Liquid crystalline behavior and fluorescent property of calix[4]arene containing azobenzene photochromic group

The reaction of 4′-hydroxy-4-methyl azobenzene (1) and 1,6-dibromohexane afforded 6-bromo-1-((4-((4-met hylphenyl)azo)phenyl)oxy)hexane (2), which further reacted with p-tert-butylcalix[4]arene to give the calix[4]arene derivative (3) whose lower rim had been modified by the azobenzene photochromic group. The structure of 3 was characterized by ¹H-nuclear magnetic resonance (NMR) and electrospray ionization-mass spectrometry (ESI-MS). The fluorescence intensity of compound 3 was two to four times higher than that of compounds 1 and 2 as the azobenzene group concentration in the range of 1.6 × 10⁻⁵ to 8.0 × 10⁻⁴ mol/L, indicating that the fluorescence quantum yield of the azobenzene group had been improved through being attached to the calix[4]arene skeleton. The liquid crystalline behavior of compound 3 was studied by polarized microscopy (POM) and differential scan calorimeter (DSC). Compound 3 exhibited the enchased texture of a smectic liquid crystal from 209.4°C to 219.5°C on heating, while 2 exhibited a liquid crystalline phase from 87.4 to 83.2°C on cooling. It was found that the calix[4]arene skeleton was a good platform for conformation immobilization of azobenzene photochromic group and the formation of liquid crystalline. Translated from Chinese Journal of Applied Chemistry, 2006, 23(9): 1023–1026 [译自: 应用化学]     

1-Benzyl-3,3,5′,6′-tetramethylspiro[indoline-2,2′-[2<Emphasis Type="Italic">H</Emphasis>]pyrano[3,2-<Emphasis Type="Italic">b</Emphasis>]-pyridinium] iodide,its hydrate,and a neutral precursor of the salts: synthesis,crystal structure,photochromic transformations in solutions and in crystals

A new 1-benzyl-3,3,5′,6′-tetramethylspiro[indoline-2,2′-[2H]pyrano[3,2-b]pyridinium] iodide, photochromic in the crystal state, was obtained. X-ray diffraction analysis was used for determination of crystal structures of the salt, its hydrate, and a neutral precursor. It was found that a replacement of the substituent in the indoline fragment leads to a considerable change in the crystal structure of both the neutral spiropyran and the salts as compared to the analogs studied earlier. Effects of crystal structure on photochromic properties were studied.     

A joint theoretical and experimental structural study of two novel 1,2,4-triazolo[3,4-<Emphasis Type="Italic">b</Emphasis>]-1,3,4-thiadiazine derivatives

In this study, two novel 1,2,4-triazolo[3,4-b]-1,3,4-thiadiazine derivatives, 3-[2-(4-methoxyphenyl)ethyl]-6-phenyl-7H-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazine (compound 1) and 3-[2-(3,4,5-trimethoxyphenyl)ethyl]-6-phenyl-7H-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazine (compound 2), having analgesic–anti-inflammatory activity were synthesized and characterized by IR, ¹H-NMR, and mass spectroscopic techniques besides elementary analysis. Additionally, the structures and molecular packings of the mentioned compounds have been investigated by X-ray single crystal diffraction. The six-membered thiadiazine ring adopts the screw boat conformation in both the compounds. In the crystal packings of the compounds 1 and 2, C–H···N and C–H···O interactions link the molecules into a two-dimensional network and generate infinite chains. Furthermore, C–H···π intermolecular interactions provide further stability to the molecular packing in both the molecules. The conformers have been predicted by the potential energy surface scan employing the AM1 method. Geometry optimizations and electrostatic properties have been obtained using AM1 and ab initio quantum methods.     

Synthesis,structure, and properties of the [RuNO(NH<Subscript>3</Subscript>)<Subscript>5</Subscript>][Co(CN)<Subscript>6</Subscript>] complex containing a photochromic cation

The salt of cobalt hexacyanide with the photochromic mononitrosyl cation [RuNO(NH₃)₅]³⁺ with the composition [RuNO(NH₃)₅][Co(CN)₆] was synthesized. Single crystals of the salt were grown, and the crystal structure was solved. The photochromic properties were studied by differential scanning calorimetry (DSC). Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 545–548, March, 2008.     

