173428-81-4Relevant articles and documents
How Large Can We Build a Cyclic Assembly? Impact of Ring Size on Chelate Cooperativity in Noncovalent Macrocyclizations
Montoro-García, Carlos,Mayoral, María J.,Chamorro, Raquel,González-Rodríguez, David
, p. 15649 - 15653 (2017/12/02)
Self-assembled systems rely on intramolecular cooperative effects to control their growth and regulate their shape, thus yielding discrete, well-defined structures. However, as the size of the system increases, cooperative effects tend to dissipate. We analyze here this situation by studying a set of oligomers of different lengths capped with guanosine and cytidine nucleosides, which associate in cyclic tetramers by complementary Watson–Crick H-bonding interactions. As the monomer length increases, and thus the number of C(sp)–C(sp2) σ-bonds in the π-conjugated skeleton, the macrocycle stability decreases due to a notable reduction in effective molarity (EM), which has a clear entropic origin. We determined the relationship between EM or ΔS and the number of σ-bonds, which allowed us to predict the maximum monomer lengths at which cyclic species would still assemble quantitatively, or whether the cyclic species would not able to compete at all with linear oligomers over the whole concentration range.
Supramolecular ruthenium-alkynyl multicomponent architectures: Engineering, photophysical properties, and responsiveness to nitroaromatics
Gatri, Rafik,Ouerfelli, Ines,Efrit, Mohamed Lofti,Serein-Spirau, Francoise,Lere-Porte, Jean-Pierre,Valvin, Pierre,Roisnel, Thierry,Bivaud, Sebastien,Akdas-Kilig, Huriye,Fillaut, Jean-Luc
supporting information, p. 665 - 676 (2014/03/21)
A series of H-bonded supramolecular architectures were built from monofunctional M-Ci - C-R and bifunctional R-Ci - C-M-Ci - C-R trans-alkynylbis(1,2-bis(diphenylphosphino)ethane)ruthenium(II) complexes and π-conjugated modules containing 2,5-dialkoxy-p-p
Two-photon absorption properties of proquinoidal D-A-D and A-D-A quadrupolar chromophores
Susumu, Kimihiro,Fisher, Jonathan A.N.,Zheng, Jieru,Beratan, David N.,Yodh, Arjun G.,Therien, Michael J.
scheme or table, p. 5525 - 5539 (2011/08/06)
We report the synthesis, one- and two-photon absorption spectroscopy, fluorescence, and electrochemical properties of a series of quadrupolar molecules that feature proquinoidal p-aromatic acceptors. These quadrupolar molecules possess either donoracceptor donor (D-A-D) or acceptordonoracceptor (A-D-A) electronic motifs, and feature 4-N,N-dihexylaminophenyl, 4-dodecyloxyphenyl, 4-(N,N-dihexylamino)benzo[c][1,2,5]thiadiazolyl or 2,5-dioctyloxyphenyl electron donor moieties and benzo[c][1,2,5]thiadiazole (BTD) or 6,7-bis(30,70-dimethyloctyl)[1,2,5]thiadiazolo[3,4-g]quinoxaline (TDQ) electron acceptor units. These conjugated structures are highly emissive in nonpolar solvents and exhibit large spectral red-shifts of their respective lowest energy absorption bands relative to analogous reference compounds that incorporate phenylene components in place of BTD and TDQ moieties. BTD-based D-A-D and A-D-A chromophores exhibit increasing fluorescence emission redshifts, and a concomitant decrease of the fluorescence quantum yield (Ff) with increasing solvent polarity; these data indicate that electronic excitation augments benzothiadiazole electron density via an internal charge transfer mechanism. The BTD- and TDQcontaining structures exhibit blue-shifted two-photon absorption (TPA) spectra relative to their corresponding one-photon absorption (OPA) spectra, and display high TPA cross sections (>100 GM) within these spectral windows. D-A-D and A-D-A structures that feature more extensive conjugation within this series of compounds exhibit larger TPA cross sections consistent with computational simulation. Factors governing TPA properties of these quadrupolar chromophores are discussed within the context of a three-state model.
