Synthesis and visible light luminescence of mononuclear nine-coordinate lanthanide complexes with 2,4,6-tris(2-pyridyl)-1,3,5-triazine

Synthesis of four nine-coordinate lanthanide (III) complexes of the type, [Ln(hfaa)₃(tptz)], where Ln = La, Nd, Sm and Tb; hfaa = the anion of 1,1,1,5,5,5-hexafluoro-2,4-pentanedione and tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine, by a new modified one pot in situ method is reported. The lanthanide ions are coordinated to three N-atoms of three 2-pyridyl units of tptz besides six O-atoms of three hfaa units. The formation of these volatile complexes is confirmed by molecular ion peak in ESI-MS, IR and NMR. The hypersensitive ⁴G_5/2, ²G_7/2 ← ⁴I_9/2 transition displays distinct band shape which is different from the band shape of known eight- and ten-coordinate complexes. The samarium and terbium complexes emit pink and green luminescence due to ⁴G_5/2 → ⁶H_j (j = 5/2, 7/2, 9/2) and ⁵D₄ → ⁷F_j (j = 3-6) transitions, respectively.     

2,4,6-三氨基酸取代-1,3,5-均三嗪衍生物的合成研究

含均三嗪“核”结构的树状大分子在有机光电材料等领域有着重要作用,首次报道以L-丙氨酸、L-丝氨酸、L-天冬氨酸和L-天冬酰胺为原料,以DIPEA为缚酸剂,分别与三聚氯氰缩合得到4个手性的2,4,6-三氨基酸取代-1,3,5-均三嗪衍生物.此方法也适用于其他氨基酸与三聚氯氰的缩合反应.目标化合物的结构经过1HNMR、MS等分析测试技术的确证.反应条件温和,收率高,具有较广阔的工业应用前景.     

Electrochemical and thermal properties of 2,4,6-tris(trifluoromethyl)-1,3,5-triazine as a flame retardant additive in Li-ion batteries

Triazines are well known as flame retardants, however, their properties for battery applications have not been much explored. Flame retardants can play an important role in preventing dangerous situations that may occur when battery packs malfunction or are misused. However, the addition of flame retardants to batteries can degrade their performance due to the non-ionic properties of the additives. In order to overcome this drawback of additives, fluorinated material has been investigated, because fluorination frequently prevents deterioration of performance. A fluoride-rich triazine used as an additive to the electrolyte, 2,4,6-tris(trifluoromethyl)-1,3,5-triazine (TTFMT), showed excellent thermal stability with charged cathodes and anodes. Addition of 5 wt.% TTFMT to the electrolyte reduced the exothermic heat from the oxygen release reaction in the cathode by 54%. Surface film formation on the cathode is discussed with reference to cyclic voltammetry combined with impedance spectroscopy and differential scanning calorimetry. The properties of the film were influenced by the additive so as to markedly reduce the charge-transfer resistance, which enhanced the charge retention during cycle life, the capacity, and the high-rate discharge capacity of the battery.     

Electrochemical and spectral properties of meta-linked 1,3,5-tris(aryl)benzenes and 2,4,6-tris(aryl)-1-phenoles, and their polymers

We present electrochemical and spectral properties of symmetric monomers 1,3,5-tris(aryl)benzenes and 2,4,6-tris(aryl)-1-phenols and their polymers. These compounds contain thienyl, furyl or EDOT moieties attached to central benzene or phenol ring at the meta-position, synthesized by a Stille cross-coupling procedure. All monomers are electroactive and undergo electropolymerization creating thin films on an electrode surface. Polymers with meta-linkages were obtained by electrochemical oxidation. Detailed cyclic voltammetry and in situ UV-vis spectroelectrochemistry show that polymers with hydroxy groups exhibit higher conductivity and better stability than with benzene core. Interesting and different behavior occurs for 2,4,6-tris(2-thienyl)-1-phenol, for which the characteristic, sharp, redox peak is observed.     

Synthesis,structure and electrochemical properties of tris (2-(2-pyridyl)-4-methylcarbonylquinoline) ruthenium(II) hexafluorophosphate

A novel ruthenium complex with 2-(2-pyridyl)-4-methylcarbonylquinoline ligand has been prepared and characterized: the first crystal structure of such complex along with its physical and chemical properties are also described.     

