Heterodinukleare Cobalt(II)‐, Nickel(II)‐, Kupfer(II)‐, Zink(II)und Palladium(II)‐Komplexe mit einem makrocyclischen Liganden vom Schiff‐Basen‐Typ: Synthesen und Strukturen

Complexes with Macrocyclic Ligands. IV. Heterodinuclear Cobalt(II), Nickel(II), Copper(II), Zinc(II) and Palladium(II) Complexes with a Macrocyclic Ligand of Schiff‐Base Type: Syntheses and Structures The synthesis and properties of nickel(II), copper(II), and palladium(II) complexes, [ML^Ph] ( 3 ; L^Ph = N,N′‐phenylene‐bis(3‐formyl‐5‐tert.‐butyl‐salicylaldimine)), are described. These neutral mononuclear complexes react with metal(II) perchlorate and 1,3‐propylenediamine to form heterodinuclear, macrocyclic, cationic complexes of the type [MM′(L^Ph,3)]²⁺ ( 4 ; M = Ni, Cu, Pd; M′ = Co, Cu, Zn). The structures of the five new compounds [NiCo(L^Ph,3)](ClO₄)₂, [NiCu(L^Ph,3)](ClO₄)₂, [CuCu(L^Ph,3)](ClO₄)₂, [CuZn(L^Ph,3)](ClO₄)₂, and [PdCu(L^Ph,3)](ClO₄)₂ were determined by X‐ray diffraction.     

Platinum and Palladium Complexes Bearing New (1R,2R)‐(–)‐1,2‐Diaminocyclohexane (DACH)‐Based Nitrogen Ligands: Evaluation of the Complexes Against L1210 Leukemia

The reaction of (1R,2R)‐(–)‐1,2‐diaminocyclohexane ( 1 ) [DACH] with the aldehyde (1R)‐(–)‐myrtenal ( 2 ) in MeOH afforded the bidentate diimine ligand, (1R,2R)‐(–)‐N¹,N²‐bis{(1R)‐(–)myrtenylidene}‐1,2‐diaminocyclohexane ( 3 ) in a high yield. Reduction of 3 using LiAlH₄ led to the formation of the desired ligand ( 4 ) (1R,2R)‐(–)‐N¹,N²‐bis{(1R)‐(–)myrtenyl}‐1,2‐diaminocyclohexane. Treatment of compound 4 with K₂PtCl₄ or K₂PdCl₄ yielded the corresponding platinum(II) and palladium(II) complexes, Pt‐5 and Pd‐6 , respectively. The reaction of compound 3 with K₂PtCl₄ gave the diimine complex Pt‐7 . The cytotoxic activity of the complexes Pt‐5 , Pd‐6 and Pt‐7 was tested and compared to the approved drugs, cisplatin ( Cis ‐Pt ) and oxaliplatin ( Ox‐Pt ). The complexes ( Pt‐5 , Pd‐6 and Pt‐7 ) inhibit L1210 cell line proliferation with an IC₅₀ of 0.6, 4.2, and 0.7 μL, respectively as evidenced by measuring thymidine incorporation.     

Novel and one‐pot Synthesis of Tetrahydropyrrolo[1,2‐a]‐2‐Methylbenzothiazole‐3‐Spiro‐1′‐Cyclohexa‐2′,5′‐Dien‐4′‐one‐4,5‐Dicarboxylate Derivatives via a Three Component Reaction

The three component condensation reactions involving 2‐methylbenzothiazole or 2,5‐dimethylbenzothiazole, dialkyl acetylenedicarboxylate, and 2,6‐dimethyl phenol or 2,6‐di‐tert‐butylphenol constitute a novel and one‐pot synthesis of tetrahydropyrrolo[1,2‐a ]‐2‐methylbenzothiazoles‐3‐spiro‐1^′‐cyclohexa‐2^′,5^′‐dien‐4^′‐one‐4,5‐dicarboxylate derivatives in good yields. The reactions proceeded at room temperature without using any catalyst. This method is very useful to functionalize benzothiazole derivatives in a one‐pot operation.     

