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A cyclometalated Pt(IV) compound, Pt(dfpypy)2(Me)Cl (1), with blue phosphorescence was prepared using 2′,6′-difluoro-2,3′-bipyridine (dfpypy) as a C^N chelate ligand. Compound 1 exhibits distorted octahedral geometries around the platinum ion and has strong intermolecular interactions via interatomic contacts (H···N/F/Cl) involving hydrogen bond interactions based on Hirshfeld surface analysis. This compound shows bright blue phosphorescence emissions with λmax = 427 and 455 nm and a high photoluminescence quantum efficiency (ΦPL = 0.60). Furthermore, a good blue colour purity with Commission Internationale de L'Eclairage (1931) coordinates ( x, y) of (0.14, 0.17) was observed in the thin film, which was close to pure blue. TD-DFT calculations revealed that the electronic transition can be attributed to a combination of intraligand charge transfer (πbpy–π*bpy) and ligand-to-ligand charge transfer [pz(Cl)–π*(dfpypy)] with a small contribution from metal-to-ligand charge transfer (Ptd−π*bpy). Owing to the introduction of the electronegative C^N chelate dfpypy, the emission of compound 1 was blueshifted by 20 nm compared with its analog [Pt(ppy)2(Me)Cl] ( λmax = 447), where ppy is 2-phenylpyridine.

In this study, the one-pot synthesis of two novel Pt(II) β-diketonate compounds, namely Pt(tpim)(O^O) (1) and Pt(mtpim)(O^O) (2) (tpim = 1-([1,1′:3′,1′′-terphenyl]-2′-yl)-2-(4-fluorophenyl)-1 H-imidazole, mtpim = 2-(4-fluorophenyl)-1-(5′-methyl-[1,1′:3′,1′′-terphenyl]-2′-yl)-1 H-imidazole, and O^O = acetylacetonato), was achieved. Both compounds had a distorted square-planar geometry without direct intermolecular Pt(II)—Pt(II) interactions, which was attributed to the bulky terphenyl group of the C^N chelate as well as strong intermolecular Pt(II)—H(terphenyl/imidazole) interaction. Compounds 1 and 2 exhibited bright sky-blue-phosphorescent emission with a λmax = 490 nm and photoluminescence quantum yields of 0.50 and 0.47, respectively. The time-dependent density functional theory calculations revealed that the electronic transitions of both compounds were attributed to the combination of intraligand charge transfer (π(phenylimidazole)–π*(terphenyl)) and ligand-to-ligand charge transfer (π(acac)–π*(terphenyl)), in addition to a contribution from the metal-to-ligand charge transfer (Ptd–π*(terphenyl)). Compounds 1 and 2, as the dopants, and 3′-di(9 H-carbazol-9-yl)-1,1′-biphenyl:9-(3'-carbazol-9-yl-5-cyano-biphenyl-3-yl)-9 H-carbazole-3-carbonitrile, as the mixed host were used to fabricate multilayer phosphorescent organic light-emitting diodes. Compound 1 doped in the emissive layer at a 10% doping level demonstrated a maximum current efficiency of 21.7 cd A−1 at 100 cd m−2.

The title compound, [Pt(CH3)(C10H5F2N2)(C10H6F2N2)], displays a distorted cis-PtN2C2 square-planar geometry around the PtII ion consisting of the bidentate C,N chelating anion, a monodentate N-bonded neutral ligand and a methyl group. In the crystal, the molecules are linked by C—H...F, C—H...N and C—H...π interactions. Time-dependent density functional theory (TD-DFT) at the B3LYP level with the 6–311++G(d,p) basis set was applied to optimize the ground-state geometry. The electronic properties, such as excitation energies and the HOMO–LUMO gap energies, were calculated and compared to related structures.

In the title compound, [Ag(CF3SO3)(C10H6F2N2)2], the AgI centre adopts a highly distorted trigonal–planar coordination environment resulting from its coordination by one O atom of the trifluoromethanesulfonate anion and the pyridine N atoms of two crystallographically independent 2′,6′-difluoro-2,3′-bipyridine ligands, which display very similar conformations to one another. Pairwise Ag...O–SO2CF3 − [Ag...O = 2.8314 (14) Å] interactions and intermolecular C—H...O interactions between inversion-related units lead to the formation of an eight-membered cyclic dimer in which the silver atoms are separated by 6.2152 (3) Å. In the crystal, the dimers are linked through C—H...O hydrogen bonds, halogen...π and weak π–π stacking interactions, resulting in the formation of a three-dimensional supramolecular network. The title compound exhibits a strong and broad emission band from 400 nm to 550 nm in solution and its photoluminescence quantum efficiency is estimated to be ca 0.2, indicating that the title compound could have applications as an emitting material in organic light-emitting diodes (OLEDs).

In the crystal of the title compound, which shows blue–green emission, the mol­ecules are connected via C—H⋯Cl/F, halogen⋯π and weak π–π stacking inter­actions., The title compound, [Pt(C21H12F2N3O)Cl], crystallizes with two crystallographically independent mol­ecules (A and B) in the asymmetric unit, which adopt similar conformations. The PtII atoms in both mol­ecules adopt distorted square-planar geometries, coordinated by one C and two N atoms from the tridentate 2′,6′-di­fluoro-6-[3-(pyridin-2-yl­oxy)phen­yl]-2,3′-bi­pyridine ligand and a chloride anion: the C and Cl atoms are trans. In the crystal, C—H⋯Cl/F hydrogen bonds, F⋯π and weak π–π stacking inter­actions between adjacent A and B mol­ecules and between pairs of inversion-related B mol­ecules lead to the formation of a two-dimensional supra­molecular network lying parallel to the ab plane. The sheets are stacked along the c-axis direction and linked by F⋯π and weak π–π stacking inter­actions between pairs of inversion-related A mol­ecules, forming a three-dimensional supra­molecular network. The photoluminescence quantum efficiency of the title compound in the blue–green region of the visible region (λmax = 517 and 544 nm) is estimated to be ∼0.2–0.3, indicating that the title compound could be a suitable candidate as the emitting material in organic light-emitting diode (OLED) applications.

