Homoleptic 2,2′‐bipyridine metalates(–I) of iron and cobalt,one cocrystallized with an anthracene radical anion and the other with neutral anthracene

Homoleptic 2,2′‐bipyridine (bipy) metalates of iron and cobalt have been synthesized directly from the corresponding homoleptic anthracene metalates. In the iron structure, bis[([2.2.2]cryptand)potassium(I)] tris(2,2′‐bipyridine)ferrate(–I) anthracene(–I), [K(C₁₈H₃₆N₂O₆)]₂[Fe(C₁₀H₈N₂)₃](C₁₄H₁₀), the asymmetric unit contains one potassium complex cation in a general position, the Fe center and one and a half bipy ligands of the ferrate complex on a crystallographic twofold axis that includes the Fe atom, and one half of an anthracene radical anion whose other half is generated by a crystallographic inversion center. The cations and anions are well separated and the geometry about the Fe center is essentially octahedral. In the cobalt structure, ([2.2.2]cryptand)potassium(I) bis(2,2′‐bipyridine)cobaltate(–I) anthracene hemisolvate tetrahydrofuran (THF) disolvate, [K(C₁₈H₃₆N₂O₆)][Co(C₁₀H₈N₂)₂]·0.5C₁₄H₁₀·2C₄H₈O, the asymmetric unit contains the cation, anion, and both cocrystallized THF solvent molecules in general positions, and one half of a cocrystallized anthracene molecule whose other half is generated by a crystallographic inversion center. The cation and anion are well separated and the ligand planes in the cobaltate anion are periplanar. Each anthracene molecule is midway between and is oriented perpendicular to a pair of symmetry‐related bipy ligands such that aromatic donor–acceptor interactions may play a role in the packing arrangement. The lengths of the bonds that connect the bipy rings support the assertion that the ligands are bipy radical anions in the iron structure. However, in the case of cobalt, these lengths are between the known ranges for a bipy radical anion and a bipy dianion, and therefore no conclusion can be made from the crystallography alone. One cocrystallized THF solvent molecule in the cobalt structure was modeled as disordered over three positions with appropriate geometric and thermal restraints, which resulted in a refined component mass ratio of 0.412 (4):0.387 (3):0.201 (3).     

Pb(m)-Phenyl (m = 1-5) complexes: an anion photoelectron spectroscopy and density functional study

The phenyl-lead metal complexes ([Pb(m)C6H5]-) produced from the reactions between benzene and lead clusters formed by laser ablation on a lead solid sample are studied by photoelectron spectroscopy (PES) and density functional theory (DFT). The adiabatic electron affinities (EAs) of [Pb(m)C6H5]- are obtained from PES at 308 nm, and the differences between the PES of [Pb(m)C6H5]- and the PES of Pbm- are discussed in detail. The results reveal that the phenyl group binds perpendicularly on lead clusters through the Pb-C sigma bond and the complexes have a closed shell structure. Calculations with DFT are carried out on the structural and electronic properties of [Pb(m)C6H5]-, and the adiabatic detachment energy for the optimized structures of anion are in agreement with the experimental PES results. The density of states (DOS) calculated is compared with experimental PES and is discussed. The most possible structures for each species are concluded, and the bonding between Pb and phenyl is analyzed, which also proves that the phenyl group binds perpendicularly on lead clusters through the Pb-C sigma bond.     

Synthesis and molecular structure of cobalt(II) complex with 1-(1-silatranylmethyl)-1,2,4-triazole

Reaction of cobalt chloride with 1-(1-silatranylmethyl)-1,2,4-triazole in benzene afforded complex CoCl₂·2L (L = 1-(1-silatranylmethyl)-1,2,4-triazole). It was isolated as the solvate [CoCl₂·2L]·CH₂Cl₂ (1) by recrystallization from dichloromethane and structurally characterized by single-crystal X-ray diffraction. It crystallizes in the monoclinic space group P2₁/m with a = 6.798(2) E, b = 20.326(5) E, c = 11.005(3) E, and Z = 4. The cobalt atom is in slightly distorted square-planar environment, coordinated to two nitrogen atoms from two ligands and two chloride ions.     

Photochemistry of the anthracene chromophore: novel isomerization of 1-(9-anthryl)-2-benzoylethylenes

Photoexcited cis-1-(9-anthryl)2-benzoylethylenes undergo a novel type of isomerization by skeletal rearrangement to give furano-annelated 5H-dibenzo[a,d]cycloheptenes.     

B-Halogen derivatives of the bis(1,2-dicarbollyl)cobalt(III) anion

The halogenation of (C₂B₉H₁₁)₂Co^?Cs⁺ by elemental halogens in alcohol and γ-radiation-induced halogenation by CHBr₃, CH     

Pentafluorophenyl complexes of cobalt(III) with 1-(diacetylmonoximatoimino)-3-(diacetylmonoximeimino)-propane (dotnH)

Cyclopalladation of vinylic oximes occurs for the sterically rigid oximes of 1-benzalcyclohexanone and 1-acetylcyclohexene giving dimeric complexes which retain the alkene double bond. The presence of the vinylic palladium bond is shown both by spectroscopic methods and cleavage reactions using carbon monoxide or cyanide ion. The complexes do not make good substrates for the synthesis of vinylic oxime derivatives.     