Kupferkomplexe des neuen Chelatliganden 1‐Methyl‐2‐(2‐thiophenolato)‐1H‐benzimidazol (mtpb) und dessen Oxidationsprodukten

Copper Complexes of the New Chelate Ligand 1‐Methyl‐2‐(2‐thiophenolato)‐1H‐benzimidazole (mtpb) and of its Oxidation Products Anodic electrolysis of copper in acetonitrile in the presence of Hmtpb leads to formation of yellow [Cu₄(mtbp)₄] which was crystallized as a dichloromethane solvate with two crystallographically independent cluster molecules in the unit cell. The copper(I) atoms exhibit slightly pyramidal S₂N coordination with bridging thiolate sulfur atoms. The two clusters contain the four copper atoms arranged in a more (Cu1‐Cu4) or less (Cu5‐Cu8) distorted bisphenoidal arrangement. Reaction of mtpb^— with Cu(ClO₄)₂ under anoxic conditions also produces [Cu₄(mtpb)₄]. However, the admittance of O₂ in the reaction of mtpb^— with copper(II) acetate in methanol causes oxidation of the sulfur atoms; a square‐pyramidal configurated copper(II) complex [Cu(CH₃CO₂‐κ²O)(L₁‐κN)(L₂‐κN, O)] has been isolated and crystallographically characterized in which L₁ is the neutral sulfinic methyl ester and L₂^— is the sulfonate derived from mtpb^—.     

Münzmetallcluster mit verbrückenden Imido‐ und Amidoliganden: [{Li(dme)3}4][Cu18(NPh)11] und [Ag6(NHPh)4(PnPr3)6Cl2]

Copper and Silver Clusters with Bridging Imido and Amido Ligands From the reactions of copper and silver chloride with tertiary phosphines and lithiated aniline the compounds [{Li(dme)₃}₄][Cu₁₈(NPh)₁₁] ( 1 ) and [Ag₆(NHPh)₄(PⁿPr₃)₆Cl₂] ( 2 ) were obtained. The structure of the anion in 1 is closely related to the structures of the reported clusters [Cu₁₂(NPh)₈]^4– [1] and [Cu₂₄(NPh)₁₄]^4– [2]: 1 represents the third phenyl imido bridged copper cluster which contains parallel Cu₃‐ and Cu₆‐planes. The dimeric compound 2 consists of two Ag₃ units with bridging phenyl amido ligands. Two chloride and six phosphine ligands complete the ligand sphere and shield the metal core effectively.     

Facially Dispersed Polyhydride Cu9 and Cu16 Clusters Comprising Apex‐Truncated Supertetrahedral and Square‐Face‐Capped Cuboctahedral Copper Frameworks

By using a linear tetraphosphine, meso‐bis[(diphenylphosphinomethyl)phenylphosphino]methane (dpmppm), nona‐ and hexadecanuclear copper hydride clusters, [Cu₉H₇(μ‐dpmppm)₃]X₂ (X=Cl ( 1 a ), Br ( 1 b ), I ( 1 c ), PF₆ ( 1 d )) and [Cu₁₆H₁₄(μ‐dpmppm)₄]X₂ (X₂=I₂ ( 2 c ), (4/3) PF₆?(2/3) OH ( 2 d )) were synthesized and characterized. They form copper‐hydride cages of apex‐truncated supertetrahedral {Cu₉H₇}²⁺ and square‐face‐capped cuboctahedral {Cu₁₆H₁₄}²⁺ structures. The hydride positions were estimated by DFT calculations to be facially dispersed around the copper frameworks. A kinetically controlled synthesis gave an unsymmetrical Cu₈H₆ cluster, [Cu₈H₆(μ‐dpmppm)₃]²⁺ ( 3 ), which readily reacted with CO₂ to afford linear Cu₄ complexes with formate bridges, leading to an unprecedented hydrogenation of CO₂ into formate catalyzed by {Cu₄(μ‐dpmppm)₂} platform. The results demonstrate that new motifs of copper hydride clusters could be established by the tetraphosphine ligands, and the structures influence their reactivity.     

