Single X-ray Structure Analysis Research Articles

The electrophilic methylating agent [SO2Me]+ parent of two cationic species.

Methylfluoride and hydrogen fluoride react with powerful methylating agent [SO2Me]+ in a temperature-dependent addition reaction to form methylated fluorosulfuric acid [FS(OMe)2][Sb2F11] and methylated fluorosulfuric acid methyl ester [FS(OH)(OMe)][SbF6], respectively. The obtained methylated fluorosulfinic acid and methylated fluorosulfinic acid methyl ester were characterized by single X-ray structure analysis and vibrational spectroscopy.

2-[2-(Diphenylphosphoryl)phenyl]-1H-perimidine

In this paper, we report the crystal structure of 2-[2-(diphenylphosphoryl)phenyl]-1H-perimidine (L1) obtained from the ring closure reaction of 1,8-diaminonaphthalene and 2-(diphenylphosphino)benzaldehyde, followed by the dehydrogenation reaction with sodium metabisulfite (Na2S2O5). L1 was characterised using 1H, 13C & 31P NMR, FT-IR and X-ray single structure analyses.

Highly efficient and concentration-insensitive OLEDs based on alkyl sterically modified red homoleptic phenylphthalazine iridium complexes

Four red homoleptic iridium (III) complexes (Ir1–Ir4) with steric phenylphthalazine ligands have been synthesized. Single X-ray structural analysis shows that the steric hindrance groups can prevent molecular aggregation. All complexes exhibited red emission with peaks between 614 and 629 nm in CH2Cl2 and photoluminescence quantum yields (QYs) of 44%–86% in doped films. They were concentration-insensitive, their QYs in neat powder and air atmosphere can reach a maximum of 15%. These complexes exhibited excellent thermal stability with Td higher than 416 °C. The OLEDs based on these complexes showed good performances at 10 wt% high doping concentration. Especially, the device based on Ir1 gave a peak current efficiency and external quantum efficiency (EQE) of 25.0 cd A−1 and 24.2% with mild efficiency roll-off, which is the most efficient OLED based on phthalazine iridium complexes. The maximum EQEs of non-doped devices are between 4.0% and 5.6%, which are considerably high, compared with the reported efficiency of iridium complexes based red-emitting non-doped devices. These studies show that increasing the density of the rigid steric groups of iridium complexes is very effective to achieve high efficiency and low concentration sensitive red phosphorescent devices.

Rearrangement of Diferrocenyl 3,4-Thiophene Dicarboxylate

Treatment of 3,4-(ClC(O))2-cC4H2S (1) with [FcCH2OLi] (2-Li) (Fc = Fe(η5-C5H5)(η5-C5H4)) in a 1:2 ratio gave 3,4-(FcCH2OC(O))2-cC4H2S (3). Compound 3 decomposes in solution during crystallization to produce FcCH2OH (2) along with 3,4-thiophenedicarboxylic anhydride (4). The cyclic voltammogram of 3 exhibits a reversible ferrocene-related redox couple (E1/2 = 108 mV, vs. Cp2Fe/Cp2Fe+) using [NnBu4] [B(C6F5)4] as the supporting electrolyte. DFT calculations reveal that the energy values of the LUMO orbitals of 3 (3,4-thiophene core) show 1 eV higher energies than that one of 2,5-(FcCH2OC(O))2-cC4H2S (5), both compounds’ HOMO orbitals are close to each other. Compound 4 was characterized by single X-ray structure analysis. It forms a band-type structure based on intermolecular O1···S1 interactions being parallel to (110) and (1–10) in the solid state, while electrostatic C···O interactions between the C=O functionalities of adjacent molecules connect both 3D-networks. Hirshfeld surface analysis was used to gain more insight into the intermolecular interactions in 4, the enrichment ratios (E) suggest that O···H, S···S, and O···C are the most favored intermolecular interactions, as shown by E values above 1.20. The relevance of the weak O···H, O···O, and O···C contacts in stabilizing the molecular structure of 4 was highlighted by the interaction energies between molecular pairs.

