Synthesis and Characterization of Novel Orange-emitting Iridium(III) Complexes with Diphenylquinoline Ligands Containing Fluorinated Substituent

Recently, the iridium complexes as phosphorescent emitter in organic light-emitting diodes (OLEDs) have attracted much attention since the realization of a high efficiency OLED device based on the complex fac tris(2-phenylpyridine)iridium [Ir(ppy)3]1-4. T…     

Synthesis and Characterization of Novel Orange-emitting Iridium（Ⅲ） Complexes with Diphenylquinoline Ligands Containing Fluorinated Substituent

Three new cyclometalated iridium（m） complexes based on ligands of diphenylquinoline with fluorinated subsfituents were prepared, and characterized by elemental analysis （EA）, ^1H NMR, and mass spectroscopy （MS）. The photophysical and electrophosphorescent properties of the complexes were briefly discussed.     

Synthesis and Characterization of Novel Lanthanocene Complexes with Dichalcogenolate o-Carboranyl Ligands

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Lantern-Type Divanadium Complexes with Bridging Ligands: Short Metal−Metal Bonds with High Multiple Bond Orders

Vanadium forms binuclear complexes with a variety of ligands often containing V≡V triple bonds. Many tetragonal divanadium paddlewheel complexes with bridging bidentate ligands have been experimentally characterized. This research exhaustively treats model tetragonal, trigonal, and digonal paddlewheel-type divanadium complexes V₂L_x (L=formamidinate, guanidinate, and carboxylate; x=2, 3, 4), each in the three lowest-energy spin states. The V−V formal bond orders are obtained from metal−metal MO diagrams for representative structures. A number of short V−V multiple bonds of order 3, 3.5, and 4 are found in these model complexes. The short V≡V triple bonds and singlet ground state predicted here for the model tetragonal complexes correspond well with the limited experimental results for the series of known tetragonal paddlewheels. Digonal divanadium lanterns with very short V−V quadruple bonds are predicted as interesting synthetic targets. The V−V bond distances are categorized into distinct ranges according to the formal bond order values from 0.5 to 4. These bond length ranges are compared with the ranges compiled for other divanadium complexes including carbonyl complexes.     

New Complexes of Ditopic Ligands with “d” and/or “s” Metal Ions

Abstract

The asymmetric compartmental macrocycles containing one N₂O₂ or N₃O₂ Schiff base and one O₂O₃ or O₂O₄ crown-ether like chamber, have been obtained by condensation reaction of the formyl precursors 3,3′-(3-oxapentane-1, 5-diyldioxy) bis (2-hydroxybenzaldehyde) or 3,3′-(3,6-dioxaoctane-1,8-diyldioxy)-bis(2-hydroxybenzaldehyde) with ethyl ethylenediamine (H₂L_A, H₂L_C), 1,5-diamino-3-azamethylpentane(H₂L_B, H₂L_D), also in the presence of metal ions as templating agents. These ditopic ligands, with dissimilar coordination sites, have been designed and used for the selective complexation of “d” and/or “s” metal ions, respectively into the Schiff base and the crown ether chamber. The selectivity of these processes strongly depends on the size and on the donor atom sets of the sites. The possibility to obtain mononuclear M(L)·nH₂O (M = Ni²⁺, Cu²⁺, Co²⁺), Mn(L)(CH₃COO)·nH₂O or Na(L) and hetero-dinuclear MNa(L)(CH₃COO) (M = Ni²⁺, Cu²⁺, Co²⁺) and MnNa(L)(CH₃COO)₂·nH₂O complexes has been successfully tested. The ligands and complexes have been characterized by ir, nmr, mass spectrometry and magnetic susceptibility measurements.

