged mode. The coordination geometries of Cu(1) and Cu(2) are both distorted square pyramids.     

Synthesis,characterization,structures and magnetic property of chiral oxalate-bridged dicopper(Ⅱ) complexes

The oxalato-bridged dicopper(II) complexes [Cu2(μ-ox)(LRR)2(H2O)2(ClO4)2] (1),[Cu2(μ-ox)(LRR)2(CH3COCH3)2(ClO4)2](1a),[Cu2(μ-ox)(LSS)2(H2O)2(ClO4)2] (2) and [Cu2(μ-ox)(LRR)(LSS)2(CH3COCH3)2(ClO4)2] (3) [LRR = (8R,10R)-(-)-[4,5]-pineno2,2′-bipyridine,LSS = (8S,10S)-(+)-[4,5]-pineno-2,2′-bipyridine;ox2= oxalate] were first prepared.A possible mechanism for the formation of the chial dicopper(II) complexes was proposed.Based on elemental analysis,conductance measurement,UV-Vis spectra,CD spectra and X-ray single-crystal diffraction,the oxalato-bridged structures of 1 and 2 were deduced to adopt two Cu(II) ions and the bridged oxalate lying in the nearly same plane.The crystal structures of 1a and 3 reveal that the coordination geometry around each Cu(II) ion is an elongated and distorted octahedron and two axial solvent molecules and two perchlorate ions are anti to each other respectively in both binuclear molecules.The solution CD spectra of 1 and 2 in the visible d-d range show very weak Cotton effects with peaks at 588 and 779 nm,which are approximately of mirror image,suggesting the optical activities may be derived from the vicinal effects of the chiragenic centers at the pinene group of LRR and LSS,respectively.Complex 1 has been characterized by variable-temperature magnetic susceptibility and the data was least-square fitted to the Blenaey-Bowers equation.The exchange integral J was found to be -338.41(4) cm-1,indicating a strong antiferromagnetic interaction between two copper(II) ions.     

A Diphenoxo-bridged Ferromagnetic Copper（Ⅱ） Dimer Based on N-（2-Hydroxybenzyl）salicylaldimine

A new dinuclear copper（Ⅱ） complex, [Cu（L）（py）]2 1 （H2L = N-（2-hydroxybenzyl）- salicylaldimine, py = pyridine）, has been synthesized and characterized by elemental analysis, IR and UV spectra. 1 crystallizes in space group P2 1/n with a = 8.2106, b = 10.715, c = 17.864A, β = 99.365°, V = 1550.7A3, Z = 4, C19H16CuN2O2, Mr = 367.88, Dc = 1.576 g/cm3,μ（MoKα） = 1.422 mm-1, F（000） = 756, the final R = 0.0280 and wR = 0.0746. Complex 1 is a centrosymmetric dimer with two copper（H） centers, two py ligands and two L2- ligands. Each L2- ligand donates its azomethine nitrogen and one of the phenolate groups to one copper（Ⅱ） ion and shares the other phenolate group between the two copper（H） ions, affording a Cu2O2 plane. Each copper（Ⅱ） center has a slightly distorted square pyramidal geometry with a bridging phenolate group at the apex. Magnetic studies suggest the presence of a weak ferromagnetic interaction Via two phenoxo bridges. The magnetic susceptibility data （2-300 K） of complex 1 were analyzed by means of H = -2JS1S2 -DSz. The least-squares fitting of the data to the theoretical equation leads to J = 10.3 cm-1, g = 2.03, D = 0.67 cm-1 and R = ∑（Xobsd -Xcalcd）2/∑Xobsd2= 2.76 × 10^-3.     

Binuclear Copper(II) Complexes with Robsori-Type Ligands. Synthesis,characterization, crystal structure,and magnetic properties

