Ionic Liquids as Protein Crystallization Additives

Among its attributes, the mythical philosopher’s stone is supposedly capable of turning base metals to gold or silver. In an analogous fashion, we are finding that protein crystallization optimization using ionic liquids (ILs) often results in the conversion of base protein precipitate to crystals. Recombinant inorganic pyrophosphatases (8 of the 11 proteins) from pathogenic bacteria as well as several other proteins were tested for optimization by 23 ILs, plus a dH2O control, at IL concentrations of 0.1, 0.2, and 0.4 M. The ILs were used as additives, and all proteins were crystallized in the presence of at least one IL. For 9 of the 11 proteins, precipitation conditions were converted to crystals with at least one IL. The ILs could be ranked in order of effectiveness, and it was found that ~83% of the precipitation-derived crystallization conditions could be obtained with a suite of just eight ILs, with the top two ILs accounting for ~50% of the hits. Structural trends were found in the effectiveness of the ILs, with shorter-alkyl-chain ILs being more effective. The two top ILs, accounting for ~50% of the unique crystallization results, were choline dihydrogen phosphate and 1-butyl-3-methylimidazolium tetrafluoroborate. Curiously, however, a butyl group was present on the cation of four of the top eight ILs.

Syntheses and Characterizations of Platinum Complexes with New Pyrene-based Salicylaldiminato-type Ligand Substituted at 7-Position of Pyrene

Many experimental data show that bulky substituents on the molecules enhance solubility, catalytic activity, and photophysical properties due to the prevention of π-π stacking in metal salicylaldimines. In order to understand the effect of bulkiness of substituents on the properties of the obtained molecules, the author researched and synthesized two new pyrene-based salicylaldiminato-type ligands that were substituted at 7-position and functionalized on imine group with bulky substituents. After the introduction of the tert-butyl group at 7-position of pyrene by Friedel-Crafts reaction, the syntheses of new ligands 1-hydroxy-2-[((2,6-dimethylphenyl)-imino)methyl]-7-(tert-butyl)-pyrene 3, 2-hydroxy-1- [((2,6-dimethylphenyl)imino)methyl]-7-(tert-butyl)-pyrene 4 and corresponding platinum complexes 3(Pt), 4(Pt) were performed in the different ways with the synthetic processes of the complexes 1(Pt) and 2(Pt). The new ligands and complexes were characterized by 1H NMR, IR spectroscopy, mass spectroscopy, elemental analysis and X-ray diffraction, only for 3(Pt). In addition to measurements of the absorption and emission spectra, TDDFT calculations using the B3LYP functions were also performed. The complexes 3(Pt) and 4(Pt) exhibit good solubility and red-shift in absorption and emission spectra because of tert-butyl group at 7-position of pyrene and extension of the delocalized π-orbitals to the 2,6-dimethylphenyl on imine group. The change of functional groups also induces the upfield shift of the protons affected by ring currents of phenyl groups Ar-3, Ar-4 on imine groups. Introduction of t-butyl groups in pyrene moieties can stabilize radical forms in oxidation processes.

Synthesis and Electro-Optical Property of Green Fluorescent Emitter Based on Anthracene Core and Optimized Side Groups

New green emitter is designed and synthesized by selecting anthracene having high photoluminescence quantum yield (PLQY) and diphenylamine side group substituted methyl and t-butyl group: N9,N10-bis(5-(tert-butyl)-2-methylphenyl)-N9,N10-bis(2,4-dimethylphenyl)anthracene-9,10-diamine (3Me-1Bu-TPADA). Photophysical, electrochemical, and electroluminescent (EL) properties of 3Me-1Bu-TPADA were investigated. The maximum photoluminescence (PL) emission wavelengths of 3Me-1Bu-TPADA in solution and in a film were 528 nm and 531 nm, respectively. 3Me-1Bu-TPADA has excellent thermal properties with glass transition temperatures (Tg) of 110 °C, melting temperatures (Tm) of 217 °C of, and degradation temperature (Td) of 330 °C. 3Me-1Bu-TPADA was used as an emitting layer in non-doped devices: ITO/2-TNATA (60 nm)/NPB (15 nm)/3Me-1Bu-TPADA (30 nm)/Alq3 (30 nm)/LiF (1 nm)/Al (200 nm). The 3Me-1Bu-TPADA device showed luminance efficiency of 6.05 cd/A, EQE of 2.68% at 10 mA/cm2.

Non-Doped Deep-Blue OLEDs Based on Carbazole-π-Imidazole Derivatives

In this work, we designed and synthesized four bipolar blue-emitting materials with carbazole, imidazole, and biphenyl as donor, acceptor, and p bridge, respectively. The twisted phenylimidazole acceptor leads to a wider band-gap and hence deeper blue emission than the conjugated phenanthrimidazole acceptor. For the substituents on the carbazole donor, the t-butyl group could prevent the intramolecular charge transfer (ICT) process more effectively than the methoxy group. A non-doped deep-blue organic light-emitting diodes (OLED) is obtained with CIE coordinates of (0.159, 0.080), a maximum luminance of 11364 cd/m2, and a maximum EQE of 4.43%.

Radical-mediated sulfonyl alkynylation, allylation, and cyanation of propellane

Bicyclo[1.1.1]pentane (BCP) is widely applied as the bioisostere for aryl, internal alkynes, and tert-butyl group in medicinal chemistry. We herein disclose an efficient and practical preparation of sulfonyl alkynyl/allyl/cyano-substituted BCP...

(E)-{[(Butylsulfanyl)methanethioyl]amino}(4-methoxybenzylidene)amine: crystal structure and Hirshfeld surface analysis

The title hydrazine carbodithioate, C13H18N2OS2, is constructed about a central and almost planar C2N2S2 chromophore (r.m.s. deviation = 0.0263 Å); the terminal methoxybenzene group is close to coplanar with this plane [dihedral angle = 3.92 (11)°]. The n-butyl group has an extended all-trans conformation [torsion angles S—Cm—Cm—Cm = −173.2 (3)° and Cm—Cm—Cm—Cme = 180.0 (4)°; m = methylene and me = methyl]. The most prominent feature of the molecular packing is the formation of centrosymmetric eight-membered {...HNCS}2 synthons, as a result of thioamide-N—H...S(thioamide) hydrogen bonds; these are linked via methoxy-C–H...π(methoxybenzene) interactions to form a linear supramolecular chain propagating along the a-axis direction. An analysis of the calculated Hirshfeld surfaces and two-dimensional fingerprint plots point to the significance of H...H (58.4%), S...H/H...S (17.1%), C...H/H...C (8.2%) and O...H/H...O (4.9%) contacts in the packing. The energies of the most significant interactions, i.e. the N—H...S and C—H...π interactions have their most significant contributions from electrostatic and dispersive components, respectively. The energies of two other identified close contacts at close to van der Waals distances, i.e. a thione–sulfur and methoxybenzene–hydrogen contact (occurring within the chains along the a axis) and between methylene-H atoms (occurring between chains to consolidate the three-dimensional architecture), are largely dispersive in nature.