Aza-triptycene-based homoleptic tris-cyclometalated iridium(III) complexes as highly efficient phosphors in green OLEDs

Three homoleptic tris-cyclometalated iridium (III) complexes (Ir1–Ir3) based on a rigid aza-triptycene unit have been synthesized via a novel one-pot method. The coordination arrangement of Ir2 was revealed by single X-ray structural analysis and the molecule showed a facial configuration. These complexes exhibited excellent thermal stability with Td of 454–520 °C. These complexes exhibit strong green phosphorescence emission with high quantum yields of over 70% due to the introduction of aza-triptycene skeleton with rigid steric hindrance reduced intermolecular interactions. Accordingly, the electroluminescence device based on Ir1, Ir2 and Ir3 exhibit high-brightness of 42194, 48807 and 46332 cd m−2, maximum luminous efficiency of 21.0, 24.7 and 28.5 cd A−1 and high EQE of 6.3, 6.8 and 8.9% at a high doping concentration of 30 wt%. Meanwhile, the non-doped green devices based on Ir1, Ir2 and Ir3 give high-brightness of 20571, 15407 and 10707 cd m−2 and luminous efficiency of 8.5, 9.5 and 5.4 cd A−1, respectively. These results suggest that these materials have potential application in OLEDs.

The novel synthesis of tris-cyclometalated iridium(III) complexes for saturated red organic light-emitting diodes with low efficiency roll-off

A series of homoleptic tris-cyclometalated iridium(III) complexes (Ir2–Ir4) have been synthesized by the direct functionalization of a template complex (Ir1) through a Suzuki cross-coupling reaction. We revealed the coordination arrangement of Ir4 by single X-ray structural analysis and the molecule showed a facial configuration. All the complexes showed red emission with emission maxima at 591–624 nm, short lifetimes of 1.38–2.19 μs and photoluminescence quantum yields in the range of 28–42%. Most importantly, the full width at half maximum (FWHM) of the emission maxima of these complexes was less than 48 nm. These complexes exhibited good thermal stability with Td of 368–400 °C. Density functional theory (DFT) calculations were used to study the electronic structure information of these iridium(III) complexes. Organic light emitting diodes (OLEDs) based on these complexes as dopant emissive materials were fabricated. Among them the device based on Ir1 has a maximum current efficiency and external quantum efficiency of 15.67 cd A−1 and 10.06%, respectively. The device with low efficiency and EQE roll-off that 97–99% efficiency and EQEmax maintained at 1000 cd m−2. Meanwhile, the CIE(x,y) coordinates of these extended complexes were (0.65, 0.33), (0.66, 0.33) and (0.68, 0.31), respectively. These data were very close to the standard red emission required by National Television System Committee (NTSC) (0.67, 0.33). These results suggest that these materials have potential application in OLEDs.

Preparation and electroluminescent application of iridium(III) complexes containing sulfur-containing phenylpyridazine ligands

Four iridium(III) complexes (1–4) with sulfur-containing phenylpyridazine ligands were successfully synthesized and characterized. The structure of complex 3 was further confirmed by single X-ray structural analysis. These complexes showed strong green phosphorescence at room temperature with peak wavelengths ranging from 524 to 539 nm in CH2Cl2 solution. These complexes exhibited medium quantum yields of 42 ~ 61% in PMMA films with lifetimes of 1.58 ~ 3.26 μs. These complexes also exhibited good thermal stability with Td > 275 °C. The phosphorescent OLEDs were fabricated using complexes 1 and 2 as dopants. The device using complex 2 displayed good performances with the maximum luminance, current efficiency, power efficiency and external quantum efficiency of 8913 cd m−2, 44.2 cd A−1, 30.7 lm W−1 and 11.8%, respectively. These results indicate excellent application prospects of these iridium(III) complexes as efficient phosphors in OLEDs.

Iron(II) Spin Crossover Complexes Based on a Redox Active Equatorial Schiff-Base-Like Ligand.