Synthesis and photochromic properties of a new biindenylidenedione compound bearing hydroxylphenyl groups in crystal state

A new biindenylidenedione compound, named [trans-anti-3,3′-Di-p-hydroxyl phenyl-3,3′-dihydroxy-[2,2′-bi-1H-indene]-1,1′-dione] (2) was synthesized and characterized by means of ¹H-NMR, IR, MS and X-ray crystallographic diffraction techniques. The photochromic behavior was investigated by means of UV–Vis spectroscopy, and the results showed that the inclusion complex of 2 with guest solvent N,N-dimethylformamide (DMF) did not exhibit photochromism in crystal state. The structure–property relation was discussed briefly in context to the intermolecular interactions and the solvent-dependent effect on photochromism.     

Spectrophotometric determination of <Emphasis Type="Italic">L</Emphasis>-ascorbic acid in pharmaceuticals

A simple and sensitive spectrophotometric method for the determination of L-ascorbic acid with leuco crystal violet is proposed. The determination is based on the oxidation of analyte by potassium iodate. The colourless oxidation products were formed in the quantity equivalent to iodide ions. The iodide ions react with the excess of iodate ions in acidic medium, to form free iodine which oxidized leuco crystal violet (LCV) to the liberated crystal violet (CV ⁺) dye, showing maximum absorption at 588 nm. The absorbance was measured at pH of 4.1–4.2 in 1 cm cuvettes. Beer’s law was obeyed in the concentration range 0.5–4.0 μg/mL. The molar absorptivity of the coloured compound is 4.14 × 10⁴ L/mol cm for L-ascorbic acid. The analytical parameters were optimized and the method was successfully applied to the determination of L-ascorbic acid in pharmaceuticals. The results were compared with those obtained by methods proposed in Polish Standard.     

Synthesis,structure, and properties of sodium <Emphasis Type="Italic">cis</Emphasis>-tetraethylcyclotetrasiloxanolate and new mesomorphic <Emphasis Type="Italic">cis</Emphasis>-tetra[ethyl(trimethylsiloxy)]cyclotetrasiloxane

Hydrolytic condensation of ethyltriethoxysilane in the presence of NaOH (Si: NaOH = 1) gave crystal solvate of sodium cis-tetraethyltetrasiloxanolate {(Na⁺)₄[EtSi(O)O⁻]₄}·nL (1, L = EtOH, H₂O) in high yield. The molecular structure of compound 1 at L = EtOH, n = 8 was determined by X-ray diffraction analysis. The reaction of compound 1 with trimethylchlorosilane affords cis-tetra[ethyl(trimethylsiloxy)]cyclotetrasiloxane cis-[EtSi(O)OSiMe₃]₄, which is the first representative of the group of mesomorphic cyclotetrasiloxanes containing alkyl groups. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 74–79, January, 2007.     

Synthesis and structure of cobalt complexes [Ph3(n-Pr)P 2+ [CoI4]2? and [Ph3(n-Am)P 2+ [CoI4]2?

Complexes Ph₃(n-Pr)P₂⁺[CoI₄]²⁻ (I) and [Ph₃(n-Am)P]₂⁺ [CoI₄]²⁻ (II) were synthesized by reactions of triphenyl(alkyl)phosphonium iodide with cobalt(II) iodide in acetone. According to the X-ray diffraction data, complexes I and II consist of tetrahedral triphenyl(alkyl)phosphonium cations (for I, P-C is 1.787(4)–1.804(4) ? and CPC is 106.73(18)°–111.4(18)°; for II P-C is 1.786(6)–1.802(6) ? and CPC is 107.6(3)°–111.7(3)°) and [CoI₄]²⁻ anions (Co-I 2.5923(6)–2.6189(6) ?, ICoI 101.86(2)°–113.25(2)° for I; Co-I 2.5899(9)–2.6171(9) 107.01(3)°–110.47(3)° for II).     

