Star‐Shaped Push‐Pull Compounds Having 1,3,5‐Triazine Cores

Meier, Herbert; Karpuk, Elena; Holst, Hans Christof

doi:10.1002/ejoc.200600066

Cited by 49 publications

(22 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The convergence limit, calculated on the basis of exponential functions [28] is predicted as 427 ± 3 nm. The analogous stars 111t-v with a stronger p -dihexylamino donor and one to three stryryl units per arm ( n = 1-3) behave different [308]. …”

Section: Compounds With Heterocyclic Coresmentioning

confidence: 99%

Star-Shaped Conjugated Systems

2010

Self Cite

View full text Add to dashboard Cite

The present review deals with the preparation and the properties of star-shaped conjugated compounds. Three, four or six conjugated arms are attached to cross-conjugated cores, which consist of single atoms (B, C+, N), benzene or azine rings or polycyclic ring systems, as for example triphenylene or tristriazolotriazine. Many of these shape-persistent [n]star compounds tend to π-stacking and self-organization, and exhibit interesting properties in materials science: Linear and non-linear optics, electrical conductivity, electroluminescence, formation of liquid crystalline phases, etc.

show abstract

Section: Compounds With Heterocyclic Coresmentioning

confidence: 99%

Star-Shaped Conjugated Systems

2010

Self Cite

View full text Add to dashboard Cite

show abstract

“…Stilbene-based probe 19 was synthesized in four steps that included: a) conversion of benzyl bromide 15 to phosphonate 16 ;[21]; b) Horner–Emmons olefination of 16 with aldehyde 6 a to form 17 ; c) lithiation of bromide 17 and formylation to produce aldehyde 18 ; d) Knoevenagel condensation of the resulting aldehyde 18 with cyano ester 7 (Scheme 4, 42 % combined yield).…”

mentioning

confidence: 99%

Rational Design of Amyloid Binding Agents Based on the Molecular Rotor Motif

et al. 2009

View full text Add to dashboard Cite

Alzheimer's disease (AD) is characterized by a progressive loss of cognitive function and constitutes the most common and fatal neurodegenerative disorder.[1] Genetic and clinical evidence supports the hypothesis that accumulation of amyloid deposits in the brain plays an important role in the pathology of the disease. This event is associated with perturbations of biological functions in the surrounding tissue leading to neuronal cell death, thus contributing to the disease process. The deposits are comprised primarily of amyloid (Aβ) peptides, a 39-43 amino acid sequence that self aggregates into a fibrillar β-pleated sheet motif. While the exact three-dimensional structure of the aggregated Aβ peptides is not known, a model structure that sustains the property of aggregation has been proposed. [2] This creates opportunities for in vivo imaging of amyloid deposits that can not only help evaluate the time course and evolution of the disease, but can also allow the timely monitoring of therapeutic treatments. [3] Keywords amyloid peptides; fluorescent probes; imaging agents; molecular rotors Historically, Congo Red (CR) and Thioflavin T (ThT) have provided the starting point for the visualization of amyloid plaques and are still commonly employed in post mortem histological analyses (Figure 1).[4] However, due to their charge these probes are unsuitable for in vivo applications. [5] To address this issue, several laboratories developed probes with noncharged, lipophilic (log P = 0.1-3.5) and low-molecular weight chemical structures (MW <650) that facilitate crossing of the blood-brain barrier.[6] Further functionalization of these compounds with radionuclides led to a new generation of in vivo diagnostic reagents (Figure 1) that target plaques and related structures for imaging with positron emission tomography (PET) and single-photon emission computed tomography (SPECT Figure 1 reveals that the majority of these probes contain an electrondonor unit in conjugation with an electron acceptor (D-π-A motif). This motif is a typical feature in molecular rotors, a family of fluorescent probes known to form twisted intramolecular charge-transfer (TICT) complexes in the excited state producing a fluorescence quantum yield that is dependent on the surrounding environment.[11] Following photoexcitation, this motif has the unique ability to relax either via fluorescence emission or via an internal nonradiative molecular rotation. This internal rotation occurs around the σ-bonds that connect the electron-rich π-system with the donor and acceptor groups, and can be modified by altering the chemical structure and microenvironment of the probe.[12] Hindrance of the internal molecular rotation of the probe by increasing the surrounding media rigidity, or by reducing the available free volume needed for relaxation, leads to a decrease in the nonradiative decay rate and consequently an increase in fluorescence. In contrast, relaxation proceeds mainly via nonradiative pathways in environments of low viscosity or of hi...

show abstract

“…八极分子无偶极矩, 其聚集体克服了分子间因偶极-偶极相互作用导致的消极作用, 有更大的可能形成非中心对称的晶格结构, 是改进分子结构的理想途径之一 [8] . 20 世纪 90 年代以来, 八极小分子的二阶非线性性能的报道结果非常鼓舞人心 [9] . 因此具有三重对称轴的八极分子二阶非线性的研究被认为是一个极其重要的方向.…”

Section: Synthesis Characterization and Properties Of A New Octupolaunclassified