Synthesis,crystal structure and luminescent properties of new tris-β-diketonate Eu(III) complex with thiadiazolophenanthroline derivative ligand

Herein we describe the synthesis, characterization and spectroscopic properties of the complex tris-(thenoyltrifluoroacetonate)([1, 2, 5]thiadiazolo[3, 4-f][1,10]phenanthroline) europium(III) acetonitrile solvate, [Eu(TTA)₃ TDPHEN] 1.5CH₃CN, where TTA = 2-thenoyl trifluoroacetone and TDPHEN = [1, 2, 5]thiadiazolo[3, 4-f][1, 10] phenanthroline. X-ray crystallography reveals that it is an eight-coordinate Eu(III) complex containing three β-diketonate chelates and one N,N′-bidentate ligand, [1, 2, 5] thiadiazolo[3, 4-f][1, 10] phenanthroline. The excitation at 340 nm of the europium complex in a solution of acetonitrile, and at room-temperature, showed the typical Eu(III) red emission as a sharp band at 611 nm, characteristic of Eu(III) due to the transition ⁵D₀ → ⁷F₂. This complex also showed red emission in the solid state phase (λ_em = 612 nm).     

Open circuit voltage increase by substituted spacer and thieno[3,4-c]pyrrole-4,6-dione for polymer solar cells

We reported on two donor polymers containing thieno[3,4-c]pyrrole-4,6-dione(TPD) derivatives as electron withdrawing units for organic photovoltaics (OPVs). To control molecular weight and solubility of polymers, hexyl side chains are inserted to thiophene spacers. Due to the electron donating characteristic of hexyl side chains, highest occupied molecular orbital (HOMO) energy level of polymer is decreased as 0.18 eV, whereas the open circuit voltage is increased to 1.08 V. When bulk heterojunction devices were fabricated, the best PCE value of 0.360% (V_OC = 0.89 V, J_SC = 1.2 mA/cm², FF = 36.3%) under 100 mW/cm² irradiation.     

Synthesis and structure study of copolymers from thiadiazole fused indolocarbazole and dithienosilole

We report synthesis and characterization of two D-A polymers (PSDT-C12 and PSDT-EH) with different side chains. Both polymers are based on alternate 12,13-dioctyl-indolo[2,3-a][1,2,5]thiadiazolo[3,4-c]carbazole (TDZIC) and dithienosilole derivative units in polymer main chain. We used TDZIC to enlarge the 2D conjugated plane of acceptor monomers by fusing benzothiadiazole (BT) unit with an indole unit having alkyl groups. PSDT-C12 exhibited 10 nm redshift compared to PSDT-EH in solid films, while their absorption spectra were almost identical in solutions. Since the backbone and side chains on the indolocarbazole group are the same, the redshift on PSDT-C12 could be resulted from the dodecyl (C12) side chain on the dithienosilole unit and different molecular weight between these two polymers. PSDT-C12 has a larger molecular weight than PSDT-EH. Therefore possibly both side chains and molecular weight contributed to the difference in the absorption spectra in solid films. The straight C-12 side chain has less steric hindrance than the branched EH side chain in solid films. PSDT-C12 has a longer main chain (larger molecule weight) than PSDT-EH, which can favour a more extended main chain interaction. The vibronic peak at 519 nm and shoulder at 563 nm in the PSDT-C12 film further confirmed stronger main chain interaction. Geometry optimization showed that head–tail (HT)-PSDT had a more twisting conjugated backbone with larger dihedral angle between dithienosilole unit and thiadiazole-fused ring compared to head–head/tail–tail (HH/TT)-PSDT.     

Hexachloroplatinate(IV) anion-induced cucurbit[5]uril and cucurbit[8]uril supramolecular assemblies with linear channels

Two Q[n]-based porous compounds, Q[5]·[PtCl₆]^2 −·2H₃O·12H₂O and 2Q[8]·[PtCl₆]^2 −·2H₃O·74H₂O in cooperating the hexachloroplatinate(IV) anion ([PtCl₆]^2 −) as an inorganic structure directing agent are demonstrated. The driving forces for the formation of such novel Q[n]-based porous compounds are considered to be the outer surface interactions of Q[n]s, including dipole interactions between Q[n]s and ion-dipole interactions between [PtCl₆]^2 − anions and Q[n]s. Moreover, the Q[5]-based porous compound displays absorption distinctness for tetrachloromethane, whereas the Q[8]-based porous compound displays absorption distinctness for methanol.     