Hydrothermal synthesis and characterization of two novel tungstovanadophosphate derivatives

Two novel tungstovanadophosphate derivatives, namely [Fe(phen)₃]₂[PW₈^VIV^VV₅^IVO₄₂] · H₂O (1) and [Fe(phen)₃]₂[PW₉V₃O₄₀] (2), were synthesized under hydrothermal conditions, and characterized by elemental analysis, IR, ESR, XPS, TGA, and single-crystal X-ray diffraction analysis. The crystal structure analyses reveal that the ‘mixed-addenda’ Keggin polyoxoanion in 1 is decorated with VO²⁺ units, such that four V atoms are disordered over eight metal sites; the anion in compound 2 has a typical Keggin structure with three V atoms disordered over 12 metal sites. The two compounds are ionic crystals with slightly different packing modes for the polyoxoanions and [Fe(phen)₃]³⁺ cations. π–π stacking interactions between phen molecules, weak hydrogen bonding interactions between phen ligands and polyoxoanions, and electrostatic forces lead to an extended 3D supramolecular framework. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Syntheses,structures, and properties of two mononuclear cobalt(III) azido complexes containing a tetradentate N-donor Schiff base as end-capping ligand

Two hexacoordinated mononuclear Co(III) compounds of the type cis-[Co(L)(N₃)₂] X [1, X = ClO₄; 2, X = PF₆; L = N,N′-(bis(pyridine-2-yl)benzylidine)-1,4-butanediamine] have been synthesized and characterized by physicochemical and spectroscopic methods. The crystal structures of complexes 1 and 2 both have distorted octahedral geometry with two terminal azides in mutual cis orientations. In the crystalline state, two mononuclear units of 1 are associated by weak C–H…π interactions to produce a dimeric unit, which packs through C–H…O hydrogen bonds and π…π interactions leading to a 2-D continuum. The mononuclear units in 2 are engaged in weak cooperative intermolecular C–H…π interactions and multiple C–H…F hydrogen bonds giving rise to a 3-D network structure. These diamagnetic compounds are redox active and show luminescence in DMF solutions.     

Molecular and crystal structure of indole derivatives fused with substituted bicyclo[3.3.1]nonane

Molecular structures of oxime 6-oxo-indolo[2,3-b]-bicyclo[3.3.1]non-2-en 1 and 6-oxo-(5-methoxy-indolo[2,3-b])-bicyclo[3.3.1]non-2-en 2 were determined by X-ray crystal investigation. It was revealed that oxime 1 has anti-configuration in respect to indole-containing framework, and both compounds adopt half-chair–chair-conformation. The distortion of rings was evaluated by calculation of the ZP- and CP-puckering parameters. The presence of the methoxy-group in compound 2 was found to lead to the changes in molecular packing in comparison with structure 1.     

Synthesis,Characterization and Structure of [Fe(2,2′-bipy)<Subscript>3</Subscript>]<Subscript>2</Subscript>[α-Mo<Subscript>8</Subscript>O<Subscript>26</Subscript>]: An α-Octamolybdate-Supported Compound Formed During the Diffuse Process

The α-octamolybdate-supported compound: [Fe(2,2′-bipy)₃]₂[α-Mo₈O₂₆] has been unexpectedly synthesized during a diffuse process and characterized by the IR spectroscopy, UV–Vis diffuse reflectance spectroscopy and the single crystal X-ray diffraction. The title compound exhibits an interesting 3D honeycomb ‘host’ supramolecular network with 1D channels, in which only α-octamolybdate anions ‘guests’ reside. The title compound shows the anisotropic property and probably will be applied as a novel semiconductor in the future.     

Synthesis and the crystal and electronic structure of Hg4AsI5

New mercury arsenide iodide Hg₄AsI₅ was synthesized and its crystal and electronic structure was determined. The crystal structure is layered. The layers are composed of alternating AsHg₄ tetrahedra and IHg₈ Archimedean antiprisms and are bound by the iodine atoms, which form short Hg-I bonds with all mercury atoms. Band structure calculations provided evidence for very weak interactions between the iodine atoms of the adjacent layers and the ionic character of the iodine atom centering the Archimedean antiprism. Hence, individual [AsHg₄I₄]⁺ clusters and I⁻ anions can be distinguished. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 736–739, May, 2006. Additional details of the crystal structure study (deposition number CSD-416238) can be obtained from the Fachinformationszentrum Karlsruhe, D-76344 Eggenstein-Leopoldshafen, Germany, fax: +(49)7247-808-666; e-mail: crysdata@fiz-karlsruhe.de.     

