2344-53-8Relevant academic research and scientific papers
Synthesis and characterization of propeller-shaped mono- to hexacationic quinolinium-substituted benzenes
Batsyts, Sviatoslav,Hübner, Eike G.,Namyslo, Jan C.,Gjikaj, Mimoza,Schmidt, Andreas
, p. 4102 - 4114 (2019)
Diels-Alder reaction of 2-, 3- and 4-(phenylethynyl)quinolines and tetraphenylcyclopentadienone gave three regioisomeric 2,3,4,5,6-pentaphenyl-1-(quinolin-2-yl, -3-yl, and -4-yl)benzenes. Restricted rotation of the 3-yl and 4-yl substituted derivatives is observed between the central core and the substituents, resulting in propeller-shaped molecules. Likewise, 1,2-diquinolinyl-3,4,5,6-tetraphenylbenzenes with 3-yl,3-yl and 3-yl,4-yl connectivity were prepared. As evidenced by NMR spectroscopy, they form two diasteromers due to their restricted rotation. A cobalt-catalyzed [2 + 2 + 2]-cyclotrimerization of 2-(phenylethynyl)quinoline resulted in the formation of triphenyl-2,4,6- and -3,5,6-tri(quinolin-2-yl)benzenes. The same reaction was applied to 3,3′-ethyne-1,2-diyldiquinoline which formed hexa(quinolin-3-yl)benzene. N-Methylation gave the title compounds. Among those, the hexacationic hexa(N-methylquinolinio-3-yl)benzene is described. Stereochemical aspects are predominantly discussed by means of results of NMR experiments. DFT-calculations on the most stable conformations and the frontier orbital profiles of the hexacation as well as of its neutral precursor have been carried out.
The Interconnection of Two Positive Charges by Conjugation and Cross-Conjugation in Bis-Quinolinium Ethynyls
Batsyts, Sviatoslav,Hübner, Eike G.,Namyslo, Jan C.,Schmidt, Andreas
, p. 6168 - 6176 (2019)
1,4-Diethynylbenzene was used as conjugated all-carbon and rigid spacer between the 2-, 3- and 4-positions of two 1-methylquinolinium rings. Thus, for a systematic study, a series of dicationic salts with 2,2-, 3,3-, 4,4-, 3,2-, and 3,4-interconnections of the two positive charges was prepared, in which all even-numbered substitution patterns are conjugated, and all odd-numbered substitution patterns are cross-conjugated. As a consequence, conjugated/conjugated, cross-conjugated/cross-conjugated, and conjugated/cross-conjugated dications have been prepared. The different combinations result in considerably different charge distributions of the positive charges within the π-electron systems according to the rules of resonance which translate into different DFT-calculated frontier orbital profiles and spectroscopic properties such as 13C NMR chemical shifts, IR and Raman absorptions, and the measured as well as calculated UV/Vis spectra.
Photophysics of monodisperse platinum-acetylide oligomers: Delocalization in the singlet and triplet excited states
Liu, Yao,Jiang, Shujun,Glusac, Ksenija,Powell, David H.,Anderson, Danielle F.,Schanze, Kirk S.
, p. 12412 - 12413 (2002)
A series of monodisperse Pt-acetylide polymers that contain the [-C≡C-(p-C6H4)-C≡C-(t-Pt(PBu3)2)-]n repeat unit has been prepared for n = 1, 2, 3, 4, 5, and 7. The photophysical properties of the series provide information concerning the relationship between the oligomer length and delocalization in the singlet and triplet excited states of the π-conjugated electron system. The results imply that the singlet excited state is delocalized over approximately 6 repeat units; however, the triplet state is considerably more localized. The triplet energy is almost invariant with oligomer length, but the phosphorescence spectra and triplet nonradiative decay rates indicate that the electron-vibrational coupling in the triplet state decreases with increasing oligomer length. Copyright
DICARBAMATE INHIBITORS OF NS5A FOR TREATMENT OF HEPATITIS C VIRUS INFECTIONS AND RELATED DISEASES
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Page/Page column 38; 39; 40, (2020/11/03)
Dicarbamate compounds as inhibitors of NS5A, and therapeutic uses and methods of preparation thereof, are disclosed. These compounds, and pharmaceutically acceptable salts, stereoisomers, tautomers, solvates, and prodmgs, and pharmaceutical compositions t
Synthesis and Photochemistry of a New Photolabile Protecting Group for Propargylic Alcohols
Ma, Chi,Zhang, Youlai,Zhang, Huan,Li, Junru,Nishiyama, Yasuhiro,Tanimoto, Hiroki,Morimoto, Tsumoru,Kakiuchi, Kiyomi
, p. 560 - 564 (2017/03/11)
A new and efficient thiochromenone S,S-dioxide-based photolabile protecting group for propargylic alcohols is described. Robust protection reactions were developed through copper (II)-catalyzed substitution of propargylic alcohols. Subsequent photodeprote
Direct Enzymatic Branch-End Extension of Glycocluster-Presented Glycans: An Effective Strategy for Programming Glycan Bioactivity
Bayón, Carlos,He, Ning,Deir-Kaspar, Mario,Blasco, Pilar,André, Sabine,Gabius, Hans-Joachim,Rumbero, ángel,Jiménez-Barbero, Jesús,Fessner, Wolf-Dieter,Hernáiz, María J.
supporting information, p. 1623 - 1633 (2017/02/10)
The sequence of a glycan and its topology of presentation team up to determine the specificity and selectivity of recognition by saccharide receptors (lectins). Structure–activity analysis would be furthered if the glycan part of a glycocluster could be efficiently elaborated in situ while keeping all other parameters constant. By using a bacterial α2,6-sialyltransferase and a small library of bi- to tetravalent glycoclusters, we illustrate the complete conversion of scaffold-presented lactoside units into two different sialylated ligands based on N-acetyl/glycolyl-neuraminic acid incorporation. We assess the ensuing effect on their bioactivity for a plant toxin, and present an analysis of the noncovalent substrate binding contacts that the added sialic acid moiety makes to the lectin. Enzymatic diversification of a scaffold-presented glycan can thus be brought to completion in situ, offering a versatile perspective for rational glycocluster engineering.