Two of the ligands used for the preparation of the solid samples, i.e., to H₂L_A and H₂L_B, have been employed to study complexation reactions of Co(II) and Na(I) in solution. In order to obtain information on the ligand preorganization effect toward the complex stabilities, a simpler open chain parent compound of H₂L_B (H₂L_E) has been also prepared and studied. FT-IR spectra show that H₂L_A is unable to complex Na⁺ in DMSO while the complexation reactions of Na⁺ by H₂L_B and of Co²⁺ by H₂L_A take place with slow kinetics. Therefore, thermodynamic data have been obtained only for the systems Co²⁺/H₂L_B and Co²⁺/H₂L_E. The thermodynamic parameters obtained for the complexation reactions show that the pre-organization of the donor atoms in H₂L_B does not add a significant contribution to the stabilities of the complexes. Both H₂L_B and H₂L_E form in DMSO 1:1, 1:2 and 1:3 = M:L complexes with very similar stabilities and almost equal enthalpies of formation. Physico-chemical studies suggest besides that the slow reaction of Na⁺ with H₂L_B is probably due to the formation of a 1:1 complex where the metal cation, initially occupying the O₃ cage of the ligand, slowly binds also the oxygens of the phenolic moieties. Spectral and calorimetric data on solutions containing H₂L_B and different Co²⁺: Na⁺ ratios evidence that in DMSO no stable heterodinuclear complexes form when the neutral ligand is considered.     

Terthienyl-Based Redox-Switchable Hemilabile Ligands: Transition Metal Polymeric Complexes with Electrochemically Tunable or Switchable Coordination Environments?

By controlling the extent of oxidation of the polymeric forms of the new class of isolable, polymerizable terthienyl Ru^II complexes 1 , one can modulate both the binding strength of the polymer backbone for Ru^II and the electronic nature of the bound metal centers.     

Synthesis and CD Spectra of Chiral Molybdenum-fullerenyl Complexes with Pineno-bipyridine Ligands

The synthesis and characterization of two chiral fullerene complexes( )4in^CD-[Mo(η^2-C60)(CO)3(L^RR)]1 and (-)430^CD-[Mo(η^2-C60)(CO3)(L^SS)2 were described,the CD spectra of 1 and 2 in the visible range show Cotton effects,which are approximately of mirror image,indicating that the appended pineno-groups with opposite chirality in bipyridines can perturb the fullcrene chromophores through the molybdenum centers and lead to induced CD effects.     

Synthesis and Crystal Structure of the Novel Chiral o—Hydroxyphenyloxazoline Metal Complexes

1 INTRODUCTION Optically active oxazolines have been extensi- vely used as valuable chiral ligands for transition metals in asymmetric catalysis[1]. The design and syntheses of new chiral oxazoline ligands have inspired many scientists to work with great efforts during the recent years. Our interest has been focus- ed on the studies of enantioselective transition- metal catalysis of heterocyclic ligands. In the pre- sent work, we choose o-hydroxyphenyloxazoline ligand for it has a rigi…     

Photoluminescence of Seven-Coordinate Zirconium and Hafnium Complexes with 2,2′-Pyridylpyrrolide Ligands

Luminescent seven-coordinated zirconium and hafnium complexes bearing three mono-anionic 2,2′-pyridylpyrrolide ligands and one chloride were synthesized. Solid-state structures and the dynamic behaviors in solution were probed by X-ray crystallography and variable temperature ¹H NMR experiments, respectively. Absorption spectroscopy and time-dependent density functional theory (TD-DFT) calculations supported a hybrid of ligand-to-metal charge transfer (LMCT)/ligand-to-ligand charge transfer (LLCT) for the visible light absorption band. The complexes (^MePMP^Me)₃MCl (M=Zr, Hf, ^MePMP^Me=3,5-dimethyl-2-(2-pyridyl)pyrrolide) are emissive in solution at room temperature upon irradiation with visible light due to a combination of phosphorescence and fluorescence characterized by excited state lifetimes in the μs and low to sub-ns timescale, respectively. Electrochemical experiments revealed that the zirconium complex possesses a reversible redox event under highly reducing condition (−2.29 V vs. Fc^+/0).     

