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Shengbin Lei, Chunhua Liu, Yanxia Yu, Wei Zhang, Qingdao Zeng
With various prospected applications in the field of nanoelectronics and catalysis, on-surface synthesis of single-layer covalent organic frameworks (surface COFs) with designable structures and properties have attracted enormous interest. Here we report on a scanning tunnelling microscopic investigation of the surface-confined synthesis of covalently bonded boronic ester network directly at the octanoic acid/HOPG interface under room temperature. The dynamic reaction process was investigated in detail. STM results indicate that the surface networks undergo structural evolution from a hybrid covalent/noncovalent multi-wall porous network to single-wall hexagonal COF with the decrease of monomer concentration...
October 6, 2016: Chemistry: a European Journal
Karine P Naidek, Cristiane R Zuconelli, Otavio M Cruz, Ronny Ribeiro, Sheila M B Winnischofer, Herbert Winnischofer
We synthesized 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP), characterized it by electrochemistry, spectroelectrochemistry, and electron paramagnetic resonance techniques, and evaluated its cytotoxicity to human cancer cell lines. The results revealed that HHTP has accessible higher-oxidation states, especially the tris-semiquinone monoradical. This species is stable and is formed after being stored for months. HHTP exhibited cytotoxic effects on 5 human cancer cell lines, including glioma and lung cancer cells...
April 2016: Biochemistry and Cell Biology, Biochimie et Biologie Cellulaire
Dana D Medina, Veronika Werner, Florian Auras, Raphael Tautz, Mirjam Dogru, Jörg Schuster, Stephanie Linke, Markus Döblinger, Jochen Feldmann, Paul Knochel, Thomas Bein
A mesoporous electron-donor covalent organic framework based on a benzodithiophene core, BDT-COF, was obtained through condensation of a benzodithiophene-containing diboronic acid and hexahydroxytriphenylene (HHTP). BDT-COF is a highly porous, crystalline, and thermally stable material, which can be handled in air. Highly porous, crystalline oriented thin BDT-COF films were synthesized from solution on different polycrystalline surfaces, indicating the generality of the synthetic strategy. The favorable orientation, crystallinity, porosity, and the growth mode of the thin BDT-COF films were studied by means of X-ray diffraction (XRD), 2D grazing incidence diffraction (GID), transmission and scanning electron microscopy (TEM, SEM), and krypton sorption...
April 22, 2014: ACS Nano
Jasper Adamson, Nicholas P Funnell, Amber L Thompson, Andrew L Goodwin
The hydrogen-bond arrangement within crystalline 2,3,6,7,10,11-hexahydroxytriphenylene tetrahydrate (HHTP·4H2O) undergoes an order-disorder transition at 240 K, as evidenced by the emergence and disappearance of systematic absence violations in variable-temperature single-crystal X-ray diffraction measurements. The low-temperature ordered phase is polar with ferroelectric coupling between neighbouring one-dimensional ice-like columns of hydrogen-bonded H2O molecules. At temperatures above 240 K the material adopts a paraelectric state characterised by the absence of long-range ordering between column polarisations...
February 14, 2014: Physical Chemistry Chemical Physics: PCCP
Anirban Karmakar, Ana E Platero-Prats, Lars Öhrström
The structure of 2,3,6,7,10,11-hexahydroxytriphenylene (hhtp) methanol monosolvate, C18H12O6·CH3OH, has triclinic symmetry (space group P-1). The compound has a three-dimensional layered network structure formed by intermolecular hydrogen bonding. Structure analysis with Hirshfeld surfaces is shown to be a sensitive method for comparing π-stacking effects in the five known solvates of hhtp. The title structure shows slightly weaker π-stacking than the dihydrate, but stronger π-stacking than the other three solvates...
March 2013: Acta Crystallographica. Section C, Crystal Structure Communications
Jing-hua Guo, Hong Zhang, Yongjian Tang, Xinlu Cheng
The hydrogen spillover mechanism, including the H chemisorption, diffusion, and H(2) associative desorption on the surface of COFs and H atoms migration from metal catalyst to COFs, have been studied via density functional theory (DFT) calculation. The results described herein show that each sp(2) C atom on COFs' surface can adsorb one H atom with the bond length d(C-H) between 1.11 and 1.14 Å, and the up-down arrangement of the adsorbed H atoms is the most stable configuration. By counting the chemisorption binding sites for these COFs, we can predict the saturation storage densities...
February 28, 2013: Physical Chemistry Chemical Physics: PCCP
F Bocquet, L Nony, S C B Mannsfeld, V Oison, R Pawlak, L Porte, Ch Loppacher
We discuss the inhomogeneous stress relaxation of a monolayer of hexahydroxytriphenylene (HHTP) which adopts the rare line-on-line (LOL) coincidence on KCl(001) and forms moiré patterns. The fact that the hexagonal HHTP layer is uniaxially compressed along the LOL makes this system an ideal candidate to discuss the influence of inhomogeneous stress relaxation. Our work is a combination of noncontact atomic force microscopy experiments, density functional theory and potential energy calculations, and a thorough interpretation by means of the Frenkel-Kontorova model...
May 18, 2012: Physical Review Letters
Eric L Spitler, Brian T Koo, Jennifer L Novotney, John W Colson, Fernando J Uribe-Romo, Gregory D Gutierrez, Paulette Clancy, William R Dichtel
Two-dimensional layered covalent organic frameworks (2D COFs) organize π-electron systems into ordered structures ideal for exciton and charge transport and exhibit permanent porosity available for subsequent functionalization. A 2D COF with the largest pores reported to date was synthesized by condensing 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP) and 4,4'-diphenylbutadiynebis(boronic acid) (DPB). The COF was prepared as both a high surface area microcrystalline powder as well as a vertically oriented thin film on a transparent single-layer graphene/fused silica substrate...
