| 1. |
- Jafri, Syed Hassan Mujtaba, 1979-, et al.
(author)
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Nanomolecular electronic devices based on AuNP molecule nanoelectrodes using molecular place-exchange process
- 2020
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In: Nanotechnology. - : IOP PUBLISHING LTD. - 0957-4484 .- 1361-6528. ; 31:22
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Journal article (peer-reviewed)abstract
- The implementation of electronics applications based on molecular electronics devices is hampered by the difficulty of placing a single or a few molecules with application-specific electronic properties in between metallic nanocontacts. Here, we present a novel method to fabricate 20 nm sized nanomolecular electronic devices (nanoMoED) using a molecular place-exchange process of nonconductive short alkyl thiolates with various short chain conductive oligomers. After the successful place-exchange with short-chain conjugated oligomers in the nanoMoED devices, a change in device resistance of up to four orders of magnitude for 4,4 '-biphenyldithiol (BPDT), and up to three orders of magnitude for oligo phenylene-ethynylene (OPE), were observed. The place-exchange process in nanoMoEDs are verified by measuring changes in device resistance during repetitive place-exchange processes between conductive and nonconductive molecules and surface-enhanced Raman spectroscopy. This opens vast possibilities for the fabrication and application of nanoMoED devices with a large variety of molecules.
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| 2. |
- Sher, Omer, et al.
(author)
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Analysis of molecular ligand functionalization process in nano-molecular electronic devices containing densely packed nano-particle functionalization shells
- 2022
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In: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 33:25
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Journal article (peer-reviewed)abstract
- Molecular electronic devices based on few and single-molecules have the advantage that the electronic signature of the device is directly dependent on the electronic structure of the molecules as well as of the electrode-molecule junction. In this work, we use a two-step approach to synthesise functionalized nanomolecular electronic devices (nanoMoED). In first step we apply an organic solvent-based gold nanoparticle (AuNP) synthesis method to form either a 1-dodecanethiol or a mixed 1-dodecanethiol/omega-tetraphenyl ether substituted 1-dodecanethiol ligand shell. The functionalization of these AuNPs is tuned in a second step by a ligand functionalization process where biphenyldithiol (BPDT) molecules are introduced as bridging ligands into the shell of the AuNPs. From subsequent structural analysis and electrical measurements, we could observe a successful molecular functionalization in nanoMoED devices as well as we could deduce that differences in electrical properties between two different device types are related to the differences in the molecular functionalization process for the two different AuNPs synthesized in first step. The same devices yielded successful NO2 gas sensing. This opens the pathway for a simplified synthesis/fabrication of molecular electronic devices with application potential.
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| 3. |
- Barnå, Fredrik, et al.
(author)
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Synthesis and crystal structures of boryl ortho-silylaryl trifluoromethanesulfonates
- 2024
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In: Acta Crystallographica Section E: Crystallographic Communications. - : International Union Of Crystallography. - 2056-9890. ; 80:2, s. 143-147
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Journal article (peer-reviewed)abstract
- We report the synthesis and structural characterization of three crystalline borylated ortho-silylaryl trifluoromethanesulfonates: 5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-2-(trimethylsilyl)phenyl trifluoromethanesulfonate, C16H24BF3O5SSi (1a), 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-2-(trimethylsilyl)phenyl trifluoromethanesulfonate, C16H24BF3O5SSi (1b), and 2-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-6-(trimethylsilyl)phenyl trifluoromethanesulfonate, C17H26BF3O5SSi (2), which are versatile aryne precursors. For all three compounds, the heteroatom substituents are almost coplanar with the central aromatic moiety. C—heteroatom bonding metrics are unexceptional and fall withing the typical range of C—B, C—Si, and C—O single bonds. Despite numerous electronegative sites, only weak intermolecular interactions are observed in the solid state.
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| 4. |
- Chepkirui, Carolyne, et al.