Ferromagnetic Interaction in μ1,3‐Cyanamido‐Derived Copper(II) Cryptates

The reaction of dinuclear copper(II ) cryptates with calcium cyanamide, CaNCN, and sodium dicyanamide, Na[N(CN)₂] results in dinuclear compounds of formulae [Cu₂(HNCN)(R3Bm)](ClO₄)₃ ( 1 ), [Cu₂(dca)(R3Bm)](ClO₄)₃?4H₂O ( 2 ), and [Cu₂(NCNCONH₂)(R3Bm)](CF₃SO₃)₃ ( 3 ), in which R3Bm=N[(CH₂)₂NHCH₂(C₆H₄‐m)CH₂NH(CH₂)₂]₃N and dca=dicyanamido ligand (NCNCN^?). The X‐ray diffraction analysis reveals for both 1 and 3 a dinuclear entity in which the copper atoms are bridged by means of the ‐NCN‐ unit. The molar magnetic susceptibility measurements of 1–3 in the 2–300 K range indicate ferromagnetic coupling. The calculated J values, by using theoretical methods based on density functional theory (DFT) are in excellent agreement with the experimental data. Catalytic hydration of a nitrile to an amide functional group is assumed responsible for the formation of 3 from a μ_1,3‐dicyanamido ligand.     

[1‐Allylpyridinium][Cu2Cl3]: Synthesis,X‐ray Structure and the Regularity of Crystal Architecture of 1‐Allyl/(amino)‐pyridinium Copper(I) Chloride π‐Complexes

By alternating‐current electrochemical technique crystals of copper(I) π‐complex with 1‐allylpyridinium chloride of [C₅H₅N(C₃H₅)][Cu₂Cl₃] ( 1 ) composition have been obtained and structurally investigated. Compound 1 crystallizes in monoclinic system, space group C2/c a = 24.035(1) Å, b = 11.4870(9) Å, c = 7.8170(5) Å, β = 95.010(5)°, V = 2150.0(2) ų (at 100 K), Z = 8, R = 0.028, for 4836 independent reflections. In the structure 1 trigonal‐pyramidal environment of π‐coordinated copper(I) atom is formed by a lengthened to 1.376(2) Å C=C bond of allyl group and by three chlorine atoms. Other two copper atoms are tetrahedrally surrounded by chlorine atoms only. The coordination polyhedra are combined into an original infinite (Cu₄Cl₆^2—)_n fragment. Structural comparison of 1 and the recently studied copper(I) chloride π‐complexes with 3‐amino‐, 2‐amino‐, 4‐amino‐1‐allylpyridinium chlorides of respective [LCu₂Cl₃] ( 2 ), [L₂Cu₂Cl₄] ( 3 ), and [LCuCl₂] ( 4 ) compositions allowed us to reveal the trend of the inorganic fragment complication which depends on pKa (base) value of the corresponding initial heterocycle.     

Metallkomplexe mit biologisch wichtigen Liganden. CLXVI Metallkomplexe mit Ferrocenylmethyl‐L‐cysteinat und 1,1′‐Ferrocenylbis‐(methyl‐L‐cysteinat) als Liganden