Three binuclear copper(II) complexes, [Cu₂(μ-L)(μ-N₃)](ClO₄)2′ 1-5 EtOH (1), [Cu₂(μ-L)(μ-MeO)(ClO₄)]-ClO₄ - EtOH ( 2 ) and [Cu₂(μ-L)(μ-C₃H₃N₂)](ClO₄)₂ · 2H₂O, ( 3 ) where L is the pentadentale bridging ligand derived from 5-(tert-butyl)-2-hydroxybenzene-1, 3-dicarbaldehyde bis(benzoylhydrazone) ( HL ) were synthesized and characterized. The crystal-structure determination of complex 2 provided the following crystal data: monoclinic, space group P2₁}/a, a = 11.412(2), b = 24.509(4), c = 14.833(4) Å, β = 104.41(2)°, K = 4018(3) ų, Z = 4. The structure shows that the Cu^II ions are bridged by the endogenous phenolato O-atom and by an exogenous bridge CH₃O^?. The analysis of variable-temperature magnetic susceptibility data (4-300 K.) indicates that there is an antiferromagnetic interaction between the Cu^II ions in these complexes with an exchange parameter (2J) of ?119.1 cm^?1 for complex 1 and ?361.8 cm^?1 for complex 3 . The effect of some exogenous bridging ligands on magnetic coupling for this type of complex is suggested.     

Ni(II) complexes with 8-aminoquinoline derivatives

Some Ni(II) complexes with 5,7-dicloro-8-aminoquinoline (dcaq), 5,7-dibromo-8-aminoquinoline(dbaq) and 5,7-diiodo-8-aminoquinoline(diaq) are described. The compounds are of stoichiometry NiL₂X₂(L= dcaq, dbaq, diaq; X= NO^?₃ and L= dbaq; X= Cl^?, Br^?, I^?, NCS^?) and NiLX₂·H₂O(L= dcaq, diaq; X= Cl^?). The electronic spectra and magnetic susceptibility data at room temperature, are consistent with octahedral geometry for the Ni(II) in each compound. I.r. spectra show the presence of ionic and bridging nitrate groups in the compounds NiL₂(NO₃)₂(L= dcaq, dbaq, diaq) and we assign them polymeric structures. Polymeric structures with bridging chloride are proposed for the compounds NiLCl₂·H₂O(L= dcaq, diaq) and monomeric octahedral structures for NiL₂X₂(L= dbaq; X= Cl, Br, I, NCS).     

Synthesis and magnetism of 6-nitrobenzimidazolate and imidazolate-bridged copper(II) complexes

Summary Four new trinuclear copper(II) complexes, [Cu(phen)-(NBzIm)] (ClO₄) (1), [Cu(bpy)(NBzIm)](ClO₄) (2), [Cu-(Me₂-bpy)(NBzIm)](Ac)·1/2H₂O (3) and [Cu(Me₂-bpy)-(Im)](ClO₄)·1/2H₂O (4) (phen = 1, 10-phenanthroline, bpy = 2,2-bipyridine, NBzIm = 6-nitrobenzimidazolate ion, Im=imidazolate ion) have been prepared and characterized by variable temperature magnetic susceptibility measurements. A weak antiferromagnetic spin exchange interaction operates between copper(II) ions, exchange integrals evaluated as J =-23.82 cm^-1 for (1); and J=-21.91 cm^-1 for (2).     

Synthesis,structures, and magnetic properties of two pyrazolato-bridged trinuclear copper(II) complexes

One nonlinear and one linear trinuclear copper(II) complex [Cu₃(dien)₂(pdc)₂CH₃OH]₂?·?6CH₃OH (1) and [Cu₃(pdc)₂(CH₃OH)₆(H₂O)₄] (2) were prepared and characterized structurally, where dien is diethylenetriamine and pdc^3? the trianion of 3,5-pyrazoledicarboxylic acid. Both complexes consist of 3,5-pyrazoledicarboxylato-bridged trinuclear copper(II) centers. In 1, copper(II) ions are five-coordinate in distorted square pyramids with bond angles 164.78° for Cu(1)–Cu(2)–Cu(3) and 164.51° for Cu(4)–Cu(5)–Cu(6). In 2, the three copper(II) ions are six-coordinate with elongated octahedral geometry. The trinuclear units of 1 and 2 interact through hydrogen bonds to form 3-D and 2-D supramolecular networks, respectively. Variable temperature magnetic susceptibility measurements show that 1 and 2 are antiferromagnetically coupled with J values of ?11.2 and ?13.3?cm^?1.     