Three cyclometalated platinum(II) β-diketonate complexes were developed to investigate the relationship between intermolecular interactions in the solid state according to the position of a bulky t...

Multicomponent oxide systems are one of the essential building blocks in a broad range of electronic devices. However, due to the complex physical correlation between the cation components and their relations with the system, finding an optimal combination for desired physical and/or chemical properties requires an exhaustive experimental procedure. Here, a machine learning (ML)-based synthetic approach is proposed to explore the optimal combination conditions in a ternary cationic compound indium-zinc-tin oxide (IZTO) semiconductor exhibiting high carrier mobility. In particular, by using support vector regression algorithm with radial basis function kernel, highly accurate mobility prediction can be achieved for multicomponent IZTO semiconductor with a sufficiently small number of train datasets (15-20 data points). With a synergetic combination of solution-based synthetic route for IZTO fabrication enabling a facile control of the composition ratio and tailored ML process for multicomponent system, the prediction of high-performance IZTO thin-film transistors is possible with expected field-effect mobility as high as 13.06 cm

In the title com­pound, the dihedral angle between the planes of the bi­pyridine and carbazole moieties connected by an O atom is 68.45 (3)°. The bi­pyridine ring system, with two meth­oxy substituents, is approximately planar. The pyridine ring in the pyridyl-substituted carbazole fragment is tilted by 56.65 (4)° with respect to the mean plane of the carbazole moiety. The title com­pound exhibits a high energy gap and triplet energy., In the title com­pound, C29H22N4O3, the carbazole system forms a dihedral angle of 68.45 (3)° with the mean plane of the bi­pyridine ring system. The bi­pyridine ring system, with two meth­oxy substituents, is approximately planar (r.m.s. deviation = 0.0670 Å), with a dihedral angle of 7.91 (13)° between the planes of the two pyridine rings. Intra­molecular C—H⋯O/N hydrogen bonds may promote the planarity of the bipyridyl ring system. In the pyridyl-substituted carbazole fragment, the pyridine ring is tilted by 56.65 (4)° with respect to the mean plane of the carbazole system (r.m.s. deviation = 0.0191 Å). In the crystal, adjacent mol­ecules are connected via C—H⋯O/N hydrogen bonds and C—H⋯π inter­actions, resulting in the formation of a three-dimensional (3D) supra­molecular network. In addition, the 3D structure contains inter­molecular π–π stacking inter­actions, with centroid–centroid distances of 3.5634 (12) Å between pyridine rings. The title com­pound exhibits a high energy gap (3.48 eV) and triplet energy (2.64 eV), indicating that it could be a suitable host material in organic light-emitting diode (OLED) applications.

The title 2,3′-bi­pyridine-based quaterpyridine derivative has a linear geometry. The pyridine rings are tilted slightly with respect to each other. In the crystal, π–π stacking and weak C—H⋯π inter­actions lead to formation of a two-dimensional layer structure., In the title compound, C24H22N4O4, the four pyridine rings are tilted slightly with respect to each other. The dihedral angles between the inner and outer pyridine rings are 12.51 (8) and 9.67 (9)°, while that between inner pyridine rings is 20.10 (7)°. Within the mol­ecule, intra­molecular C—H⋯O and C—H⋯N contacts are observed. In the crystal, adjacent mol­ecules are linked by π–π stacking inter­actions between pyridine rings and weak C—H⋯π inter­actions between a methyl H atom and the centroid of a pyridine ring, forming a two-dimensional layer structure extending parallel to the ac plane. Hirshfeld surface analysis and two-dimensional fingerprint plots indicate that the most important contributions to the crystal packing are from H⋯H (52.9%) and H⋯C/C⋯H (17.3%) contacts.

In the solvated title compound, [Ir(C12H11N2)2(C11H19O2)]·CH3CO2C2H5, the IrIII ion adopts a distorted octahedral coordination environment resulting from its coordination by two C,N-chelating 2,6-dimethyl-3-(pyridin-2-yl)pyridin-4-yl ligands and one O,O′-chelating 2,2,6,6-tetramethylheptane-3,5-dionate ligand. The C,N-chelating ligands are perpendicular to each other [dihedral angle between the least-squares planes = 87.86 (5)°] and are arranged in a cis-C,C′ and trans-N,N′ fashion. In the crystal, pairwise C—H...π interactions between inversion-related IrIII complexes are present, forming a dimeric structure. The title complex shows bright bluish–green emission with good quantum efficiency in solution at room temperature.

The reaction of HgII with the bridging ligand bis­(pyridin-3-ylmeth­yl)sulfane afforded a one-dimensional zigzag chain polymeric structure, with the charge balanced by two coordinated chloride anions. C—H⋯Cl hydrogen bonds and Hg—Cl⋯π inter­actions, together with C—H⋯π hydrogen bonds, stabilize the crystal structure., The reaction of mercury(II) chloride with bis­(pyridin-3-ylmeth­yl)sulfane (L, C12H12N2S) in methanol afforded the title crystalline coordination polymer catena-poly[[di­chlorido­mercury(II)]-μ-bis­(pyridin-3-ylmeth­yl)sulfane-κ2 N:N′], [HgCl2 L]n. The asymmetric unit consists of one HgII cation, one L ligand and two chloride anions. Each HgII ion is coordinated by two pyridine N atoms from separate L ligands and two chloride anions. The metal adopts a highly distorted tetra­hedral geometry, with bond angles about the central atom in the range 97.69 (12)–153.86 (7)°. Each L ligand bridges two HgII ions, forming an infinite –(Hg–L)n– zigzag chain along the b axis, with an Hg⋯Hg separation of 10.3997 (8) Å. In the crystal, adjacent chains are connected by inter­molecular C—H⋯Cl hydrogen bonds, together with Hg—Cl⋯π inter­actions [chloride-to-centroid distance = 3.902 (3) Å], that form between a chloride anion and the one of the pyridine rings of L, generating a two-dimensional layer extending parallel to (101). These layers are further linked by inter­molecular C—H⋯π hydrogen bonds, forming a three-dimensional supra­molecular network.