Photo-and thermochromic properties of 1′,3′,3′-trimethyl-6-nitro-8-pyridiniomethylspiro[2H-[1]benzopyran-2,2′-indoline] chloride in the crystalline state

1′,3′,3′-Trimethyl-6-nitro-8-pyridiniomethylspiro[2H-[1]benzopyran-2,2′-indoline] chloride (1) was synthesized. Single crystals (crystal hydrates) of the open merocyanine form of compound 1 were obtained under the dark conditions, and their crystal structure was studied. On irradiation with visible light compound 1 crystallizes from propan-2-ol in the polycrystalline closed form. The spectral and photochemical properties of compound 1 in the polycrystalline state and the kinetic characteristics on thermal transformation of the closed form to the open form were studied. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1548–1553, September, 2006.     

Photochromic hybrid sol–gel films containing naphthopyrans

Abstract  

Several photochromic benzo- and naphthopyrans were embedded in hybrid organic–inorganic ureasilicate based films obtained by a sol–gel process. The resulting films, containing 0.1% (w/w) of the photochromic compound, were transparent and flexible and for naphthopyrans they were colourless or presented just a slight colouration. Under UV continuous irradiation the films developed a significant absorption in the visible region that fades in the dark with variable kinetics depending on the naphthopyran structure. 2,2-Diphenyl-3H-naphtho[2,1-b]pyran films showed a very fast colouration under UV light giving rise to coloured open forms, containing mainly the TC isomer (98%) along with a very small amount of the more stable TT isomer (2%), that practically returned to the initial absorbance in 1 min.     

Crystal structure of 1,9-dimethyl-4,5-dihydro-6H-pyrido[3’,2’:4,5]thieno[2,3-f] pyrrolo[1,2-a][1,4]diazepin-6-one

A new tetracyclic compound, 1,9-dimethyl-4,5-dihydro-6H-pyrido[3’,2’:4,5]thieno[2,3-f]pyrrolo[l,2-a][1,4]diazepin-6-one (2) was isolated and studied by X-ray crystallography. Compound 2 crystallizes in the orthorhombic system, space group Pna2₁, a = 11.1098(8) ?, b = 8.4815(6) ?, c = 28.367(2) ?, V= 2673.0(3) ?³, Z=8. The crystal structure comprises two crystallographically independent molecules of the compound. They relate as stereoisomers; in each the diazepine ring exhibits a boat conformation. The crystal packing reveals zigzag H-bonded chains with two distinct hydrogen bonds. The H…O distances and N-H…O angles for N3-H3…O1’ are 2.012? and 174°, and for N3’-H3’…O1 are 1.974? and 154°, respectively.     

Crystal structure and synthesis of benzimidazole substituted acrylonitriles and benzimidazo[1, 2-a]quinolines

The benzimidazole compounds and benzoannulated cyclic benzimidazole analogues, such as benzimidazo[1,2-a]quinolines, are a part of our wider investigation on biologically active compounds, potential antitumor drugs. Here, we present the synthesis of two compounds, [2-(1H-benzimidazol-2-yl)-3-(4-bromophenyl)-acrylonitrile, 5] and [2-bromo-benzimidazo[1,2-a]quinoline-6-carbonitrile, 7] and their crystal structures revealed by X-ray single crystal diffractometry. We also report the molecular and crystal structures of two additional compounds [2-(1H-benzimidazol-2-yl)-3-(4-cyanophenyl)-acrylonitrile, 4] and [benzimidazo[1,2-a]quinoline-2,6-dicarbonitrile, 6], whose synthesis and spectroscopic characterization have been published earlier by us too (Hranjec and Karminski-Zamola, Molecules 12:1817, 2007). The compounds 4 and 5 crystallize as monohydrates. The dihedral angles calculated between phenyl and benzimidazole ring reflect not significant deviation from molecular planarity in the crystalline state for 4 and 5, while benzoannulated cyclic benzimidazole derivatives 6 and 7 are essentially planar. The crystal structures of 4 and 5 are characterized by O–H···N and N–H···O hydrogen bonds between water molecule of crystallization and imidazole NH group as well as CN group, while in 6 and 7 only weak C–H···N intermolecular hydrogen bonds exist. Although, crystal packings are analogous in 4 and 5, the molecular conformations differ slightly. In 6 there is one C–H···N hydrogen bond that do not exist in 7.     