Metal Complexes of Biologically Important Ligands. CLXVI Metal Complexes with Ferrocenylmethylcysteinate and 1,1′‐Ferrocenylbis‐(methylcysteinate) as Ligands A series of complexes of transition metal ions ( Cr³⁺, Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺ ) and of lanthanide ions ( La³⁺, Nd³⁺, Gd³⁺, Dy³⁺, Lu³⁺ ) with the anions of ferrocenylmethyl‐L‐cysteine [(C₅H₅)Fe(C₅H₄CH(R)SCH₂CH(NH₃⁺)CO₂^?] (L¹) and with the dianions of 1,1′‐ferrocenylbis(methyl‐L‐cysteine) [Fe(C₅H₄CH(R)SCH₂CH(NH₃⁺) CO₂^?)₂] (R = H, Me, Ph) (L²) as N,O,S‐donors were prepared. With the monocysteine ferrocene derivative L¹ as ligands complexes [M^IIL¹₂] or [Cr^IIIL¹₂]Cl type complexes are formed whereas the bis(cysteine) ligand L² yields insoluble complexes of type [ML²]_n, presumably as coordination polymers. The magnetic moments of [Mn^IIL²]_n, [Pr^IIIL²]_n(OH)_n and [Dy^IIIL²]_n(OH)_n exhibit “normal” paramagnetism.     

Synthesen und Strukturen von Übergangsmetall‐Komplexen mit Dithiophosphinato‐ und Trithiophosphonato‐Liganden

Syntheses and Structures of Transition Metal Complexes with Dithiophosphinato and Trithiophosphinato Ligands The reactions of MnCl₂ with Ph₂P(S)(SSiMe₃) produced [Mn(S₂PPh₂)₂(thf)₂] ( 1 ) and [Mn(S₂PPh₂)₂(dme)] ( 2 ) (DME = 1,2‐Dimethoxyethane). The compounds [Co₆(S₃PPh)₂(μ⁴‐S)₂(μ³‐S)₂(PPh₃)₄] ( 3 ), [Co₂(S₃PPh)₂(PPh₃)₂] ( 4 ), [Ni(S₂PPh)(PPhEt₂)₂] ( 5 ), [Ni(S₃PPh)(PPhEt₂)₂] ( 6 ) and [Cu₄(S₃PPh)₂(dppp)₂] ( 8 ) [dppp = 1,3‐Bis(diphenylphosphanyl)propane] were obtained from reactions of first‐row transition metal halides with PhP(S)(SSiMe₃)₂ in the presence of tertiary phosphines. In a reaction of PhP(S)(SSiMe₃)₂ with PhPEt₂ PhPEt₂PS₂Ph ( 7 ) was isolated. All compounds were characterized by X‐ray crystallography.     

Zinc(II) Complexes with 1H‐Imidazol‐4‐yl‐Containing Polyamine Ligand

The protonation and Zn^II/Cu^II complexation constants of tripodal polyamine ligand N¹‐(2‐aminoethyl)‐N¹‐(1H‐imidazol‐4‐ylmethyl)‐ethane‐1,2‐diamine (HL) were determined by potentiometric titration. Three new compounds, i.e. [H₃(HL)](ClO₄)₃ ( 5 ), [Zn(HL)Cl](ClO₄) ( 6 ) and {[Zn(L)](ClO₄)}_n ( 7 ) were obtained by reactions of HL · 4HCl with Zn(ClO₄)₂ · 6H₂O under different reaction pH, and they were compared with the corresponding Cu^II complexes reported previously. The results indicate that the reaction pH and metal ions have remarkable influence on the formation and structure of the complexes.     

Metallkomplexe mit N2O2S2‐Koordinationssphäre. Synthese und Charakterisierung der Cobalt(II)‐, Nickel(II)‐ und Kupfer(II)‐Komplexe eines 15‐ und eines 16‐gliedrigen N,N′‐bis(2‐hydroxyethyl)‐funktionalisierten makrocyclischen Liganden