The asymmetric unit of the title compound, [Co(NO3)2L]n,L=N-(pyridine-2-ylmethyl)pyridine-3-amine (C11H11N3), contains one CoIIcentre, two nitrate anions and oneLligand in which the Cpy—C—N—Cpymoiety adopts atransconformation with a torsion angle of −173.1 (3) Å. The coordination geometry of the CoIIatom is a distorted pentagonal bipyramid. One amine N atom from theLligand and four O atoms from two η2-nitrato ligands form the basal plane and two pyridyl N atoms from two symmetry-relatedLligands occupy the apical positions [N—Co—N = 171.86 (11)°]. The displacement of the central CoIIatom from the basal plane (r.m.s. deviation = 0.085 Å) is 0.1491 (12) Å. Each bidentate nitrate group is bonded asymmetrically to the cobalt atom in an chelating fashion. The CoIIions are linked by theLligands to form a zigzag chain propagating along thec-axis direction. Within the zigzag chain, C—H...O hydrogen bonds between the ligands and the nitrate anions are observed. Adjacent zigzag chains are connectedviaintermolecular π–π stacking interactions [centroid-to-centroid distance = 3.844 (2) Å] between the pyridine rings together with N/C—H...O hydrogen bonds.

Iridium(III) complexes based on 2,3′-bi­pyridine ligands are known to exhibit strong emission from blue to green that makes them of inter­est for organic light-emitting diodes and organic lighting uses. In the title compound, the IrIII ion adopts a distorted octa­hedral coordination environment defined by three C,N-chelating 2,6-di­fluoro-3-[5-(2-fluoro­phen­yl)pyridin-2-yl]pyridin-4-yl ligands in a meridional manner. In the crystal, inter­molecular C—H⋯F and C—H⋯π hydrogen bonds, as well as inter­molecular C—F⋯π inter­actions, are present, leading to a two-dimensional network., The asymmetric unit of the title compound, [Ir(C17H11F2N2)3]·0.5CH3(CH2)4CH3·0.5CH2Cl2, comprises one IrIII atom, three 2,6-di­fluoro-3-[5-(2-fluoro­phen­yl)pyridin-2-yl]pyridin-4-yl ligands and half each of an n-hexane and a di­chloro­methane solvent mol­ecule located about crystallographic inversion centres. The IrIII atom displays a distorted octa­hedral coordination geometry, having three C,N-chelating 2,6-di­fluoro-3-[5-(2-fluoro­phen­yl)pyridin-2-yl]pyridin-4-yl ligands arranged in a meridional manner. The IrIII ion lies almost in the equatorial plane [deviation = 0.0069 (15) Å]. The average distance [2.041 (3) Å] of Ir—C bonds is slightly shorter than that [2.076 (3) Å] of Ir—N bonds. A variety of intra- and inter­molecular C—H⋯F and C—H⋯π hydrogen bonds, as well as inter­molecular C—F⋯π inter­actions, contribute to the stabilization of the mol­ecular and crystal structures, and result in the formation of a two-dimensional network parallel to the ab plane. No inter­actions between n-hexane solvent mol­ecules and the other components in the title compound are observed.

The asymmetric unit in the title compound, [Ag(C11H11N3)]PF6·2CH3CN or {[AgL]·PF6·2CH3CN}n,L=N-(pyridin-3-ylmethyl)pyridin-3-amine, comprises one AgIatom, oneLligand, two acetonitrile solvent molecules and one PF6−anion disordered over two orientations in a 0.567 (11):0.433 (11) ratio. Each AgIatom is coordinated by two pyridine N atoms from twoLligands in a slightly distorted linear coordination geometry [N—Ag—N = 170.55 (8)°]. EachLligand bridges two AgIions, resulting in the formation of a zigzag chain propagating along the [101] direction. In the crystal, Ag...Ag contacts [3.3023 (5) Å] and intermolecular π–π stacking interactions [centroid-to-centroid distance = 3.5922 (15) Å] between the pyridine rings link these chains into a corrugated layer parallel to the (\overline{1}01) plane. The layers are stacked with a separation of 10.4532 (5) Å, and acetonitrile solvent molecules and PF6−anions as guests are intercalated between the layers. The layers are connected through several N/C—H...F hydrogen bonds and P—F...π interactions [F...ring centroid = 3.241 (8) Å] between the layer and the intercalated guests and between the intercalated guests, forming a three-dimensional supramolecular network.

In order to obtain triplet emitters with high stability and efficiency, three homoleptic iridium(III) compounds — specifically, Ir( tpim ) 3 ( 1 ), Ir( mtpim ) 3 ( 2 ), and Ir( itpim ) 3 ( 3 ), where tpim = 1-([1,1′:3′,1″-terphenyl]-2′-yl)-2-(4-fluorophenyl)-1H-imidazole, mtpim = 2-(4-fluorophenyl)-1-(5′-methyl-[1,1′:3′,1″-terphenyl]-2′-yl)-1H-imidazole, and itpim = 2-(4-fluorophenyl)-1-(5′-isopropyl-[1,1′:3′,1″-terphenyl]-2′-yl)-1H-imidazole — were prepared by one-pot reaction of the corresponding phenylimidazole ligand with an Ir(I) complex as a starting material. Compounds 1 – 3 emit bright sky-blue phosphorescence with λ max = 459–463 nm and phosphorescent quantum efficiencies of 0.38–0.50. Multi-layer phosphorescent organic light-emitting diodes using compounds 1 – 3 as the triplet emitters and mCBP (3,3-di(9H-carbazol-9-yl)biphenyl) as the host have been fabricated. Compound 3 doped in the emissive layer demonstrate external quantum efficiency as high as 20.1% at 1000 cd/m 2 . In addition, the device based on compound 1 as an emitter shows a stable lifetime greater than 300 h at 1000 cd/m 2 , which is one of the best results concerning the device lifetime.