Epoxidation of natural propenylbenzenes catalyzed by [FeIII(Salen)Cl] and [FeIII(TPP)Cl]

Epoxidation of natural propenylbenzenes (safrol, isosafrol, anethol, eugenol and isoeugenol) was carried out using iron complexes as catalysts ([Fe^III(TPP)Cl] and [Fe^III(Salen)Cl] · H₂O, where TPP = 5, 10, 15, 20-meso-tetraphenylporphyrin and Salen = N,N′-(salicylaldehyde)ethylenediamine) in presence of hydrogen peroxide 30% and glacial acetic acid. Reaction products were identified by gas chromatography and satisfactory yields were obtained. Quantitative conversion of isosafrol to the corresponding epoxide was achieved in presence of [Fe^III(TPP)Cl] as catalyst.     

Synthesis and two-photon absorption properties of 2,5-bis[4-(2-arylvinyl)phenyl]-1,3,4-oxadiazoles

Two symmetrical 2,5-bis[4-(2-arylvinyl)phenyl]-1,3,4-oxadiazoles that exhibit strong two-photon absorption and enhanced two-photon excited fluorescence were designed and synthesized based on “push-core-pull-core-push” molecules built from embedding electron-transporting 1,3,4-oxadiazole in aromatic conjugated system through Wittig–Horner reaction. Pumped by nanosecond laser at 800 nm, strong up-conversion emissions with the central wavelength at 507 nm (green) of 2,5-bis[4-(2-N,N-diphenylaminostyryl)phenyl]-1,3,4-oxadiazole and 475 nm (blue) of 2,5-bis[4-{2-(3-N-ethylcarbazolyl)vinyl}phenyl]-1,3,4-oxadiazole in the solution of CHCl₃ have been observed. Their two-photon absorption cross-sections obtained by nonlinear transmission method are 107 × 10⁻⁴⁸ cm⁴ s photon⁻¹ and 66 × 10⁻⁴⁸ cm⁴ s photon⁻¹. A very effective energy transfer from the excited terminal units to the π-conjugated bridging units of the 2,5-bis[4-(2-arylvinyl)phenyl]-1,3,4-oxadiazoles is the dominant contribution to the two-photon absorption.     

Synthesis,structure and electronic calculation of alkali metals borate Li2Na[B5O8(OH)2]

A new alkali metals borate complex, Li₂Na[B₅O₈(OH)₂], has been successfully synthesized by a facile hydrothermal method. Single-crystal X-ray diffraction analysis reveals that it crystallizes in orthorhombic space group Pbcn with a = 8.919(3) Å, b = 9.181(3) Å, c = 8.416(2) Å, Z = 4. The crystal structure is constructed of two dimensional (2D) [(B₅O₈)(OH)₂]_∞ layers, while stacking along b axis and then connected by Li⁺ and Na⁺ cations to extend to 3D framework Li₂Na[B₅O₈(OH)₂]. UV-vis-NIR spectrum shows that Li₂Na[B₅O₈(OH)₂] possesses a wide range of transparency and a UV cut-off edge below 190 nm which indicates that it may be applied in the deep ultraviolet region. The calculated band structures and the density of states indicate that Li₂Na[B₅O₈(OH)₂] is a direct band gap compound with a band gap of 5.68 eV. In addition, IR spectroscopy, thermal stability and theoretical calculations of Li₂Na[B₅O₈(OH)₂] are also reported in this work.     

Absorption properties of an inverted cucurbit[7]uril-based porous coordination polymer induced by [ZnCl4]2 − anions

Coordination of an inverted cucurbit[7]uril (iQ[7]) with a series of alkali cations (A⁺), revealed that iQ[7] can interact with potassium to form iQ[7]-K⁺-based porous coordination polymer in the presence of [ZnCl₄]^2 − anions as a structure directing agent. Unexpectedly, isothermal titration calorimetry revealed no obvious interaction of iQ[7] with any A⁺ cation. Moreover, the iQ[7]-K⁺-based porous coordination polymer showed selective sorption of polar volatile organics, which may have potential applications for molecular sieves, sensors, and absorption and separation processes.     

