Synthesis of Rigid <i>π</i>‐Conjugated Mono‐, Bis‐, Tris‐, and Tetrakis(terpyridine)s: Influence of the Degree and Pattern of Substitution on the Photophysical Properties

“…Intermediates 4,4'-bis[(diethoxyphosphoryl)methyl]stilbene P5, [43] 1,2-bis[(diethoxyphosphoryl)methyl]benzene P6, [44,46] 1,3-bis[(diethoxyphosphoryl)methyl]benzene P7 [45,46] and 2,6-bis[(diethoxyphosphoryl)methyl]-pyridine P8, [47] the p-conjugated connectors 9 [48] and 10, [49] the ligand 1 [34] …”

mentioning

confidence: 99%

Coordination‐Driven Hierarchical Organization of π‐Conjugated Systems: From Molecular to Supramolecular π‐Stacked Assemblies

Yao

Shen

Nohra

et al. 2010

Chemistry A European J

View full text Add to dashboard Cite

The reaction of U-shaped, bimetallic, Cu(I) complexes, assembled from a heteroditopic pincer, with cyano-capped pi-conjugated linkers gives a straightforward access to pi-stacked metallocyclophanes in good yields. In these assemblies, the pi-walls have an almost face-to-face arrangement. The versatility of this rational supramolecular synthesis is demonstrated with the use of linkers that have nanoscale lengths (up to 27.7 A), different chemical compositions (oligo(para-phenylenevinylene)s OPVs, oligo(phenylene)s, oligo(phenylethynylene)s), and alternative geometries (linear, angular). Linkers that incorporate an internal pyridyne moiety can also be employed. X-ray diffraction studies revealed that the metallocyclophanes based on linear linkers self-organize into infinite pi-stacked columns in the solid state with intermolecular distances of about 3.6 A. This approach, based on coordination-driven self-assembly, provides a novel and rational strategy for the stacking of extended pi-systems in the solid state.

show abstract

“…Elemental analysis data for 4a, 6a–10a , 12a–15a , 6–16 and 29 . Synthetic procedures for 16 ,25 17 ,26 19b 37 and 19c ,37 20a – 20e ,22,32,38–40 22b 22 and 22c ,41 24 ,42 25 ,42 28 43 …”

mentioning

confidence: 99%

Phenolic Bis-styrylbenzenes as β-Amyloid Binding Ligands and Free Radical Scavengers

et al. 2010

View full text Add to dashboard Cite

Starting from bisphenolic bis-styrylbenzene DF-9 (4), β-amyloid (Aβ) binding affinity and specificity for phenolic bis-styrylbenzenes, mono-styrylbenzenes and alkyne controls were determined by fluorescence titration with β-amyloid peptide Aβ 1-40 and a fluorescence assay using APP/PS1 transgenic mouse brain sections. Bis-styrylbenzene SAR is derived largely from work on symmetrical compounds; this study is the first to describe Aβ binding data for bis-styrylbenzenes unsymmetrical in the outer rings. With one exception, binding affinity and specificity were decreased by adding and/or changing the substitution pattern of phenol functional groups, changes to the orientation about the central phenyl ring, replacing the alkene with alkyne bonds, or elimination of the central phenyl ring. The only compound with an Aβ binding affinity and specificity comparable to 4 was its 3-hydroxy regioisomer 8. Like 4, 8 crossed the blood-brainbarrier and bound to Aβ plaques in vivo. Using a DPPH assay, phenol functional groups with para orientations seem to be a necessary, but insufficient, criterion for good free radical scavenging properties in these compounds.Alzheimer's disease (AD) 1 is a common neurodegenerative disorder in the elderly 2 characterized by an accumulation of β-amyloid (Aβ) plaques in the brain parenchyma and neurofibrillary tangles (NFTs) in the neuron. 3,4 Although Aβ and NFTs are commonly observed in nondemented elderly, 80 years and older, the molecular pathogenesis of AD is believed to be effected by Aβ production and its clearance. 5,6 The amyloid cascade hypothesis 7 for AD pathogenesis proposes that accumulation and aggregation of Aβ triggers a cascade that leads to the characteristic pathologies of AD. Evidence in support of this hypothesis is obtained from studies of familial AD, which reveal that Aβ accumulation and aggregation are elevated by mutations of the APP, PS1 and PS2 genes. 8 The discovery of the diazo dye Congo red as an Aβ binding ligand 9 provided a starting point in the search for potential in vivo imaging agents using positron emission tomography (PET), single photon emission computed tomography (SPECT) and magnetic resonance imaging (MRI). Investigation of Congo red led to the discovery of bis-styrylbenzenes as a class of compounds with strong Aβ plaque binding properties. These compounds are exemplified by the salicylate bis-styrylbenzenes X-34 (1) 10 shown to penetrate the blood -brain barrier (BBB) and bind to Aβ plaques deposited in APP or APP/PS1 mice. 11 As shown by K114 (3) and DF-9 (4), acidic functional groups are not necessary for good Aβ binding. 12,13 Several stilbene-based compounds, such as SB-13 and BAY94-9172, have been studied for early detection in AD. 14,15 While the structure-activity relationship (SAR) of bis-styrylbenzene compounds has been extensively investigated, the common thread in these studies is that Aβ-binding SAR has been elucidated based largely on symmetrical bis-styrylbenzenes. DesignPreviously, we showed that the bis-styrylbenzene, (E,E)-1...

show abstract

Synthesis of Rigid π‐Conjugated Mono‐, Bis‐, Tris‐, and Tetrakis(terpyridine)s: Influence of the Degree and Pattern of Substitution on the Photophysical Properties

Cited by 68 publications

References 75 publications

Novel kinetics model for third-liquid phase-transfer catalysis system of the “complex” carbanion: Competitive role between catalytic cycles

Novel kinetics model for third-liquid phase-transfer catalysis system of the “complex” carbanion: Competitive role between catalytic cycles

Coordination‐Driven Hierarchical Organization of π‐Conjugated Systems: From Molecular to Supramolecular π‐Stacked Assemblies

Phenolic Bis-styrylbenzenes as β-Amyloid Binding Ligands and Free Radical Scavengers

Contact Info

Product

Resources

About