In the title compound, {[Ag(C29H25N3)2]NO3·CH3OH·H2O}n, the AgIcation is four-coordinated by two pyridine N atoms and two imidazole N atoms from four individual 4-(1-(5′-isopropyl-[1,1′:3′,1′′-terphenyl]-2′-yl)-1H-imidazol-2-yl)pyridine (i-pro-pyim) ligands. This gives rise to a highly distorted tetrahedral geometry with bond angles falling in the range 100.33 (19)–122.76 (19)°. Two crystallographically independenti-pro-pyim ligands (AandB) adopt very similar conformations to one another, such that the dihedral angles between the pyridyl and imidazolyl rings in the two ligands are 40.7 (3) and 42.2 (3)°, respectively. Eachi-pro-pyim ligand binds two symmetry-related Ag+cations, leading to the formation of 14-membered cyclic dimers, in which the AgIatoms are separated by 6.963 (2) Å for the Ag–A2–Ag dimer and 7.020 (2) Å for Ag–B2–Ag. These cyclic dimers are alternately connected to each other by sharing AgIatoms, resulting in the formation of a looped-chain structure extending along the [100] direction. Moreover, adjacent looped chains are connected by intermolecular π–π interactions [centroid-to-centroid distance = 3.689 (4) Å], giving rise to the formation of a two-dimensional supramolecular network propagating parallel to (110). Several intermolecular C—H...O and O—H...O hydrogen bonds further contribute to the stabilization of the crystal structure.

The reaction of AgI with the tridentate ligand bis­(pyridin-3-ylmeth­yl)sulfane afforded a one-dimensional double-stranded chain polymeric structure with the charge balanced by a nitrate anion that is disordered over two sites. The AgI cation adopts a highly distorted trigonal–planar geometry coordinated by two pyridine N atoms and one S atom from three individual ligands. Each ligand bridges the AgI atoms to form a zigzag chain. Two adjacent chains are connected by an Ag—S bond, resulting in the formation of a twisted-ribbon type double-stranded chain. These chains are linked by π–π inter­actions, generating a three-dimensional supra­molecular network., The asymmetric unit in the title compound, {[Ag(C12H12N2S)]·NO3}n or {[AgL]·NO3}n, L = bis­(pyridin-3-ylmeth­yl)sulfane, consists of an AgI cation bound to a pyridine N atom of an L ligand and an NO3 − anion that is disordered over two orientations in an 0.570 (17):0.430 (17) occupancy ratio. Each AgI cation is coordinated by two pyridine N atoms from adjacent L ligands to form an infinite zigzag chain along [110]. In addition, each AgI ion binds to an S donor from a third L ligand in an adjacent parallel chain, resulting in the formation of a twisted-ribbon type of double-stranded chain propagating along the [110] or [1-10] directions. The AgI atom is displaced out of the trigonal N2S coordination plane by 0.371 (3) Å because of inter­actions between the AgI cation and O atoms of the disordered nitrate anions. Inter­molecular π–π stacking inter­actions [centroid-to-centroid distance = 3.824 (3) Å] occur between one pair of corresponding pyridine rings in the double-stranded chain. In the crystal, the double-stranded chains are alternately stacked along the c axis with alternate stacks linked by inter­molecular π–π stacking inter­actions [centroid-to-centroid distance = 3.849 (3) Å], generating a three-dimensional supra­molecular architecture. Weak inter­molecular C—H⋯O hydrogen bonds between the polymer chains and the O atoms of the nitrate anions also occur.

The title mol­ecule adopts a helical structure, in which two 2,3′-bipyridyl units are twisted up and down relative to the plane of the central benzene ring. Weak inter­molecular C—H⋯π inter­actions lead to formation of a two-dimensional supra­molecular network. Hirshfeld surface analysis indicates that the mol­ecular packing in the title compound is mainly dominated by inter­molecular H⋯H and H⋯C/C⋯H inter­actions., The title mol­ecule, C38H42N4O4, displays a helical structure induced by the combination of the C—C—C—C torsion angle [−10.8 (2)°] between two 2,3′-bipyridyl units attached to the 1,2-positions of the central benzene ring and consecutive connections between five aromatic rings through the meta- and ortho-positions. Intra­molecular C—H⋯π inter­actions between an H atom of a pyridine ring and the centroid of a another pyridine ring contributes to the stabilization of the helical structure. In the crystal, weak C—H⋯π inter­actions link the title mol­ecules into a two-dimensional supra­molecular network extending parallel to the ac plane, in which the mol­ecules with right- and left-handed helical structures are alternately arranged. Hirshfeld surface analysis and two-dimensional fingerprint plots indicate that the mol­ecular packing is dominated by van der Waals inter­actions between neighbouring H atoms, as well as by C—H⋯π inter­actions. One isopropoxyl group is disordered over two sets of sites [occupancy ratio 0.715 (5):0.285 (5)].

