- Strongly Luminescent Tungsten Emitters with Emission Quantum Yields of up to 84 %: TADF and High-Efficiency Molecular Tungsten OLEDs
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Metal-TADF (thermally activated delayed fluorescence) emitters hold promise in the development of next generation light-emitting materials for display and lighting applications, examples of which are, however, largely confined to CuI and recently AuI, AgI, and AuIII emitters. Herein is described the design strategy for an unprecedented type of metal-TADF emitter based on inexpensive tungsten metal chelated with Schiff base ligand that exhibit high emission quantum yields of up to 56 % in solutions and 84 % in thin-film (5 wt % in 1,3-bis(N-carbazolyl)benzene, mCP) at room temperature. Femtosecond time-resolved emission (fs-TRE) spectroscopy and DFT calculations were undertaken to decipher the TADF properties. Solution-processed OLEDs fabricated with the W-TADF emitter demonstrated external quantum efficiency (EQE) and luminance of up to 15.6 % and 16890 cd m?2, respectively.
- Chan, Kaai-Tung,Lam, Tsz-Lung,Yu, Daohong,Du, Lili,Phillips, David Lee,Kwong, Chun-Lam,Tong, Glenna So Ming,Cheng, Gang,Che, Chi-Ming
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- Freeze-drying synthesis, characterization and in vitro bioactivity of chitosan/graphene oxide/hydroxyapatite nanocomposite
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Polycrystalline and dispersed hydroxyapatite (HAP) nanoparticles were successfully prepared via a simple precipitation method with the aid of a new capping agent based on Schiff base compounds. After that, a composite of chitosan (CT), graphene oxide (GO)
- Mohandes,Salavati-Niasari
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- Methylene spacer regulated variation in conformation of tetradentate N2O2 donor Schiff bases trapped in manganese(III) complexes
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Seven mononuclear manganese(iii) complexes having the general formula [Mn(L)(X)(Y)] [where H2L represents the tetradentate N2O2 donor salen-type Schiff base, and X and Y are monodentate ligands, e.g. pseudohalide, DMSO, H
- Sarkar, Nandita,Drew, Michael G.B.,Harms, Klaus,Bauzá, Antonio,Frontera, Antonio,Chattopadhyay, Shouvik
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- Simultaneous extraction and preconcentration of some metal ions using eucalyptus-wood based activated carbon modified with silver hydroxide nanoparticles and a chelating agent: Optimization by an experimental design
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In the present work, the solid phase extraction (SPE) of Cr(iii), Cu(ii), Pb(ii), Ni(ii), Cd(ii), and Co(ii) metal ions was carried out using a new adsorbent, activated carbon modified with silver hydroxide nanoparticles and a chelating agent. The activat
- Rajabi, Maryam,Rezaie, Alireza,Ghaedi, Mehrorang
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- A theoretical insight on the rigid hydrogen-bonded network in the solid state structure of two zinc(ii) complexes and their strong fluorescence behaviors
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A reduced Schiff base has been synthesized and characterized and used as a fluorescence chemo-sensor for the selective detection of zinc(ii). Fluorescence titrations have also been conducted for the ligand and the binding constant for the ligand (K= 1.056 × 106M?1) has been evaluated using the Benesi-Hildebrand equation. Two mononuclear zinc(ii) complexes have also been synthesized with the ligand andS0andS1of their electronic structures were calculated. The HOMO-LUMO energy difference in each complex isca.4.69 eV inS0states and the energy gap is reduced toca.4.3 eV inS1facilitating easier electronic transition. Their strong fluorescence behaviors may be correlated with the presence of a rigid hydrogen-bonded network in their solid state structure. Two types of intermolecular hydrogen bonding are noticed in the dimeric form of the complexes. The hydrogen bonding environment is well supported qualitatively and quantitatively with the help of NCI-RDG (noncovalent interaction reduced density gradient) and QTAIM. The physical nature of other weak non-covalent interactions in both complexes was also examined. Based on the optimized ground state geometry (S0), the TDDFT/B3LYP method combined with the SMD solvation model in methanol media was used to calculate the absorption properties of the investigated complexes. Additionally, analysis on the electronic structure of the excited states employing NTO (natural transition orbital) representation showed that theS1state can be mainly characterized by an inter-ligand charge-transfer (ILCT) transition, populating the highest-occupied (HO) NTO and lowest-unoccupied (LU) NTO, which describe the hole and the excited electron state, respectively. The calculation indicates that the fluorescence originates from the charge transfer from N3/NCS to the reduced Schiff base.
