The SAMPL6 SAMPLing challenge: assessing the reliability and efficiency of binding free energy calculations

Journal of Computer-Aided Molecular Design - Approaches for computing small molecule binding free energies based on molecular simulations are now regularly being employed by academic and industry...     

Multifunctional red phosphorescent bis-cyclometallated iridium complexes based on 2-phenyl-1,2,3-benzotriazole ligand and carbazolyl moieties

Multifunctional phosphorescent bis-cyclometallated iridium(III) complexes based on the 2-phenyl-1,2,3-benzotriazole moiety and bearing branched hole-transporting carbazole fragments were synthesized. The isolated compounds were found to be amorphous and expressed very good solubility. Introduction of flexible aliphatic chains of various lengths into the iridium complexes enabled manipulation of their glass transition temperature. The iridium complexes exhibited red phosphorescence emission at 650 nm with the lifetime of 5.7 μs and phosphorescence quantum yields of 0.22 and 0.17 in solution and solid state, respectively, at room temperature. The shielding effect of the carbazolyl moieties on the concentration quenching of phosphorescence of the iridium centers was found to result in the increased excited state lifetime and quantum yield due to the suppressed exciton migration. Non-optimized OLED devices, based on the phosphorescent bis-cyclometallated iridium(III) complex without host material were fabricated and their electroluminescence properties were evaluated.     

Cationic ring-opening polymerization of carbazolyl-containing epoxy monomers by triphenyl carbenium salts as thermal- and photolatent initiators

Abstract  

Photoinitiated cationic polymerizations of various epoxy monomers bearing a carbazole moiety, 9-[3-(allyloxy)-2-(oxiran-2-ylmethoxy)propyl]-9H-carbazole, 9-[3-methoxy-2-(oxiran-2-ylmethoxy)propyl]-9H-carbazole, 9-[2-(oxiran-2-ylmethoxy)ethyl]-9H-carbazole, as well as a composition of 3,6-dibromo-9-(oxiran-2-ylmethyl)-9H-carbazole with 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexane carboxylate were investigated in bulk using triphenyl carbenium salts having anions such as BF₄ ⁻, SnCl₅ ⁻, and SbCl₆ ⁻. Dark polymerizations of the carbazolyl monomers in the presence of the initiators are studied. These photoinduced polymerization reactions give oligomers of degree of polymerization 4-22. The effect of the anion of the photoinitiator and polymerization time on the polymerization reaction is discussed.     

Reactions of 5-oxo-1-phenylpyrrolidine-3-carbohydrazides with 1,4-naphthoquinone derivatives and the properties of the obtained products

N′-(4-Oxo-1,4-dihydronaphthalen-1-ylidene)-1-phenyl-5-oxopyrrolidine-3-carbohydrazides and N′-(3-methyl-4-oxo-1,4-dihydronaphthalen-1-ylidene)-1-phenyl-5-oxopyrrolidine-3-carbohydrazides were synthesized by reactions of 5-oxo-1-phenylpyrrolidine-3-carbohydrazides with 1,4-naphthoquinone or 2-methyl-1,4-naphthoquinone. The alkylated analogues of the above products were obtained using ethyl iodide. The interaction of 5-oxo-1-phenylpyrrolidine-3-carbohydrazides with 2,3-dichloro-1,4-naphthoquinone was followed by formation of N′-(3-chloro-1,4-dioxo-1,4-dihydronaphthalen-2-yl)-1-phenyl-5-oxopyrrolidine-3-carbohydrazides. All these compounds were characterized using ¹H, ¹³C NMR, IR and mass spectra. Some of the new compounds were tested for the antimicrobial and antifungal activity.     

Easily functionalizable carbazole based building blocks with extended conjugated systems for optoelectronic applications

Carbazole based building blocks, possessing diphenylethenyl fragments, have been synthesized. Condensation of the carbazol-2-ol with diphenylacetaldehyde yields 1,3-substituted derivatives. Change of the synthesis sequence, however, (i.e., substitution at the hydroxyl and NH groups, followed by the condensation reaction) results in the 3,6-substituted products. Thermal, optical, electrochemical and photophysical properties of the synthesized derivatives have been investigated. Room temperature hole-drift mobilities, evaluated using xerographic time-of-flight technique, were found to exceed 10⁻⁴ cm² V⁻¹ s⁻¹ at strong electric fields. The obtained results indicate high charge mobility for molecularly doped polymers, especially considering the fact that these measurements were carried out under ambient conditions and not in high vacuum. Commercial availability and relative cheapness of the starting materials, simple synthetic method, number of sites available for easy functionalization and covalent linking to other molecules makes these precursors attractive building blocks for the construction of more complex low-molecular-weight or polymeric materials for optoelectronic applications.