Single‐armed salamo‐like dioxime and its multinuclear Cu (II), Zn (II) and Cd (II) complexes: Syntheses,structural characterizations,Hirshfeld analyses and fluorescence properties

Three multinuclear Cu (II), Zn (II) and Cd (II) complexes, [Cu₂(L)(μ‐OAc)]·CHCl₂ ( 1 ), [Zn₂(L)(μ‐OAc)(H₂O)]·3CHCl₃ ( 2 ) and [{Cd₂(L)(OAc)(CH₃CH₂OH)}₂]·2CH₃CH₂OH ( 3 ) with a single‐armed salamo‐like dioxime ligand H₃L have been synthesized, and characterized by FT‐IR, UV–vis, X‐ray crystallography and Hirshfeld surfaces analyses. The ligand H₃L has a linear structure and C‐H···π interactions between the two molecules. The complex 1 is a dinuclear Cu (II) complex, Cu1 and Cu2 are all five‐coordinate possessing distorted square pyramidal geometries. The complex 2 also forms a dinuclear Zn (II) structure, and Zn1 and Zn2 are all five‐coordinate bearing distorted trigonal bipyramidal geometries. The complex 3 is a symmetrical tetranuclear Cd (II) complex, and Cd1 is a hexa‐coordinate having octahedral configuration and Cd2 is hepta‐coordinate with a pentagonal bipyramidal geometry, and it has π···π interactions inside the molecule. In addition, fluorescence properties of the ligand and its complexes 1 – 3 have also been discussed.     

An acetatopalladium(II) complex with 1‐benzyl‐N‐(3,5‐di‐tert‐butylsalicylidene)piperidin‐4‐amine: Synthesis,structure and catalytic applications in Suzuki–Miyaura coupling of arylboronic acids with hydroxyaryl halides

The Schiff base 1‐benzyl‐N ‐(3,5‐di‐tert ‐butylsalicylidene)piperidin‐4‐amine (HL) and its acetatopalladium(II) complex having the formula [Pd(L)(OAc)] were synthesized. Both HL and [Pd(L)(OAc)] were characterized using elemental analysis and various spectroscopic (infrared, UV–visible, ¹H NMR and ¹³C NMR) and mass spectrometric measurements. The molecular structure of the complex was determined using X‐ray crystallographic analysis. In the complex, the pincer‐like NNO‐donor L⁻ and the monodenate OAc⁻ provide a distorted square‐planar N₂O₂ coordination environment around the metal centre. The physicochemical properties and the spectroscopic features of [Pd(L)(OAc)] are consistent with its molecular structure. The complex was found to be an effective catalyst for the Suzuki–Miyaura cross‐coupling reactions of hydroxyaryl halides with arylboronic acids in predominantly aqueous media. The reactions afforded hydroxybiaryl products in good to excellent yields with a wide substrate scope.     

Structurally rigid bis(pyrazolyl)pyridine Zn(II) and Cu(II) complexes: Structures and kinetic studies in ring‐opening polymerization of ε‐caprolactone

Four bis(pyrazolyl)pyridine Zn(II) and Cu(II) carboxylate complexes have been structurally elucidated and used as initiators in the ring‐opening polymerization (ROP) of ε‐carprolactone (ε‐CL). Reactions of bis(3,5‐dimethyl‐pyrazol‐1‐yl)pyridine ( L1 ) with the appropriate Zn(II) and Cu(II) carboxylates afforded the corresponding complexes; [Zn(L1)(C₆H₅COO)₂] ( 1 ), [Zn(L1)(2‐Cl‐C₆H₄COO)₂] ( 2 ), [Zn(L1)(OAc)₂] ( 3 ) and [Cu(L1)(OAc)₂] ( 4 ) in moderate to good yields. Molecular structures of compounds 1 , 2 , 3 confirmed the presence of one tridentate bound ligand L1 in the metal coordination sphere and two carboxylate anions to give five coordination number around Zn(II) and Cu(II) atoms. Complexes 1 , 2 , 3 , 4 initiated the ROP of ε‐CL at 110 °C to give polymers of moderate molecular weights. Kinetic analyses of the ROP reactions indicate pseudo ‐first‐order dependency on ε‐CL monomer and initiator. ¹H NMR and mass spectral data established a coordination insertion mechanistic pathway and behaviour of 1 , 2 , 3 , 4 as initiators in the ROP of ε‐CL. Copyright © 2016 John Wiley & Sons, Ltd.     