Extraction of cobalt(II) with 7-(1-decenyl)-8-quinolinol into chloroform

Extraction of cobalt(II) with 7-(1-decenyl)-8-quinolinol (HRql) into chloroform was examined. The best cobalt extraction occurs in the pH region 5.5–9. In this region several other cations are extracted. The values of K_ex and pH_0.5 for cobalt extraction were found to be ?8.6 and 3.19 respectively. The composition of the extracted complex was found to be Co(Rql)₃. Cobalt is poorly reextracted from Co-HRql complex into the aqueous phase, the best results were obtained using HCl as a stripping agent.     

Tris-2-(3-methylindolyl)phosphine as an anion receptor

A C3-symmetric phosphine with indolyl substituents has been synthesized that demonstrates the capability to bind anions through the indole NH sites and coordinate metal centres through the phosphorus centre.     

Spectrophotometric determination of cobalt with 1-(2-pyridylazo)-2-naphthol and surfactants

A simple and highly selective spectrophotometric method for the determination of cobalt based upon the rapid reaction with PAN in the presence of surfactants and minute amounts of ammonium persulphate at pH 5.0 is described. The cobalt(III) chelate is made water-soluble by a neutral surfactant. Triton X-100, combined with sodium dodecylbenzene sulphonate (DBS). Iron(III), bismuth, tin(IV) and aluminium are masked with oxalate or citrate. Iron(II) must be absent. The other metal-PAN chelates, except that of nickel, are readily decomposed by EDTA. Up to 150 microg of nickel does not interfere. When larger amounts up to 625 microg are present, the absorbance can be corrected by measurements at two wavelengths. In a strongly acid medium (below pH 0.5) the nickel and other metal chelates are completely and instantaneously decomposed, while the cobalt(III) chelate remains unchanged. When, in place of EDTA, several ml of 6M hydrochloric acid are added after the colour development, nickel in quantities up to 1250 microg can be tolerated. A several hundredfold excess of zinc and manganese does not interfere. At 620 nm Beer's law is obeyed over the cobalt concentration range 0.4-3.2 microg/ml. The precision (95% confidence) is +/- 1.0 microg for 100 microg of cobalt. The molar absorptivity is 1.90 x 10(4) l. mole(-1) .cm(-1).     

Synthesis and Solvatochromatic properties of 9-(4-Aminophenylethynyl)-10-(4-nitrophenylethynyl)anthracene

9-(4-Aminophenylethynyl)-10-(4-nitrophenylethynyl)anthracene (2) was synthesized in high yield by using a route involving sequential Sonogashira cross coupling reactions of 9-bromo-10-iodoanthracene with 4-nitrophenylacetylene and 4-aminophenylacetylene. Solvatochromism was observed in the absorption and fluorescence spectra of 2 in a variety of solvents. In less polar solvents, such as hexane and benzene, the fluorescence emission band of 2 appears in the green to orange region while this substance does not fluoresce in polar solvents, such as acetonitrile and DMF.     

Interaction of Co(m)O(-) (m = 1-3) with water: anion photoelectron spectroscopy and density functional calculations

We investigated the reactions between cobalt-oxides and water molecules using photoelectron spectroscopy and density functional calculations. It has been confirmed by both experimental observation and theoretical calculations that dihydroxide anions, Co(m)(OH)(2)(-) (m = 1-3), were formed when Co(m)O(-) clusters interact with the first water molecule. Addition of more water molecules produced solvated dihydroxide anions, Co(m)(OH)(2)(H(2)O)(n)(-) (m = 1-3). Hydrated dihydroxide anions, Co(m)(OH)(2)(H(2)O)(n)(-), are more stable than their corresponding hydrated metal-oxide anions, Co(m)O(H(2)O)(n+1)(-).     

Generation of 1-azapentadienyl anion from N-(tert-butyldimethylsilyl)-3-buten-1-amine

N-(tert-Butyldimethylsilyl)-3-buten-1-amine undergoes allylic deprotonation at the 2-position when exposed to 2 equiv of nBuLi in THF. This allylic anion undergoes lithium hydride elimination to generate a 1-azapentadienyl anion. The anion is generated cleanly and completely.     

9-氯甲基蒽的实验室制备法

介绍一个在室温条件下反应制备9-氯甲基蒽——构造荧光分子探针的常用中间体的,方法。该实验以9-蒽甲醇和二氯亚砜为原料,苯为溶剂,在吡啶催化下反应,经水洗,干燥,旋转蒸发除去溶剂,最后得到固体产品。推荐该方法作为高校实验室自制9-氯甲基蒽的方法。