Synthesis and characterization of [Cu(mb2en)2]ClO4 and [Cu(mb2en)(PPh3)2]BPh4: crystal structure of [Cu(mb2en)2]ClO4

The ligand, N,N′-bis-(4-methoxy-benzylidene)-ethane-1,2-diamine (mb₂en), and its corresponding copper(I) complexes, [Cu(mb₂en)₂]ClO₄ (1), and [Cu(mb₂en)(PPh₃)₂]BPh₄ (2), have been synthesized and characterized by CHN analyses, ¹H and ¹³C-NMR, IR, and UV-Vis spectroscopies. The crystal and molecular structure of [Cu(mb₂en)₂]ClO₄ (1), were determined by X-ray crystallography from a single-crystal. The coordination polyhedron about copper(I) is best described as a distorted tetrahedron. Quasi-irreversible redox behavior was observed for 1 and 2 (E _1/2?=?0.55 and 0.95?V, respectively).     

Synthesis,Characterization, and Crystal Structures of [Cu(ca2en)2]ClO4, and [Cu(ca2en)(PPh3)2]ClO4 Complexes

Synthesis, spectroscopy, and crystal structures of [Cu(ca₂en)₂]ClO₄ ( 1 ) and [Cu(ca₂en)(PPh₃)₂]ClO₄ ( 2 ) (ca₂en=N,N′‐bis(trans‐cinnamaldehyde)ethylenediimine) are reported. Compound 1 crystallizes in the orthorhombic space group Pbca, with a=12.5647(7), b=21.8203(11), c=27.992(2) Å, V=7674.3(7) ų, Z=8. Compound 2 crystallizes in the triclinic space group P , with a=13.0540(11), b=14.2935(13), c=14.9863(13) Å, α=84.130(2), β=69.761(2), γ=87.749(2)°, V=2609.8(4) ų, Z=2. The coordination polyhedron about the Cu^I center in the two complexes is best described as a distorted tetrahedron. The ¹H‐NMR and electronic spectra of these complexes are also reported and discussed. The cyclic voltammetry of the complexes indicate a quasireversible redox behavior for complex 1 (E_1/2=0.51 V). However, complex 2 displays an irreversible oxidation wave at 0.91 V. A weak emission is observed for complex 2 in CHCl₃ at room temperature.     

Novel copper(II)-dien-imidazole/imidazolate-bridged copper(II) complexes. Crystal structure of [Cu(dien)(Him)](ClO4)2 and of [(dien)Cu(mu-im)Cu(dien)](ClO4)3, a homobinuclear model for the copper(II) site of the CuZn-superoxide dismutase

The imidazolate-bridged binuclear copper(II)-copper(II) complex [(dien)Cu(mu-im)Cu(dien)](ClO(4))(3) and related mononuclear complexes [Cu(dien)(H(2)O)](ClO(4))(2), [Cu(dien)(Him)](ClO(4))(2) were synthesized with diethylenetriamine (dien) as capping ligand. The crystal structure of mononuclear [Cu(dien)(Him)](ClO(4))(2) and binuclear complex [(dien)Cu(mu-im)Cu(dien)](ClO(4))(3) have been determined by single crystal X-ray diffraction methods. The mononuclear complex [Cu(dien)(Him)](ClO(4))(2) crystallizes in the orthorhombic, Pca2(1) with a = 9.3420(9) A, b = 12.3750(9) A, c = 14.0830(9) A, beta = 90.000(7)(o) and Z = 4 and binuclear complex [(dien)Cu(mu-im)Cu(dien)](ClO(4))(3) crystallizes in the monoclinic space group P2(1)/a, with a = 15.017(7) A, b = 11.938(6) A, c = 15.386(6) A, beta = 110.30(4)(o) and Z = 4. The molecular structures show that copper(II) ions in an asymmetrically elongated octahedral coordination (type 4 + 1 + 1) and in binuclear complex Cu(1) atom has a asymmetrically elongated octahedral coordination (type type 4 + 1 + 1) and Cu(2) atom exhibits a square base pyramidal coordination (type 4 + 1). The bridging ligand (imidazolate ion, im) lies nearly on a straight line between two Cu(2+), which are separated by 5.812 A, slightly shorter than the value in copper-copper superoxide dismutase (Cu(2)-Cu(2)SOD). Magnetic measurements and electron spin resonance (ESR) spectroscopy of the binuclear complex have shown an antiferromagnetic exchange interaction. From pH-dependent cyclic voltametry (CV) and electronic spectroscopic studies the complex has been found to be stable over a wide pH range (7.75-12.50).     