Self‐assembly properties of Salamo‐type trinuclear Cu(II) and Co(II) complexes based on the regulation of H+/OHˉ

A novel naphthalenediol‐based bis(salamo)‐type tetraoxime compound (H₄L) was designed and synthesized. Two new supramolecular complexes, [Cu₃(L)(μ‐OAc)₂] and [Co₃(L)(μ‐OAc)₂(MeOH)₂]·4CHCl₃ were synthesized by the reaction of H₄L with Cu(II) acetate dihydrate and Co(II) acetate dihydrate, respectively, and were characterized by elemental analyses and X‐ray crystallography. In the Cu(II) complex, Cu1 and Cu2 atoms located in the N₂O₂ sites, and are both penta‐coordinated, and Cu3 atom is also penta‐coordinated by five oxygen atoms. All the three Cu(II) atoms have geometries of slightly distorted tetragonal pyramid. In the Co(II) complex, Co1 and Co3 atoms located in the N₂O₂ sites, and are both penta‐coordinated with geometries of slightly distorted triangular bipyramid and distorted tetragonal pyramid, respectively, while Co2 atom is hexa‐coordinated by six oxygen atoms with a geometry of slightly distorted octahedron. These self‐assembling complexes form different dimensional supramolecular structures through inter‐ and intra‐molecular hydrogen bonds. The coordination bond cleavages of the two complexes have occurred upon the addition of the H⁺, and have reformed again via the neutralization effect of the OH^?. The changes of the two complexes response to the H⁺/OH^? have observed in the UV–Vis and ¹H NMR spectra.     

Multi‐Dimensional Cobalt(II) and Nickel(II) Coordination Polymers

A series of metal coordination polymers, [Co₂(NB)₄(bpp)₂(H₂O)]·H₂O ( 1 ), [Co₂(e,e‐trans‐chdc)(e,a‐cis‐chdc)(bpp)₂] ( 2 ), [Ni(e,e‐trans‐chdc)(bpp)(H₂O)₂] ( 3 ), [Ni₂(PDA)₂(bpp)₂(H₂O)₃]·H₂O ( 4 ), and [Ni‐(mBDC)(bpp)] ( 5 ) (NB = 3‐nitrobenzoate anion; bpp = 4,4′‐trimethylene dipyridine; chdc = cyclohexane‐1,4‐dicarboxylate anion; PDA = 1,4‐phenylenediacetate anion; mBDC = 1,3‐benzene dicarboxylate anion), were synthesized from metal ions and organic mixed‐ligands by hydrothermal reactions. The single crystal structure analysis revealed that 1, 3, and 4 were 2D sheets with bilayer (1 and 4) and 2‐fold interpenetrated layers (3), 2 is a 3D binodal (4,5)‐connected framework, and 5 is a 1D chains. The non‐covalent interactions of H‐bonds and π–π stacking caused this conformation of highly cross‐linked networks. Compounds 1‐5 were further characterized by thermal gravimetric analysis, powder X‐ray diffraction, UV‐vis, infrared, and PL spectroscopy.     

Synthesis,crystal structures,DNA/bovine serum albumin binding,DNA cleavage and cytotoxicity of five mononuclear zinc(II) complexes

Five new mononuclear zinc(II) complexes containing ligands with extended planar phenanthroline moieties (dipyrido‐[3,2‐a:2′,3′‐c]phenazine (dppz) or dipyrido[3,2‐d:2′,3′‐f] quinoxaline (dpq)), namely [Zn(dppz)(acac)₂]⋅CH₃OH ( 1 ), [Zn(dppz)(dbm)(OAc)] ( 2 ), [Zn(dpq)(dbm) (OAc)] 1.5H₂O ( 3 ), [Zn(dpq)(tfnb)(OAc)] ( 4 ) and [Zn(dpq)(tfnb)₂] ( 5 ), where acac = acetylacetonate, tfnb = benzoyltrifluoroacetone and dbm = dibenzoylmethane, were synthesized and structurally characterized. The binding ability of complexes 1 – 5 with calf thymus DNA was investigated by spectroscopic titration methods and viscosity measurements. Results indicate that all complexes bind to calf thymus DNA via intercalative mode, and the DNA binding affinities of dppz complexes 1 and 2 are apparently stronger than those of dpq complexes 3 – 5 . DNA photocleavage experiments reveal that these complexes are efficient DNA cleaving agents and they are more active in UV‐A (365 nm) than in visible light. In particular, the in vitro cytotoxicity of the complexes for human cancer cell line A549 demonstrates that the five compounds have anticancer activity with low IC₅₀ values. Meanwhile, interaction of the complexes with bovine serum albumin investigated using UV–visible and fluorescence methods indicates that all complexes can quench the intrinsic fluorescence of bovine serum albumin in a static quenching process.     