邻苯二甲酸单甲酯双核铜配合物的强反铁磁性和磁构关联研究

以邻苯二甲酸单甲酯(mMP)为配体合成了一个新的双核铜配位化合物[Cu₂(mMP)₂(H₂O)₂]₂·2H₂O (1), 并通过元素分析、红外光谱和X射线单晶衍射等方法对化合物晶体结构进行了表征. 化合物1通过四羧酸桥联的方式形成了桨轮状双金属笼结构. 每个Cu(II)离子采用四方单锥的五配位构型, 其中四个氧原子来自于四个不同的邻苯二甲酸单甲酯配体, 轴向位置上的氧原子则来自于水分子. 配位水分子和溶剂水分子与配体中未配位的氧原子形成了分子间氢键, 并进一步形成三维网络结构. 磁性数据显示双核铜内为强的反铁磁交换作用, 磁耦合作用常数2J=-324 cm^-1. 通过与相关双核铜化合物的对比, 详细分析了化合物的磁构关联并讨论了羧酸类双核铜中强反铁磁性作用的结构因素. 研究表明, 影响羧酸类双核铜强反铁磁性作用的主要结构因素是配体中桥联双核铜的O－C－O部分的电子结构.     

Synthesis and Magnetic Studies of Copper (II)‐Manganese (II) Heterobinuclear Complexes with an Oxamido Bridge

Four new copper (II)‐manganese (II) heterobinuclear complexes bridged byN, N'‐bis[2‐(dimethylamino)ethyl)]oxamido dianion (dmoxæ) and end‐capped with 1, 10‐phenanthroline (phen), 5‐methyl‐1, 10‐phenanthroline (Mephen), diaminoethane (en) or 1,3‐di‐aminopropane (pn). respectively, namely, [Cu(dmoxae)MnL₂] (CIO₄)₂ (L=phen, Mephen, en, pn), have been synthesized and characterized by elemental analyses, IR, electronic spectral studies, and molar conductivity measurements. The electronic reflectance spectrum indicates the presence of spin exchange‐coupling interaction between bridged copper(II) and manganese (II) ions. The cryomagnetic measurements (4.2‐300 K) of [Cu(dmoxae)Mn(phen)₂](CIO₄)₂ (1) and [Cu(dmoxae)Mn(Mephen)₂](CIO₄)₂(2) complexes demonstrated an antiferromagnetic interaction between the adjacent manganese(II) and copper (II) ions through the oxamido‐bridge within each molecule. On the basis of spin Hamiltonian, H= ‐ 2JS₁. S₂. the magnetic analysis was carried out for the two complexes and the spin‐coupling constant (J) was evaluated as ?35.9 cm^?1 for 1 and ‐ 32.6 cm^?1 for 2. The influence of methyl substitutions in the amine groups of the bridging ligand on magnetic interactions between the metal ions of this kind of complexes is also discussed.     

Preparation, characterization and crystal structures of copper(II) hexaazamacrotetracyclic complexes with organic ligands

The reaction of [Cu(L)](ClO₄)₂ · H₂O (L=1,3,10,12,16,19-hexaazatetracyclo[17,3,1,1^12.16,0^4.9]tetracosane) with NaN₃ and Na₂tp yields mononuclear and dinuclear copper(II) complexes, [Cu(L)(N₃)](ClO₄) (1) and [Cu(L)(μ-tp)](ClO₄) · 2H₂O (2). These complexes have been characterized by X-ray crystallography, electronic absorption, cyclic voltammetry and magnetic susceptibility. The crystal structure of (1) shows that the copper(II) ion has a distorted square-pyramidal geometry with the two secondary and two tertiary amines of the macrocycle and one nitrogen atom from the azide group coordinating the axial position. The copper(II) ions in (2) are bridged by the terephthalate anion to form a dinuclear complex, in which each copper(II) ion reveals a distorted square-pyramid with four nitrogen atoms of the macrocycle and the oxygen atom of bridging tp ligand. Cyclic voltammetry of the complexes gives two one-electron waves corresponding to Cu^II/Cu^III and Cu^II/Cu^I processes. The magnetic susceptibility measurement for (2) exhibits a weak antiferromagnetic interaction between copper(II) centers with a 2J value of −2.21 cm⁻¹ (H = −2JΣS₁ · S₂). The electronic spectra and electrochemical behavior of the complexes are significantly affected by the nature of the organic ligands.     

