Low-dimensional compounds containing bioactive ligands. I: Crystal structure,spectroscopic, and thermal properties of the first row transition metal coordination compounds with clioquinol

Abstract  

Coordination compounds of first row transition metals from Mn to Zn with clioquinol (5-chloro-7-iodo-8-hydroxyquinoline, CQ) were prepared and characterized by infrared spectroscopy and thermal analysis. The composition of these compounds determined by elemental analysis is [M(CQ)₂(H₂O)₂] for Mn and Zn, [M(CQ)₂] for Fe, Co, Ni, and Cu, and NH₂(CH₃)₂[Ni(CQ)₃]·DMF·H₂O (DMF = N,N-dimethylformamide). X-ray structure analysis revealed that the [Ni(CQ)₂] complex is a molecular coordination compound with Ni(II) square-planarly coordinated by nitrogen and oxygen atoms of two trans-arranged bidentate molecules of clioquinol. On the other hand, NH₂(CH₃)₂[Ni(CQ)₃]·DMF·H₂O is an ionic compound containing three clioquinol molecules coordinated to the central atom in a deformed octahedral geometry thus forming a complex anion. Its negative charge is balanced by the dimethylammonium cation and the structure also contains solvated water and DMF molecules. Long-range interactions and hydrogen bonds in these two complexes were also investigated.     

A lanthanum pyromellitate coordination polymer with three-dimensional structure

A new three-dimensional metal-organic coordination polymer, [La₂(H₂O)₂(H₂BTEC)(BTEC)], 1, was hydrothermally synthesized and characterized by single crystal X-ray diffraction. The three-dimensional framework is built up from La₂O₁₆ dimers connected by carboxylate anions. The polymer exhibits strong photoluminescence at room temperature with the main emission band at 390 nm (λ_ex = 338 nm). Crystal data: triclinic, space group P(−1),a = 6.4486(3),b = 9.4525(5),c = 9.6238(5) ?, α= 88.24(1), β = 74.67(2), γ= 76.76(1)°,V = 550.45(5)     

Boron coordination compounds derived from 2-phenyl-benzimidazole and 2-phenyl-benzotriazole bidentate ligands

The syntheses and structural analyses of a series of boron heterocycles derived from 2-(1H-benzimidazol-2-yl)-phenylamine (1), 2-(1H-benzimidazol-2-yl)-phenol (2), 2-(1H-benzimidazol-2-yl)-benzenedisulfide (3), 2-[3-(1,1,1,3,-tetramethyl-butyl)-phenyl]-2H-benzotriazole (4), 2-[3,5-bis-(1-methyl-1-phenylethyl)-phenyl]-2H-benzotriazole (5) and (C₆H₅)₂BOH or BF₃·OEt₂ are reported. The new boron compounds: diphenyl-[2-(1H-benzimidazol-2-yl-κN)-phenylamide-κN]-boron (6), diphenyl-[2-(1H-benzimidazol-2-yl-κN)-phenolate-κO]-boron (7), diphenyl-[2-(1H-benzimidazol-2-yl-κN)-benzenethiolate-κS]-boron (8), diphenyl-[2-(2H-benzotriazol-2-yl-κN)-4-(1,1,3,3-tetramethyl-butyl)-phenolate-κO]-boron (9), diphenyl-[2-(2H-benzotriazol-2-yl-κN)-4,6-(1-methyl-1-phenylethyl)-phenolate-κO]-boron (10), difluoro-[2-(1H-benzimidazol-2-yl-κN)-phenolate-κO]-boron (11), difluoro-[2-(2H-benzotriazol-2-yl-κN)-4-(1,1,3,3-tetramethylbutyl)-phenolate-κO]-boron (12) and difluoro-[2-(2H-benzotriazol-2-yl-κN)-4,6-(1-methyl-1-phenylethyl)-phenolate-κO]-boron (13) have four fused rings, with boron included in a six-membered ring and bound to N, O or S atoms and strongly coordinated by a nitrogen atom from the imidazole or triazole rings. Their structures are zwitterionic, with a negative charge on the boron and a delocalized positive charge on the ligand. Compounds 6-12 were studied by NMR, IR, mass spectrometry, and 6-10 and 12 by X-ray diffraction analyses.     

Molecular kinetic aspects of vaporization of volatile coordination compounds with organic ligands

We present results of the experimental study and numerical simulation of radiation-convective heat and mass transfer during the sublimation of spherical particles of metal β-diketonates in a high-temperature inert gas flow (argon or helium). The sublimation process is visualized, and experimental data on the temperature variation dynamics and particle size are obtained. It is shown that at stable transfer of the compound from the particle surface the sublimation proceeds with the formation of large pores in its structure. The effect of inert gas properties on the kinetics of the vaporization process of precursor particles with various initial diameters is analyzed in the temperature range from 200 °C to 330 °C. Due to a higher thermal conductivity and heat capacity of helium as compared with argon, the choice of helium as carrier gas causes an increase in the sublimation intensity.     