Effect of Organic Dicarboxylates with Different Rigidity on the Construction of Cobalt(II) Complexes with a Semi‐rigid Tripyridyl‐bis‐amide Ligand

Three coordination compounds with dimensions from 0D to 2D, namely, [Co(bppdca)₂(HL1)₂] ( 1 ) [Co(bppdca)(L2)(H₂O)] · 2H₂O ( 2 ) and [Co(bppdca)(L3)] · 3H₂O ( 3 ) [bppdca = N,N′‐bis(pyridine‐3‐yl)pyridine‐2,6‐dicarboxamide, H₂L1 = 2,5‐pyridinedicarboxylic acid, H₂L2 = 4,4′‐oxybisbenzoic acid, H₂L3 = 2‐carboxymethylsulfanyl nicotinic acid] were hydrothermally synthesized and structurally characterized. Single crystal X‐ray diffraction analysis reveals that complex 1 is a discrete 0D complex, in which the bppdca ligand and the H₂L1 act as the terminal groups to coordinate with the Co^II ions. In coordination polymer 2 , two bppdca ligands coordinate in anti configuration with two Co^II ions to generate a 28‐membered Co₂(bppdca)₂ loop, which is further extended into 1D ladder‐like double chain by pairs of L2 ligands. In 3 , the Co^II ions are linked by bppdca ligands to generate 1D wave‐like chain, which is further connected by the L3 to form a 2D network. Finally, the coordination compounds 1 – 3 are extended into 3D supramolecular frameworks through the hydrogen bonding interactions. The Co^II ions and the bppdca ligands in the title coordination compounds exhibit different coordination characters and conformations. The effect of organic dicarboxylates with different rigidity and length on the structures of Co^II coordination compounds was investigated. In addition, the fluorescence and electrochemical behaviors of coordination compounds 1 – 3 were reported.     

Six Coordination Polymers based on 4‐(1H‐Imidazol‐1‐yl)phthalic Acid: Structural Diversities,Magnetism and Luminescence Properties

The coordination polymers (CPs), [Ni(L)(H₂O)₄]_n ( 1 ), [Co(HL)₂(H₂O)₂]_n ( 2 ), {[Cu(L)(H₂O)₃] · H₂O}_n ( 3 ), [Mn(L)(H₂O)₂]_n ( 4 ), [Cd(L)(H₂O)₂]_n ( 5 ), and {[Zn₂(L)₂] · H₂O}_n ( 6 ), were solvothermally synthesized by employing the imidazol‐carboxyl bifunctional ligand 4‐(1H‐imidazol‐1‐yl) phthalic acid (H₂L). Single‐crystal X‐ray diffraction indicated that the L^2–/HL^– ligands display various coordination modes with different metal ions in 1 – 6 . Complexes 1 and 2 show one‐dimensional (1D) chain structures, whereas complexes 3 – 6 show 2D layered structures. The magnetic properties of these complexes were investigated. Complexes 1 and 3 indicate weak ferromagnetic interactions, whereas complexes 2 and 4 demonstrate antiferromagnetic interactions. In addition, luminescence properties of 5 and 6 were measured and studied in detail.     

Three Transition Metal(II) Coordination Polymers Constructed by a Semi‐rigid Bis‐pyridyl‐bis‐amide and Dicarboxylates Mixed Ligands: Assembly,Structures and Properties