Synthesis and Luminescence Study of Europium Complexes with Carboxylic Acid and 1,10-Phenanthroline Ligands

A series of euroPium(Ⅱ)eomPlexes with earboxylie aeids andl,10-Phenantl飞ro-line:Eu(L):·pllen·jHoO,wl:ereL-formate,3-hydroxy-4-metlloxybenzoate,4一metl、oxybenzoate,4一ehloroPhenoxyaeetate,and diPI、enylaeetate,were synthesizedand el、araeterized by elemental analysis,UV sPeetrum,IR speetrum and melting point.IR da亡a eonfirmed tllat euroPium 15 eoordinated wirh 0 donor atoms in earboxy!ie aeidand N donor atoms inl,10一phenanthroline.A strong ligand一loealized absorption at270 nm!ed to a series of meta!一eentered emission bands between 580 and 710 nm as-signedto ~5D_0-7F_(0.1.2.3.)     

Silver(Ⅰ) Complexes with Mixed Diphosphine Ligands:Syntheses,Characterization and Spectroscopic Properties

Two novel silver(I) complexes [Ag(DPEphos)(dppe)]Cl O4(1) and [Ag(DPEphos)-(dppe)]SCN(2)(DPEphos = bis[2-(diphenylphosphino)phenyl]ether, dppe = bis(diphenylphosphino)ethane) are synthesized and characterized by IR, 1H/31 P NMR spectroscopy and fluorescence spectra. Complex 1 crystallizes in monoclinic, space group P21/c with a = 14.8821(12), b = 12.6620(11), c = 36.025(3) ?, β = 112.633(2)°, V = 6265.7(9) ?3, C62H52 Cl O5P4Ag, Mr = 1144.24, Z = 4, Dc = 1.213 g/cm3, F(000) = 2352, μ = 0.510 mm-1, the final R = 0.0616 and w R = 0.1192 for 4003 observed reflections(I 2σ(I)). Complex 2 crystallizes in monoclinic, space group P21/c with a = 14.9021(13), b = 12.6100(11), c = 35.920(3) ?, β = 112.852(2)°, V = 6220.2(9) ?3, C63H52NOP4 SAg, Mr = 1102.87, Z = 4, Dc = 1.178 g/cm3, F(000) = 2272, μ = 0.498 mm-1, the final R = 0.0912 and w R = 0.1706 for 3287 observed reflections(I 2σ(I)). In mono-nuclear complexes 1 and 2, the Ag(I) atom is chelated by DPEphos and dppe ligand. In the 31 P NMR spectra, there are splitting signals(doublets or triplets) which can be attributed to the coupling of the 107,109Ag–31P(from DPEphos or dppe ligand). All the emission peaks of these complexes are attributed to ligand-centered(π-π*) transitions.     

Transitional Metal Complexes with 1,2,4-Triazole Ligand： Syntheses and Crystal Structures

Four novel transitional metal complexes with 3-（4-pyridly）-4-phenyl-5-sulfhydryl- 1,2,4- triazole （HL1） and 3-（3-pyridly）-4-phenyl-5-sulfhydryl-l,2,4-triazole （HLz） were synthesized and characterized by elemental analysis, IR and X-ray diffraction. Complexes 1, 3 and 4 have two-dimensional （2-D） neutral rhombohedral grid with a （4, 4） topology. In 1, 3 and 4, all the metal ions are six-coordinated to four nitrogen atoms of four distinct ligands and two O atoms from water molecules. Complex 2 has tetranuclear CuaCI4 units which are interconnected by four desulfuri- zation ligands （L1-S） via Cu-N bonds to form a 2-D layer with （4,4） topology.     

Syntheses and Crystal Structures of Two Novel Cobalt(Ⅱ) Complexes with 2-Amino-5-substituted-1,3,4-thiadiazole as Ligands

Two novel cobalt(Ⅱ) compounds were obtained and characterized by X-ray single-crystal diffraction,IR,1H NMR and elemental analysis.Compound 1 crystallizes in monoclinic,space group P21/n,with a = 18.046(4),b = 11.335(3),c = 19.157(5) ,β = 92.707(3)o,Z = 4,V = 3914.4(16) 3,Mr = 968.56,Dc = 1.644 g/cm3,μ = 1.378 mm-1,F(000) = 1960,the final R = 0.0367 and wR = 0.0895.The crystal of compound 2 is of monoclinic,space group P21/c with a = 8.7253(10),b = 10.9031(13),c = 18.235(2) ,β = 93.2210(10)o,Z = 4,V = 1732.0(3) 3,Mr = 464.21,Dc = 1.780 g/cm3,μ = 1.560 mm-1,F(000) = 932,the final R = 0.0322 and wR = 0.0743.     