Electrochromic performance and ion sensitivity of a terthienyl based fluorescent polymer

A novel terthienyl based fluorescent polymer bearing strong electron-withdrawing substituents directly attached to the 3,4-positions of the central thiophene ring was synthesized by electrochemical polymerization of diethyl 2,5-di(3,4-ethylenedioxythiophen-2-yl)thiophene-3,4-dicarboxylate. The corresponding polymer was characterized by cyclic voltammetry, FT-IR and UV–vis spectroscopy. The polymer has a well-defined redox process (E_p,1/2 = 0.74 V) and demonstrates a reversible electrochromic behavior; lilac in the neutral state and transparent sky blue in the oxidized state. Also, the polymer had low band gap (E_g = 1.82 eV) and high redox stability (retaining 94.0% of its electro-activity after 500th switch). Moreover, the sensitivity of both the monomer and its polymer towards metal cations was investigated by monitoring the change in the fluorescence intensity. Among various common ions both the monomer and its polymer were found to be selective towards Cu²⁺ and Cu⁺ ions by quenching the fluorescence efficiency with a Stern–Volmer constant (K_sv) of (1.4–1.6 × 10³ M^?1) and (1.5–1.8 × 10² M^?1) for monomer and polymer solutions, respectively.     

Electro-optical and electrochemical properties of an ionic polyacetylene derivative with azobenzene anisole moieties

An ionic polyacetylene derivative with azoanisole moieties was prepared by the activated polymerization of 2-ethynylpyridine by using 4-[4-(9-bromononyloxy)phenylazo]anisole without any additional initiator or catalyst in high yield. The chemical structure of poly[2-ethynyl-N-(p-methoxyphenylazophenyl)oxynonylpyridinium bromide] (PEMPB) was characterized by instrumental methods such as NMR (¹H and ¹³C), IR, UV–vis spectroscopies to have a conjugated polymer backbone system with the designed azobenzene moieties as substituents. This polymer was completely soluble in organic solvents and well processible. The electrochemical and electro-optical properties of PEMPB were studied. The cyclovoltammograms of this polymer exhibited the irreversible electrochemical behaviors between the oxidation and reduction peaks. The oxidation current density of PEMPB versus the scan rate is approximately linear relationship in the range of 30 mV/s–120 mV/s. The exponent of scan rate, x value of PEMPB, is found to be 0.6. The absorption spectrum starts around 700 nm and shows a characteristic absorption band at visible region of 464 nm due to the π → π* interband transition of the polymer backbone, which is a peak of the conjugated polyene backbone. The photoluminescence spectrum showed that the PL peak is located at 539 nm corresponding to the photon energy of 2.30 eV.     

Synthesis,crystal structure,and optical property of a one-dimensional selenidostannate: [AEPPH2]2[Sn5Se12] (AEPP = N-aminoethylpiperazine)

A one-dimensional (1-D) selenidostannate, [AEPPH₂]₂[Sn₅Se₁₂] (AEPP = N-aminoethylpiperazine) (1), has been prepared under solvothermal condition and characterized. Single crystal X-ray analysis reveals that compound 1 crystallizes in the triclinic space group P-1, a = 10.6351(7) Å, b = 10.6850(7) Å, c = 10.7771(7) Å, α = 61.3440(10)°, β = 62.4420(10)°, γ = 67.4680(10). With distinct linkage modes between SnSe₄ tetrahedrons and SnSe₆ octahedrons, a secondary building unit (SBU) [Sn₅Se₁₄] is formed. Compound 1 contains infinite bead-like chains built up by the [Sn₅Se₁₄] SBUs, and the protonated [AEPPH₂]^2 + cations are located between the chain spaces. A pseudo 3-D network is formed through C–H···Se and N–H···Se hydrogen bonds between adjacent chains. Its optical property and theoretical band structure and density of state (DOS) calculations have also been studied.     