Three coordination polymers, namely [Co(BDC)( L )] · H₂O ( 1 ), [Co(NPH)( L )] · H₂O ( 2 ), and [Ni(NPH)( L )(H₂O)₃] · H₂O ( 3 ) [H₂BDC = 1, 3‐benzenedicarboxylic acid, H₂NPH = 3‐nitrophthalic acid, L = N,N′‐bis(3‐pyridyl)‐terephthalamide] were hydrothermally synthesized by self‐assembly of cobalt/nickel chloride with a semi‐rigid bis‐pyridyl‐bis‐amide ligand and two aromatic dicarboxylic acids. Single crystal X‐ray diffraction analyses revealed that complexes 1 and 2 are two‐dimensional (2D) coordination polymers containing a one‐dimensional (1D) ribbon‐like Co‐dicarboxylate chain and a 1D zigzag Co‐ L chain. Although the coordination numbers of Co^II ions and the coordination modes of two dicarboxylates are different in complexes 1 and 2 , they have a similar 3, 5‐connected {4².6⁷.8}{4².6} topology. In complex 3 , the adjacent Ni^II ions are linked by L ligands to form a 1D polymeric chain, whereas the 1D chains does not extend into a higher‐dimensional structure due to the ligand NPH with monodentate coordination mode. The adjacent layers of complexes 1 and 2 and the adjacent chains of 3 are further linked by hydrogen bonding interactions to form 3D supramolecular networks. Moreover, the thermal stabilities, fluorescent properties, and photocatalytic activities of complexes 1 – 3 were studied.     

Novel structurally characterized hetero-bimetallic [Zn(II)2M(II)] (M = Ca and Sr) bis(salamo)-type complexes: DFT calculation,Hirshfeld analyses,antimicrobial and fluorescent properties

Two hetero-bimetallic [Zn(II)₂M(II)] (M = Ca and Sr) complexes [Zn₂Ca(L)(OAc)₂] ( 1 ) and [Zn₂Sr(L)(OAc)₂] ( 2 ) with a novel asymmetrical bis(salamo)-type tetraoxime ligand (H₅L) were designed and synthesized, and characterized by elemental analyses, FT-IR spectra, UV–vis absorption spectra, Density Functional Theory (DFT) calculation, Hirshfeld surface analyses and X-ray single crystal diffractions. Compared with the symmetric bis(salamo)-type ligands, the ligand H₅L and its [Zn(II)₂M(II)] (M = Ca and Sr) asymmetrical bis(salamo)-type complexes synthesized for the first time in this paper have more novel structures and better properties. The results of ultraviolet titration show that the coordination ratio of ligand, alkaline earth metal and transition metal is 1:1:2. Complexes 1 and 2 have good luminescent properties and obvious antimicrobial activities.     

Three multinuclear Co(II), Zn(II) and Cd(II) complexes based on a single-armed salamo-type bisoxime: syntheses,structural characterizations and fluorescent properties

Three multinuclear complexes, [Co(L)(OAc)Co(CH₃CH₂OH)₂]·H₂O, [Zn(L)(OAc)Zn(CH₃OH)], and [{Cd(L)(OAc)Cd(CH₃OH)}₂], containing a single-armed salamo-type bisoxime H₃L have been synthesized and characterized structurally. The Co(II) complex forms a dimeric unit by intermolecular hydrogen bond interactions of neighboring dimeric molecules. The Zn(II) complex also forms a dimeric unit by intermolecular hydrogen bond interactions. Interesting features of the crystal structure include O?O short contacts. Meanwhile, self-assembling infinite 1-D, 2-D, and 3-D supramolecular structures are formed by intermolecular hydrogen bond and C–H?π interactions. The Cd(II) complex forms an infinite 2-D supramolecular structure by intermolecular hydrogen bond interactions. The photophysical properties of the Co(II), Zn(II), and Cd(II) complexes have also been discussed.     

Zn(II) and Cu(II) unsymmetrical formamidine complexes as effective initiators for ring‐opening polymerization of cyclic esters