- Banerjee, Snehasis,Basak, Tanmoy,Chattopadhyay, Shouvik,Mondal, Ipsita
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p. 3005 - 3019
(2020/05/18)
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- An investigation of some Schiff base derivatives as chemosensors for Zn(II): The performance characteristics and potential applications
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The fluorescence properties of four simple Schiff bases (LH2, LDMH2, LH2 H and LDMHH2) and their potential application as chemosensors for the detection of zinc ion in aqueous solution have been investigated. While LH2 and LDMH2 have displayed specific recognition to Zn(II), the reduced derivatives (LH2 H and LDMHH2) of these ligands have shown no fluorescence response due to the lack of C[dbnd]N group. The Job plots, fluorescence titration experiments and ESI-MS results indicate the formation of 1:1 complexes between sensors and Zn(II). The analytic methods based on LH2 and LDMH2 as chemosensors have been proposed and optimized to detect Zn(II) ions in aqueous solution. The optimized methods have shown a good range of linearity, high precision, good accuracy and low detection limit. As an alternative to these methods, LH2 and LDMH2 have the capability to detect Zn(II) ions by naked eye under UV lamp. Moreover, LH2-Zn and LDMH2-Zn complexes have the ability to be a staining agent for identifying the radiation treatment of food by DNA comet assay.
- Ergun, Ece,Ergun, ümit,?leri, ?zgür,Kü?ükmüzevir, Muhammed Fatih
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p. 273 - 286
(2018/06/19)
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- Csp3-H bond activation with triel metals: Indium and gallium zwitterions through internal hydride abstraction in rigid salan ligands
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The hydropyrimidine salan (salan=N,N'-dimethyl-N,N'-bis[(2-hydroxyphenyl) methylene]-1,2-diaminoethane) proteo-ligands with a rigid backbone {ON^(CH 2)^NO}H2 react with M(CH2SiMe3) 3 (M=Ga, In) to yie
- Maudoux, Nicolas,Fang, Jian,Roisnel, Thierry,Dorcet, Vincent,Maron, Laurent,Carpentier, Jean-Francois,Sarazin, Yann
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p. 7706 - 7717
(2014/07/07)
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- Synthesis, structure and magnetic properties of Ni(II)-Co(II) heterodinuclear complexes with ONNO type Schiff bases as ligands
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Four new heterodinuclear Ni(II)-Co(II) complexes, NiL·CoCl 2·(DMF)2 (I), NiL·CoBr2· (DMF)2 (II), NiL′·CoCl2·(DMF) 2 (III) and NiLDM·CoCl2(DMF)2 (IV), have been prepared in non-aqueous DMF using the ONNO type Schiff bases N,N′-bis(2-hydroxyphenylidene)-1,3-propanediamine (LH2), N,N′-bis(2-hydroxyphenylidene)-1,4-butanediamine (L′H2) and N,N′-bis(2-hydroxyphenylidene)-2,2′-dimethyl-1,3-propanediamine (LDMH2), and the inorganic salts NiCl2 and CoCl 2. The complexes were characterized by elemental analysis, IR spectroscopy, thermogravimetry and X-ray diffraction. An XRD study revealed that the Ni(II) ion is situated at the center of a distorted octahedral coordination sphere formed by two iminic nitrogen and two phenolic oxygen atoms of the ONNO type Schiff base and two other oxygen atoms belonging to coordinated DMF molecules. On the other hand, the Co(II) ion is situated inside a distorted tetrahedral coordination sphere, members of which being the two halogen atoms and two oxygen atoms, bonded to form a μ-bridge. The magnetic susceptibility of the complexes was studied using a SQUID magnetometer between 2.0 and 300 K at B = 0.1 T, and the magnetization data were taken up to B = 7 T at T = 2.0 and 4.6 K. The exchange interaction between the metal centers is of a ferromagnetic nature (typically JCo-Ni/hc = +2 cm-1) and at low temperature single-ion zero-field splitting applies (DNi/hc = +8 cm-1, DCo/hc = +14 cm-1).