Syntheses and structures of three new coordination polymers with the flexible 1,2-bis(1,2,4-triazol-1-yl)ethane ligand

Three new coordination polymers {[Ni(bte)₂(NCO)₂](H₂O)} _n (1), {[Ni(bte)₂(N₃)₂](H₂O)} _n (2) and {[Ag(bte)₂](NO₃)} _n (3) (bte?=?1,2-bis(1,2,4-triazol-1-yl)ethane) were synthesized and characterized by X-ray crystallography, IR and thermogravimetric analysis. The coordination geometry of the Ni(II) atom is distorted octahedral, coordinated equatorially by four nitrogen atoms from four triazole rings of four symmetry-related bte ligands, and axially by two nitrogen atoms from two isocyanate anions in 1 and azide anions in 2, respectively. The structures of 1 and 2 are both polymeric, with 18-membered spiro-fused rings and each 18-membered ring involving two inversion-related bte molecules. The coordination geometry of the Ag(I) atom in 3 is distorted tetrahedral, formed by four nitrogen atoms from four triazole rings of four symmetry-related bte ligands. Each bte ligand links two Ag(I) atoms and forms a two-dimensional undulated (4,4) network in 3.     

Synthesis,structure, and antioxidative properties of a copper(II) complex with 1,2-bis(benzimidazol-2-yl)ethane ligand

1,2-Bis(benzimidazol-2-yl)ethane (bbe) and its copper(II) complex, {[Cu(bbe)Br₂]₂}·2DMF ( 1 ), have been synthesized and characterized by elemental analysis, ultraviolet–visible, and infrared spectra. The single crystal structure analysis of 1 shows two crystallographically independent but chemically identical [Cu(bbe)Br₂] molecules. The coordination geometry of the copper atoms may best be described as a distorted tetrahedron (τ₄ = 0.740 for Cu1 and 0.696 for Cu2). The cyclic voltammogram of complex 1 represents quasi-reversible Cu²⁺/Cu⁺ pairs. in vitro antioxidant tests showed that complex 1 has significant antioxidant activity against superoxide and hydroxy radicals. Photoluminescence investigations showed that the fluorescence intensity of complex 1 is significantly weaker than that of the ligand. This may be due to the paramagnetic effect of divalent copper to cause quenching of fluorescence.     

Syntheses and structures of five cadmium(II) coordination polymers from 1,2-bis(1,2,4-triazol-1-yl)ethane

Five structually distinct coordination polymers [Cd(bte)₃](NO₃)_{2 n} (1), [Cd(bte)₂(H₂O)₂](NO₃)_{2 n} (2), [Cd(bte)(NO₂)₂] _n (3), [Cd(bte)₂(H₂O)₂](H₂O)₂(ClO₄)_{2 n} (4) and [Cd(bte)(NCS)₂]_n (5) (bte = 1,2-bis(1,2,4-triazol-1-yl)ethane) have been synthesized and characterized. The structures of 1, 2, 3, 4 and 5 consist of a double interpenetrating three-dimensional -poloniumn cubic network, a two-dimensional (4,4) network, a two-dimensional rhombic network, a one-dimensional double chain containing 18-membered [Cd₂(bte)₂] rings and a two-dimensional rhombic network containing eight-membered [Cd₂(SCN)₂] rings, respectively.     

Synthesis, characterization, solvatochromic behavior and crystal structures of complexes [CoIII(salophen)(thioacetamide)2]ClO4 and [CoIII(salophen)(thiobenzamide)2]ClO4

Two new cobalt(III) complexes of the Schiff base N,N′-disalicylidene-1,2-phenylendiimine dianion (salophen), trans- [Co^III(salophen)(ta)₂]ClO₄, (ta = thioacetamide) (1) and trans-[Co^III(salophen)(tb)₂]ClO₄, (tb = thiobenzamide) (2) were synthesized and characterized using single-crystal X-ray diffraction and spectroscopic techniques. Both complexes show solvatochromism in a variety of solvents. Complex (1) crystallized from CHCl₃ as a solvate of orthorhombic symmetry, space group Pca2₁ with a = 17.3480(10) Å, b = 18.7522(10) Å, c = 18.8128(11) Å, α = β = γ = 90°, and Z = 8. The cobalt(III) center lies in a distorted octahedral environment. The crystal structure of (1) consists of two independent [Co^III(salophen)(ta)₂]⁺ cations and ClO₄ ^- anions held together essentially via hydrogen bonds and π-π stacking interactions. Complex (2), forming also a CHCl₃ solvate, crystallized in the monoclinic space group P2₁/n with a = 14.710(3) Å, b = 13.506(3) Å, c = 18.595(4) Å, β = 100.295(4)°, and Z = 4. The geometry around cobalt(III) center is a distorted octahedron. The crystal structure of (2) contains a [Co^III(salophen)(tb)₂]⁺ complex with a remarkably twisted salophen ligand. Both complexes, (1) and (2), contain approximately one disordered CHCl₃ molecule per Co in the solid state.     

