1,491 results match your criteria 5-6 rings


Identification of novel inhibitors of rat Mrp3.

Eur J Pharm Sci 2021 Mar 19;162:105813. Epub 2021 Mar 19.

Drug Delivery and Disposition, KU Leuven Department of Pharmaceutical and Pharmacological Sciences, Campus Gasthuisberg, O&N2, Herestraat 49 box 921, B-3000 Leuven, Belgium; BioNotus GCV, Wetenschapspark Universiteit Antwerpen, Galileilaan 15, B-2845 Niel, Belgium. Electronic address:

Multidrug resistance-associated protein (MRP; ABCC gene family) mediated efflux transport plays an important role in the systemic and tissue exposure profiles of many drugs and their metabolites, and also of endogenous compounds like bile acids and bilirubin conjugates. However, potent and isoform-selective inhibitors of the MRP subfamily are currently lacking. Therefore, the purpose of the present work was to identify novel rat Mrp3 inhibitors. Read More

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Rapid separation and purification of two C25 steroids with bicyclic [4.4.1] A/B rings from the marine fungus sp. LS116 by high-speed counter-current chromatography in stepwise elution mode.

Nat Prod Res 2021 Feb 14:1-5. Epub 2021 Feb 14.

Li Dak Sum Yip Yio Chin Kenneth Li Marine Biopharmaceutical Research Center, Ningbo University, Ningbo, China.

Two C25 steroids with bicyclic [4.4.1] A/B rings were successfully separated from the marine fungus sp. Read More

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February 2021

DFT study of structural and electronic properties of 1,4-diarylcyclopenta[d] pyridazines and oxazines for non-linear optical applications.

J Mol Model 2021 Jan 31;27(2):60. Epub 2021 Jan 31.

Department of Physical Sciences, University of Findlay, Findlay, OH, 45840, USA.

Polymer and molecular-based electronic materials incorporating heterocycles like thiophenes and pyrroles are attractive possibilities as substitutes for semimetal materials. Heterocyclic materials are heavily studied in this regard due to the large variations in possible substrates. Herein we evaluated four different 5,6-fused ring heterocycles to gain a better understanding of any favorable optical and electronic properties that were due to incorporation of certain moieties. Read More

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January 2021

Alternaria alternata causing Alternaria Leaf Spot of Cucumis melo (Muskmelon) in Pakistan.

Plant Dis 2021 Jan 26. Epub 2021 Jan 26.

University of Agriculture Faisalabad, 66724, Plant Pathology, virology lab, University of Agriculture, Faisalabad, Faisalabad, Punjab, Pakistan, 38000;

In July 2019, leaf spot symptoms were observed on muskmelon (Cucumis melo L.) cv. Jackball-1 plants in an experimental field of 2. Read More

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January 2021

Newly synthesized peripherally octa-substituted zinc phthalocyanines carrying halogen terminated phenoxy-phenoxy moiety: comparative photochemical and photophysical features.

Turk J Chem 2020 16;44(6):1556-1564. Epub 2020 Dec 16.

Department of Chemistry, Yıldız Technical University, İstanbul Turkey.

This study reports the 3 new phthalonitrile derivatives, namely 4, 5 Bis-[4-(4-bromophenoxy) phenoxy] phthalonitrile ( ), 4,5 Bis-[4-(4-chlorophenoxy) phenoxy]phthalonitrile ( ), and 4, 5 Bis[4-(4-fluorophenoxy) phenoxy] phthalonitrile ( ). Their octa-substituted zinc phthalocyanines ( , , ) are reported for the first time in this study. The resulting compounds were characterized by utilizing some spectroscopic methods, such as UV-Vis, 1HNMR, FT-IR spectroscopy, as well as mass spectraand elemental analysis. Read More

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December 2020

Thiophene-Fused Naphthodiphospholes: Modulation of the Structural and Electronic Properties of Polycyclic Aromatics by Precise Fusion of Heteroles.

Chempluschem 2021 Jan;86(1):130-136

Department of Molecular Engineering, Graduate School of Engineering, Kyoto University Nishikyo-ku, Kyoto, 615-8510, Japan.

For polycyclic aromatics with heterole-fused structures, the orientation of fused heterole rings as well as the geometry of their fused structures has a large impact on the physicochemical properties. In this study, a series of isomers of thiophene-fused naphthodiphospholes was designed and synthesized. Systematic investigation unveiled the explicit impact of heterole-fused structures on their structural and electronic properties. Read More

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January 2021

Impact of Solvent Polarity on the Ligand Configuration in Tetravalent Thorium N-Donor Complexes.