Crystal Inclusion Formation of a New Type of Dumbbell-Shaped Host Compound Featuring Two Bulky 2,3,4,5-Tetraphenylcyclopenta-2,4-dien-1-ol Terminal Groups Attached to a Linear Spacer Unit
Ruffani, Alexander,Seichter, Wilhelm,Schwarzer, Anke,Weber, Edwin
, p. 3826 - 3837 (2016/07/16)
Four new host compounds of dumbbell shape featuring bulky 2,3,4,5-tetraphenylcyclopenta-2,4-dien-1-ol moieties attached to both ends of a linear spacer element of different lengths comprising both 1,4-phenylene and ethynylene subunits are synthesized and
Electrochemically active porous organic polymers based on corannulene
Karunathilake, Arosha A.K.,Thompson, Christina M.,Perananthan, Sahila,Ferraris, John P.,Smaldone, Ronald A.
supporting information, p. 12881 - 12884 (2016/11/06)
For the first time, porous organic polymers (POPs) based on the smallest buckybowl, corannulene (BB-POPs) have been synthesized. Three POPs were synthesised via Sonogashira co-polymerization of 1,2,5,6-tetrabromocorannulene and alkyne linkers. BB-POP-3 exhibits the highest surface area (SABET = 560 m2 g-1) and CO2 adsorption of 11.7 wt%, while they retain the redox properties of corannulene.
Tetramethoxybenzene is a good building block for molecular wires: Insights from photoinduced electron transfer
Heinz, Luisa G.,Yushchenko, Oleksandr,Neuburger, Markus,Vauthey, Eric,Wenger, Oliver S.
, p. 5676 - 5684 (2015/06/16)
Two donor bridge-acceptor molecules with terminal triarylamine and Ru(bpy)32+ (bpy = 2,2′-bipyridine) redox partners were synthesized and investigated by cyclic voltammetry, optical absorption, luminescence, and transient absorption spectroscopy. The two dyads differ only by the central bridging unit, which was tetramethoxybenzene (tmb) in one case and unsubstituted phenylene (ph) in the other case. Photoirradiation of the Ru(bpy)32+ complex of the two dyads triggers intramolecular electron transfer from the triarylamine to the 3MLCT-excited metal complex, and this process occurs with time constants of 1.5 and 6.8 ns for the tmb- and ph-bridged dyads, respectively. Thermal electron transfer in the reverse direction then leads to disappearance of the photoproduct with a time constant of 10 ns in both dyads. The faster rate of photoinduced charge transfer in the tmb-bridged dyad can be understood in the framework of a hole-tunneling model in which the electron-rich tmb bridge imposes a more shallow barrier than the less electron-rich ph spacer. Until now tmb-based molecular wires have received very little attention, and alkoxy substituents have been mostly used for improving the solubility of oligo-p-phenylene vinylene (OPV) and oligo-p-phenylene ethynylene (OPE) wires. Our study illustrates how four alkoxy-substituents on a phenylene backbone can have a significant influence on the charge-transfer properties of a molecular wire, and this is relevant in the greater context of a future molecular electronics technology.
Polytriazole bridged with 2,5-diphenyl-1,3,4-oxadiazole moieties: A highly sensitive and selective fluorescence chemosensor for Ag+
Cao, Shoupeng,Pei, Zhichao,Xu, Yongqian,Zhang, Ruina,Pei, Yuxin
, p. 45888 - 45896 (2015/06/08)
Fluorescent conjugated polytriazoles (FCP 1-4) containing both 2,5-diphenyl-1,3,5-oxadiazole (OXD) and 1,2,3-triazole moieties in the main chain were synthesized from aromatic diazide (1) and dialkynes (2-5) via click polymerization, respectively. In the polymers, OXDs (fluorophores) and triazole rings (generated via CuAAC acting as metal ion ligands) comprise a fluorescent system. The polytriazoles displayed relatively strong emission with quantum yields in the range of 0.20-0.28 at room temperature in DMF. The study on their ion-responsive properties showed that, although all four FCPs have good selectivity for Ag+, the integration of alkoxy side groups (methoxy for FCP 2, hexyloxy for FCP 3 and 2-ethylhexyloxy for FCP 4) to the main chains of the polytriazoles decreased their sensitivity for Ag+via alteration of the polymer aggregation status and electron density of the main chains. Thus FCP 1 is highly sensitive for Ag+, where its Ksv is as high as 1.44 × 105 M-1 and its lowest detection limit is in the ppb range (4.22 × 10-7 M). This study provides an efficient click approach to the synthesis of a novel fluorescence sensor for Ag+ detection, which could expand the application of click polymerization in designing fluorescence sensors based on the triazole unit. This journal is