Synthesis,structure and stability of fac-[FeII(CO)3X3]1− (X = Br,I)

fac-[Fe^II(CO)₃X₃]^1? (X = Br, I) are synthesized and their structures have been determined. They are the first crystallographically characterized iron tricarbonyl trihalide complexes. fac-[Fe^II(CO)₃X₃]^1? (X = Br, I) are fairly thermally stable and therefore lead themselves as excellent starting materials for the preparation of various iron carbonyl complexes since both the halide and carbonyl ligands are substitutionally labile.     

A nitrogen rich Ni(II)–dithiolate system exhibiting acid–base behavior: Synthesis,supramolecular structure and spectroscopy of [Bu4N]2[NiII(ppdt)2] (ppdt = pyrido[2,3-b]pyrazine-2,3-dithiolate)

The compound [Bu₄N]₂[Ni(ppdt)₂] (1) (ppdt = pyrido[2,3-b]pyrazine-2,3-dithiolate) has been synthesized, starting from pyrido[2,3-b]pyrazine-2,3-dithiol, nickel chloride and tetrabutylammonium bromide in methanol. Compound 1 crystallizes in P2₁/c space group (monoclinic system). Its crystal structure is characterized by interesting C–H?S and C–H?N supramolecular weak interactions. Its solution state has been described with acid–base (protonation–deprotonation) behavior, that has rarely been investigated for a metal–dithiolene system. Compound 1 is first instance of a metal–dithiolene compound that has three ring nitrogen on each dithiolate ligand. The pH dependent changes in the charge-transfer absorption band are attributed to the protonation on an imine nitrogen of the ppdt ligand. The complex is electrochemically quasi-reversible with an oxidation potential of E_1/2 = +0.46 V vs. Ag/AgCl in methanol.     

pH-controlled the formation of 4-sulfocalix[4]arene-based 1D and 2D coordination polymers

Three manganese/4-sulfocalix[4]arene complexes, namely, {H[(C₂₈H₂₀O₁₆S₄)Mn(H₂O)₄Mn_0.5(H₂O)₂]}_n ·6nH₂O (1), {NH₄[(C₂₈H₂₀O₁₆S₄)Mn(H₂O)₄Mn_0.5(H₂O)₂]}_n · 5nH₂O (2), [(C₂₈H₂₀O₁₆S₄)Mn₂(H₂O)₈]_n · 6nH₂O (3), have been synthesized under different pH conditions. Complex 1, which exhibits a one-dimensional (1D) structure, is formed at [H⁺] = 2.0 mol L⁻¹. Reaction at pH 4 leads to another one-dimensional (1D) coordination polymer of 2. At pH 5, a two-dimensional (2D) coordination polymer of complex 3 is formed, showing clearly structural effects on pH response.     

Photochemical reductive elimination of [PtIV(NH3)4(NH2)Cl]2 +: Photogeneration of hydrazine

When [Pt^IV(NH₃)₅Cl]^3 + is deprotonated the complex [Pt^IV(NH₃)₄(NH₂)Cl]^2 + is formed. Upon NH₂⁻ → Pt^IV LMCT excitation (λ_irr > 250 nm) a reductive elimination takes place: [Pt^IV(NH₃)₄(NH₂)Cl]^2 + → [Pt^II(NH₃)₃Cl]⁺ + N₂H₄ + H⁺. Since Pt(II) ammine complexes can be reoxidized to Pt(IV) by H₂O₂ it is suggested that in a cyclic process the overall reaction could proceed according to the equation: 2 NH₃ + H₂O₂ → N₂H₄ + 2 H₂O.     

Morphological and impedance studies on electropolymerized 3,4-(2,2-dibenzylpropylenedioxy)thiophene nanostructures on micron sized single carbon fiber

Micron sized single carbon fibers were cyclovoltammetrically coated with poly[3,4-(2,2-dibenzylpropylenedioxy)thiophene] resulting in a nanofiber network at the surface. The method provides conjugated polymer nanostructures covalently and uniformly bound to micron sized substrates. When the electropolymerization is carried out with different electrolytes in acetonitrile the dopant influences the structure of the coating layer what is proved by electrochemical impedance spectroscopy and electron microscopy. Electrodes based on poly[3,4-(2,2-dibenzylpropylenedioxy)thiophene] on single carbon fiber microelectrodes (SCFMEs) prepared in Bu₄NPF₆/ACN show the best capacitance performance due to their higher surface area. The improvement is attributed to the formed nanofiber network structure which results in a more efficient charge transport and collection.Impedance spectra show the typical form of Z_IM vs. Z_RE curves for transmission-line at a frequency of 10 Hz, with transition to almost pure capacitive behavior up to 10 MHz. Equivalent circuit modeling was simulated for the electrolyte/polymer film/SCFME system. A good agreement was achieved for the calculated capacitances in comparison with the experimental EIS measurement results.     