Synthesis,structures and properties of copper(II) and zinc(II) complexes with 1,2-bis(benzimidazol-2-yl)ethane ligands

Transition Metal Chemistry - 1,2-Bis(benzimidazol-2-yl)ethane (bbe) and its transition metal complexes, [Cu(bbe)Cl2]·DMF (1) and [Zn(bbe)Cl2]2(2), have been synthesized and characterized by...     

Synthesis,Characterization and X‐ray Crystal Structures of [Cu(ncaen)2]ClO4 and [Cu(nca2en)(PPh3)2]BPh4 Complexes

A novel ligand, N,N′‐Bis‐[3‐(2‐nitrophenyl)‐allylidene]‐ethane‐1,2‐diamine (nca₂en), and their corresponding copper(I) complexes, [Cu(ncaen)₂]ClO₄ ( 1 ), and [Cu(nca₂en)(PPh₃)₂]BPh₄ ( 2 ), have been synthesized and characterized by CHN analyses, ¹H and ¹³C‐NMR, IR, and UV‐Vis spectroscopy. The crystal and molecular structures of [Cu(ncaen)₂]ClO₄ ( 1 ), and [Cu(nca₂en)(PPh₃)₂]BPh₄ ( 2 ), were determined by X‐ray crystallography from single‐crystal data. The coordination polyhedron about the copper(I) atom in the two complexes is best described as a distorted tetrahedron. A quasireversible redox behavior is observed for complex 1 and 2 (E_1/2 = 0.55 and 0.95 V, respectively).     

Synthesis and spectroscopic characterization of [CoIII(salophen)(amine)2]ClO4 (amine=morpholine,pyrrolidine, and piperidine) complexes. The crystal structures of [CoIII(salophen)(morpholine)2]ClO4 and [CoIII(salophen)(pyrrolidine)2]ClO4

Three Co(III) complexes of the type [Co(salophen)(amine)₂]ClO₄, salophen=N,N′-disalicylidene-1,2-phenylendiamine dianion and amine=morpholine (1), pyrrolidine (2), and piperidine (3), have been synthesized and characterized by elemental analysis, IR, UV–Vis, ¹H, and ¹³C NMR spectroscopy. [Co(salophen)(morpholine)₂]ClO₄ (1) and [Co(salophen)(pyrrolidine)₂]ClO₄ (2) have been studied by X-ray diffraction. Compound 1 crystallizes in ribbons of complexes and perchlorates held together by weak NH⋯O and CH⋯O hydrogen bonds between morpholines and perchlorates. The latter also interconnect the chains to a 3D network. Some minor π–π interactions exist. Compound 2 crystallizes as endless chains of complexes linked by weak CH⋯O hydrogen bonds to the disordered perchlorates. The pyrrolidine moiety is turned by 90° with respect to 1 and forms intramolecular NH⋯O hydrogen bonds. The coordination polyhedra of 1 and 2 possess C_s symmetry, and the salophens are not planar in either of them.     

Photochromic dihetarylethenes. 10. Photochromic 1,2-bis[2-(benzothiazol-2-yl)-3-thienyl]- and 1,2-bis[2-(benzothiazol-2-yl)benzothiophen-3-yl]ethenes

Dithienylethenes containing the thiophene rings with benzothiazolyl substituents in position 2 were synthesized. 1,2-Bis[2-(benzothiazol-2-yl)benzothiophen-3-yl]hexafluorocyclopentene and 1,2-bis[2,5-di(benzothiazol-2-yl)-3-thienyl]hexafluorocyclopentene possess photochromic properties. The open forms of 1,2-bis(2-benzothiazolylhetaryl)ethenes fluoresce, but introduction of the benzothiazole rings into dihetarylethenes significantly lowers the fatigue resistance of photochromes and favors thermal reversibility.     

Crown ethers based on bis(benzimidazol-2-yl)alkanes and 1,2-bis(benzimidazol-2-ylsulfanyl)ethane

Dibenzimidazo crown ethers were synthesized by alkylation of α,ω-bis(benzimidazol-2-yl)alkanes and 1,2-bis(benzimidazol-2-ylsulfanyl)ethane with tri- and tetraethylene glycol bis(4-toluenesulfonates). The structure of 6,7,9,10,12,13,21,22-octahydro[1,14,6,9,4,11]dioxadithiadiazacyclohexadecino[4,5-a:11,10-a′]dibenzimidazole was studied by X-ray analysis.