In this work, two iron(II) coordination compounds with a N2O2 coordinating Schiff base-like ligand bearing a redox active tetrathiafulvalene (TTF) unit and pyridine or trans-1,2-bis(4-pyridylethylene) as an axial ligand are synthesized. Crystals suitable for single X-ray structure analysis were obtained for the new ligand. The complexes were characterized by magnetic susceptibility measurements, T-dependent UV-vis spectroscopy, and cyclic voltammetry. Both complexes display spin transition behavior below room temperature with T1/2 values of 146 and 156 K. The mononuclear iron(II) complex [FeTTFL(py)2] is relatively stable up to 400 K compared to similar complexes, showing no loss of axial ligands upon heating. Temperature dependent Mössbauer spectroscopy was conducted for the coordination polymer {[FeTTFL(bpee)]}n to get more information regarding the origin of the stepwise spin crossover (SCO) behavior observed in the magnetic measurements. The change of the spin state is accompanied by a change of the optical properties, which can be monitored by VT-UV-vis spectroscopy for the mononuclear complex and has been analyzed in theoretical studies. The redox behavior of the iron(II) complexes reveals three reversible redox steps which are located at the iron center and at the TTF unit of the ligand. Oxidation of the TTF unit induces characteristic changes in the UV-vis spectrum that can be followed by spectroelectrochemical UV-vis spectroscopy. Addressing the potential of the iron-centered redox process results in similar changes in the UV-vis spectrum, which indicates an electronic coupling of the redox active unit with the metal center under certain circumstances.

Pharmaceutical Cocrystal Development of TAK-020 with Enhanced Oral Absorption

The objective of this study was to improve the solubility of poorly water-soluble drugs by pharmaceutical cocrystal engineering techniques and select the best pharmaceutical forms with high solubility and solubilized formulations for progress from the early discovery stage toward the clinical stage. Several pharmaceutical cocrystals of TAK-020, a Bruton tyrosine kinase inhibitor, were newly discovered in the screening based on the solid grinding method and the slurry method, considering thermodynamic factors that dominate cocrystal formation. TAK-020/gentisic acid cocrystal (TAK-020/GA CC) was selected based on a physicochemical property of enhanced dissolution rate. TAK-020/GA CC was proven to be a reliable cocrystal formation with a definitive stoichiometric ratio by a variety of analytical techniques—pKa calculation, solid-state nuclear magnetic resonance, and single X-ray structure analysis from the view of regulation. Furthermore, its absorption was remarkable and beyond those achieved in currently existing solubilized formulation techniques, such as nanocrystal, amorphous solid dispersion, and lipid-based formulation, in dog pharmacokinetic studies. TAK-020/GA CC was the best drug form, which might lead to good pharmacological effects with regard to enhanced absorption and development by physicochemical characterization. Through the trials of solid-state optimization from early drug discovery to pharmaceutical drug development, the cocrystals can be an effective option for achieving solubilization applicable in the pharmaceutical industry.

The facile synthesis of homoleptic phenylpyridazine iridium(III) complexes and their application in high efficiency OLEDs

Abstract Two one-pot methods have been used to synthesize various homoleptic phenylpyridazine iridium (III) complexes (2–4). The coordination arrangements of 2 and 3 were revealed by carrying out single X-ray structural analyses. These complexes showed green emission. Their peak wavelengths ranged from 508 to 538 nm with quantum yields greater than 70%. Density functional theory (DFT) was used to discuss the correlation between substituent nature and photophysical characteristics of these complexes. Organic light-emitting diodes (OLEDs) were fabricated by taking 2–4 as dopants. The green device based on complex 4 shows a maximum current efficiency and external quantum efficiency of 78.6 cd A−1 and 21.9%, respectively, and mild efficiency roll-off. The results suggest that these homoleptic phenylpyridazine iridium(III) complexes have potential application as efficient emitters in OLEDs.

