271250-99-8Relevant academic research and scientific papers
Conjugated polymers with 2,2′-bipyridine and diethinylenebenzene units: Absorption and luminescence properties
Grummt,Birckner,Klemm,Egbe,Heise
, p. 112 - 126 (2000)
Alternating oligomers and polymers consisting of 2,2′-bipyridine and diethinylenebenzene units and corresponding model compounds were synthesized and investigated in dilute solutions by absorption spectroscopy and by stationary and time-resolved emission spectroscopy. The strictly linear (rod-like) π-chain oligomers/polymers were compared with the angularly linked oligomers/polymers and with related model compounds. The model compounds which already show the essential spectroscopic properties of the oligomers/polymers consist of three (hetero)aromatics linearly connected by two diethenylene groups. These models exhibit fluorescence quantum yields close to unity and short fluorescence decay times around 1 ns. Fluorescence anisotropy and rotational relaxation times are consistent with the Stokes-Einstein equation and the Perrin equation. The absorption and emission spectra of the polymers and their radiative rate constants determined by fluorescence quantum yield and lifetime and according to the Strickler/Berg equation show a conjugation length of one to two repetition units. The conjugation along the chain is stronger in linear than in angular polymers and stronger in alkoxy-substituted than in unsubstituted polymers. In angular polymers at least two different emitting segments were found. The shortened mean lifetimes and the reduced fluorescence quantum yields and anisotropies of the oligomers/polymers indicate an additional radiationless deactivation channel which is opened by energy migration along the chain. Rates of energy transfer calculated for linear and angular polymers correlate with rates of radiationless deactivation. Copyright
Structure-Activity Relationships for Negative Allosteric mGluR5 Modulators
Kaae, Birgitte H.,Harpsoe, Kasper,Kvist, Trine,Mathiesen, Jesper M.,Molck, Christina,Gloriam, David,Jimenez, Hermogenes N.,Uberti, Michelle A.,Nielsen, Soren M.,Nielsen, Birgitte,Braeuner-Osborne, Hans,Sauerberg, Per,Clausen, Rasmus P.,Madsen, Ulf
experimental part, p. 440 - 451 (2012/06/04)
A series of compounds based on the mGluR5-selective ligand 2-methyl-6-(phenylethynyl)pyridine (MPEP) were designed and synthesized. The compounds were found to be either structural analogues of MPEP, substituted monomers, or dimeric analogues. All compounds retained mGluR5 selectivity with only weak or no activity at other mGluRs or iGluRs. The substituted analogue, 1,3-bis(pyridin-2-ylethynyl)benzene (19), is a potent negative modulator at mGluR5, whereas all other compounds lost potency relative to MPEP and showed that activity is highly dependent on the position of the nitrogen atom in the pyridine moieties. A homology modeling and ligand docking study was used to understand the binding mode and the observed selectivity of compound 19.
Toward the self-assembly of metal-organic nanotubes using metal-metal and π-stacking interactions: Bis (pyridylethynyl) silver(I) metallo-macrocycles and coordination polymers
Kilpin, Kelly J.,Gower, Martin L.,Telfer, Shane G.,Jameson, Geoffrey B.,Crowley, James D.
experimental part, p. 1123 - 1134 (2011/04/26)
Shape-persistent macrocycles and planar organometallic complexes are beginning to show considerable promise as building blocks for the self-assembly of a variety of supramolecular materials including nanofibers, nanowires, and liquid crystals. Here we report the synthesis and characterization of a family of planar di-and tri-silver(I) containing metallo-macrocycles designed to self-assemble into novel metal-organic nanotubes through a combination of n-stacking and metal-metal interactions. The silver(I) complexes have been fully characterized by elemental analysis, high resolution electrospray ionization mass spectrometry (HR-ESI-MS), IR, 1H and 1C NMR spectroscopy, and the solution data are consistent with the formation of the metallo-macrocycles. Four of the complexes have been structurally characterized using X-ray crystallography. However, only the di-silver(I) complex formed with 1,3-bis(pyridin-3-ylethynyl) benzene is found to maintain its macrocyclic structure in the solid state. The di-silver(I) shape-persistent macrocycle assembles into a nanoporous chicken-wire like structure, and ClO4- anions and disordered H 2O molecules fill the pores. The silver(I) complexes of 2,6-bis(pyridin-3-ylethynyl)pyridine and 1,4-di(3-pyridyl)buta-1,3-diyne ring-open and crystallize as non-porous coordination polymers.