A series of Zn(II) and Cu(II) complexes were synthesized using unsymmetrical N,N′‐ diarylformamidine ligands, i.e. N‐(2‐methoxyphenyl)‐N′‐2,6‐dichorophenyl)‐formamidine ( L1 ), N‐(2‐methoxyphenyl)‐N′‐phenyl)‐formamidine ( L2 ), N‐(2‐methoxyphenyl)‐N′‐(2,6‐dimethylphenyl)‐formamidine ( L3 ) and N‐(2‐methoxyphenyl)‐N′‐(2,6‐diisopropylphenyl)‐formamidine ( L4 ). The complexes, [Zn₂( L1 )₂(OAc)₄] ( 1) , [Zn₂( L2 )₂(OAc)₄] ( 2 ), [Zn₂( L3 )₂(OAc)₄] ( 3 ), [Zn₂( L4 )₂(OAc)₄] ( 4 ), [Cu₂( L1 )₂(OAc)₄] ( 5 ), [Cu₂( L2 )₂(OAc)₄] ( 6 ), [Cu₂( L3 )₂(OAc)₄] ( 7 ) and [Cu₂( L4 )₂(OAc)₄] ( 8 ), were prepared via a mechanochemical method with excellent yields between 95 ‐ 98% by reacting the metal acetates and corresponding ligands. Structural studies showed that both complexes are dimeric with a paddlewheel core structure in which the separation between the two metal centres are 2.9898 (8) and 2.6653 (7) Å in complexes 3 and 7 , respectively. Complexes 1 – 8 were used in ring‐opening polymerization of ε‐caprolactone (ε‐CL) and rac‐lactide (rac‐LA). Zn(II) complexes were more active than Cu(II) complexes, with complex 1 bearing electron withdrawing chloro groups being the most active (k_app = 0.0803 h^‐1). Low molecular weight poly‐(ε‐CL) and poly‐(rac‐LA) ranging from 1720 to 6042 g mol^‐1, with broad molecular weight distribution (PDIs, 1.78 – 1.87) were obtained. Complex 2 gave reaction orders of 0.56 and 1.52 with respect to ε‐CL and rac‐LA, respectively.     

Copper(II) and Cadmium(II) Complexes Based on N,N‐Bis(3, 5‐dimethyl‐2‐hydroxybenzyl)‐N‐(2‐pyridylmethyl)amine Ligand: Syntheses,Structures, Magnetic,and Luminescent Properties

The reaction of the aryl‐oxide ligand H₂L [H₂L = N,N‐bis(3, 5‐dimethyl‐2‐hydroxybenzyl)‐N‐(2‐pyridylmethyl)amine] with CuSO₄ · 5H₂O, CuCl₂ · 2H₂O, CuBr₂, CdCl₂ · 2.5H₂O, and Cd(OAc)₂ · 2H₂O, respectively, under hydrothermal conditions gave the complexes [Cu(H₂L¹)₂] · SO₄ · 3CH₃OH ( 1 ), [Cu₂(H₂L²)₂Cl₄] ( 2 ), [Cu₂(H₂L²)₂Br₄] ( 3 ), [Cd₂(HL)₂Cl₂] ( 4 ), and [Cd₂(L)₂(CH₃COOH)₂] · H₂L ( 5 ), where H₂L¹ [H₂L¹ = 2, 4‐dimethyl‐6‐((pyridin‐2‐ylmethylamino)methyl)phenol] and H₂L² [H₂L² = 2‐(2, 4‐dimethyl‐6‐((pyridin‐2‐ylmethylamino)methyl)phenoxy)‐4, 6‐dimethylphenol] were derived from the solvothermal in situ metal/ligand reactions. These complexes were characterized by IR spectroscopy, elementary analysis, and X‐ray diffraction. A low‐temperature magnetic susceptibility measurement for the solid sample of 2 revealed antiferromagnetic interactions between two central copper(II) atoms. The emission property studies for complexes 4 and 5 indicated strong luminescence emission.     

Nickel(II) N‐Benzyl‐N‐methyldithiocarbamato Complexes as Precursors for the Preparation of Graphite Oxidation Accelerators

The nickel(II) N‐benzyl‐N‐methyldithiocarbamato (BzMedtc) complexes [Ni(BzMedtc)(PPh₃)Cl] ( 1 ), [Ni(BzMedtc)(PPh₃)Br] ( 2 ), [Ni(BzMedtc)(PPh₃)I] ( 3 ), and [Ni(BzMedtc)(PPh₃)(NCS)] ( 4 ) were synthesized using the reaction of [Ni(BzMedtc)₂] and [NiX₂(PPh₃)₂] (X = Cl, Br, I and NCS). Subsequently, complex 1 was used for the preparation of [Ni(BzMedtc)(PPh₃)₂]ClO₄ ( 5 ), [Ni(BzMedtc)(PPh₃)₂]BPh₄ ( 6 ), and [Ni(BzMedtc)(PPh₃)₂]PF₆ ( 7 ). The obtained complexes 1 – 7 were characterized by elemental analysis, thermal analysis and spectroscopic methods (IR, UV/Vis, ³¹P{¹H} NMR). The results of the magnetochemical and molar conductivity measurements proved the complexes as diamagnetic non‐electrolytes ( 1 – 4 ) or 1:1 electrolytes ( 5 – 7 ). The molecular structures of 4 and 5· H₂O were determined by a single‐crystal X‐ray analysis. In all cases, the Ni^II atom is tetracoordinated in a distorted square‐planar arrangement with the S₂PX, and S₂P₂ donor set, respectively. The catalytic influence of selected complexes 1 , 3 , 5 , and 6 on graphite oxidation was studied. The results clearly indicated that the presence of the products of thermal degradation processes of the mentioned complexes has impact on the course of graphite oxidation. A decrease in the oxidation start temperatures by about 60–100 °C was observed in the cases of all the tested complexes in comparison with pure graphite.     

