Organic soluble deoxyribonucleic acid (DNA) bearing carbazole moieties and its blend with phosphorescent Ir(III) complexes

A functionalized deoxyribonucleic acid (Cz‐DNA) was prepared with carbazolyl ammonium lipid as a triplet host material for phosphorescent material system. It is soluble in organic solvents, which facilitates the sample preparation for the absorption and luminescent properties in solid states. A highly soluble iridium complex, Ir(Cz‐ppy)₃ with carbazolyl‐substituted 2‐phenylpyridine ligands was employed for studying the phosphorescence in Cz‐DNA. There is a good overlap between the photoluminescence spectrum of Cz‐DNA and the metal‐to‐ligand charge transfer (MLCT) absorption bands of the iridium complex. This overlap enables efficient energy transfer from the excited state in the host to the MLCT band of Ir(Cz‐ppy)₃. In addition, photoluminescence quantum yield of Cz‐DNA was found to be relatively larger than the copolymer (PCzSt) with vinylcarbazole and styrene. Thus, Cz‐DNA was employed as a triplet host material for fabricating multilayered electrophosphorescence devices via modification of its property by doping 5,4‐tert‐butylhexyl‐1,3,4‐oxadiazole (PBD). After doping 30 wt % PBD and 10 wt % Ir(Cz‐ppy)₃ into Cz‐DNA, we achieved much improvement in electron injection/transport from an adjacent carrier transport layer, resulting in much improved device performances. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1913–1918, 2010     

Total synthesis of (±)-erythravine based on ring closing dienyne metathesis

The first total synthesis of (±)-erythravine was achieved in thirteen steps from 3,4-dimethoxyphenethylamine using ring closing dienyne metathesis as the key step.     

Studies on the Synthesis of Morphinan Alkaloid： Preparation of the Key Allylic Silyl Ether Precursor

Morphinan alkaloid consisting of many diverse molecules has been attracting much attention of synthetic chemists because of their biologically significant activities and the intriguing structures1. As shown in the common nucleus 1 of these polycyclic frameworks, there is a unique quaternary carbon center with an aryl substituent representing a central synthetic challenge2. In connection with our constant investigations on the quaternary carbon chemistry3, we proposed a general and conceptually…     

Alkaloids from Arundo donax. XVII. Structure of the Dimeric Indole Alkaloid Arundaphine

The newdimeric alkaloid arundaphine, a tryptamine-tryptamine base, was isolated from roots and rhizomes of Arundo donax (Poaceae). Spectral data and an x-ray structure analysis established its structure as 1-[3-(2-dimethylaminoethyl)-5-hydroxy-1H-4-indolyl]-3-hydroxy-3-(2-methylaminoethyl)-2-indolinone.     

聚乙烯基咔唑与8-羟基喹啉铝混合体系的荧光衰减

报道了8－羟基喹啉铝和聚乙烯基咔唑薄膜及其混合体系膜的荧光衰减特性。聚乙烯基咔唑／8－羟基喹啉铝重量比100：4的混合膜在波长540nm和460nm处的荧光衰减时间分别为6．47ns和8．5ns。重量比100：10混合膜在波长540nm和460nm处的荧光衰减时间分别为5．5ns和7．9ns。上述两波长对应8－羟基喹啉铝和聚乙烯基咔唑分子荧光发射。混合体系的荧光寿命仅为8－羟基喹啉铝分子荧光的40％，同时也低于聚乙烯基咔唑14ns的荧光寿命。荧光寿命的减少反映出两种分子之间存在较强的相互作用或形成了分子复合体。     

Synthesis of Carbazole Alkaloids by Ring‐Closing Metathesis and Ring Rearrangement–Aromatization

Aprocess for the assembly of carbazole alkaloids has been developed on the basis of ring‐closing metathesis (RCM) and ringrearrangement–aromatization (RRA) as the key steps. This method is based on allyl Grignard addition to isatin derivatives to provide smooth access to 2,2‐diallyl 3‐oxindole derivatives through a 1,2‐allyl shift. The diallyl derivatives were used as RCM precursors to afford a novel class of spirocyclopentene‐3‐oxindole derivatives, which underwent a novel RRA reaction to afford carbazole derivatives. The synthetic sequence to carbazoles was shortened by combining the RCM and RRA steps in an orthogonal tandem catalytic process. The utility of this methodology was further demonstrated by the straightforward synthesis of carbazole alkaloids, including amukonal derivative, girinimbilol, heptaphylline, and bis(2‐hydroxy‐3‐methylcarbazole).     

