An updated version of the computational package SIMPRE that uses the standard conventions for Stevens crystal field parameters

The crystal field approach used by SIMPRE is analyzed, verifying the exactness of the results concerning energy levels and magnetic properties calculated by the package. To coincide with the prevailing conventions, we reformulate the presentation of the crystal field parameters, so that the results are now, also from a formal point of view, strictly correct. New calculations are presented to test the influence of neglecting the excited J states, a common but critical approximation employed by SIMPRE. For that, we examine the case of Er(trensal) complex (H₃trensal = 2,2′,2″‐tris(salicylideneimino)triethylamine) where the influence of this approximation is found to be minimal. A patched version of the code, SIMPRE 1.1, and an updated version of the user manual are now available. Finally, we comment on “Software package SIMPRE – revisited,” which apparently revisits a software package without inspecting or using the code. © 2014 Wiley Periodicals, Inc.     

Effect of HAP on Stability and Plugging Property of LPFR Dispersion

To improve the stability and plugging property of low-solubility phenol formaldehyde resin (LPFR) in the injection water from Daqing Oilfield, hydrophobically associating polymers (HAP) as a stabilizing agent were used. The size and zeta potential of LPFR, LPFR/HAP molecule aggregates, and turbidity and plugging properties of LPFR dispersions were measured in deionized water, simulation water, and injection water, respectively. The results show that the hydrophobic grouping on the HAP molecule has a similar molecular structure as LPFR, and HAP and LPFR can form complex molecule aggregates in the injection water. The zeta potential of LPFR/HAP molecule aggregates is larger than that of LPFR molecule aggregates. Therefore, the repulsive force operating between LPFR/HAP complex molecule aggregates is increased. HAP enhances the stability of LPFR in the injection water and plugging property of LPFR dispersion in porous medium.     

Highly Efficient Orange and Warm White Phosphorescent OLEDs Based on a Host Material with a Carbazole–Fluorenyl Hybrid

A new carbazole–fluorenyl hybrid compound, 3,3′(2,7‐di(naphthaline‐2‐yl)‐9H‐fluorene‐9,9‐diyl)bis(9‐phenyl‐9H‐carbazole) (NFBC) was synthesized and characterized. The compound exhibits blue‐violet emission both in solution and in film, with peaks centered at 404 and 420 nm. In addition to the application as a blue emitter, NFBC is demonstrated to be a good host for phosphorescent dopants. By doping Ir(2‐phq)₃ in NFBC, a highly efficient orange organic light‐emitting diode (OLED) with a maximum efficiency of 32 cd A^?1 (26.5 Lm W^?1) was obtained. Unlike most phosphorescent OLEDs, the device prepared in our study shows little efficiency roll‐off at high brightness and maintains current efficiencies of 31.9 and 26.8 cd A^?1 at a luminance of 1000 and 10 000 cd m^?2, respectively. By using NFBC simultaneously as a blue fluorescence emitter and as a host for a phosphorescent dopant, a warm white OLED with a maximum efficiency of 22.9 Lm W^?1 (21.9 cd A^?1) was also obtained.     

o‐Fluorination of Aromatic Azides Yields Improved Azido‐Based Fluorescent Probes for Hydrogen Sulfide: Synthesis,Spectra, and Bioimaging

Hydrogen sulfide (H₂S) is an endogenously produced gaseous signaling molecule with multiple biological functions. To visualize the endogenous in situ production of H₂S in real time, new coumarin‐ and boron‐dipyrromethene‐based fluorescent turn‐on probes were developed for fast sensing of H₂S in aqueous buffer and in living cells. Introduction of a fluoro group in the ortho position of the aromatic azide can lead to a greater than twofold increase in the rate of reaction with H₂S. On the basis of o‐fluorinated aromatic azides, fluorescent probes with high sensitivity and selectivity toward H₂S over other biologically relevant species were designed and synthesized. The probes can be used to in situ to visualize exogenous H₂S and D ‐cysteine‐dependent endogenously produced H₂S in living cells, which makes them promising tools for potential applications in H₂S biology.     

(5RS)‐5‐(4‐Methoxyphenyl)‐2‐(methylsulfanyl)benzo[g]pyrimido[4,5‐b]quinoline‐4,6,11(3H,5H,12H)‐trione,with Z′ = 3, forms a three‐dimensional hydrogen‐bonded framework containing five types of hydrogen bond

The title compound, C₂₃H₁₇N₃O₄S, crystallizes with Z′ = 3 in the space group P. Two of the three independent molecules are broadly similar in terms of both their molecular conformations and their participation in hydrogen bonds, but the third molecule differs from the other two in both of these respects. The molecules are linked by a combination of N—H...O, N—H...N, C—H...O, C—H...N and C—H...π(arene) hydrogen bonds to form a continuous three‐dimensional framework structure within which a centrosymmetric six‐molecule aggregate can be identified as a key structural element.     