Oxamido‐bridged N4 Macrocyclic Complexes CuII/MII/CuII (M = Mn,Co): Synthesis,Crystal Structures and Magnetic Properties

Two new oxamido‐bridged N₄ macrocyclic complexes [(CuL)₂Mn(C₂H₅OH)₂](ClO₄)₂ · 2C₂H₅OH ( 1 ) and [(CuL)₂Co‐(C₂H₅OH)₂](ClO₄)₂ · 2C₂H₅OH ( 2 ) (H₂L = 2,3‐dioxo‐5,6:14,15‐di‐benzo‐7,13‐diphenyl‐1,4,8,12‐tetraazacyclo‐pentadeca‐7,13‐diene) have been synthesized and structurally characterized by X‐ray crystallographic investigations. In the two complexes, all copper(II) ions adopt a slightly distorted square‐planar configuration and the central manganese(II) and cobalt(II) ions are set in a distorted octahedral coordination sphere, connected to the other CuL fragments through exo‐cis oxamido bridges. The analyses of the magnetic properties were carried out by means of the theoretical expression of the magnetic susceptibility deduced from the spin Hamiltonian ? = –2J?₁?₂, leading to J = –14.58 cm^–1 for complex 1 and J = –26.95 cm^–1 for complex 2 , respectively.     

π–π Stacking,hydrogen bonding and anti-ferromagnetic coupling mechanism on a mononuclear Cu(II) complex

Weak anti-ferromagnetic coupling is observed in a mononuclear copper(II) complex, [Cu(Pid)(OSO₃)(H₂O)]?·?(H₂O) (Pid?=?2,2′-(1,10-phenanthrolin-2-ylimino)diethanol). The Cu(II) complex is a distorted square pyramid. Analysis of the crystal structure indicates that there are two types of magnetic coupling pathways, where one pathway involves π–π stacking between adjacent complexes and the second one involves the O–H?···?O hydrogen bonds between adjacent complexes. The variable-temperature magnetic susceptibilities show that there is a weak anti-ferromagnetic coupling between adjacent Cu(II) ions with Curie–Weiss constant θ?=??13.71?K?=??9.93?cm^?1. Theoretical calculations reveal that the π–π stacking resulted in anti-ferromagnetic coupling with 2J?=??6.30?cm^?1, and the O–H?···?O hydrogen-bonding pathway led to a weaker anti-ferromagnetic interaction with 2J?=??3.38?cm^?1. The theoretical calculations also indicate that anti-ferromagnetic coupling sign from the π–π stacking accords with the McConnell I spin-polarization mechanism.     

Crystal Structures,Magnetic Properties and Catecholase‐Like Activities of μ‐Alkoxo‐μ‐Carboxylato Double Bridged Dinuclear and Tetranuclear Copper(II) Complexes

One μ‐alkoxo‐μ‐carboxylato bridged dinuclear copper(II) complex, [Cu₂(L¹)(μ‐C₆H₅CO₂)] ( 1 )(H₃L¹ = 1,3‐bis(salicylideneamino)‐2‐propanol)), and two μ‐alkoxo‐μ‐dicarboxylato doubly‐bridged tetranuclear copper(II) complexes, [Cu₄(L¹)₂(μ‐C₈H₁₀O₄)(DMF)₂]·H₂O ( 2 ) and [Cu₄(L²)₂(μ‐C₅H₆O₄]·2H₂O·2CH₃CN ( 3 ) (H₃L² = 1,3‐bis(5‐bromo‐salicylideneamino)‐2‐propanol)) have been prepared and characterized. The single crystal X‐ray analysis shows that the structure of complex 1 is dimeric with two adjacent copper(II) atoms bridged by μ‐alkoxo‐μ‐carboxylato ligands where the Cu···Cu distances and Cu‐O(alkoxo)‐Cu angles are 3.5 11 Å and 132.8°, respectively. Complexes 2 and 3 consist of a μ‐alkoxo‐μ‐dicarboxylato doubly‐bridged tetranuclear Cu(II) complex with mean Cu‐Cu distances and Cu‐O‐Cu angles of 3.092 Å and 104.2° for 2 and 3.486 Å and 129.9° for 3 , respectively. Magnetic measurements reveal that 1 is strong antiferromagnetically coupled with 2J =‐210 cm^?1 while 2 and 3 exhibit ferromagnetic coupling with 2J = 126 cm^?1 and 82 cm^?1 (averaged), respectively. The 2J values of 1–3 are correlated to dihedral angles and the Cu‐O‐Cu angles. Dependence of the pH at 25 °C on the reaction rate of oxidation of 3,5‐di‐tert‐butylcatechol (3,5‐DTBC) to the corresponding quinone (3,5‐DTBQ) catalyzed by 1–3 was studied. Complexes 1–3 exhibit catecholase‐like active at above pH 8 and 25 °C for oxidation of 3,5‐di‐tert‐butylcatechol.