Three anion-dependent Ag(I) coordination complexes—specifically, [Ag2(pyim)2(NO3)2] (1), {[Ag(pyim)2]·ClO4·CH3OH·(H2O)1.25}n (2), and [Ag4(pyim)4]·(CF3SO3)4 (3)—were prepared by the reaction of the corresponding silver salts with a rigid ditopic N-terphenyl-substituted 2-(4-pyridyl)imidazole (pyim) ligand possessing an “L”-type coordination vector. Complex 1, in which the nitrate anion acts as a monodentate terminal ligand, exhibits a discrete cyclic dimer structure, whereas complex 2, incorporating a perchlorate anion with weak coordination ability, displays an anion-free one-dimensional (1D) looped chain structure resulting from the Ag sharing of consecutive cyclic dimers. When using a trifluoromethanesulfonate (triflate) as a counteranion with moderate affinity toward the metal center, the resulting complex 3 exhibits an unusual cyclic tetramer structure. In 3, the triflate anions act as bridges between adjacent cyclic tetramers via the weak interaction with the Ag(I) ions, yielding a parquet-like two-...

Solvothermal reactions of the calix[4]arene tetraacetic acid (H4 CTA) with zinc nitrate in the presence of α,ω-diaminoalkanes afford two-dimensional metallopolycapsular networks of the formula {[Me2 NH2 ]2 [G@(Zn2 (CTA)2 )]⋅(DMF)2 ⋅(H2 O)4 }n (G=(+) NH3 -(CH2 )n -NH3 (+) , n=2, 3, 4; DMF=N,N-dimethylformamide). These metallopolycapsular networks are built up of metallocapsules that consist of two CTA and two Zn(II) ions. Short alkanediyldiammonium ((+) NH3 -(CH2 )n -NH3 (+) , n=2, 3, 4) guest ions are accommodated in each capsule of the metallopolycapsular network through a variety of supramolecular interactions. The thermal behaviours and the solid-state photoluminescent properties of these complexes were also investigated.

In the title compound, [Ir(C11H8N)2(C18H14N)], the IrIIIion adopts a distorted octahedral coordination environment defined by threeC,N-chelating ligands, one stemming from a 2-(4-phenyl-5-methylpyridin-2-yl)phenyl ligand and two from 2-(pyridin-2-yl)phenyl ligands, arranged in a facial manner. The IrIIIion lies almost in the equatorial plane [deviation = 0.0069 (15) Å]. In the crystal, intermolecular π–π stacking interactions, as well as intermolecular C—H...π interactions, are present, leading to a three-dimensional network.

Blue phosphorescent (dfpypy)2Ir(mppy), where dfpypy = 2',6'-difluoro-2,3'-bipyridine and mppy = 5-methyl2-phenylpyridine, has been synthesized by newly developed effective method and its solid state structure and photoluminescent properties are investigated. The glass-transition and decomposition temperature of the compound appear at 160 o C and 360 o C, respectively. In a crystal packing structure, there are two kinds of intermolecular interactions such as hydrogen bonding (C-HF) and edge-to-face C-Hπ(py) interaction. This compound emits bright blue phosphorescence with λmax = 472 nm and quantum efficiencies of 0.23 and 0.32 in fluid and the solid state. The emission band of the compound is red-shifted by 40 nm relative to homoleptic congener, Ir(dfpypy)3. The ancillary ligand in (dfpypy)2Ir(mppy) has been found to significantly destabilize HOMO energy, compared to Ir(dfpypy)3, (dfpypy)2Ir(acac) and (dfpypy)2Ir(dpm), without significantly changing LUMO energy.

The reaction of AgBF4 with the unsymmetrical ligand N-(pyridin-4-ylmeth­yl)pyridine-3-amine afforded a helical coordination polymer. The AgI atom adopts a slightly distorted linear coordination geometry. The symmetry-related right- and left-handed helical chains are arranged alternately via Ag⋯Ag and Ag⋯F inter­actions and π–π stacking inter­actions, resulting in the formation of a two-dimensional supra­molecular network., The asymmetric unit of the title compound, {[AgL]·BF4·0.5CH3OH}n, L = N-(pyridin-4-ylmeth­yl)pyridine-3-amine, C11H11N3, contains one AgI ion, one ligand L, one tetra­fluorido­borate anion disordered over two orientations in a 0.669 (13):0.331 (13) ratio and one half of a methanol solvent mol­ecule situated on an inversion center. Each AgI ion is coordinated by two N atoms from two L ligands in a distorted linear geometry [N—Ag—N = 174.70 (19)°]. Each L ligand bridges two AgI ions, thus forming polymeric helical chains propagating in [010]. In the crystal, Ag⋯Ag [3.3369 (10) Å] and π–π inter­actions between the aromatic rings [centroid-to-centroid distance = 3.676 (4) Å] link these chains into layers parallel to (10-1). Ag⋯F and weak N(C)—H⋯F inter­actions further consolidate the crystal packing.

The PtII atom adopts a distorted square-planar coordination geometry, being C,N-chelated by a 2′,6′-di­fluoro-2,3′-bi­pyridine ligand and O,O′-chelated by a pentane-2,4-dionato anionic ligand., The asymmetric unit of the title compound, [Pt(C10H5F2N2)(C5H7O2)], comprises one PtII atom, one 2,6-di­fluoro-2,3-bi­pyridine ligand and one acetyl­acetonate anion. The PtII atom adopts a distorted square-planar coordination geometry, being C,N-chelated by the 2,6-di­fluoro-3-(pyridin-2-yl)pyridin-4-yl ligand and O,O′-chelated by the pentane-2,4-dionate ligand. The two pyridine rings of the bi­pyridine ligand are approximately coplanar, making a dihedral angle of 1.2 (2)°. A variety of intra- and inter­molecular C—H⋯O and C—H⋯F hydrogen bonds, as well as π–π inter­actions [centroid–centroid distances = 4.337 (3) and 3.774 (3) Å] contribute to the stabilization of the mol­ecular and crystal structures, and result in the formation of a three-dimensional supra­molecular framework.