Polymerization of ε-Caprolactone and its Copolymerization with γ-Butyrolactone using Metal Complexes

Solution polymerization of ε-caprolactone (ε-CL) was performed using four different initiators namely: tin(II) octanoate (Sn(Oct)₂)/ethanolamine, aluminium Schiff's base complex-HAPENAlOⁱPr, lithium diisopropyl amide (LDA) and aluminium isopropoxide. The reaction conditions varied with the initiator used. LDA gave rise to the most rapid polymerization with the highest amount of cyclic species as detected by ¹³C NMR. However, no cyclic species were detected when HAPENAlOⁱPr was used as initiator. The tin(II) octanoate/ethanolamine system lead to an α,ω-dihydroxy-polycaprolactone (PCL). The copolymerization of ε-CL was then performed with the hard to oligomerize γ-butyrolactone using the four initiators. GPC (Gel Permeation Chromatography) analyses showed the formation of copolymers. The highest incorporation of polybutyrolactone (PBL) in the copolymer was obtained using HAPENAlOⁱPr as evidenced by ¹H NMR. ¹³C NMR indicated the presence of pseudoperiodic random copolymers with short blocks of PCL whose block length varied with initiator used. The longest and shortest block length were obtained using Sn(Oct)₂ and HAPENAlOⁱPr respectively as calculated from ¹³C NMR. The reactivity ratios were determined using the Finemann-Ross method at low conversion with HAPENAlOⁱPr as initiator. The values obtained, r_CL = 19.4 and r_BL = 0.11, confirmed the presence of long blocks of CL units in the copolymer.     

Synthesis and Structural Characterization of Three Novel Macrocyclic Coordination Complexes Formed by Self-assembly of Bridged Bi-or Tetrapyridine with Transition Metal Salts

Serf-assembly of a ferrocenyl-bridged bipyridine ligand bpef [bpef=1, 1＇-bis（trans-2-pyrid-4＇-ylethenyl）ferrocene] with silver triflate in CH2Cl2/MeOH or mercuric diiodide in MeCN/CH2Cl2 gave the corresponding macrocyclic coordination complexes [bpef]2[AgSO3CF3]2 （1） and [bpef]2[Hg3I6] （2） in 93% and 89% yields, respectively, whereas the pentaerythritolyl-bridged tetrapyridine ligand ptpc [ptpc=pentaerythritol tetrakis-（4-pyridinecarboxylate）] reacted with cobalt thiocyanate via self-assembly to afford the macrocyclic coordination polymer [Co（NCS）2（ptpc）], （3） in 90% yield. The X-ray diffraction analyses for 1-3 confirmed their novel macrocyclic structures and revealed that （i） the two silver atoms in complex 1 have an essentially linear geometry with N-Ag-N bond angle of 175.7° and 172.9°, （ii） the geometry of the middle mercury atom in complex 2 is square-planar, while the other two mercury atoms in the other two complexes are tetrahedral, and （iii） all the cobalt atoms in complex 3 adopt an octahedral geometry. In addition, the synthetic procedure for the known tetrapyridine ligand ptpc has been improved.     

Syntheses and Crystal Structures of Two Novel Cobalt（Ⅱ） Complexes with 2-Amino-5-substituted-l,3,4-thiadiazole as Ligands

Two novel cobalt（Ⅱ） compounds were obtained and characterized by X-ray sing- le-crystal diffraction, IR, 1H NMR and elemental analysis. Compound 1 crystallizes in monoclinic, space group P21/n, with a = 18.046（4）, b = 11.335（3）, c = 19.157（5）A, β = 92.707（3）°, Z = 4, V = 3914.4（16） A3, Mr = 968.56, Dc = 1.644 g/cm3, μ = 1.378 mm^-1, F（000） = 1960, the final R = 0.0367 and wR = 0.0895. The crystal of compound 2 is of monoclinic, space group P211c with a = 8.7253（10）, b = 10.9031（13）, c = 18.235（2）A,β = 93.2210（10）°, Z = 4, V = 1732.0（3）A3, Mr = 464.21, Dc = 1.780 g/cm3,μ = 1.560 mm-1, F（000） = 932, the final R = 0.0322 and wR = 0.0743.     

