87350-76-3Relevant academic research and scientific papers
Fluorocarbon and hydrocarbon N-heterocyclic (C5-C7) imidazole-based liquid crystals
Chen, Hongren,Hong, Fengying,Shao, Guang,Hang, Deyu,Zhao, Lei,Zeng, Zhuo
, p. 3418 - 3430 (2015/01/09)
By using three synthetic protocols, a series of fluorocarbon and hydrocarbon N-heterocyclic imidazolebased liquid crystals (LCs) and related imidazolium-based ionic liquid crystals (ILCs) have been prepared. The ring size of the N-heterocycle and the length of the N-terminal chain (on the imidazolium unit in the ILCs) were modified, and the influence of these structural parameters on liquid-crystal phases was investigated by means of polarizing optical microscopy (POM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). These new ILCs exhibit a disordered smectic phase (SmA), good thermal stabilities, a broad smectic phase range, a high dipole moment, relatively low melting points, but high clearing points and strong emission fluorescence relative to imidazole-based LCs. These encouraging results have led us to believe these fluorocarbon and hydrocarbon N-heterocyclic imidazole-based LCs and related imidazolium-based ILCs could be used as new liquid-crystalline materials.
Unexpectedly similar charge transfer rates through benzo-annulated bicyclo[2.2.2]octanes
Goldsmith, Randall H.,Vura-Weis, Josh,Scott, Amy M.,Borkar, Sachin,Sen, Ayusman,Ratner, Mark A.,Wasielewski, Michael R.
, p. 7659 - 7669 (2008/12/22)
A 4-(pyrrolidin-1-yl)phenyl electron donor and 10-cyanoanthracen-9-yl electron acceptor are attached via alkyne linkages to the bridgehead carbon atoms of bicyclo[2.2.2]octane and all three benzo-annulated bicyclo[2.2.2] octanes. The σ-system of bicyclo[2.2.2]octane provides a scaffold having nearly constant bridge geometry on which to append multiple, weakly interacting benzo π-bridges, so that the effect of incrementally increasing numbers of π-bridges on electron transfer rates can be studied. Surprisingly, photoinduced charge transfer rates measured by transient absorption spectroscopy in toluene show no benefit from increasing the number of bridge π-systems, suggesting dominant transport through the σ-system. Even more surprisingly, the significant changes in hybridization undergone by the σ-system as a result of benzo-annulation also appear to have no effect on the charge transfer rates. Natural Bond Orbital analysis is applied to both σ- and π-communication pathways. The transient absorption spectra obtained in 2-methyltetrahydrofuran (MTHF) show small differences between the benzo-annulated molecules that are attributed to changes in solvation. All charge transfer rates increase significantly upon cooling the MTHF solutions to their glassy state. This behavior is rationalized using combined molecular dynamics/electronic structure trajectories.
First synthesis and electrogenerated chemiluminescence of novel p-substituted phenyl-2-quinolinylethynes
Elangovan, Arumugasamy,Chen, Ting-Yu,Chen, Chih-Yuan,Ho, Tong-Ing
, p. 2146 - 2147 (2007/10/03)
A series of p-substituted phenyl-2-quinolinylethynes as blue-green emitters were synthesized using a modified Sonogashira coupling reaction and their electrogenerated chemiluminescence properties are reported.
Copper-catalyzed amination of aromatic halides with 2-N,N-dimethylaminoethanol as solvent
Lu, Zhikuan,Twieg, Robert J.,Huang, Songping D.
, p. 6289 - 6292 (2007/10/03)
A copper-catalyzed amination of aromatic halides under mild conditions using N,N-dimethylaminoethanol as solvent is described. We have studied this reaction in some detail varying the copper source, base, water content and other parameters including the scope of useful amine and aromatic halide structures. A variety of 4-halo-N,N-cycloalkylanilines and 2-N,N-cycloalkylaminothiophenes were synthesized for further elaboration into chromophores for optoelectronic applications.
Synthesis, Structure, and Spectral Behavior of Donor-Acceptor Substituted Biphenyls
Effenberger, Franz,Agster, Wolfgang,Fischer, Peter,Jogun, Kurt H.,Stezowski, John J.,et al.
, p. 4649 - 4658 (2007/10/02)
Reaction of the activated halonitrobenzenes 2a-f with the bis- and tris(dialkylamino)benzenes 1a-e affords, via a direct nucleophilic substitution, the highly substituted biphenyls 3a-o; the lesser substituted biphenyls 5 and 6 were prepared by an Ullmann reaction.All these biphenyls are deeply colored; the dark red color can be assigned to an intramolecular charge transfer.A crystal structure determination was carried out for 2,4,6-tripyrrolidino-2',4',6'-trinitrobiphenyl (3a): space group C2/c, a = 16.071 (2) Angstroem, b = 14.545 (1) Angstroem, c = 20.177 (2) Angstroem, β = 91.361 (9)deg, Z = 8 (temperature ca. 120 K).The dihedral angle between the two arene rings was found to be only 52.5 deg, despite the four bulky substituents in the o,o'-positions.With this far-from-orthogonal torsional angle about the biphenyl linkage, the strong intramolecular charge transfer from the ? system of the donor into the ? system of the acceptor arene becomes easily understandable.A PPP calculation with the torsional angles taken from the X-ray structure analysis satisfactorily reproduces the experimental absorption spectrum of 3a.The shift of the long-wavelength absorption between the individual biphenyls 3a-o, 5, and 6 likewise is accounted for satisfactorily by the calculation; it depends primarily on the intrinsic donor strength of the different NR2 moieties (pyrrolidino > dimethylamino > piperidino > morpholino).The 1H NMR spectra (in dilute solution) likewise mirror this gradation in NR2 donor capacity; they also show that steric hindrance at the biphenyl linkage is mainly the result of interaction between the o-dialkylamino groups and the C6 skeleton of the acceptor arene.This is borne out by the crystal structure analysis.