Self-assembly of novel supramolecular silver(I) compound based on mixed ligands bipy/TST3−, H3TST = 2,4,6-tris (4-sulfophenylamino)-1,3,5-triazine

The novel supramolecular silver(I) compound with formula [Ag₆(TST)₂(bipy)₆(H₂O)₂]_n · 3nH₂O (1) based on assembly of Ag(I) and mixed ligand bipy/TST³⁻, bipy = 2,2′-bipyridine, H₃TST = 2,4,6-tris(4-sulfophenylamino)-1,3,5-triazine, has been prepared by hydrothermal method. In the solid-state structure of 1, two-dimensional layered polymeric structures extended with subunits [Ag₆(TST)₂(bipy)₆(H₂O)₂] interact each other in the form of π–π attractions between bipy, forming a three-dimensional supramolecular architecture. Compound 1 represents a Ag-containing polymeric compound possessing room-temperature luminescence.     

Design and syntheses of blue luminescent Cu(II) and Zn(II) polymeric complexes with 2-(2′-pyridyl)benzimidazole derivative ligand

The polymeric complexes of 4,4′-bis[2-(2′-pyridyl)benzimidazolyl]biphenyl (Bmbp) with Cu(II) (1), Zn(II) (2) and 1,3,5-tris[2-(2′-pyridyl)benzimidazolyl]benzene (Tmb) with Cu(II) (3), Zn(II) (4) were successfully synthesized and characterized by IR spectroscopy, elemental analysis, thermal analysis and conductivity measurements. The results indicate that the stoichiometry of these metal complexes is metal: Bmbp (or Tmb) = 1:1 for 1 and 2 (2:1 for 3 and 4). Ligands coordinated with metal ions to get a five-membered chelate ring and formed polymeric complexes with metal ion. Their luminescence properties were also studied by UV–vis and fluorescence spectra. At room temperature, complexes 1–4 emit blue luminescence from 419 to 483 nm in the solid state and purple/blue luminescence from 385 to 437 nm in DMF solution. Thermal properties measurement and analysis shows that they have good thermal stabilities.     

Ethylene oligomerization promoted by group 8 metal complexes containing 2-(2-pyridyl)quinoxaline ligands

Ni^II, Co^II and Fe^II complexes of 2-(2-pyridyl)quinoxaline were synthesized and used in the ethylene oligomerization with methyl-aluminoxane (MAO) as cocatalyst. The nickel complex system mainly produced α-olefins with good activity, while the cobalt and iron complexes showed only marginal activity.     

Synergistic flame retardancy of tris(1-methoxy-2,2,6,6-tetramethyl-piperidin-4-yl)phosphite and tris(2,4,6-tribromophenoxy)-1,3,5-triazine/Sb2O3 in high-impact polystyrene

Synergistic flame retardancy of tris(1-methoxy-2,2,6,6-tetramethyl-piperidin-4-yl) phosphite (NORPM) and tris(2,4,6-tribromophenoxy)-1,3,5-triazine (TTBPC)/Sb₂O₃ in high-impact polystyrene (HIPS) was studied by limiting oxygen index (LOI) determination, UL-94 test, and cone calorimetry test (CCT). NORPM has an exceptional synergistic effect in HIPS. When the dosage of TTBPC, Sb₂O₃, and NORPM was 12.8, 3.2, and 0.5 wt% respectively, flame retardant effectivity and synergistic effectivity were 0.424 and 1.15 respectively. Compared with the Flame retardant (FR)-HIPS containing 16.0 wt% of TTBPC/Sb₂O₃, the LOI of FR-HIPS increases from 23.8% to 25.4%, the flame-retardant rating of FR-HIPS can be improved from UL 94 V-2 to V-0, and the peak heat release rate and total heat release are significantly reduced by combining NORPM in 0.5 wt% concentration. NORPM induces the synergistic effect mainly through the following mechanisms: the active radicals produced by the pyrolysis of NORPM promote the release of bromine radicals from TTBPC and the formation of HBr, which improves the flame retardancy of TTBPC; the above active radicals, together with HBr, quench active free radicals, such as the hydroxyl radical (·OH) and decompose the free radical source, which interrupts the chain reaction during combustion and results in a more efficient flame retardant effect in gaseous phase.     