Monodentate imido coordination of 1,2-diaminobenzene to rhenium(V)

The complex trans-[Re(dab)Cl₃(PPh₃)₂] (H₂dab?=?1,2-diaminobenzene) was prepared from the reaction of trans-[ReOCl₃(PPh₃)₂] with H₂dab in ethanol. The ligand dab is coordinated to the rhenium(V) centre only through a dianionic imido nitrogen to give a distorted octahedral coordination geometry around the metal ion.     

Substituted group-directed assembly of six coordination compounds based on pyrazole bifunctional ligands

Six new complexes [Mn₈(μ₄-O)₄(phpz)₈(MeOH)₄]·(MeOH)(H₂O) (1) [Co₂(HphpzH)(Hphpz)₂(phpz)₂]·4(MeOH) (2), Ni(Hphpz)₂ (3), [Ni(Hphpz)₂]·H₂O (4), [Zn₄(pzpy)₄Cl₄] (5) and [Cu₂(pzpy)₂(HCO₂)₂(H₂O)₂] (6) have been synthesized by hydrothermal reactions of MCl₂·4H₂O (M = Mn, Co, Ni, Zn or Cu) with 5-(2-hydroxyphenyl)-3-pyrazole (HphpzH) or 2-(1H-pyrazol-3-yl)pyridine (Hpzpy). The complexes were characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. Complex 1 is an octanuclear Mn(III) cluster, complexes 2 and 6 are binuclear Co(III) and Cu(II), respectively, complexes 3 and 4 are isomorphous mononuclear species, while complex 5 is a tetranuclear Zn(II) cluster. The magnetic behavior of complex 1 was investigated. Magnetic susceptibility measurements revealed antiferromagnetic exchange interactions between the metal centers in the clusters. The luminescence properties of the complexes were investigated at room temperature in the solid state.     

Monodentate coordination of N-[di(phenyl/ethyl)carbamothioyl]benzamide ligands: synthesis, crystal structure and catalytic oxidation property of Cu(I) complexes

New four-coordinated tetrahedral copper(I) complexes have been synthesized from the reactions between [CuCl(2)(PPh(3))(2)] and N-(diphenylcarbamothioyl)benzamide (HL1) or N-(diethylcarbamothioyl)benzamide (HL2) in benzene. These complexes have been characterized by elemental analyses, IR, UV/Vis, (1)H, (13)C and (31)P NMR spectroscopy. The molecular structure of both the complexes, [CuCl(HL1)(2)(PPh(3))] (1) and [CuCl(HL2)(PPh(3))(2)] (2) were determined by single-crystal X-ray diffraction, which reveals distorted tetrahedral geometry around each Cu(I) ion. The combination of 2 (0.005 mmol) with hydrogen peroxide (2.5 mmol) in acetonitrile is found to be an active catalyst for the oxidation of primary and secondary alcohols (0.5 mmol) to their corresponding acids and ketones, respectively, at room temperature.     

Pseudo-polyrotaxane and beta-sheet layer-based three-dimensional coordination polymers constructed with silver salts and flexible pyridyl-type ligands

A fascinating 3D pseudo-polyrotaxane architecture with 1D polymeric [Ag(bpp)](n) chains penetrating 2D (6,3) [Ag(2)(bpp)(2)(ox)](n) sheets and a 3D coordination network constructed with 2D infinite [Ag(ppa)](n) beta-sheetlike layers pillared by ox ligands (bpp = 1,3-bis(4-pyridyl)propane; ppa = N-(4-pyridinylmethyl)-4-pyridinecarboxamide; ox = oxalate) have been prepared by utilizing flexible pyridyl-type ligands and have been crystallographically characterized. Crystal data for 1: monoclinic, space group C2/c, a = 7.619(2) A, b = 19.781(4) A, c = 26.799(5) A, beta = 94.720(10) degrees, U = 4025.2(15) A(3), and Z = 4. Crystal data for 2: monoclinic, space group C2/c, a = 28.947(8) A, b = 8.617(3) A, c = 16.307(6) A, beta =121.07(1) degrees, U = 3484(2) A(3), and Z = 4.     

Monodentate imido coordination of 2-aminodiphenylamine to rhenium(V)

The complex trans-[Re(ada)Cl₃(PPh₃)₂] (H₂ada?=?2-aminodiphenylamine) was prepared from the reaction of trans-[ReOCl₃(PPh₃)₂] with H₂ada in acetonitrile. The ligand ada is coordinated to the rhenium(V) centre solely through a dianionic imido nitrogen, with distorted octahedral coordination geometry around the metal ion. Surprisingly, the Re–Cl bond trans to the Re=N bond is shorter than the two equatorial Re–Cl bonds. The Re?=?N–C bond angle of the phenylimido moiety equals 178.7(4)°.