- ?z, Sevi,Titi?, Ján,Nazir, Hasan,Atakol, Orhan,Bo?a, Roman,Svoboda, Ingrid,Fuess, Hartmut
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- Thermal decomposition of new mononuclear NiII complexes with ONNO type reduced Schiff bases and Pseudo halogens
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Mononuclear nickel(II) complexes were prepared by reaction, of the three ONNO type reduced Schiff bases bis-N,N'-(2-hydroxybenzyl)-1,3-propanediamine (LHH2), bis-N,N'-(2-hydroxybenzyl)-2,2′-dimethyl-1, 3-propanediamine (LDMHH2), and bis-N,N'-[1-(2- hydroxyphenyl)ethyl]-1,3-propanediamine (LACHH2) with NiII ions in the presence of pseudo halides (OCN-, SCN- and N3-). The complexes were characterized with the use of elemental analyses, IR spectroscopy, and thermal analyses. The molecular structure of one of the complexes was obtained by single-crystal X-ray diffraction. The obtained complexes are mononuclear, and a pseudo halide molecule is attached. One of the oxygen atoms of the ligand is in phenolate and the other was in phenol form. According to the thermogravimetry results, it was thought that the pseudo halide thermally detaches from the structure as hydropseudo halide. In azide-containing complexes an endothermic reaction was observed although the azide group usually decomposes with an exothermic reaction.
- Ates, B. Meltem,Zeybek, Buelent,Aksu, Mecit,Ergun, Uemit,Ercan, Filiz,Aksu, M. Levent,Atakol, Orhan
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experimental part
p. 840 - 845
(2010/09/04)
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- New compounds of tetradentate Schiff bases with vanadium(IV) and vanadium(V)
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A new range of potentially tetradentate proligands, H2L, derived from aromatic aldehydes and ketones and aliphatic diamines has been prepared. Their vanadyl(IV) and vanadyl(V) complexes [VO(L)] and [VO(L)]+, and also some adducts [VO(L)→VO(L)]+, have been synthesized. The structures of four selected complexes have been determined and it is shown that these must be a result of both steric and electronic factors that make prediction of conformation and stacking difficult. The adducts [VO(L)→VO(L)]+ have structures that persist in solution in dichloromethane, where they can undergo redox chemistry, but they apparently dissociate into their component complexes in the donor solvent acetonitrile. The Royal Society of Chemistry 1999.
- Choudhary, Nosheen F.,Connelly, Neil G.,Hitchcock, Peter B.,Leigh, G. Jeffery
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p. 4437 - 4446
(2007/10/03)
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- The dimeric complex {2,2′-[2,2-dimethyl-1,3-propanediylbis(aminomethyl)]diphenolato-N,N′ ,O,O′}copper(II) ethanol solvate
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The title complex, [Cu(C19H24N2O2)]2.2C 2H5OH, is a centrosymmetric dimer. Each Cu atom is coordinated by two N and two O atoms from the amine-phenol ligand in a distorted square
- Yao, Hsueh-Hua,Chen, Bor-Hann,Lo, Jem-Mau,Liao, Fen-Ling
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p. 1222 - 1224
(2007/10/03)
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- The Preparation and Structure of *CH2Cl2 and of Some Homologues of Related Schiff Bases
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The elusive and some of its homologues have been successfully prepared.The structure of *CH2Cl2 has been determined by X-ray crystallography, and the conformation is trans-octah
- Hughes, David L.,Kleinkes, Uwe,Leigh, G. Jeffery,Maiwald, Michael,Sanders, J. Roger,et al.
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p. 3093 - 3096
(2007/10/02)
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