Metal Complexes with N₂O₂S₂ Donor Set. Synthesis and Characterization of the Cobalt(II), Nickel(II), and Copper(II) Complexes of a 15‐ and a 16‐Membered Bis(2‐hydroxyethyl) Pendant Macrocyclic Ligand The macrocyclic ligands 6, 10‐bis(2‐hydroxyethyl)‐7, 8, 9, 11, 17, 18‐hexahydro‐dibenzo‐[e, n][1, 4, 8, 12]‐dithiadiaza‐cyclopentadecine ( 1 ) (L¹) and 5, 13‐bis(2‐hydroxyethyl)‐7, 8, 9, 10, 16, 17, 18, 19, 20‐nonahydro‐dibenzo‐[g, o][1, 9, 5, 13]‐dithiadiaza‐cyclohexadecine (L⁴) have been prepared. They form the stable complexes [CoL¹(‐H)CoL¹](ClO₄)₃ ( 2 ), [NiL¹](ClO₄)₂·MeOH ( 3 ), Λ‐[CuL¹](ClO₄)₂·MeOH ( 4a ) and rac‐[CuL¹](ClO₄)₂·MeOH ( 4b ), [NiL⁴](ClO₄)₂ ( 5 ), and [CuL⁴](ClO₄)₂ ( 6 ). The compounds 1 to 6 have been characterized by standard methods and single‐crystal X‐ray diffraction. In the complexes 2 to 6 the metal atoms are octahedrally coordinated by the N₂O₂S₂ donor set of the ligands. L¹ and L⁴ are folded herein along the N···M···S‐ and the N···M···N′‐axes, respectively. This results at the metal atom in a all‐cis‐configuration for the complexes of L¹ and a trans‐N₂‐cis‐O₂‐cis‐S₂‐configuration for the complexes of L⁴. The cobalt(II) complex 2 is a dimer, bridged by a rather short hydrogen bridge of 2.402(12)Å length. The copper(II) complexes of L¹ and L⁴ differ with respect to the Jahn‐Teller‐distortion.     

Copper(II) Complexes with Asymmetrical Schiff Base Ligands Derived from 2‐Acetylpyrazine

New copper(II) complexes of asymmetrical tetradentate Schiff bases containing pyrazine have been prepared and thoroughly characterised by elemental analysis, IR and electronic spectroscopy, mass spectrometry and magnetic measurements. Two alternative methods were used in the isolation of the complexes: template synthesis in the preparation of Cu(SalDpyz)ClO₄ (HSalDPyz = derived from the condensation of salicylaldehyde, acetylpyrazine and 1,2‐ethylendiamine, 2‐methyl‐1,2‐propylendiamine, 1,2‐phenylendiamine) and direct interaction between copper perchlorate and the corresponding Schiff base, as in the isolation of Cu(AEPyz)(ClO₄) (HAEPyz = (Z)‐4‐[2‐{[2‐{[(E)‐1‐(pyrazinyl)ethylidene]amino} ethyl)amino]‐3‐penten‐2‐one)]. [Cu(SalEn)(py)(OClO₃)][Cu(SalEn)(py)]ClO₄ ( 1 ) (SalEn = 4‐(2‐hydroxyphenyl)‐3‐aza‐3‐buten‐1‐amino, py = pyridine), metal precursor in the preparation of Cu(SalEnpyz)(ClO₄) (HSalEnpyz = 2‐{E(2‐{[(E)‐1‐(2‐pyrazinyl)ethylidene]amino}ethyl)imino]methyl}phenol), was crystallographically characterised. The crystal structure of [Cu(AEpyz)]ClO₄ ( 2 ) is also reported.     

Copper(II) Complexes of 3,4,5‐Trisubstituted Pyrazolates: In Situ Formation of Pyrazole Rings from Different Carbon Centers

The synthesis and characterization of two pyrazolate‐bridged dicopper(II) complexes, [Cu₂(L¹)₂(H₂O)₂](ClO₄)₂ ( 1 , HL¹=3,5‐dipyridyl‐4‐(2‐keto‐pyridyl)pyrazole) and [Cu₂(L²)₂(H₂O)₂](ClO₄)₂ ( 2 , HL²=3,5‐dipyridyl‐4‐benzoylpyrazole), are discussed. These copper(II) complexes are formed from the reactions between pyridine‐2‐aldehyde, 2‐acetylpyridine (for compound 1 ) or acetophenone (for compound 2 ), and hydrazine hydrate with copper(II) perchlorate hydrate under ambient conditions. The single‐crystal X‐ray structure of compound 1? 2 H₂O establishes the formation of a pyrazole ring from three different carbon centers through C? C bond‐forming reactions, mediated by copper(II) ions. The free pyrazoles (HL¹ and HL²) are isolated from their corresponding copper(II) complexes and are characterized by using various analytical and spectroscopic techniques. A mechanism for the pyrazole‐ring synthesis that proceeds through C? C bond‐forming reactions is proposed and supported by theoretical calculations.     