Two blue phosphorescent Ir(III) compounds with a main fluorine-free bipyridine ligand have been synthesized. These molecules have the general formula of Ir(C⁁N)2(L⁁X), where C⁁N = 2′,6′-dimethoxy-4-methyl-2,3′-bipyridine [(MeO)2pypy] and L⁁X = ancillary ligand, such as acetylacetonate (acac) (1) or 2-picolinate (pic) (2). Thermal, photophysical, and electrochemical properties of 1 and 2 have also been investigated systematically. The two compounds show high thermal stability with a decomposition temperature of ∼350 °C due to strong and varied intermolecular interactions. A sky-blue emission with moderate phosphorescence quantum efficiency (ΦPL = 0.49–0.54) is observed in the spectral region of 460–470 nm for all compounds, which is attributed to both metal-to-ligand charge transfer (MLCT) and ligand-centered (LC) transition. Compounds 1 and 2 show only ∼10 nm red-shifted emission in the fluid state, compared to similar fluorinated iridium counterparts. Multi-layered electroluminescent devices using compounds 1 and 2 as the dopant and 9-(3-(9H-carbazol-9-yl)phenyl)-9H-carbazol-3-yl)diphenylphosphine oxide as a host material have been fabricated. The electroluminescent device of 2 at a doping level of 5 wt% shows the best performance with an external quantum efficiency of 15.3% and the color coordinate of (0.16, 0.28) at a brightness of 100 cd m−2.

Highly efficient deep blue phosphorescent organic light-emitting diodes (PHOLEDs) using two heteroleptic iridium compounds, (dfpypy)2Ir(acac) and (dfpypy)2Ir(dpm), as a dopant and 9-(3-(9H-carbazol-9-yl)phenyl)-9H-carbazol-3-yl)diphenylphosphine oxide as a host material have been developed. The electroluminescent device of (dfpypy)2Ir(dpm) at the doping level of 3 wt% shows the best performance with external quantum efficiency of 18.5–20.4% at the brightness of 100–1000 cd/m2 and the color coordinate of (0.14, 0.18) at 1000 cd/m2.

We investigated toluene decomposition with a single-stage plasma catalytic system operated at atmospheric pressure and working at reduced temperature (T < 75 degrees C), where a synergistic catalyst was integrated on ferroelectric BaTiO3 beads with a high dielectric constant. The catalyst species were characterized by FE-SEM and XPS before and after the experiment. The MnO2/BaTiO3 catalyst showed high stability in igniting plasma during destruction of toluene for 230 hours in a lifetime test.

Organic sensitizers have been recently improved and reached high efficiencies in the range of 8-9% in the performance of dye sensitized solar cells (DSSCs). In particular, carbazole based dyes (MK dyes) and bis-fluorenylamine based dyes (JK dyes) have shown to have high efficiencies and long-term stability in DSSCs preformance. Koumura et al. has recently reported that the existence of long alkyl chains on the oligothiophene linkage of MK dye molecules can increase the electron lifetime and the open-circuit voltage by suppressing the aggregation of the dyes and electron recombination. However, for MK dyes, there is a problem to be addressed in terms of relatively low short-circuit current density compared with other efficient organic dyes. The low short-circuit current density (10-14 mAcm) in MK dyes based DSSCs is originated from weak light harvesting ability in the long wavelength region (650-750 nm) due to the weak donor ability of carbazole. While bis-fluorenylamine based JK dyes have shown to have high short-circuit current density (> 14 mAcm) in DSSCs performance. This high current density can be due to the strong donor ability of amine and absorption in the long wavelength region compared to MK dyes. Therefore, we envision that the combination of the oligothiophene linkage with long alkyl chains and carbazolefunctionalized amine donor in organic dyes will be highly desirable. Moreover, there is no report on the DSSC performance base on this kind of dyes until now. These facts prompted us to develop new organic dyes containing carbazole and thiophene linker with long alkyl chain. Herein, we describe the results of our investigation on the preparation

Highly fluorescent π-conjugated polycyclic azaborines can be prepared from B,N-heterocyclic compounds with a BR2 -CH2 unit through the elimination of an R-H molecule (see scheme). These clean photoelimination reactions occur both in solution and in polymers doped with the precursors.

Recently, organic sensitizers-based dye sensitized solar cells (DSSCs) have attracted much attention due to their several advantages such as low cost preparation, structural diversity, and high power conversion efficiency (η: 8-9%). Organic sensitizers consist typically of three segments of donor, π-linker, and acceptor (D-π-A), which are shown to have efficient intramolecular charge transfer (ICT) characteristics. Particularly, organic sensitizers bearing dithienosilole (DTS) as a π-linker have shown to have high efficiencies (η: 7.6-10.5%) in DSSCs performance due to its unique photophysical properties (σ-π conjugation) and coplanarity. In addition, the efficiency in DSSC performance is a quite sensitive depending on the nature of substituents at 3position of DTS ring. For examples, the bulky substitution on silicon atom of DTS ring may reduce the π-π stacking interactions of dyes and may be beneficial to high electron injection yield and the power conversion efficiency. These facts prompted us to develop new organic dyes containing DTS π-linker and investigate the effect of bulky substituent at 3-position of DTS ring in DSSC performance. Herein, we report the results of our investigation on the preparation, photophysical properties, electrochemical behavior, and DSSC performance of two novel DTS dyes.

Three new Ir(III) compounds with deep-blue phosphorescence have been synthesized. These molecules have the general formula of Ir(C∧N)2(L∧X), where C∧N = 2′,6′-difluoro-2,3′-bipyridine (dfpypy) and L∧X = ancillary ligand such as 2-picolinate, pic (1), acetylacetonate, acac (2), or dipivaloylmethanoate, dpm (3). The ancillary ligands have been found to significantly destabilize both HOMO and LUMO levels of the Ir(III) complexes, compared to Ir(dfpypy)3, without significantly changing the phosphorescence energy. Compounds 1–3 emit bright blue phosphorescence with λmax = 440–460 nm and quantum efficiencies of 0.60–0.95 in solution and the solid state. Double-layer electroluminescent devices using compounds 1–3 as the dopant, CDBP (4,4′-bis(9-carbazolyl)-2,2′-dimethylbiphenyl) as the host/hole transporting layer, and TPBi (1,3,5-tris(N-phenylbenzimidazole-2-yl)benzene) as the electron transport layer have been fabricated. These EL devices show pure blue colour with high efficiency. The EL device of compound 3 at the doping level of 20 wt% shows the best performance with EQE of 10–15% at the brightness of 10–1000 cd m−2 and the maximum current efficiency of 22 cd A−1.