Inorg Chem 2021 Jan 6;60(2):1092-1098. Epub 2021 Jan 6.

Ruprecht-Karls-Universität Heidelberg, Institut für Physikalische Chemie, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany.

A combined NMR spectroscopic and theoretical study on the complexation of diamagnetic Th(IV) with 2,6-bis(5,6-dipropyl-1,2,4-triazin-3-yl)pyridine (Pr-BTP) was performed. Different ligand configurations were observed for [Th(Pr-BTP)] complexes depending on the solvent's ability to actively form hydrogen bonds. In polar aprotic solvents, a complex is observed, which is isostructural with [M(Pr-BTP)] (M = Am, Ln) complexes studied earlier. Read More

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January 2021

[Distribution Characteristics and Source Apportionment of Polycyclic Aromatic Hydrocarbons in Atmospheric Deposition in Areas Adjacent to a Large Petrochemical Enterprise].

Huan Jing Ke Xue 2021 Jan;42(1):106-113

Shanghai Academy of Environmental Sciences, Shanghai 200233, China.

In order to explore the influence of polycyclic aromatic hydrocarbons (PAHs) emissions by petrochemical enterprises on the surrounding environment, atmospheric deposition samples of the PAHs were collected in the industrial and residential areas adjacent to a petrochemical enterprise from March 2017 to February 2018. Deposition fluxes and the composition of PAHs were studied. The source of PAHs was analyzed by a positive matrix factor (PMF) model. Read More

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January 2021

Chemical Bonding as a New Avenue for Controlling Excited-State Properties and Excitation Energy-Transfer Processes in Zinc Phthalocyanine-Fullerene Dyads.

Chemistry 2021 Feb 28;27(12):4159-4167. Epub 2021 Jan 28.

College of Chemistry, Beijing Normal University, Beijing, 100875, P. R. China.

Whether chemical bonding can regulate the excited-state and optoelectronic properties of donor-acceptor dyads has been largely elusive. In this work, we used electronic structure and nonadiabatic dynamics methods to explore the excited-state properties of covalently bonded zinc phthalocyanine (ZnPc)-fullerene (C ) dyads with a 6-6 (or 5-6) bonding configuration in which ZnPc is bonded to two carbon atoms shared by the two hexagonal rings (or a pentagonal and a hexagonal ring) in C . In both cases, the locally excited (LE) states on ZnPc are spectroscopically bright. Read More

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February 2021

An Aluminosilicate Zeolite Containing Rings of Tetrahedral Atoms with All Odd Numbers from Five to Eleven.

Angew Chem Int Ed Engl 2021 Mar 26;60(11):5936-5940. Epub 2021 Jan 26.

Center for Ordered Nanoporous Materials Synthesis, Division of Environmental Science and Engineering, POSTECH, Pohang, 37673, Korea.

Herein we report the synthesis, structure solution, and catalytic properties of PST-31, which has an unprecedented framework topology. This high-silica (Si/Al=16) zeolite was synthesized using a pyrazolium-based dication with a tetramethylene linker as an organic structure-directing agent (OSDA) in hydroxide media. The PST-31 structure is built from new building layers containing four-, five-, six-, and seven-membered rings, which are connected by single four-membered rings in the interlayer region to form a two-dimensional pore system. Read More

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Placement of dual capsular tension rings for the combined management of traumatic cyclodialysis cleft and zonular dialysis.

Eye Vis (Lond) 2020 Nov 23;7(1):54. Epub 2020 Nov 23.

Eye Institute and Department of Ophthalmology, Eye Ear Nose and Throat Hospital, Fudan University, 83 Fenyang Rd, Shanghai, 200031, China.

Background: To evaluate the efficacy and safety of placing dual capsular tension rings for the combined management of traumatic cyclodialysis cleft and zonular dialysis.

Methods: A modified capsular tension ring was inserted into the ciliary sulcus and a capsular tension ring or modified capsular tension ring was inserted into the capsular bag in 20 eyes in 20 consecutive patients showing signs of ocular hypotony and ectopia lentis. Outcome measures included intraocular pressure, best-corrected visual acuity, and postoperative complications. Read More

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November 2020

Differentiation of the binding of two ligands to a tetrameric protein with a single symmetric active site by F NMR.

Protein Sci 2021 Feb 11;30(2):477-484. Epub 2020 Dec 11.

Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee-Knoxville, Knoxville, Tennessee, USA.