Synthesis and crystal structure of the dinuclear copper(II) Schiff base complex μ‐hydroxido‐μ‐chlorido‐bis{[bis(trans‐2‐nitrocinnamaldehyde)ethylenediamine]chloridocopper(II)} dichloromethane sesquisolvate

Transition metal complexes of Schiff base ligands have been shown to have particular application in catalysis and magnetism. The chemistry of copper complexes is of interest owing to their importance in biological and industrial processes. The reaction of copper(I) chloride with the bidentate Schiff base N,N′‐bis(trans‐2‐nitrocinnamaldehyde)ethylenediamine {Nca₂en, systematic name: (1E,1′E,2E,2′E)‐N,N′‐(ethane‐1,2‐diyl)bis[3‐(2‐nitrophenyl)prop‐2‐en‐1‐imine]} in a 1:1 molar ratio in dichloromethane without exclusion of air or moisture resulted in the formation of the title complex μ‐chlorido‐μ‐hydroxido‐bis(chlorido{(1E,1′E,2E,2′E)‐N,N′‐(ethane‐1,2‐diyl)bis[3‐(2‐nitrophenyl)prop‐2‐en‐1‐imine]‐κ²N,N′}copper(II)) dichloromethane sesquisolvate, [Cu₂Cl₃(OH)(C₂₀H₁₈N₄O₄)₂]·1.5CH₂Cl₂. The dinuclear complex has a folded four‐membered ring in an unsymmetrical Cu₂OCl₃ core in which the approximate trigonal bipyramidal coordination displays different angular distortions in the equatorial planes of the two Cu^II atoms; the chloride bridge is asymmetric, but the hydroxide bridge is symmetric. The chelate rings of the two Nca₂en ligands have different conformations, leading to a more marked bowing of one of the ligands compared with the other. This is the first reported dinuclear complex, and the first five‐coordinate complex, of the Nca₂en Schiff base ligand. Molecules of the dimer are associated in pairs by ring‐stacking interactions supported by C—H…Cl interactions with solvent molecules; a further ring‐stacking interaction exists between the two Schiff base ligands of each molecule.     

Syntheses and X‐ray Structure Analyses of the First Bis(chelated) Copper and Iron Bisguanidine Complexes

The synthesis of N¹,N²‐bis(1,3‐dimethylimidazolidin‐2‐ylidene)ethane‐1,2‐diamine and the synthesis and structure determination of bis{N¹,N²‐bis(1,3‐dimethylimidazolidin‐2‐ylidene)ethane‐1,2‐diamine}copper(II)‐tetraiododicuprate(I) ([Cu(DMEG₂e)₂][Cu₂I₄]) and bis{N¹,N²‐bis(1,3‐dimethylimidazolidin‐2‐ylidene)ethane‐1,2‐diamine}iron(II)‐octacarbonyl‐diferrate(‐I) ([Fe(DMEG₂e)₂][Fe₂(CO)₈]) which represent the first bis(chelated) bisguanidine complexes are described. The dicationic [M(DMEG₂e)₂]²⁺ molecules with M = Cu, Fe follow the same structural principles and thus differ in their coordination geometries from ideal‐typical expectations.     