Synthesis of 1,2-bis[2-methyl-5(3,4-difluorophenyl)-3-thienyl] perfluorocyclopentene

2-Methylthiophene (1) was treated at 0°C with liquid bromine to form 3,5-dibromo-2-methylthiophene (2) which reacted with tributyl borate to give 2-methyl-3-bromo-5-boronate thiophene (3) at −78°C. Treatment of 3 with 3,4-difluorobrombenzene gave 2-methyl-3-bromo-5-(3,4-difluorophenyl)thiophene (4). Finally, a novel photochromic dithienylethene compound, 1,2-bis [2-methyl-5(3,4-difluorophenyl)-3-thienyl]perfluorocyclopentene (DT-1), was synthesized by the reaction of 4 with perfluorocyclopentene at −78°C. The compound (DT-1) was characterized by IR, NMR, MS, elemental analysis and its photochromic behavior was also discussed. __________ Translated from Chinese Journal of Organic Chemistry, 2007, 27(10): 1282–1284 [译自: 有机化学]     

[Cu2(μ-(3,4,5-meo-ba)2bn)(μ-I)2]n, a new 1D polymeric copper(I) chain Synthesis, crystal structure, spectral and thermal studies

New 1D-chain copper(I) complex [Cu₂(μ-(3,4,5-MeO-ba)₂bn)(μ-I)₂] _n (1), where (3,4,5-MeO-ba)₂bn = N,N′-bis(3,4-dimethoxybenzylidene)-butane-1,4-diamine, involving a new bidentate Schiff-base containing a flexible spacer (=N–C–C–C–C–N=) has been synthesized and characterized by elemental analyses (CHN) and FT-IR spectroscopy. The crystal structure of 1 was determined from single-crystal X-ray diffraction analyses and shows the (3,4,5-MeO-ba)₂en acts as a bridging ligand with the nitrogen atoms of the two imine functions and leading to the dinuclear [Cu₂((μ-(3,4,5-MeO-ba)₂en)] groups. Such dinuclear [Cu₂((μ-(3,4,5-MeO-ba)₂en)] groups are bridged by two iodine anions [(μ-I)₂] to form a neutral 1D-chain copper(I) iodide coordination polymer. The coordination polyhedron about the copper(I) center in 1 is best described as a distorted trigonal planar. Thermogravimetric analyses reveal the thermal stability and decomposition pattern of 1.     

Syntheses,structures, and properties of two binuclear cadmium(II) iodides containing a bis(tridentate) Schiff base/tetradentate tripodal amine: control of coordination numbers by varying ligand matrices

Two binuclear cadmium(II) iodide compounds of the types [Cd₂(L1)(I)₄] (1) and [(L2)Cd(μ-I)CdI₃] (2) [L1 = N,N′-(bis(pyridine-2-yl)formylidene)triethylenetetramine and L2 = tris(2-aminoethyl)amine] are synthesized and characterized. X-ray structural study shows that each cadmium(II) in 1 has a distorted square pyramidal geometry with a CdN₃I₂ chromophore and that L1 behaves as a binucleating bis(tridentate) ligand bridging the metal centers with iodides remaining as terminals. In 2, one cadmium(II) adopts a distorted tetrahedral geometry with a CdI₄ chromophore surrounded by four iodides, while the other has a distorted trigonal bipyramidal environment with CdN₄I chromophore bound by four N atoms of L2 and one bridging iodide. Weak C–H···π interactions in 1 result in an infinite 1D chain; however, such weak non-covalent interactions are absent in 2. The Schiff base complex, 1, shows high-energy intraligand ¹(π–π*) fluorescence in DMF solution at room temperature, whereas compound 2 containing tripodal amine is fluorescent-inactive.