R67 dihydrofolate reductase (R67 DHFR) is a plasmid-encoded enzyme that confers resistance to the antibacterial drug trimethoprim. R67 DHFR is a tetramer with a single active site that is unusual as both cofactor and substrate are recognized by symmetry-related residues. Such promiscuity has limited our previous efforts to differentiate ligand binding by NMR. Read More

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February 2021

A one-year monitoring of spatiotemporal variations of PM-bound PAHs in Tehran, Iran: Source apportionment, local and regional sources origins and source-specific cancer risk assessment.

Environ Pollut 2021 Apr 6;274:115883. Epub 2020 Nov 6.

Department of Geophysics, School of Geology, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece.

PM-bound PAHs were analyzed in a total of 135 daily samples collected during four seasons from 2018 to 2019, at three urban sites in Tehran, Iran. This study aims to investigate spatio-temporal variations, source apportionment, potential local and regional sources contributions and lung cancer risks associated with the 16 US EPA priority PAHs. PM concentrations ranged from 43. Read More

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Flexible or rigid ring in mitral annuloplasty-do the results differ?

Indian J Thorac Cardiovasc Surg 2020 Nov 27;36(6):566-571. Epub 2020 Aug 27.

Department of Cardiovascular and Thoracic Surgery, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, 695011 India.

Introduction: Mitral valve annuloplasty has evolved over the decades since its introduction and Carpentier played a major role in developing the technique. Mitral valve repair is preferred over replacement for severe primary mitral regurgitation, as it restores normal life expectancy when successful and does not require lifelong anticoagulation. There is an ongoing debate regarding the choice of ring for mitral valve annuloplasty-rigid or flexible. Read More

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November 2020

Risk assessment of PAHs and N-PAH analogues in sediment cores from the Niger Delta.

Mar Pollut Bull 2020 Dec 6;161(Pt A):111684. Epub 2020 Oct 6.

Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, United Kingdom.

Chemical-surveys of sediments are source of information about historical-pollution in aquatic-ecosystems, because ecological/human-health risks may arise from polycyclic-aromatic-hydrocarbons (PAHs) and nitrogen-PAHs presence in aquatic-environments, particularly sediments, where they partition. Despite this, sediment-PAHs/N-PAHs have not been reported in the Niger Delta. This study investigated vertical-profiles of PAHs/N-PAHs in 2 cm-intervals-segments from Bonny Estuary, Niger Delta. Read More

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December 2020

Protein synthesis with conformationally constrained cyclic dipeptides.

Bioorg Med Chem 2020 11 23;28(22):115780. Epub 2020 Sep 23.

Biodesign Center for BioEnergetics and School of Molecular Sciences, Arizona State University, Tempe, AZ 85287, United States. Electronic address:

We have synthesized several conformationally constrained dipeptide analogues as possible substrates for incorporation into proteins. These have included three cyclic dipeptides formed from Boc derivatives of 2,4-diaminobutyric acid, ornithine and lysine, having 5-, 6-, and 7-membered lactam rings, respectively. These dipeptides were used to activate a suppressor tRNA transcript, the latter of which had been prepared by in vitro transcription. Read More

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November 2020

A new microporous 12-ring zincosilicate THK-2 with many terminal silanols characterized by automated electron diffraction tomography.

Dalton Trans 2020 Oct 16;49(37):12960-12969. Epub 2020 Sep 16.

Department of Physical Science, Graduate School of Science, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, 599-8531, Japan.

A newly synthesized microporous zincosilicate THK-2 (estimated structural composition: |(HO)(CHN)|[LiZnSiO(OH)]) was characterized by single-crystal electron diffraction using the automated electron diffraction tomography (ADT) approach in combination with powder X-ray diffraction. The lattice constants and space group of as-synthesized THK-2 were a = 2.50377(7) nm, b = 1. Read More

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October 2020

Expression of the Clifednamide Biosynthetic Pathway in Generates 27,28--Derivatives.

J Nat Prod 2020 09 11;83(9):2803-2808. Epub 2020 Sep 11.

Key Laboratory of Chemical Biology of Ministry of Education, School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan 250012, China.

Polycyclic tetramate macrolactams (PoTeMs) are a group of hybrid PK-NRP natural products having a variable set of carbocyclic rings, a conserved assembly pathway, and diverse bioactivities. We report here the identification of seven new PoTeMs, clifednamides D-J (-), along with the known clifednamides A () and B () through rational pathway refactoring and heterologous expression. Remarkably, clifednamides D (), G (), and H () feature an unprecedented 27,28- skeleton. Read More

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September 2020

Arachidonic Acid Metabolites of CYP450 Enzymes and HIF-1α Modulate Endothelium-Dependent Vasorelaxation in Sprague-Dawley Rats under Acute and Intermittent Hyperbaric Oxygenation.