Copper(II) Halide Complexes with 1‐tert‐Butyl‐1H‐1,2,4‐triazole and 1‐tert‐Butyl‐1H‐tetrazole

1‐tert‐Butyl‐1H‐1,2,4‐triazole (tbtr) was found to react with copper(II) chloride or bromide to give the complexes [Cu(tbtr)₂X₂]_n and [Cu(tbtr)₄X₂] (X = Cl, Br). 1‐tert‐Butyl‐1H‐tetrazole (tbtt) reacts with copper(II) bromide resulting in the formation of the complex [Cu₃(tbtt)₆Br₆]. The obtained crystalline complexes as well as free ligand tbtr were characterized by elemental analysis, IR spectroscopy, thermal and X‐ray analyses. For free ligand tbtr, ¹H NMR and ¹³C NMR spectra were also recorded. In all the complexes, tbtr and tbtt act as monodentate ligands coordinated by Cu^II cations via the heteroring N⁴ atoms. The triazole complexes [Cu(tbtr)₂Cl₂]_n and [Cu(tbtr)₂Br₂]_n are isotypic, being 1D coordination polymers, formed at the expense of single halide bridges between neighboring copper(II) cations. The isotypic complexes [Cu(tbtr)₄Cl₂] and [Cu(tbtr)₄Br₂] reveal mononuclear centrosymmetric structure, with octahedral coordination of Cu^II cations. The tetrazole compound [Cu₃(tbtt)₆Br₆] is a linear trinuclear complex, in which neighboring copper(II) cations are linked by single bromide bridges.     

X‐ray characterization and magnetic properties of dioxygen‐bridged CuII and MnIII Schiff base complexes

The coordination chemistry of multinuclear metal compounds is important because of their relevance to the multi‐metal active sites of various metalloproteins and metalloenzymes. Multinuclear Cu^II and Mn^III compounds are of interest due to their various properties in the fields of coordination chemistry, inorganic biochemistry, catalysis, and optical and magnetic materials. Oxygen‐bridged binuclear Mn^III complexes generally exhibit antiferromagnetic interactions and a few examples of ferromagnetic interactions have also been reported. Binuclear Cu^II complexes are important due to the fact that they provide examples of the simplest case of magnetic interaction involving only two unpaired electrons. Two novel dioxygen‐bridged copper(II) and manganese(III) Schiff base complexes, namely bis(μ‐4‐bromo‐2‐{[(3‐oxidopropyl)imino]methyl}phenolato)dicopper(II), [Cu₂(C₁₀H₁₀BrNO₂)₂], (1), and bis(diaqua{4,4′‐dichloro‐2,2′‐[(1,1‐dimethylethane‐1,2‐diyl)bis(nitrilomethanylylidene)]diphenolato}manganese(III)) bis{μ‐4,4′‐dichloro‐2,2′‐[(1,1‐dimethylethane‐1,2‐diyl)bis(nitrilomethanylylidene)]diphenolato}bis[aquamanganese(III)] tetrakis(perchlorate) ethanol disolvate, [Mn(C₁₈H₁₆Cl₂N₂O₂)(H₂O)₂]₂[Mn₂(C₁₈H₁₆Cl₂N₂O₂)₂(H₂O)₂](ClO₄)₄·2C₂H₅OH, (2), have been synthesized and single‐crystal X‐ray diffraction has been used to analyze their crystal structures. The structure analyses of (1) and (2) show that each Cu^II atom is four‐coordinated, with long weak Cu…O interactions of 2.8631 (13) Å linking the dinuclear halves of the centrosymmetric tetranucelar molecules, while each Mn^III atom is six‐coordinated. The shortest intra‐ and intermolecular nonbonding Mn…Mn separations are 3.3277 (16) and 5.1763 (19) Å for (2), while the Cu…Cu separations are 3.0237 (3) and 3.4846 (3) Å for (1). The magnetic susceptibilities of (1) and (2) in the solid state were measured in the temperature range 2–300 K and reveal the presence of antiferromagnetic spin‐exchange interactions between the transition metal ions.     