The synthesis of di-orthometallated triphenyl phosphite iridium(III) complexes with steric groups and their application in OLEDs

A series of di-orthometallated triphenyl phosphite iridium(III) complexes [Ir(tdbpit)(bpy)Cl (1), Ir(tdbpit)(dbbpy)Cl (2), Ir(tdbpit)(sb)Cl (3) (tdbpitH2 = tris (2,4-di-tert-butylphenyl) phosphite, bpy = 2,2′-bipyridine, dbbpy = 4,4′-diterbutyl-2,2′-bipyridine, sb = 4,5-diaza-9,9′-spirobifluorene)] with steric groups had been synthesized and characterized. Single X-ray structural analyses were conducted on 2 and 3 to reveal their coordination arrangement. In CH2Cl2 solution, complexes 1–3 show strong yellow-green phosphorescent emission at 569 nm, 562 nm and 559 nm, respectively. The observed emission lifetimes are between 1.39 μs and 1.54 μs, together with quantum yields between 0.31 and 0.63 in PMMA film. The extra steric groups on the diimine ligands had obviously increased the quantum yields by decreasing the intermolecular interaction. Using these iridium(III) complexes as dopant, the OLEDs show good performance at 15 wt% high doping concentration. OLED device based on complex 2 shows the highest luminous efficiencies of (10.1%, 32.5 cd A−1). Device based on complex 3 displays the highest peak luminance of 15990 cd m−2, and exhibits a maximum luminous efficiency of 31.5 cd A−1 with an external quantum efficiency of 9.6% and small efficiency roll-off values. At a practical luminance of 1000 cd m−2, the efficiency values are maintained as high as 9.0% and 29.5 cd A−1. The results show that the sterically hindered tert butyl and spirofluorene spacers in these phosphor molecules can effectively reduce the self-quenching.

A Novel Layer Crystal Structure of Sr(II) Complex based on 2-methyl-1H-imidazole-4,5-dicarboxylate Ligand

A layer coordination polymer of [Sr(H2MIDC)2(H2O)2]n, (H3MIDC = 2-methyl-1H-imidazole-4,5-dicarboxylate) has been synthesized and characterized. Single X-ray structural analysis indicates the title compound crystallizes in a monoclinic lattice, P21/n with a = 6.902(1) b = 14.469(3), c = 16.641(3) A, β = 98.58(3)°, Z = 4, V = 1643.2(6) A3, ρc = 1.867 g/cm3, F(000) = 928, S = 1.079, R1 = 0.1346, wR2 = 0.3892 (CIF file CCDC no. 791212). Crystal structure analysis reveals that Sr2+ ion is eight-coordinate and lies in a bicapped tetragonal bipyramid environment with one nitrogen atom and seven oxygen atoms. For the variaties of the ligand’s coordination modes and the bridging oxygen atom in carboxylate group, the structure presents a two-dimensional layer molecular network. This coordination polymer exhibited intense fluorescent emissions in the solid state at room temperature.

High efficiency green OLEDs based on homoleptic iridium complexes with steric phenylpyridazine ligands.

A series of steric phenylpyridazine based homoleptic iridium(iii) complexes (1-3) have been synthesized with novel one-pot methods. Single X-ray structural analyses are conducted on complexes 1 and 2 to reveal their coordination arrangement. These complexes exhibit a very strong green phosphorescence emission with high quantum yields of over 64%. The relationship between photophysical properties and the substituent nature of the complexes is discussed by density functional theory (DFT) and time-dependent DFT. Self-quenching is significantly reduced for these complexes in solid even at very high concentrations because the sterically hindered bicyclo [2.2.2] oct-2-ene and m-substituted CF3 spacers in the phosphor molecules lead to minimum bimolecular interactions. Accordingly, the electroluminescence device based on complex 3 exhibits a maximum luminous efficiency of 64.1 cd A-1 with a high EQE of 25.2% at a high doping concentration of 15 wt%. Meanwhile, when neat 3 was adopted as the emitting layer, the non-doped green device gives a state-of-the-art EQE as high as 15.2% (40.1 cd A-1) along with CIE coordinates of (0.346, 0.599).

