Probing the Strongest Aromatic Cyclopentadiene Ring by Hyperconjugation

Hyperconjugation, an interaction of electrons in a σ orbital or lone pair with an adjacent π or even σ antibonding orbital, can have a strong effect on aromaticity. However, most work on hyperconjugative aromaticity has been limited to main-group substituents. Here, we report a thorough density functional theory study to evaluate the aromaticity in various cyclopentadienes that contain both main-group and transition-metal substituents. Our calculations reveal that the strongest aromatic cyclopentadiene ring can be achieved by the synergy of trans influence and hyperconjugation caused by transition-metal substituents. Our findings highlight the great power of transition metals and trans influence in achieving hyperconjugative aromaticity, opening an avenue to the design of other novel aromatic organometallics

Single Gyroid Self-Assembled by Linear BABAB Pentablock Copolymer

Although the double-gyroid (DG) structure has been commonly formed from the self-assembly of block copolymers, the single-gyroid (SG) structure is rarely reported. Moreover, the SG structure even shows better performance than DG in some optical applications. How to prepare the SG structure has become an attractive but challenging topic. We speculate that the SG structure can be stabilized by the synergistic effect of released packing frustration and stretched bridging block in AB-type block copolymers. Accordingly, we propose the minimum conditions for the design of architecture that enables the two mechanisms simultaneously. Following these conditions, a simple linear BABAB pentablock copolymer is successfully devised. SCFT calculations confirm that the SG phase can be stabilized by tailoring the architecture. Our work is hopeful to promote relevant experimental studies for engineering the unusual SG structure

Additional file 1 of MicroRNA-33-5p inhibits cholesterol efflux in vascular endothelial cells by regulating citrate synthase and ATP-binding cassette transporter A1

Additional file 1. The origin band of WB

Additional file 2 of MicroRNA-33-5p inhibits cholesterol efflux in vascular endothelial cells by regulating citrate synthase and ATP-binding cassette transporter A1

Additional file 2. Supplementary information of cells in multiple fileds

Microwave-Assisted Synthesis of Phenanthridines by Radical Insertion/Cyclization of Biphenyl Isocyanides

A rapid microwave-assisted approach for the synthesis of phenanthridine derivatives from the radical insertion/cyclization reaction of biphenyl isocyanides with a C­(sp³)–H bond adjacent to a heteroatom has been developed. The protocol achieves wide substrate scope and good to excellent yields. The kinetic isotope effect (KIE) studies, radical inhibition studies, and Hammett plot analysis clearly disclose that the current reaction supports a radical mechanism

Bonded to Carbon or Nitrogen? This is a Question on the Regioselectivity in Hyperconjugative Aromaticity

In chemistry, regioselectivity is the preference of one direction of chemical bond making or breaking over all other possible directions. Although it has been extensively investigated in various reactions, the regioselectivity of hyperconjugative aromaticity on either main group systems or transition metal ones remains elusive due to the challenge of synthesizing the target products. Here we report a joint theoretical and experimental study on this issue. Theoretical calculations predicted that electron-withdrawing groups prefer an attachment to the sp3-hybridized carbon atom rather than the nitrogen atom in indoliums. For the electron-donating groups, the two isomers bonded to the sp3-hybridized carbon or nitrogen atom are almost isoenergetic. When both sp2- and sp3-hybridized carbon and nitrogen atoms in the five-membered ring of indoliums are considered, the isomer with the polyaurated substituents bonded to the sp3-hybridized carbon atom is thermodynamically more stable than that with the polyaurated substituents bonded to the sp3-hybridized nitrogen atom. This prediction is reasonably verified by experimental observation. Bond dissociation energy is found to be more important than aromaticity in rationalizing such a preference. Our findings could help experimentalists to design and realize more novel hyperconjugative aromatics

Bonded to Carbon or Nitrogen? This is a Question on the Regioselectivity in Hyperconjugative Aromaticity

In chemistry, regioselectivity is the preference of one direction of chemical bond making or breaking over all other possible directions. Although it has been extensively investigated in various reactions, the regioselectivity of hyperconjugative aromaticity on either main group systems or transition metal ones remains elusive due to the challenge of synthesizing the target products. Here we report a joint theoretical and experimental study on this issue. Theoretical calculations predicted that electron-withdrawing groups prefer an attachment to the sp3-hybridized carbon atom rather than the nitrogen atom in indoliums. For the electron-donating groups, the two isomers bonded to the sp3-hybridized carbon or nitrogen atom are almost isoenergetic. When both sp2- and sp3-hybridized carbon and nitrogen atoms in the five-membered ring of indoliums are considered, the isomer with the polyaurated substituents bonded to the sp3-hybridized carbon atom is thermodynamically more stable than that with the polyaurated substituents bonded to the sp3-hybridized nitrogen atom. This prediction is reasonably verified by experimental observation. Bond dissociation energy is found to be more important than aromaticity in rationalizing such a preference. Our findings could help experimentalists to design and realize more novel hyperconjugative aromatics

2012_China_Labor-force_Dynamics_Survey_1 – Supplemental material for A National Cross-Sectional Survey on Work Environment Associated With Psychological Well-Being and Job Satisfaction Among Chinese Employees

Supplemental material, 2012_China_Labor-force_Dynamics_Survey_1 for A National Cross-Sectional Survey on Work Environment Associated With Psychological Well-Being and Job Satisfaction Among Chinese Employees by Zhi Zeng, Jun Liu, Qiong Xie, Yali Wu, Hua Wang and Liming Lu in Asia Pacific Journal of Public Health</p