Supramolecular Architectures of Four New Transition Metal Complexes with 3‐[4‐(Carboxymethoxy)phenyl]propanoic Acid and N‐[4‐(Carboxymethoxy)phenyl]iminodiacetic Acid

Four new transition metal complexes: [Cu(Hcppa)₂(H₂O)₂] ( 1 ), [Co₂(cppa)₂(H₂O)₁₀] ( 2 ), [Co₃(cpia)₂(H₂O)₈] · 2H₂O ( 3 ) and [Ni₃(cpia)₂(H₂O)₁₂] · 6H₂O ( 4 ) {H₂cppa = 3‐(4‐(carboxymethoxy)phenyl]propanoic acid; H₃cpia = N‐[4‐(carboxymethoxy)phenyl]iminodiacetic acid} were synthesized and characterized. Complexes 1 and 2 show mononuclear structures, complexes 3 and 4 exhibit dinuclear structures. All complexes extend to 3D supramolecular networks through hydrogen bonds, of which complexes 3 and 4 display microporous structures. In complexes 2 – 4 the water clusters are trapped by the cooperative association of coordinate interactions as well as hydrogen bonds, forming different 1D metal‐water chain structures. Thermal stabilities of complexes 1 – 4 were discussed.     

Synthesis of Heteroleptic Cerium(IV) Complexes Using a Heptadentate (N4O3) Tripodale Schiff‐base Ligand

The Cerium(IV) complexes [{N[CH₂CH₂N=CH(2‐O‐3,5‐^tBu₂C₆H₂)]₃}CeCl] ( 1 ) and [{N[CH₂CH₂N=CH(2‐O‐3,5‐^tBu₂C₆H₂)]₃}Ce(NO₃)] ( 2 ) were derived from the condensation of tris(2‐aminoethyl)amine and 3,5‐di‐tert‐butylsalicylaldehyde and the appropriate Ce starting material CeCl₃(H₂O)₆ and (NH₄)₂[Ce(NO₃)₆], respectively. Single crystal X‐ray diffraction studies reveal monomeric complexes.     

Synthesis and Magnetic Properties of Two New Cobalt Complexes Constructed by Semirigid V‐shaped 5‐(4‐Carboxyphenoxy)‐pyridine‐2‐carboxylic Acid

Two cobalt complexes, [Co₃(L)₂(CH₃OH)₂(μ₃‐OH)₂] ( 1 ) and [Co(L)(bpe)_0.5] · H₂O ( 2 ) [H₂L = 5‐(4‐carboxyphenoxy)‐pyridine‐2‐carboxylic acid; bpe = 1, 2‐bis(4‐pyridyl)ethylene] were synthesized and fully characterized by elemental analyses, IR spectroscopy, single‐crystal X‐ray diffraction, thermogravimetric analysis (TGA), and magnetic analysis. Complex 1 has a two‐dimensional (2D) structure with puckered Co–O–Co chains, and 2 displays a three‐dimensional (3D) network containing one‐dimensional rectangular channels with dimensions of 9.24 × 13.84 Å. In complex 1 , variable‐temperature magnetic susceptibility measurements indicate antiferromagnetic interactions between cobalt magnetic centers.     