Blue-to-green electrophosphorescence from iridium(III) complexes with cyclometalated pyrimidine ligands

A series of 4, 6-disubstituted pyrimidine based iridium(III) complexes (1-5), has been synthesized with a simple method. Single X-ray structural analyses were conducted on 5 to reveal their coordination arrangement. These complexes exhibit almost single peak emission with the peak wavelength located in the range of 468–505 nm and quantum yields of over 75%. The relationship between photophysical properties and the substituent nature of the complexes was discussed by density functional theory. Organic light-emitting diodes (OLEDs) were also fabricated using these complexes as dopants in 15 wt%. The green device based on 1 shows a maximum external quantum efficiency, current efficiency, and power efficiency of 9.7%, 46.5 cd A−1 and 29.0 lm W−1, respectively, while the blue device based on 5 exhibits an external quantum efficiency of up to 14.5%, peak luminance efficiency of 28.0 cd A−1 and power efficiency of 19.5 lm W−1. Moreover, the Commission Internationale de L'Eclairage (CIE) coordinates of 5 are (0.15, 0.30) which is closer to blue emission than that of FIrpic.

Atomically Precise Bimetallic Au19Cu30 Nanocluster with an Icosidodecahedral Cu30 Shell and an Alkynyl–Cu Interface

Bimetallic nanoclusters Au19Cu30 with chemical composition of [Au19Cu30(C≡CR)22(Ph3P)6Cl2](NO3)3 (where RC≡C is from 3-ethynylthiophene (H3C4S-3-C≡CH) or ethynylbenzene (PhC≡CH)) has been synthesized. Single X-ray structural analysis reveals that Au19Cu30 has a multishelled core structure of Au@Au12@Cu30@Au6, comprising a centered icosahedral Au13 (Au@Au12) surrounded by an icosidodecahedral Cu30 shell and an outmost shell of a chairlike hexagonal Au6. The alkynyl carbon is bound to the hollow sites on the Au19Cu30 nanocluster surface, which is a novel interfacial binding mode in alkynyl-protected alloy nanoclusters. The Cu30 icosidodecahedron is unprecedented and Au19Cu30 represents the first alkynyl-protected Au-Cu alloy nanocluster.

NiII formate complexes with bi- and tridentate nitrogen-donor ligands: synthesis, characterization, and magnetic and thermal properties.

The synthesis of four NiII formate complexes of the type [Ni(N∩N)n][O2CH]2 (2, adduct with 3/4 EtOH, N∩N = en, e[combining low line]thylen[combining low line]ediamine, n = 3; 4, N∩N = dien, N,N',N''-d[combining low line]i[combining low line]e[combining low line]thylen[combining low line]etriamine, n = 2), [Ni2(O2CH)4(H2O)(tmeda)2] (3, tmeda = N,N,N',N'-t[combining low line]etram[combining low line]ethyle[combining low line]thylened[combining low line]ia[combining low line]mine) and [{Ni(O2CH)2(pmdta)}2·H2O] (5, pmdta = N,N',N',N'',N''-p[combining low line]entam[combining low line]ethyld[combining low line]iethylenet[combining low line]ria[combining low line]mine) by a reaction of [{Ni(O2CH)2}·2H2O] (1) with the respective N-donor bases is reported. The structures of 2-5 in the solid state were determined by single X-ray structure analysis, revealing a discrete dinuclear structure of 3 and the formation of polymeric networks in the case of 2, 4 and 5 due to intermolecular hydrogen bonding. SQUID and ESR measurements of 3 evidenced a weak antiferromagnetic coupling between the NiII ions and an easy plane magnetic anisotropy. Accompanying quantum chemical studies of the magnetic properties and IR characteristics of 3 were performed to strengthen the conclusions drawn from experimentally obtained data. The thermal decomposition temperatures of 2-5 were determined by TG (thermogravimetry) and obtained residues were analyzed by PXRD (powder X-ray diffraction) measurements. The decomposition processes were completed at 207 (3), 215 (5), 250 (2) and 273 °C (4) and are shown to result in the formation of pure metallic nickel.