Asymmetric Reformatsky Reaction of Aldehydes Catalyzed by Novel β-Amino Alcohols and Zinc Complexes

A series of β-amino alcohols derived from (1R, 2S)-2-amino-1,2-diphenylethanol and substituted salicylaldehydes as novel chiral tridentate ligands has been applied to an asymmetric Reformatsky reaction of aldehydes with ethyl iodoacetate in the presence of ZnMe₂. This novel catalytic system produced the desired β-hydroxyl esters with moderate to good enantioselectivities (up to 81% ee) and yields for many aldehydes, including aromatic, heteroaromatic, conjugated, and aliphatic aldehydes.     

Polynuclear Silver(Ⅰ) Complexes with Phosphorus Ligands and 4,4'-Bipyridine:Synthesis,Structural Characterization and Spectroscopic Properties

Two novel silver(I) complexes {[Ag(OTf)(PPh3)(4,4'-bipy)]}∞(1) and {[Ag2-(OTf)2(dppb)3](CH3CN)4}∞(2)(OTf = trifluoromethanesulfonate, PPh3 = triphenylphophine, 4,4'-bipy = 4,4'-bipyridine, dppb = bis(diphenylphosphino)butane) have been synthesized and characterized by IR, single-crystal X-ray diffraction, fluorescence spectrum and 1H NMR spectroscopy. Complex 1 crystallizes in orthorhombic, space group Pna21 with a = 19.259(2), b = 9.85070(12), c = 16.3827(17) ?, V = 3108.0(5) ?3, C29H23F3N2O3 PSAg, Mr = 675.39, Z = 4, Dc = 1.443 g/cm3, F(000) = 1360, μ = 0.816 mm-1, the final R = 0.0675 and w R = 0.1722 for 3662 observed reflections(I 2σ(I)). Complex 2 crystallizes in triclinic, space group P1 with a = 12.9370(11), b = 13.5261(13), c = 16.4539(15) ?, α = 106.7120(10), β = 97.3830(10), γ = 113.027(2)?, V = 2441.2(4)?3, C94H96F6N4O6P6S2Ag2, Mr = 1957.43, Z = 1, Dc = 1.331 g/cm3, F(000) = 1006, μ = 0.605 mm-1, the final R = 0.0717 and w R = 0.1795 for 5128 observed reflections(I 2σ(I)). Complex 1 is of zigzag chain structure, in which each Ag atom is coordinated by one OTf- anion, two N atoms from two 4,4'-bipy molecules and one P atom from PPh3 ligand. In 2, the central Ag atom is coordinated with one OTf- anion and three P atoms from three dppb ligands, which leads to the formation of a zigzag ring-bridge-ring chain with each ring consisting of two Ag atoms and two dppb ligands.     

Metal Complexes of Donor-functionalized Fluorinated β-Ketoiminates – Synthesis,Structure, and CVD Application

Six alkali metal complexes of partly-fluorinated, donor-functionalized β-ketoiminate ligands [L¹Li ( 1 ), L¹Na ( 2 ), L¹K ( 3 ), L¹Cs ( 4 ), L¹ = OC(CF₃)CHC(CH₃)NCH₂CH₂OCH₃; L²Li ( 5 ), L²Na ( 6 ), L² = OC(CF₃)CHC(CH₃)NCH₂CH₂N(CH₃)₂] were prepared and structurally characterized. Reactions of L¹Li with PtCl₂ gave the homoleptic Pt complex L¹₂Pt ( 7 ), which was characterized spectroscopically and by single-crystal X-ray diffraction and whose promising application as CVD precursor (chemical vapor deposition) is shown. Polycrystalline, pure Pt films were grown at 500 °C on SiO₂@Si(100) substrates at 10^–3 mbar and characterized by XRD, SEM, AFM, EDX and XPS.