Int J Mol Sci 2020 Sep 1;21(17). Epub 2020 Sep 1.

Institute and Department of Physiology and Immunology, Faculty of Medicine Osijek, Josip Juraj Strossmayer University of Osijek, J. Huttlera 4, 31000 Osijek, Croatia.

Acetylcholine-induced vasorelaxation (AChIR) and responses to reduced pO (hypoxia-induced relaxation (HIR), 0% O) were assessed in vitro in aortic rings of healthy male Sprague-Dawley rats (N = 252) under hyperbaric (HBO) protocols. The studied groups consisted of the CTRL group (untreated); the A-HBO group (single HBO; 120 min of 100% O at 2.0 bars); the 24H-HBO group (examined 24 h after single exposure) and the 4D-HBO group (four consecutive days of single HBO). Read More

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September 2020

Chiral 1,3,2-Oxazaborolidine Catalysts for Enantioselective Photochemical Reactions.

Acc Chem Res 2020 09 3;53(9):1933-1943. Epub 2020 Sep 3.

Department of Chemistry and Catalysis Research Center (CRC), Technical University of Munich, Lichtenbergstrasse 4, 85747 Garching, Germany.

Asymmetric synthesis has posed a significant challenge to organic chemists for over a century. Several strategies have been developed to synthesize enantiomerically enriched compounds, which are ubiquitous in the pharmaceutical and agrochemical industries. While many organometallic and organic catalysts have been found to mediate thermal enantioselective reactions, the field of photochemistry lacks similar depth. Read More

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September 2020

Tuning the Excited State of Tetradentate Pd(II) Complexes for Highly Efficient Deep-Blue Phosphorescent Materials.

Inorg Chem 2020 Sep 1;59(18):13502-13516. Epub 2020 Sep 1.

State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, Zhejiang, P. R. China.

Deep-blue-light-emitting materials are urgently desired in high-performance organic light-emitting diodes (OLEDs) for full-color display and solid-state lighting applications. However, the development of stable and efficient deep-blue emitters remains a great challenge. Herein, a series of stable and efficient tetradentate Pd(II)-complex-based deep-blue emitters with rigid 5/6/6 metallocycles and no F atom were designed and synthesized. Read More

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September 2020

Computational design of transmembrane pores.

Nature 2020 09 26;585(7823):129-134. Epub 2020 Aug 26.

Institute for Protein Design, University of Washington, Seattle, WA, USA.

Transmembrane channels and pores have key roles in fundamental biological processes and in biotechnological applications such as DNA nanopore sequencing, resulting in considerable interest in the design of pore-containing proteins. Synthetic amphiphilic peptides have been found to form ion channels, and there have been recent advances in de novo membrane protein design and in redesigning naturally occurring channel-containing proteins. However, the de novo design of stable, well-defined transmembrane protein pores that are capable of conducting ions selectively or are large enough to enable the passage of small-molecule fluorophores remains an outstanding challenge. Read More

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September 2020

A water resistance magnetic graphene-anchored zeolitic imidazolate framework for efficient adsorption and removal of residual tetracyclines in wastewater.

Water Sci Technol 2020 Jun;81(11):2322-2336

State Key Laboratory of High-Efficiency Utilization of Coal and Green Chemical Engineering, College of Chemistry and Chemical Engineering, Ningxia University, Yinchuan 750021, China E-mail:

Water-resistant magnetic graphene-anchored zeolite imidazolate (FeO/ZIF-8-G) composite materials with the largest surface area are formed by directly growing a hydrophobic ZIF-8 skeleton onto a graphene support through self-assembly in methanol. FeO/ZIF-8-G hybrid composite has water resistance and super strong adsorption capacity, and is used as an effective adsorbent for adsorption and removal of residual tetracycline in wastewater. The morphologies and structure, as well as water resistance of FeO/ZIF-8-G, were characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetry analysis (TGA), N adsorption and pH. Read More

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Kinetics and pathways of the degradation of PPCPs by carbonate radicals in advanced oxidation processes.

Water Res 2020 Oct 24;185:116231. Epub 2020 Jul 24.

Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, China. Electronic address:

The carbonate radical (CO) is a typical secondary radical observed in engineering and natural aquatic systems. This study investigated the degradation kinetics of 20 pharmaceuticals and personal care products (PPCPs) by CO and the transformation pathways of a typical PPCP (naproxen) that is susceptible to CO. CO is highly selective for compounds containing aniline and phenolic hydroxyl groups as well as naphthalene rings, such as sulfamethoxazole, sulfamethazine, salbutamol, propranolol, naproxen, and macrolide antibiotics such as azithromycin, for which the second-order rate constants range from 5. Read More

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October 2020

How biofilms affect the uptake and fate of hydrophobic organic compounds (HOCs) in microplastic: Insights from an In situ study of Xiangshan Bay, China.

Water Res 2020 Oct 1;184:116118. Epub 2020 Jul 1.

Faculty of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, PR China.

Microplastic (MP) has been identified as an emerging vector that transports hydrophobic organic compounds (HOCs) across aquatic environments due to its hydrophobic surfaces and small size. However, it is also recognized that environmental factors affect MP's chemical vector effects and that attached biofilms could play a major role, although the specific mechanisms remain unclear. To explore this issue, an in situ experiment was conducted at Xiangshan Bay of southeastern China, and dynamics of HOCs (i. Read More

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October 2020

Comparing Benzodithiophene Unit with Alkylthionaphthyl and Alkylthiobiphenyl Side-Chains in Constructing High-Performance Nonfullerene Solar Cells.

Polymers (Basel) 2020 Jul 27;12(8). Epub 2020 Jul 27.

State Key Laboratory of Bio-Fibers and Eco-Textiles, Qingdao University, Qingdao 266071, China.

Using single-bonded and fused aromatic rings are two methods for extending the π-conjugation in the vertical direction of benzo [1,2-b:4,5-b'] dithiophene (BDT) unit. To investigate which method is more efficient in nonfullerene systems, two novel polymers based on alkylthionaphthyl and alkylthiobiphenyl substituted BDT named PBDTNS-FTAZ and PBDTBPS-FTAZ are designed and synthesized. Two polymers only exhibit small differences in structure, but huge differences in photovoltaic properties. Read More

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An exhaustive perspective on structural insights of SGLT2 inhibitors: A novel class of antidiabetic agent.

Eur J Med Chem 2020 Oct 19;204:112523. Epub 2020 Jul 19.

Department of Pharmaceutical Sciences, Dr. Harisingh Gour University (A Central University), Sagar, MP, India. Electronic address:

Diabetes mellitus is the global health issue and become an alarming threat in the modern era where human lifestyle gets compromised with modernization. According to the latest statistical report 2020, USA has 9.47% (31 million among 32. Read More

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October 2020

Thermally Induced Formation of HFTCNQ in FTCNQ-Doped Regioregular P3HT.

J Phys Chem Lett 2020 Aug 3;11(16):6586-6592. Epub 2020 Aug 3.

Department of Chemistry and Centre for Plastic Electronics, Imperial College London, London, U.K.

The prototypical system for understanding doping in solution-processed organic electronics has been poly(3-hexylthiophene) (P3HT) p-doped with 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (FTCNQ). Multiple charge-transfer states, defined by the fraction of electron transfer to FTCNQ, are known to coexist and are dependent on polymer molecular weight, crystallinity, and processing. Less well-understood is the loss of conductivity after thermal annealing of these materials. Read More

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Crystal structure of 5-[(benzo-yloxy)meth-yl]-5,6-dihy-droxy-4-oxo-cyclo-hex-2-en-1-yl benzoate.

Acta Crystallogr E Crystallogr Commun 2020 Jul 19;76(Pt 7):1096-1100. Epub 2020 Jun 19.

Department of Chemistry, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand.

The crystal structure of the natural product zeylenone, CHO, was confirmed by single-crystal X-ray diffraction. The crystal structure has three chiral centers at positions C1, C5 and C6 of the cyclo-hexa-none ring, but the absolute configuration could not be determined reliably. The methyl benzoate and benzo-yloxy substituents at positions C1 and C5 of the cyclo-hexenone ring are on the same side of the ring with the dihedral angle between their mean planes being 16. Read More

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Time-Dependent Density Functional Theory Investigation on the Electronic and Optical Properties of Poly-C,Si,Ge-acenes.

ACS Omega 2020 Jul 26;5(27):16654-16663. Epub 2020 Jun 26.

Department of Physics, University of Cagliari, S.P. 8 Km 0,7, I-09042 Monserrato CA, Italy.

We report a comparative computational investigation on the first six members of linear poly-C,Si,Ge-acenes (XH, X = C,Si,Ge; = 1, 2, 3, 4, 5, 6). We performed density functional theory (DFT) and time-dependent DFT calculations to compare morphological, electronic, and optical properties. While C-acenes are planar, Si- and Ge-acenes assume a buckled configuration. Read More

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