Two-Dimensional Iron(II) Spin Crossover Complex Constructed of Bifurcated NH···O^- Hydrogen Bonds and π−π Interactions: [Fe^II(HL^H,Me)₂](ClO₄)₂·1.5MeCN (HL^H,Me = Imidazol-4-yl-methylidene-8-amino-2-methylquinoline)

A 2D iron(II) spin crossover complex, [FeII(HLH,Me)2](ClO4)2·1.5MeCN (1), was synthesized, where HLH,Me = imidazol-4-yl-methylidene-8-amino-2-methylquinoline. 1 showed a gradual spin transition between the HS (S = 2) and LS (S = 0) states from 180 to 325 K within the first warming run from 5 to 350 K, in which 1.5MeCN is removed, and there was an abrupt spin transition at T1/2↓ = 174 K in the first cooling run from 350 to 5 K. Following the first cycle, the compound showed an abrupt spin transition at T1/2↑ = 185 K and T1/2↓ = 174 K with 11 K wide hysteresis in the second cycle. The crystal structures of 1 were determined at 296 (an intermediate between the HS and LS states) and 150 K (LS state). The structure consists of a 2D extended structure constructed of both the bifurcated NH···O- hydrogen bonds between two ClO4- ions and two neighboring imidazole NH groups of the [FeII(HLH,Me)2]2+ cations and the π−π interactions between the two quinolyl rings of the two adjacent cations. Thermogravimetric analysis showed that solvent molecules are gradually eliminated even at room temperature and completely removed at 369 K. Desolvated complex 1‘ showed an abrupt spin transition at T1/2↑ = 180 K and T1/2↓ = 174 K with 6 K wide hysteresis

Revisiting Dehydrothiopheno[12]annulenes: Synthesis, Electronic Properties, and Aromaticity

The aromaticity and electronic properties of acetylene-bridged hexadehydrotristhiopheno[12]­annulenes (HDTAs) were revisited using a combined experimental and theoretical approach. Moreover, we attempted the synthesis of the butadiyne-bridged octadehydrobisthiopheno[12]­annulenes (ODTAs). While the formation of ODTAs was indicated by NMR spectroscopy, mass spectrometry, and UV–vis absorption measurements, our attempts to isolate ODTAs were unsuccessful on account of its instability. Instead, their structure and energetic properties were predicted using DFT calculations. HDTA isomers in which the position where the thiophene rings are fused to the 12-membered ring differs (b- vs c-position) show distinct differences in their HOMO–LUMO energy gaps (EGap). ODTAs also show large EGap differences depending on the fusion position of the thiophene rings. The diene character of the thiophene ring significantly changes the electronic properties; i.e., EGap differences of >1 eV were observed between the isomers of both HDTAs and ODTAs. A theoretical evaluation of HDTAs and ODTAs revealed significant variation in the local aromaticity/antiaromaticity between the b- and c-isomers. The antiaromatic character of the 12-membered ring is attenuated for the b-isomers, whereas it is decreased substantially for the c-isomers. The results of this study are useful for a detailed understanding of the fundamental aspects of dehydrothiopheno[12]­annulenes

Porous Self-Assembled Molecular Networks as Templates for Chiral-Position-Controlled Chemical Functionalization of Graphitic Surfaces

Controlled covalent functionalization of graphitic surfaces with molecular scale precision is crucial for tailored modulation of the chemical and physical properties of carbon materials. We herein present that porous self-assembled molecular networks (SAMNs) act as nanometer scale template for the covalent electrochemical functionalization of graphite using an aryldiazonium salt. Hexagonally aligned achiral grafted species with lateral periodicity of 2.3, 2.7, and 3.0 nm were achieved utilizing SAMNs having different pore-to-pore distances. The unit cell vectors of the grafted pattern match those of the SAMN. After the covalent grafting, the template SAMNs can be removed by simple washing with a common organic solvent. We briefly discuss the mechanism of the observed pattern transfer. The unit cell vectors of the grafted pattern align along nonsymmetry axes of graphite, leading to mirror image grafted domains, in accordance with the domain-specific chirality of the template. In the case in which a homochiral building block is used for SAMN formation, one of the 2D mirror image grafted patterns is canceled. This is the first example of a nearly crystalline one-sided or supratopic covalent chemical functionalization. In addition, the positional control imposed by the SAMN renders the functionalized surface (homo)­chiral reaching a novel level of control for the functionalization of carbon surfaces, including surface-supported graphene

P21 Deficiency Delays Regeneration of Skeletal Muscular Tissue

<div><p>The potential relationship between cell cycle checkpoint control and tissue regeneration has been indicated. Despite considerable research being focused on the relationship between p21 and myogenesis, p21 function in skeletal muscle regeneration remains unclear. To clarify this, muscle injury model was recreated by intramuscular injection of bupivacaine hydrochloride in the soleus of p21 knockout (KO) mice and wild type (WT) mice. The mice were sacrificed at 3, 14, and 28 days post-operation. The results of hematoxylin-eosin staining and immunofluorescence of muscle membrane indicated that muscle regeneration was delayed in p21 KO mice. <i>Cyclin D1</i> mRNA expression and both Ki-67 and PCNA immunohistochemistry suggested that p21 deficiency increased cell cycle and muscle cell proliferation. F4/80 immunohistochemistry also suggested the increase of immune response in p21 KO mice. On the other hand, both the mRNA expression and western blot analysis of <i>MyoD</i>, <i>myogenin</i>, and <i>Pax7</i> indicated that muscular differentiation was delayed in p21KO mice. Considering these results, we confirmed that muscle injury causes an increase in cell proliferation. However, muscle differentiation in p21 KO mice was inhibited due to the low expression of muscular synthesis genes, leading to a delay in the muscular regeneration. Thus, we conclude that p21 plays an important role in the <i>in vivo</i> healing process in muscular injury.</p></div

Immunofluorescence analysis of muscle basement membrane and plasma membrane.

<p>The expression of DAPI, laminin, and dystrophin was examined in wild-type (WT; upper panel) and p21 knockout (KO; lower panel) mice. (A) Expression in control, (B) Expression in 3 days, (C) Expression in 14 days, and (D) Expression in 28 days post-operation. (Scale bar = 50μm). (E) Quantification of laminin expression, (F) Quantification of dystrophin expression. (A-F) The injured membrane structure was almost repaired 14 days after injury in WT group, but not in the p21 KO group (p < 0.05).</p

Additional file 1: of p21 deficiency is susceptible to osteoarthritis through STAT3 phosphorylation

The primer sequence for detection of human p21, COL2A1, ACAN, MMP-3, MMP-13, ADAMTS-4, ADAMTS-5. (TIFF 58 kb