Stepwise Halide‐Triggered Double and Triple Catenation of Self‐Assembled Coordination Cages

A simple self‐assembled [Pd₂ L ₄] coordination cage consisting of four carbazole‐based ligands was found to dimerize into the interpenetrated double cage [3 X@Pd₄ L ₈] upon the addition of 1.5 equivalents of halide anions (X=Cl^?, Br^?). The halide anions serve as templates, as they are sandwiched by four Pd^II cations and occupy the three pockets of the entangled cage structure. The subsequent addition of larger amounts of the same halide triggers another structural conversion, now yielding a triply catenated link structure in which each Pd^II node is trans‐coordinated by two pyridine donors and two halide ligands. This simple system demonstrates how molecular complexity can increase upon a gradual change of the relative concentrations of reaction partners that are able to serve different structural roles.     

A novel synthesis route to furo[3,2-a]carbazole

In this paper,we report a novel approach to the heteroaryl-condensed nuclei of natural furo[3,2-a]carbazole alkaloids.Our synthetic studies use N-phthaloyl tryptophan methyl ester as starting material and zinc ion mediated transamination reaction as the key step.This work also implicated a novel strategy to assemble other [a]-fused carbazoles.     

Unprecedented C_(19)-diterpenoid alkaloid glycosides from an aqueous extract of “fu zi”: Neoline 14-O-L-arabinosides with four isomeric L-anabinosyls

Four structurally unprecedented aconitane-type C_(19)-diterpenoid alkaloid glycosides with isomeric arabinosyls, named aconicarmichosides A–D(1–4), were isolated from an aqueous extract of "fu zi", the lateral roots of Aconitum carmichaelii. Their structures were determined as neoline 14-O-a-and 14-O-b-L-arabinopyranosides(1 and 2) and 14-O-a-and 14-O-b-L-arabinofuranosides(3 and 4), by spectroscopic and chemical methods including 2D NMR experiments and acid hydrolysis. Compounds 1–4 represent the first examples of glycosidic diterpenoid alkaloids.     

Crystal structure of 5,6‐bis(9H‐carbazol‐9‐yl)benzo[c][1,2,5]thiadiazole: distortion from a hypothetical higher‐symmetry structure

Nucleophilic substitution of F atoms in 5,6‐difluorobenzo[c ][1,2,5]thiadiazole (DFBT) for carbazole could be potentially interesting as a novel way of synthesizing building blocks for new conjugated materials for applications in organic chemistry. The crystal structures of 5,6‐bis(9H‐carbazol‐9‐yl)benzo[c ][1,2,5]thiadiazole (DCBT), C₃₀H₁₈N₄S, and its hydrate, C₃₀H₁₈N₄S·0.125H₂O, were investigated using single‐crystal X‐ray analysis. The hydrate contains two symmetry‐independent DCBT molecules. The dihedral angles between the plane of the central benzothiadiazole fragment and that of the carbazole units vary between 50.8 and 69.9°, indicating conformational flexibility of the DCBT molecule in the crystals, which is consistent with quantum chemical calculations. The analysis of the crystal packing of DCBT revealed that the experimental triclinic structure could be described as a distortion from a hypothetical higher‐symmetry monoclinic structure. The quantum chemical calculations of two possible monoclinic structures, which are related to the experimental structure by a shifting of molecular layers, showed that the proposed structures are higher in energy by 5.4 and 10.1 kcal mol⁻¹. This energy increase is caused by less dense crystal packings of the symmetric structures, which results in a decrease of the number of intermolecular interactions.