Synthesis and characterization of (pyrazolylethylphosphinite)nickel(II) complexes and catalytic activity towards ethylene oligomerization

Compounds (2‐(3,5‐dimethyl‐1H‐pyrazol‐1‐yl)ethyldiphenylphosphinite ( L1 ), 2‐(3,5‐di‐tert‐butyl‐1H‐pyrazol‐1‐yl)ethyldiphenylphosphinite ( L2 ) , and 2‐(3,5‐diphenyl‐1H‐pyrazol‐1‐yl)ethyldiphenylphosphinite ( L3 ) were prepared using the synthetic routes reported in literature. These compounds were reacted with [NiCl₂(DME)₂] or [NiBr₂(DME)₂] under appropriate reaction conditions to afford six new nickel(II) compounds ([NiCl₂( L1)] ( 1 ), [NiCl₂( L2 )] ( 2 ), [NiCl₂( L3 )] ( 3 ), [NiBr₂( L1 )] ( 4 ), [NiBr₂( L2 )] ( 5 ) and [NiBr₂( L3 )] ( 6 )). The new nickel(II) pre‐catalysts catalyze the oligomerization of ethylene, in the presence of ethylaluminium dichloride as co‐catalyst, to produce butenes, hexenes, octenes and higher carbon chain ethylene oligomers with very little Friedel‐Crafts alkylation products when the reactions were run in toluene.     

Synthese und Charakterisierung neuer fünf‐ und sechsfach koordinierter Mangan(II)‐Komplexe als Modellsysteme für manganabhängige Catecholdioxygenasen

Synthesis and Characterization of Novel Five‐ and Six‐coordinate Manganese Complexes as Catechol Dioxygenase Models The five‐ and six‐coordinate manganese complexes [Mn(tphhp)Cl₂] {tphhp = N,N′‐bis(2‐pyridylmethyl)‐2‐(2‐pyridyl)hexahydropyrimidine} ( 1 ), [Mn(bpma)Cl](ClO₄) {bpma = bis((2‐pyridylmethyl)((1‐methylbenzimidazol‐2‐yl)‐methyl)amine} ( 2 ) and [Mn(L)TCC] {HL = (1‐hydroxy‐4‐nitrobenzyl)((1‐methylimidazol‐2‐yl)methyl)(2‐pyridylmethyl)amine} ( 3 ) were synthesized and characterized by various techniques such as single crystal X‐ray structure analysis, mass spectrometry, IR and UV/vis spectroscopy, cyclic voltammetry, and elemental analysis. 1 and 2 crystallize in the monoclinic space group P2₁/n (No. 14) ( 1 ) and P2₁/c (No. 14) ( 2 ). The ligand and the chlorine ions provide the N₃Cl₂‐donorset in 1 and the N₃Cl₂‐donorset in 2 , respectively. Compounds 1 and 2 show catalytic activity regarding the oxidation of 3,5‐di‐tertbutylcatechol to 3,5‐di‐tert‐butylchinon. To our knowledge, 1 and 2 are the first five‐coordinate manganese complexes that show catecholase activity. 3 crystallize in the orthorhombic space group P2₁2₁2₁ (No. 19) and the ligand and tetrachlorocatechol (TCC) build the N₃O₃‐donorset in 3 .     

Syntheses,Structures, and Catalytic Properties of Two 2D Manganese(II) Coordination Polymers Containing Flexible Bis(benzimidazole) Ligands

Two Mn^II coordination polymers based on the flexible bis(benzimidazole) and dicarboxylic acids, namely, [Mn(L1)(bpdc)(H₂O)_0.5]_n ( 1 ) and [Mn(L2)(Htbi)₂]_n ( 2 ) [L1 = 1,4‐bis(5,6‐dimethylbenzimidazol‐1‐ylmethyl)benzene, H₂bpdc = 4,4′‐biphenyldicarboxylic acid, L2 = 1,4‐bis(5,6‐dimethylbenzimidazole)butane, H₂tbi = 5‐tert‐butyl isophthalic acid] were hydrothermally synthesized and characterized by elemental analysis, IR spectroscopy, as well as single‐crystal X‐ray diffraction. Both of the complexes crystallize in the triclinic P$\bar{1}$ space group and present distorted octahedral configurations. Complex 1 possesses a 2D binodal (3,5)‐connected 3,5L2 network with the point symbol of (4².6⁷.8)(4².6), whereas 2 features a 2D uninodal 3‐connected hcb topology and the Schläfli symbol is (6³). Complexes 1 and 2 ultimately are extended into 3D supramolecular framework via π–π stacking and O–H ··· O hydrogen bonding interaction, respectively. Moreover, both of the complexes manifest excellent catalytic activities for the degradation of Congo red.