Generation of a low temperature NO linkage isomer in a transition metal complex of group 9: K[IrCl5NO]

The [IrCl₅NO]^− 1 ion in the potassium salt can be partially transformed into a metastable state by light irradiation in the violet-near UV region at low temperature (77 K). The excitation process was followed by infrared spectroscopy, comparing the spectra before and after irradiation.A new band grew at 1812 cm^− 1 after irradiation with light in the 308–420 nm spectral region. The metastable state behavior is verified as this band decays upon heating the samples above 90 K or by subsequent irradiation using 450–680 nm light. The band at 1812 cm^− 1 was assigned to ν(NO) of metastable state 1 (or an IrON linkage isomer) for comparison with the band position reported for other transition metal nitrosyls. To our knowledge, this is the first generation of a M-ON linkage isomer reported for a nitrosyl of transition metal of group 9. Its behavior is similar to that observed in other nitrosyl complexes of group 8.     

Blue light-emitting diodes from 2-(10-naphthylanthracene)-spiro[fluorene-7,9′-benzofluorene] host material

A novel, spiro-type host material 2-(10-naphthylanthracene)-spiro[fluorene-7,9′-benzofluorene] was prepared by reacting 2-bromo-spiro[fluorene-7,9′-benzofluorene] with 9-(2-naphthylanthracene)-10-boronic acid via the Suzuki reaction. 2-4′-(Phenyl-4-vinylbenzeneamine)phenyl-spiro[fluorene-7,9′-benzofluorene], 4-[2-naphthyl-4′(phenyl-4-vinylbenzeneamine)]phenyl and diphenyl-[4-(2-[1,1;4,1]terphenyl-4-yl-vinyl)-phenyl]-amine were used as dopant materials. Devices with the configuration of ITO/N,N′-bis[4-(di-m-tolylamino)phenyl]-N,N′-diphenylbiphenyl-4,4′-diamine)/bis[N-(1-naphthyl)-N-phenyl]benzidine/2-(10-naphthylanthracene)-spiro[fluorene-7,9-benzofluorene]:5% dopant/aluminum tris(8-hydroxyquinoline)/Al-LiF showed a maximum power efficiency of 3.7 cd/A at 17.93 mA/cm² and a maximum luminance of 5018 cd/m² at 10 V with a turn-on voltage of 4.5 V.     

Crystal structure analysis of twisted cucurbit [14]uril conformations

In the present work, twisted cucurbit [14]urils were complexed with Dy^3 + cations in the presence of [CdCl₄]^2 − anions (compound 1) or with 1,12-dodecanedipyridyl (compound 2). Crystal structures were determined for the resultant Dy^3 +-bound and metal-free twisted cucurbit [14]uril complexes, and their conformations were found to be comparable.     

Tetrapyrazolyl-calix[4]arene-based supramolecular architectures from [Pd16L4] macrocycle to three-dimensional microporous channels

By employing di-palladium complex [(bpy)₂Pd₂(NO₃)₂](NO₃)₂ (where bpy = 2, 2′-bipyridine) as corners and tetrapyrazolate calix[4]arene-based ligand (L^4 −) as linkers, a novel cavity-containing high-positively-charged polypyrazolate-bridged metallo-macrocycle [Pd₁₆L₄]^16 +·16NO₃ with Pd(II)⋯Pd(II) dimetal-coordination motifs has been synthesized by a directed coordination driven self-assembly with spontaneous deprotonation of the 1H-bipyrazole ligands in aqueous solution. The counter ions NO₃⁻ were trapped within the amphiphilic 3-D microporous channels in the solid state.