Synthesis,topology analysis and luminescent property of a 3D AgCN coordination polymer based on 2-tptz (2-tptz = 2,4,6-tri(2-pyridyl)-1,3,5-triazin)

The solvothermal reaction of AgCN with 2-tptz (2-tptz = 2,4,6-tri(2-pyridyl)-1,3,5-triazin) afforded a 3D coordination polymer [(AgCN)₃(2-tptz)]_n (1). It was characterized by infrared spectroscopy, elemental analysis and X-ray single-crystal analysis. The structure of this polymer features a 2D wavelike [AgCN]_n substructure constructed from 18-membered of Ag₆(CN)₆ rings and 22-membered of Ag₈(CN)₆C₂ rings. When silver?sliver interactions are taken into account, the structure of 1 exhibits a (3 · 8 · 9)(4 · 8 · 9)(3 · 4 · 8 · 9³)(3 · 8 · 9² · 10²) topological network which has not been reported for the (3, 4)-connected nets. The photoluminescent property of the present coordination polymer was also investigated.     

Chromogenic mercury ions recognition of a new ruthenium(II) complex with cyclometalated 2-(2-thienyl)pyridine in CH3CN-aqueous system

A new cyclometalated complex [Ru(II)(deeb)₂(thpy)]PF₆ (1) was synthesized using 4,4′-diethylester-2,2′-bipyridine (deeb) and 2-(2-thienyl)pyridine (thpy) as ligands. Its maximum MLCT absorption is about 575 nm, extending beyond 750 nm. When Hg^2 + was added to the CH₃CN-aqueous solution of 1, a remarkable color change from dark-red to yellow with a blue-shift of 120 nm occurred, which indicated that the as-prepared complex 1 can serve as a sensitive “naked-eye” indicator for Hg^2 +.     

Anion-directed assembly of two fluorescent Cd(II) coordination polymers with a versatile multidentate N-donor building block 3-(2-pyridyl)-4,5-bis(4-pyridyl)-1,2,4-triazole

Assembly of Cd(II) nitrate with a novel tripyridyltriazole building block 3-(2-pyridyl)-4,5-bis(4-pyridyl)-1,2,4-triazole (L¹) and pseudohalide anion dicyanamide (dca) or azide (N₃) yields two coordination polymers {[Cd(L¹)₂(dca)₂](H₂O)₂}_n (1) and {[Cd₂(L¹)(μ_1,1-N₃)₂(μ_1,3-N₃)(N₃)](H₂O)_1.5}_n (2). Single crystal X-ray diffraction analysis indicates that the Cd(II) centers in 1 are bridged by the bidentate L¹ ligands to form 1D arrays, which are further extended to a 3D network via hydrogen bonding and aromatic stacking. Significantly, the L¹ ligands in 2 display the unusual pentadentate coordination and the azide anions take different μ_1,1-, μ_1,3-, and unidentate binding modes, interlinking the Cd(II) ions to afford a complicated 3D open framework with the inclusion of lattice water guests. Both complexes exhibit strong solid state fluorescent emissions at room temperature.     

Solvent-controlled assemblies,structures, and properties of two Hg(II) coordination polymers with a multidentate N-donor tecton 3,4-bis(2-pyridyl)-5-(4-pyridyl)-1,2,4-triazole

Coordination polymers [Hg(L²)Cl₂]_n (1) and {[Hg₂(L²)Cl₄](DMF)}_n (2) have been assembled from Hg(II) chloride and a novel tripyridyltriazole tecton 3,4-bis(2-pyridyl)-5-(4-pyridyl)-1,2,4-triazole (L²) in different solvent media. Both complexes have been characterized by IR, microanalysis, powder X-ray diffraction, and thermogravimetric analysis. Single crystal X-ray diffraction indicates that the L² ligands take the (η³, μ₂) and (η⁴, μ₃) binding modes in 1 and 2, respectively, which connect the Hg(II) centers to afford linear and ladder-like 1D arrays. Interestingly, complex 1 exhibits strong solid state fluorescent emission at room temperature due to the intraligand transitions, whereas complex 2 is non-fluorescent.     