December 7, 2011: Journal of the American Chemical Society
Swee Lay Thein
Professor Titus H.J. Huisman is best known for his work on hemoglobin (Hb) variants. To date, more than 1,000 Hb variants have been discovered and characterized, of which about one-third were discovered in Titus Huisman's laboratory at the Medical College of Georgia, Augusta, GA, USA. A registry of these Hb variants and other information, a legacy from Professor Huisman, is now available online, at HbVar database (hhtp:// During the last century, major developments in Hb research have been made using physical, chemical, physiological and genetic methods...
2011: Hemoglobin
Barbara Lawrenz, Julia Jauckus, Markus S Kupka, Thomas Strowitzki, Michael von Wolff
INTRODUCTION: Data on the characteristics of female patients counselled for fertility preservation and the efficacy and risk of the applied procedures are still poor. We therefore analysed the registry of a network of 70 infertility centers which are involved in fertility preservation in Germany, Switzerland and Austria, called FertiPROTEKT ( hhtp:// ). MATERIALS AND METHODS: 1,280 counselled patients (15-40 years) were analysed regarding characteristics and different fertility preservation treatments before cytotoxic therapy in 2007-2009...
March 2011: Archives of Gynecology and Obstetrics
Ozcan Kocyigit, Ahmed N Kursunlu, Ersin Guler
We presented the synthesis of a novel Schiff base and its complexation properties with some transition metal ions in this work. For this, the 2,3,4,6,7,10,11 hexahydroxytriphenylene (HHTP) as starting material was synthesized according to known procedure. Moreover, the 2-((2-chloroethylimino)methyl) phenol material was prepared with reaction of salicylaldehyde and 2-chloroethylamine hydrochloride. To give the 2,3,4,6,7,10,11-hexakis(salicyliminoethoxy)triphenylene (HSE-TP) as a novel Schiff base, the HHTP were treated with 2-((2-chloroethylimino)methyl)phenol in acetone media...
November 15, 2010: Journal of Hazardous Materials
Christopher S Grange, Anthony J H M Meijer, Michael D Ward
The trinuclear complexes [{(R2bipy)2Ru}3(mu3-HHTP)](PF6)3 [1(PF6)3, R = H; 2(PF6)3, R = 4-tBu] contain three {Ru(R2bipy)2}2+ fragments connected to the triangular tris-chelating ligand hexahydroxytriphenylene (H6HHTP). This bridging ligand contains three dioxolene-type binding sites, each of which can reversibly convert between dianionic catecholate (cat), monoanionic semiquinone (sq) or neutral quinone (q) redox states. The bridging ligand as a whole can therefore exist in seven different redox states from fully reduced [cat,cat,cat]6- through to fully oxidised, neutral [q,q,q]...
January 7, 2010: Dalton Transactions: An International Journal of Inorganic Chemistry
Nikolas A A Zwaneveld, Rémy Pawlak, Mathieu Abel, Daniel Catalin, Didier Gigmes, Denis Bertin, Louis Porte
The development of nanoscale masking for particle deposition is exceedingly important to push the future of nanoelectronics beyond the current limits of lithography. We present the first example of ordered hexagonal covalent nanoporous structures deposited in extended arrays of near monolayer coverage across a Ag(111) surface. The networks were formed from the deposition of the reagents from a heated molybdenum crucible between 370 and 460 K under ultrahigh vacuum (UHV) onto a cleaned Ag(111) substrate and imaged using a scanning tunneling microscope (STM)...
May 28, 2008: Journal of the American Chemical Society
Ursula Mayr, Manuel Mayr, Xiaoke Yin, Shajna Begum, Edward Tarelli, Robin Wait, Qingbo Xu
In an accompanying study (in this issue, DOI 10.1002/pmic.200402044), we have characterised the proteome of Sca-1(+) progenitor cells, which may function as precursors of vascular smooth muscle cells (SMCs). In the present study, we have analysed and mapped protein expression in aortic SMCs of mice, using 2-DE, MALDI-TOF MS and MS/MS. The 2-D system comprised a non-linear immobilised pH 3-10 gradient in the first dimension (separating proteins with pI values of pH 3-10), and 12%T SDS-PAGE in the second dimension (separating proteins in the range 15,000-150,000 Da)...
November 2005: Proteomics
V V Gorbakov, V P Galik, S M Kirillov
AIM: Heptral trial in alcoholic, drug and viral diseases of the liver. MATERIALS AND METHODS: 67 patients with chronic diffuse liver diseases were treated with heptral. The examination covered AlAt, AP, HHTP, bilirubin, cholesterol, CT of the liver, esophagogastroduodenoscopy. Heptral was given by two steps: 14 days of intravenous drops (800 mg/day) followed by 14 days of oral use (2 tablets, 400 mg each) before meal at 8 a.m. and 2 p.m. RESULTS: In alcoholic disease of the liver, heptral relieved depression, reduced AlAT, AP, HHTP, bilirubin, density of the liver...
1998: Terapevticheskiĭ Arkhiv
P Cugini, P Lucia, G Scibilia, L Di Palma, A R Cioli, B Marino, A Cianetti, L Gasbarrone, R Canova
AIM OF THE STUDY: The present study is aimed to investigate the 24-hour pattern of Atrial Natriuretic Peptide (ANP) plasma concentration in normotensive (N) and hypertensive (H) heart transplanted patients (HTP) in order to detect the pathophysiological role of blood pressure regimen for ANP increase in HTP. METHODS: Eight NHTP and five HHTP have been investigated, all being hemodynamically compensated, without histological evidence of rejection and treated by Cyclosporine, Azathioprine and Prednisone...
1996: Acta Cardiologica
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