高效吡嗪铱类配合物有机电致磷光材料的合成研究

研究了料比、反应时间、溶剂类型与用量等反应条件对3种以吡嗪环为配体的铱电致磷光材料(MDPP)2Ir(acac),(DBQ)2Ir(acac)和(MDQ)2Ir(acac)合成各步反应的影响。结果表明,1,2-二羰基化合物与乙二胺(或1,2-丙二胺)以1∶1.2的料比进行反应时收率最高,分别为80%,78%和75%;配体合成最佳反应时间分别为(1.5+2.0),6.0,6.0 h;用乙二醇单甲醚替代乙二醇单乙醚对氯桥化合物和金属铱配合物的合成几乎没有影响,金属铱和配体以及氯桥化合物与乙酰丙酮摩尔比以1∶2.2时收率最高,分别为75%,70%,73%和72%,75%,72%。     

二丁基二硫代氨基甲酸镧的合成及其在丁苯橡胶中的应用

研究了二丁基二硫代氨基甲酸镧配合物的合成,以工业级的二丁基二硫代氨基甲酸钠与氯化镧为反应物,采用液-液合成法合成了二丁基二硫代氨基甲酸镧,作为硫化促进剂应用于丁苯橡胶的基础配方中。结果表明二丁基二硫代氨基甲酸镧对丁苯橡胶的硫化性能有下列作用：延长燃烧时间,提高碳化速率。提高材料力学性能。     

Antiphotobleaching: A Type of Structurally Rigid Chromophore Ready for Constructing Highly Luminescent and Highly Photostable Europium Complexes

Antiphotobleaching is a critical challenge in the field of luminescent lanthanide complexes (LLCs) as well as in many disciplines concerning organic luminescent processes. In this work, a type of structurally rigid organic ligand, 4‐hydroxy‐1,5‐naphthyridine (ND), is developed, which can not only efficiently sensitize the europium emission but also demonstrate unique photostability. A series of ND derivatives with different substituent groups are synthesized and their singlet and triplet excited state energy levels are systematically investigated. Photophysical characterizations of the corresponding europium complexes reveal that the sensitization efficiencies (η_sens) are close to 100% and the total photoluminescence quantum yields can reach up to 84%. Most importantly, these structurally rigid luminescent europium complexes exhibit outstanding photostability and thermostability. Unlike the widely used β‐diketone complexes that are easily photodegraded, ND‐based chelates show no obvious degradation during the UV aging test (10 W m^?2 340 nm Ultraviolet A irradiation) within 200 h. Such superior UV resistance is even better than that of the famous compound tris(8‐hydroxyquinolate)aluminum (Alq₃). Possible reasons are discussed and a general rule for designing photostable LLCs is proposed. Such a chromophore is very promising for introducing luminescent materials with good photostability in potential application in many disciplines.     

Variations in the crystalline deposits formed upon electrochemical oxidation of the anions, [Ir(CO)2X2] (X = Cl, Br, and I)

The electrochemical properties of the ions [Ir(CO)₂X₂]⁻ (X = Cl, Br, and I) have been studied in dichloromethane solutions using cyclic voltammetry, chronoamperometry, electrochemical quartz crystal microbalance (EQCM), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and infrared spectroscopy. For the chloro and bromo salts, the anion [Ir(CO)₂X₂]⁻ is oxidized initially to form [Ir(CO)₂X₂]⁺. The standard rate constants for the two-electron oxidations of [Ir(CO)₂X₂]⁻ are 7.8(±0.6) × 10⁻³ and 9.2(±0.9) × 10⁻⁴ cm s⁻¹ for the redox couples, [Ir(CO)₂Cl₂]^−/+ and [Ir(CO)₂Br₂]^−/+, respectively. The processes following electrolysis lead to the formation of two types of crystalline deposits on the electrode surface: needles and plates. The relative amounts of these solid phases that form depend mainly on the concentration of iridium complex in solution and on the time window of experiment. The strong intermetallic Ir-Ir interaction is responsible for the formation of the one-dimensional iridium complex chain. The crystal structures of the needle phases formed from [Ir(CO)₂Cl₂]⁻ and [Ir(CO)₂Br₂]⁻ are the same and belong to the space group Cmcm (no. 63). The stoichiometry of the one-dimensional crystals depends on the constitution of the supporting electrolyte: (TAA)_0.6[Ir(CO)₂Cl₂] and (TAA)_0.7[Ir(CO)₂Br₂] (TAA is tetra(alkyl)ammonium cation) salts are formed on the electrode surface. The formation of large three-dimensional crystal is responsible for the accumulation of electroactive materials on the electrode surface. The irreversible oxidation of [Ir(CO)₂I₂]⁻ leads only to the formation of large, plate-like crystals on the electrode surface, no needles are formed.     