Synthesis of a new class of cyclometallated ruthenium(II) complexes and their application in dye-sensitized solar cells

We synthesized a new class of cyclometallated ruthenium(II) complexes, Ru(tctpy)(C^N)(NCS) (1, 2), where C^N is a bidentate cyclometallating ligand such as 2-phenylpyridinato or 2-(4-(2-phenylethynyl)phenyl)pyridinato. Although these complexes exist as stereoisomers, the microwave synthetic technique yielded only one isomer. These compounds act as light sensitizers and have excellent light-harvesting properties, especially in the near-IR region. Therefore, they can be used in dye-sensitized solar cells (DSCs). A DSC sensitized with 2 shows a 10% incident photon-to-current conversion efficiency at 900 nm.     

A unique diruthenium(II,III) unit surrounded by tridentate ligands of N-(2-pyridyl)-2-oxy-5-chlorobenzylaminate

A new metal–metal bonded diruthenium(II, III) compound with a dianionic tridentate ligand, N-(2-pyridyl)-2-oxy-5-chlorobenzylaminate (5-Clsalpy²⁻), was synthesized and structurally characterized as Li₂(THF)₄Cl[Ru₂(5-Clsalpy)₃] (1). The 5-Clsalpy²⁻ ligand that acts as a bridging/chelating co-ligand afforded a unique coordination mode of [M–M bridging/equatorial-chelating] in addition to the “common” mode of [M–M bridging/axial-chelating] around the diruthenium unit of 1.     

One new nickel coordination polymer with an unsymmetric 5-(4-pyridyl)-1,3,4-oxadiazole-2-thione: Synthesis,structure and characterization

A new neutral 2D coordination polymer, {[Ni(pot)₂(H₂O)₂] · 6H₂O}_n (1) (Hpot = 5-(4-pyridyl)-1,3,4-oxadiazole-2-thione), has been prepared by reacting Ni^II salt with the Hpot ligand under a mixed solvents medium; 1 possesses large rectangular channels to trap water molecules. It has been characterized by IR and gas sorption property as well as TG analysis.     

显色剂1-偶氮苯-3-(5-溴-2-吡啶)三氮烯的合成及其与镉的显色反应

合成了显色剂1-偶氮苯-3-(5-溴-2-吡啶)三氮烯,并研究了它与镉的显色反应。在pH10~12的Na2B4O7-NaOH缓冲溶液中,TritonX-100表面活性剂存在下,试剂与镉生成4∶1型红色配合物。配合物的最大吸收峰位于525nm,表观摩尔吸光系数为1.83×105L.mol-1.cm-1。Cd2+浓度在0~15μg/25mL范围内符合比尔定律。用拟定方法测定废水和湖水中微量镉,结果满意。     

Synthesis and spectroscopic and electrochemical properties of new ligand 1,3-bis(4′-methyl-2,2′-bipyridin-4-yl)propan-2-one and its ruthenium(II) complexes

A new bridging ligand, 1,3-bis(4′-methyl-2,2′-bipyridin-4-yl)propan-2-one (L) and its mono- and dinuclear Ru(II) complexes have been synthesized and characterized. The carbonyl group in L keeps its character and does not affect the Ru(II) moieties. In addition, the two Ru(II) terminuses of the dinuclear complex have no interaction through the bridging linkage.     

Eight-coordination in nitrato manganese(II) complexes with tetradentate di-Schiff bases derived from 2-pyridyl ketones: preparation,characterization and catalytic activity for alkene epoxidation

The reactions of Mn(NO₃)₂·6H₂O with the tetradentate Schiff bases N,N′-bis[1-(pyridin-2-yl)ethylidene]ethane-1,2-diamine (L_A) and N,N′-bis[1-(pyridin-2-yl)benzylidene]ethane-1,2-diamine (L_B) afforded the novel eight-coordinate complexes [Mn(NO₃)₂(L_A)] (1) and [Mn(NO₃)₂(L_B)] (2), which have a distorted dodecahedral coordination geometry. The catalytic activity of 1 and 2 for alkene epoxidation is reported and discussed.