Inaddition, the former is readily oxidized than the latter in electrochemical behavior.Key Words : Blue phosphorescence, Facial/meridional isomer, Thermal property, Crystal structure, Photo-physical propertyIntroductionIr(III) complexes with C^N chelated ligand such asphenylpyridine(ppy) have attracted much attention becauseof their applicability to Phosphorescence Organic Light-Emitting Diodes (PHOLEDs).

E-mail: sjonglee@lgdisplay.comReceived August 5, 2011, Accepted September 14, 2011Key Words : Triazine, Host, Red phosphorescence, OLEDsOrganic light-emitting diodes (OLEDs) using organicfluorescent dyes as emitting materials have multilayeredstructure of the following order in general: cathode/holeinjection layer/hole transporting layer/emissive layer/elec-tron-transporting layer/electron-injection layer/anode.

Department of Chemistry (WCU) and Research Institute of Natural Science, Gyeongsang National University, Jinju 660-701, Korea. *E-mail: kmpark@gnu.ac.kr †Division of Science Education, Kangwon National University, Chuncheon 200-701, Korea ‡Subdivision of Food Science, Kyungnam College of Information and Technology, Busan 616-701, Korea §Department of Chemistry, College of Natural Sciences, Jeju National University, Jeju 690-756, Korea *E-mail: jchbyun@cheju.ac.kr Received June 28, 2010, Accepted August 18, 2010

Fluorophore plays an important role in fluorescent chemosensors since it evolves a detecting signal (fluorescence) upon metal recognition of macrocycles. For this reason, anthracene derivatives with high quantum effi-ciency are mainly used as fluorophore in fluorescence chemo-sensors.

The homoleptic Ir(III) complex, fac-tris{2-(3′-trimethylsilylphenyl)-5-trimethylsilylpyridinato}iridium, has been synthesized and characterized to investigate the effect of the substitution of bulky silyl groups on the photophysical properties and electroluminescence (EL) characteristics of Ir(ppy)3 (ppy = 2-phenylpyridine). The absorption, emission, cyclic voltammetry and electroluminescent performance of the complex have also been evaluated. A power efficiency of 17.3 lm/W at 10 mA/cm2 compared to 11.7 lm/W for Ir(ppy)3 is achieved with the new complex as a dopant in phosphorescent organic light-emitting diodes (OLEDs). In addition, the complex shows a narrow emission band of a small full width at half-maximum (fwhm, ca. 50 nm) value.

Copper(I) halide, Coordination polymer, Dipyridyl ligand, Crystal structure, PhotoluminescenceThe structural and photophysical properties of transition-metal complexes have been attracted an increasing attentionbecause of their chemically-interesting structural features aswell as their potential applications such as sensors and lightemitting diodes.

Due to their unique photophysical properties, highly fluorescent compounds are currently of great interest for material science applications, such as photo-electronics, organic light-emitting diodes (OLEDs) and chemical sensors. In particular, efforts have focused on the improvement of fluorescence quantum yields (ΦF), since the ΦF of emitting materials and the device efficiency in OLEDs are generally related. For this purpose, several approaches have been suggested including the attachment of anthracene and/or pyrene units having high ΦF to the molecular framework, the extension of π-conjugation and the introduction of electronwithdrawing groups (F, CN, etc) as substituents. Among such approaches, the introduction of electron-withdrawing groups to the molecular backbone has received greater attention, because the molecules containing these groups have shown unusual and high fluorescence quantum efficiency through the intermolecular interactions. Such phenomenon is often called aggregation induced emission (AIE). During our ongoing efforts on the development of luminescent materials, we have observed that fluoreneand anthracene-based compounds linked by a perfluorocyclopentene core unit have high fluorescence quantum efficiency as compared to 9,10-diphenylanthracene (DPA). Our interest in the synthesis of highly fluorescent materials containing a perfluorocyclopentene core unit, which can provide binding sites for hydrogen atoms of adjacent molecules via intermolecular interactions, has prompted us to investigate the syntheses and photophysical properties of their derivatives. Here, we report on the syntheses, crystal structure and optical properties of a series of V-shaped molecules containing the linker of an electron-withdrawing moiety. In addition, the effect of electron-withdrawing substituents on fluorescence quantum efficiency has been systematically evaluated at the molecular level. Scheme 1 outlines the synthesis of the series of benzothiophene derivatives. Compound 1 and 2 were prepared by the addition of octafluorocyclopentene to the corresponding lithiated compound, prepared from the reaction of a small excess of n-BuLi and the bromoarene at −78 C. The standard work up and crystallization from CH2Cl2/hexane produces compounds as colorless or pale yellow solids in moderate yields (45-55%). In addition, to evaluate the effect of a perfluorocyclopentene ring on structural features and photoluminescence, we have synthesized an aromatic analogue of compound 3, through Pd-mediated Suzuki coupling. The structures of 1-3 have been characterized by H-NMR, C-NMR and elemental analyses, including Xray diffraction analysis of 2. Yellow crystals of 2 that were suitable for X-ray analysis were obtained by the slow evaporation in CH2Cl2 and hexane. The crystal structures and selected bond lengths and angles of 1 are presented in Figure 1. As shown in the Figure, two benzothiophene groups connected by the hexafluorocyclopentene linker are twisted with respect to each other. Note that the hexafluorocyclopentene linker and one (S1 ring) of two benzothiophene rings are arranged a nearly coplanar manner with a dihedral angle of 5.44, while the other (S2 ring) is highly tilted toward the hexafluorocyclopentene core with a dihedral angle of 71.96. This observation is very uncommon in diarylethene derivatives