Unsymmetrical α‐diimine nickel (II) complex with rigid bicyclic ring ligand: Synthesis,characterization, and ethylene polymerization in the presence of AlEt2Cl

Unsymmetrical α‐diimine ligand 1 was successfully synthesized via condensation of trimethylaluminum (TMA) metalated 2‐methyl‐6‐isopropyl‐aniline with rigid bicyclic aliphatic diketone camphorquinone. Syn‐ and anti‐stereoisomers were detected by ¹³C NMR in the condensation product. The corresponding α‐diimine nickel (II) complex 1 was prepared from the exchange reaction of (DME)NiBr₂ with the ligand 1 , and displayed high activity for ethylene polymerization in the presence of diethylaluminum chloride (AlEt₂Cl). The resultant polymers were confirmed by gel permeation chromatography and ¹³C NMR characterization to be broad molecular weight distribution polyethylene with various branches, and high degree of branching, even at low polymerization temperature ?10°C. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Investigation of the structure of poly(vinyl alcohol)-iodine complex hydrogels prepared from the concentrated polymer solutions

The structure and dynamics of poly(vinyl alcohol) (PVA)-iodine complex hydrogels that were prepared from concentrated PVA solutions have been characterized by high-resolution solid-state ¹³C NMR spectroscopy. The fully relaxed dipolar decoupling (DD)/MAS ¹³C NMR spectrum indicates that the hydrogels contain at least two components, a highly mobile and broader components. The former is assigned to the soluble or well water-swollen PVA chains that are not closely associated with the PVA-iodine complexes, whereas the latter may be mainly ascribed to the aggregated PVA chains that are produced by the formation of the PVA-iodine complexes because no diffraction peaks due to the conventional PVA crystallites are observed by wide-angle X-ray diffractometry. Furthermore, ¹³C spin-lattice relaxation time (T_1C) analyses reveal that the broader component is composed of the highly restricted component probably assignable to PVA molecular chain aggregates containing the PVA-iodine complexes and the less mobile component. As for the former component, their CH resonance line measured by the T_1C-filtering method is successfully resolved into 7 constituent lines by the least-squares curve fitting. The statistical analysis of the integrated intensities of the constituent lines thus obtained also reveals that the probability f_a for the formation of intramolecular hydrogen bonding in the successive two OH groups along each chain and another probability f_t of the trans conformation are, respectively, as high as 0.86 and 0.88. This fact indicates that the PVA molecular chain aggregates containing the PVA-iodine complexes should be composed of PVA segments with the trans-rich conformation and the PVA-iodine complexes therein may also be formed with these several trans-rich segments surrounding the rod-like polyiodine cores in agreement with the so-called aggregation model. Moreover, several new diffraction peaks that should be interpreted in terms of the hexagonal structure are observed for the PVA-iodine complex hydrogels in the low 2θ region in the wide-angle X-ray diffraction (WAXD) profile measured by a strong X-ray source at SPring-8. This suggests the necessity of more detailed WAXD characterization to propose a new structure model, which should be referred to as the hexagonal aggregation model, for the PVA-iodine complexes.     

Stereocontrolled styrene-isoprene copolymerization and styrene-ethylene-isoprene terpolymerization with a single-component allyl ansa-neodymocene catalyst

The ansa-metallocene complex (CpCMe₂Flu)Nd(C₃H₅)(THF) (1) is an effective single-component catalyst for the production of syndiotactic styrene-rich polymer materials modified by isoprene and/or ethylene. The recovered copolymers have high molecular weights (M_n = 12,000-91,000 g/mol) and unimodal, relatively narrow molecular weight distributions (M_w/M_n = 1.3-2.8). The comonomer feeds can be easily manipulated to tune the respective amounts of monomers incorporated in the copolymer and eventually modify the final properties (T_m, T_g) of the obtained materials.     

Biodiversity of the vascular plants in the young fluvioglacial landscapes in the Severo-Chuiskiy centre of present-day glaciation (the Central Altai)

Abstract

This article reports the species richness of vascular plants in the young fluvioglacial landscapes in the Severo-Chuiskiy centre of present-day glaciation using the example of the fluvioglacial deposits of the mountain-glacial basin Aktru. These landscapes are four well distinguished classes of habitats: open pebble fields with minimal vegetation, young larch forests on elevated parts of the relief, shrub thickets on the banks of the Aktru river, and sites with ground-frazil near the valley slopes. There are 132 species of vascular plants in the young fluvioglacial landscapes. These include 36 families and 77 genera. There are 3 species of pteridophytes (only Equisetum), 4 species of gymnosperms, and 125 species of angiosperms. The highest species diversity was recorded for Asteraceae, Poaceae and Salicaceae families, and for Salix, Poa, and Carex genera. The highest species richness – 100 species – were recorded for open pebble fields. There were 76 species in the young larch forests, and 58 species occurred in shrub thickets. The lowest richness is characterised for the sites with ground frazil, where 31 species were recorded.     

杯芳烃的配位化学─—（5）对叔丁基杯芳烃与铜的固体配合物的合成和表征

合成了对叔丁基杯［４］芳烃（Ｈ４Ｌ）及对叔丁基杯［８］芳烃（ＨｓＬ’）与铜的固体配合物，并采用ＩＲ、ＥＡ、１ＨＮＭＲ、ＤＴＡ等方法对产物进行了表征。结果表明，所得的固体配合物组成分别为ＣＵ（Ｈ２Ｌ）·ＮＨ３·Ｈ２Ｏ（Ⅰ），ＣＵ２（Ｈ４Ｌ’）．４ＮＨ３·ＺＨ２Ｏ（Ⅱ）