A mixed‐valence chair‐like tetranuclear copper(I,II) cluster with three linking modes of the 3,5‐bis(2‐pyridyl)‐1,2,4‐triazole ligand

In the tetranuclear copper complex tetrakis[μ‐3,5‐bis(2‐pyridyl)‐1,2,4‐triazolido]bis[3,5‐bis(2‐pyridyl)‐1,2,4‐triazolido]dicopper(I)dicopper(II) dihydrate, [Cu^I₂Cu^II₂(C₁₂H₈N₅)₆]·2H₂O, the asymmetric unit is composed of one Cu^I center, one Cu^II center, three anionic 3,5‐bis(2‐pyridyl)‐1,2,4‐triazole (2‐BPT) ligands and one solvent water molecule. The Cu^I and Cu^II centers exhibit [Cu^IN₄] tetrahedral and [Cu^IIN₆] octahedral coordination environments, respectively. The three independent 2‐BPT ligands adopt different chelating modes, which link the copper centers to generate a chair‐like tetranuclear metallomacrocycle with metal–metal distances of about 4.4 × 6.2 Å disposed about a crystallographic inversion center. Furthermore, strong π–π stacking interactions and O—H...N hydrogen‐bonding systems link the tetracopper clusters into a two‐dimensional supramolecular network.     

Soluble Monometallic Salen Complexes Derived from O‐functionalized Salicylaldehydes as Metalloligands for the Synthesis of Heterobimetallic Complexes

The reaction of 2,3‐diamino‐2,3‐dimethylbutane (tmen) with 3‐hydroxysalicylaldehyde (3hsal), 4‐hydroxysalicylaldehyde (4hsal), and 5‐hydroxysalicylaldehyde (5hsal) or 3‐carboxysalicylaldehyde (3csal) gave the hydroxy‐functionalized salen ligands H₄3hsaltmen, H₄4hsaltmen and H₄5hsaltmen, or the 3‐carboxy‐functionalized ligand H₄3csaltmen, which were characterized by ¹H, ¹³C{¹H} NMR and IR spectroscopy. The nickel(II) and copper(II) complexes [Ni(H₂3hsaltmen)], [Ni(H₂4hsaltmen)], [Ni(H₂5hsaltmen)], [Cu(H₂3hsaltmen)] and [Cu(H₂4hsaltmen)] were synthesized in high yield (78–99 %) starting from H₄3hsaltmen, H₄4hsaltmen and H₄5hsaltmen and the corresponding metal(II) acetates. The complexes are soluble in acetone, ethanol, methanol, thf and dmso. The reaction of H₄3csaltmen and nickel(II) acetate gave [Ni(H₂3csaltmen)] in 40 % yield. The disodium salt of the corresponding copper(II) complex [Cu(Na₂3csaltmen)] was obtained in 66 % yield in a template reaction from 3‐carboxysalicylaldehyde, tmen, copper(II) acetate and sodium hydroxide, and was characterized by EPR spectroscopy and mass spectrometry. All complexes were identified by IR spectroscopy and elemental analysis, the nickel complexes also by NMR spectroscopy, and [Ni(H₂3hsaltmen)], [Ni(H₂4hsaltmen)] and [Ni(H₂3csaltmen)] by X‐ray crystallography. The homobinuclear copper complex [Cu₂(3hsaltmen)] was prepared in 91 % yield from H₄3hsaltmen, two equivalents of Cu(CH₃COO)₂·H₂O and four equivalents of LiOH·H₂O and was characterized by IR spectroscopy, elemental analysis and mass spectrometry. The trinuclear complex [Zr{Ni(3hsaltmen)}₂] was obtained from [Zr(NEt₂)₄] and [Ni(H₂3hsaltmen)] (ratio 1:2) and characterized by FAB and APPI mass spectrometry and X‐ray crystallography. The redox potential of the trinuclear complex [Zr{Ni(3hsaltmen)}₂] is shifted by 0.04 V to positive potential compared to [Ni(H₂3hsaltmen)], while the redox potential of the binuclear copper complex [Cu₂(3hsaltmen)] is shifted by 0.22 V to negative potential compared to [Cu(H₂3hsaltmen)].