[2,5‐Bis(2,2′‐bipyridyl‐6‐yl)‐3,4‐diazahexa‐2,4‐diene]dichloridomanganese(II): from a mononuclear compound to a three‐dimensional supramolecular framework through C—H...Cl hydrogen bonds and π–π stacking interactions

The title compound, [MnCl₂(C₂₄H₂₀N₆)], has been synthesized and characterized based on the multifunctional ligand 2,5‐bis(2,2′‐bipyridyl‐6‐yl)‐3,4‐diazahexa‐2,4‐diene (L). The Mn^II centre is five‐coordinate with an approximately square‐pyramidal geometry. The L ligand acts as a tridendate chelating ligand. The mononuclear molecules are bridged into a one‐dimensional chain by two C—H...Cl hydrogen bonds. These chains are assembled into a two‐dimensional layer through π–π stacking interactions between adjacent uncoordinated bipyridyl groups. Furthermore, a three‐dimensional supramolecular framework is attained through π–π stacking interactions between adjacent coordinated bipyridyl groups.     

Sn-Al-β分子筛酸性在葡萄糖转化反应中作用的固体NMR研究

制备了一系列具有不同酸性质的β分子筛催化剂, 通过固体核磁共振(NMR)探针分子技术对其酸性质进行了表征, 并考察了其催化葡萄糖转化为乙酰丙酸甲酯的性能. 吸附三甲基磷的³¹P NMR实验结果表明, 含有骨架Sn以及Al原子的Sn-Al-β催化剂同时具有Br?nsted与Lewis酸性. 通过2-¹³C-丙酮探针分子区分出 3种酸强度的Br?nsted酸位, 其中一种酸强度接近“超强酸”, 可能是由于空间邻近的Br?nsted酸位和Lewis酸位发生协同作用产生的. 葡萄糖转化为乙酰丙酸甲酯的催化反应结果表明, 相比于分别只含有Lewis酸位和Br?nsted酸位的Sn-β和Al-β样品以及两者的物理混合样品, Sn-Al-β分子筛催化剂具有高催化活性与产物选择性, 这主要是由于Br?nsted酸位和Lewis酸位的协同作用产生了强Br?nsted酸位, 这种强Br?nsted酸位进一步导致了更高的催化活性.     

可见光驱动丰产金属卟啉类配合物催化的二氧化碳选择性还原反应

随着能源短缺和环境问题日益突出, 寻找清洁和可再生能源来替代化石燃料是本世纪科学家面临的最紧迫的任务之一. 为了实现我国“双碳”战略目标, 利用太阳能将二氧化碳(CO₂)转化为清洁燃料和化学品是实现社会可持续发展的途径之一. 催化剂是CO₂光还原技术的核心组成部分, 其可以吸附气态CO₂分子, 在可见光照射下将CO₂还原为一氧化碳(CO)、 甲酸(HCOOH)、 甲醇(CH₃OH)或甲烷(CH₄)等能源小分子. 目前, 新型CO₂还原光催化体系的开发取得了很好的进展. 本文综合评述了近年来均相及非均相丰产金属卟啉类催化剂在光催化CO₂还原中的研究进展, 并对在金属卟啉均相催化剂作用下, CO₂光还原为CO或CH₄的反应机理分别进行了介绍, 还讨论了金属卟啉基多孔有机聚合物与卟啉有机金属框架在光催化CO₂方面的重要应用. 最后, 对可见光驱动卟啉类金属配合物催化的CO₂还原的发展前景进行了展望.     

Long-Term,Single-Molecule Imaging of Proteins in Live Cells with Photoregulated Fluxional Fluorophores

Single-molecule localization microscopy (SMLM) can reveal nanometric details of biological samples, but its high phototoxicity hampers long-term imaging in live specimens. A significant part of this phototoxicity stems from repeated irradiations that are necessary for controlled switching of fluorophores to maintain the sparse labeling of the sample. Lower phototoxicity can be obtained using fluorophores that blink spontaneously, but controlling the density of single-molecule emitters is challenging. We recently developed photoregulated fluxional fluorophores (PFFs) that combine the benefits of spontaneously blinking dyes with photocontrol of emitter density. These dyes, however, were limited to imaging acidic organelles in live cells. Herein, we report a systematic study of PFFs that culminates in probes that are functional at physiological pH and operate at longer wavelengths than their predecessors. Moreover, these probes are compatible with HaloTag labeling, thus enabling timelapse, single-molecule imaging of specific protein targets for exceptionally long times.     

Labile Base-Stabilized Silyliumylidene Ions. Non-Metallic Species Capable of Activating Multiple Small Molecules

Several base-stabilized silyliumylidene ions ( 2 and 3 ) with different ligands were synthesized. Their behaviour appeared strongly dependent on the nature of ligand. Indeed, in contrast to the poorly reactive silyliumylidene ions 3 c,d stabilized by strongly donating ligands (DMAP, NHC), the silylene- and sulfide-supported one ( 2-H and 3 a ) exhibits higher reactivity toward various small molecules. Furthermore, their capability to successively activate multiple small molecules was clearly demonstrated by processes involving successive reactions with silane/formamide, CO₂ and H₂. Moreover, HBPin adduct of 3 a ( 8-C ) catalyzes the hydroboration of pyridine. Of particular interest, silylene-supported silyliumylidene complex 2-H is one of the rare species able to activate two H₂ molecules.