In many cases, the fluorescentchemosensors have been made through the combination of areceptor molecule and a fluorophore. Owing to their selec-tive complexation with metal species, macrocyclic ligandsmake them ideal candidates for the receptor molecules.However, the introduction of such cyclic receptors is oftenlimited by high cost and the synthetic complexity. The alter-nate way to avoid such limitations is to develop the acyclicanalogues for the cyclic receptors. Our interest has focusedon the dipodal receptors containing quinoline moietybecause this receptor has shown not only similar behaviorswith cyclic receptors

Herein, we report the effects of geometric morphology of ZnO nanostructures on the extraction efficiency of GaN-based light emitting diodes (LEDs). We performed numerical analysis based on the two-dimensional (2D) finite difference of time domain (FDTD) method that was utilized to calculate the light extraction efficiency of the LEDs. We found that the extraction efficiency of the LED increased upon changing the shape of ZnO nanostructure from nanorods to pencil-likenanorods. The current-voltage characteristics of the LED with ZnO nanorods or pencil-like nanorods were similar to those of the LED that did not contain any ZnO nanostructures. The light output power of the LEDs containing ZnO nanorods or pencil-like nanorods at 100 mA increased additionally to 28% and 39%, respectively, relative to that of the LED that did not contain any ZnO nanostructures. These results confirm that the geometric morphology of the ZnO nanostructure plays an important role in improving the extraction efficiency of the LEDs.

This study examined the effects of the alignment of ZnO nanorod arrays (NRAs) on the light extraction enhancement of GaN-based light emitting diodes (LEDs), where ZnO NRAs were synthesized hydrothermally. The shape of the ZnO NRAs was controlled using seed layers for flower and vertical structures. Numerical analysis based on the two-dimensional (2D) finite difference of time domain (FDTD) method showed that the extraction efficiency of LED with bare (without ZnO NRA), vertical ZnO NRA and flower shaped ZnO NRA was 37%, 60% and 49%, respectively. The optical output power of the LEDs with vertical ZnO NRA and flower ZnO NRA was improved by 50% and 30% compared to that of the LED without ZnO NRA at an input current of 100 mA. These results suggest that the vertical alignment of ZnO NRA is important for enhancing the light extraction of GaN based LEDs.

New group 15 organometallic compounds, M(phenanthrenyl) 3 (M = P (1), Sb (2), Bi (3)) have been prepared from the reactions of 9-phenanthrenyllithium with MCl 3 . A reaction of 9-(diphenylphosphino)phenanthrene with 2,6-diisopropylphenyl azide led to the formation of (phenanthrenyl)(Ph 2 P=N-(2,6- i Pr 2 C 6 H 3 ) (4). The crystal structures of 2 and 4 have been determined by single-crystal X-ray diffractions, both of which crystallize with two independent molecules in the asymmetric unit. Compound 2 shows a trigonal-pyramidal geometry around the Sb atom with three phenanthrenyl groups being located in a screw-like fashion with an approximately C 3 symmetry. A significant amount of CH---π interaction exists between two independent molecules of 4. The phosphorus center possesses a distorted tetrahedral environment with P-N bond lengths of 1.557(3)A (P(1)-N) and 1.532(3)A (P(2)-N), respectively, which are short enough to support a double bond character. One of the most intriguing structural features of 4 is an unusually diminished bond angle of C-N-P, attributable to the hydrogen bonding of N(1)-H(5A) [ca. 2.49A] between two adjacent molecules in crystal packing. The compounds 1-3 show purple emission both in solution and as films at room temperature with emission maxima (λ m a x ) at 349, 366, and 386 nm, respectively, attributable to the ligand-centered π → π* transition in phenanthrene contributed by the lone pair electrons of the Gp 15 elements. Yet the nature of luminescence observed with 4 differs in that it originates from π (diisopropylbenzene)-π* (phenanthrene) transitions with the pπ-contribution from the nitrogen atom. The emission maximum of 4 is red-shifted ranging 350-450 nm due to-the internal charge transfer from the phenanthrenyl ring to the N-arylamine group as deduced from the ah initio calculations.

New silole compounds based on the 7-azaindolyl and 2,2‘-dipyridylamino groups, 1,1-dimethyl-2,5-bis(4-N-7-azaindolylphenyl)-3,4-diphenylsilole (1), 1,1-dimethyl-2,5-bis(4‘-N-7-azaindoylbiphenylyl)-3,4-diphenylsilole (2), 1,1-dimethyl-2,5-bis(p-2,2‘-dipyridylaminophenyl)-3,4-diphenylsilole (3), and 1,1-dimethyl-2,5-bis(p-2,2‘-dipyridylaminobiphenylyl)-3,4-diphenylsilole (4), have been synthesized and structurally characterized. These new silole compounds are capable of binding to metal ions as demonstrated by the zinc(II) complex 5 obtained from the reaction of 3 with Zn(O2CCF3)2(H2O)3, where 3 functions as a bridging-chelating ligand to zinc(II) ions. The structure of siloles 1 and 3, and complex 5 were determined by single-crystal X-ray diffraction analyses. Compound 5 displays an extended 1D polymer structure in the solid state with alternating molecules of 3 and a dinuclear unit of Zn2(O2CCF3)4(H2O). Compounds 1−4 are bright green emitters in solution and in the solid state with emission λmax at 506, 5...

Among these transition metalcomplexes, Ir complexes are regarded as the most effectivematerials in OLEDs, in which they show a high thermalstability, a shorter life time in excited states than that of othertransition metal complexes, and tunable emission energy inthe region of blue to red through the modification of