Synthesis of new pyrido-benzodiazepine salts and their antimicrobial activities

Recently, we reported the antiprotozoal activity of tetrahydropyridylidene ammonium salts. We inserted this motif into a fused ring system, a pyrido-benzodiazepine. The synthesis includes an enamine formation followed by a Mannich reaction to cyclic products and an S-methylation. The last step is a regioselective reduction process. All new compounds were characterized by UV–Vis spectroscopy, ATR FTIR spectroscopy, and HRMS as well as NMR spectroscopy. The structures of the reduction products were established using a single X-ray structure analysis. The new compounds were investigated for their antitrypanosomal and antiplasmodial activities as well as for their cytotoxicity using microplate assays. Furthermore, their inhibitory properties against Mycobacterium smegmatis were determined using a microbroth dilution assay. The potencies against some Gram-positive and Gram-negative bacteria as well as against yeasts were detected using an agar diffusion assay. Structure–activity relationships are discussed.

A Pair of Manganese(III) Schiff-Base Enantiomers: Synthesis, Crystal Structure and Magnetic Characterization

Based-on the quasi-planar tetra-dentate Schiff-base ligand, a pair of manganese(III) Schiff-base enantiomers formulated as {[Mn(R,R-3-MeOSalcy)(H2O)(CH3OH)]ClO4}2 (1) and {[Mn(S,S-3-MeOSalcy)(H2O)(CH3OH)]ClO4}2 (2) (3-MeOSalcy = N,N′-(1,2-cyclohexanediylethylene)bis(3-methoxysalicylideneiminato)dianion) have been synthesized and characterized by element analysis. Single X-ray structure analysis showed that the coordination sphere of the Mn(III) ion is an elongated octahedron with the four equatorial positions occupied by N2O2 unit from the Schiff-base ligand and two O atoms of the coordinated solvent molecules completing the additional two axial sites. The mononuclear manganese(III) Schiff-base compounds are self-complementary into a supramolecular dimer structure through the coordinated solvent ligand from one complex and the free O4 compartment from the neighboring complex. Investigation of the magnetic susceptibility of the manganese complexes reveals the overall weak antiferromagnetic interactions between the adjacent mental centers.

A New Mn(II) Coordination Polymer Based on Mixed 2-Aminoterephthalic Acid and 2,6-Bis(1-imdazoly)pyridine Ligands: Synthesis, Structure, and Luminescent Property

A new Mn(II) coordination polymer, namely [Mn(impy)(NH2-pbc)]n (1 NH2-H2pbc = 2-aminoterephthalic acid, impy = 2,6-bis(1-imdazoly)pyridine), has been synthesized through solvothermal reactions of MnCl2, NH2-H2pbc and impy. Single X-ray structural analysis reveals that compound 1 features a 2D layered structure, and these 2D sheets are further stacked into a 3D supramolecular framework via weak van der Waals interactions. In addition, the luminescent properties of compound 1 and free impy ligand were also investigated at room temperature.

Ultrasound assisted synthesis, characterization and electrochemical study of a tetradentate oxovanadium diazomethine complex

The oxovanadium (IV) complex “VOL” of a tetradentate Schiff base ligand derived from the condensation of diaminoethane and 2-hydroxy-1-naphthaldehyde was efficiently prepared via ultrasound irradiation and the template effect of VO(acac)2.The resulting product was characterized by elemental analysis, infrared, electronic absorption and molar conductance measurement. Single X-ray structure analysis showed that the complex is a monomeric five-coordinate with a distorted square pyramidal geometry. It crystallizes in monoclinic system having unit cell parameters a = 8.3960 (5) Å; b = 12.5533 (8) Å and c = 18.7804 (11) Å; α = γ = 90°; β = 104.843°(2), with P 21/c space group.Cyclic voltammetry of the complex, carried out on a glassy carbon (GC) electrode in DMF, showed reversible cyclic voltammograms response in the potential range 0.15–0.60 V involving a single electron redox wave VV/VIV, the diffusion coefficient is determinedusing GC rotating disk electrode. The Levich plot Ilim = f(ω1/2), was used to calculate the diffusion-convection controlled currents.