(author)
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Benzo[b]naphtho[2,1-d]furans and 2-Phenylnaphthalenes from Streblus usambarensis
- 2023
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In: Journal of Natural Products. - : American Chemical Society (ACS). - 0163-3864 .- 1520-6025. ; 86:4, s. 1010-1018
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Journal article (peer-reviewed)abstract
- Three new benzo[b]naphtho[2,1-d]furans, usambarins A–C (1–3), five new 2-phenylnaphthalenes, usambarins D–H (4–8), a new flavan (9), and a new phenyl-1-benzoxepin (10) as well as two known compounds (11 and 12) were isolated from the extract of the stem and roots of Streblus usambarensis (Moraceae). The structures were deduced using NMR spectroscopic and mass spectrometric analyses, and those of compounds 1 and 4 were confirmed by X-ray crystallography. Usambarin D (4) demonstrated moderate antibacterial activity (MIC 9.0 μM) against Bacillus subtilis, while none of the tested compounds were effective against Escherichia coli.
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| 5. |
- Clausing, Simon T., et al.
(author)
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Preparation, photo- and electrochemical studies of a homoleptic imine-phosphaalkene Cu(I) complex
- 2020
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In: Inorganica Chimica Acta. - : Elsevier BV. - 0020-1693 .- 1873-3255. ; 513
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Journal article (peer-reviewed)abstract
- A 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) functionalized phosphaalkene was used as a bidentate ligand towards a [Cu(I)L-2](+) complex. The spectroscopic, electrochemical and photophysical properties of the compound were studied revealing a rich redox chemistry indicative of ligand non-innocence. The compound is weakly emissive with excited state lifetimes of up to 9 ns. NMR and electrochemical analysis indicate a complex dynamic behavior of this photosensitizer in solution.
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| 6. |
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Cover Feature : Analysis of Anion Binding Effects on the Sensitized Luminescence of Macrocyclic Europium(III) Complexes (Anal. Sens. 6/2022)
- 2022
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In: Analysis & Sensing. - : John Wiley & Sons. - 2629-2742 .- 2629-2742.
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Artistic work (peer-reviewed)abstract
- The cover feature image represents the differences in the luminescence response upon fluoride vs cyanide binding to a 1,4,7-triazacyclonane-based Eu(III) complex equipped with a carbostyril light-harvesting antenna. The addition of excess of fluoride boosts the Eu(III) emission quantum yield by up to 6-fold for such compounds. Cyanide addition extinguishes Eu(III) luminescence despite partial anion binding to a lanthanide 3+ ion. These compounds showed opposite responses upon fluoride and cyanide binding, and the results could facilitate the design of responsive probes for multiple anion types. More information can be found in the Research Article (https://doi.org/10.1002/anse.202200015) by K. E. Borbas and co-workers.
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| 7. |
- Deka, Rajesh, et al.
(author)
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Carbene chemistry of arsenic, antimony, and bismuth : origin, evolution and future prospects
- 2022
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In: Dalton Transactions. - : Royal Society of Chemistry (RSC). - 1477-9226 .- 1477-9234. ; 51:22, s. 8540-8556
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Research review (peer-reviewed)abstract
- The discovery of the first isolable N-heterocyclic carbene in 1991 ushered in a new era in coordination chemistry. The remarkable bonding properties of carbenes have led to their rapid proliferation as auxiliary ligands for a wide range of transition metals and main group elements. In the case of group 15, while carbene-stabilized nitrogen and phosphorus compounds are extensively studied, the scope of research has shrunk significantly from arsenic to bismuth. This is essentially attributed to the decrease in stability of the C-E bond upon descending the group. Even so, modulating the carbene backbone or introducing alternative synthetic strategies not only alleviates the stability issues but also offers promising results in terms of the bonding and reactivities of these compounds. The purpose of the present perspective is to provide a comprehensive overview of the origins and development of carbene chemistry of arsenic, antimony, and bismuth, as well as to highlight the future prospects of this field.
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| 8. |
- D'Imperio, Nicolas, et al.
(author)
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Highly Conjugated Bis(benzo[b]phosphole)-P-oxides : Synthesis and Electrochemical, Optical, and Computational Studies
- 2023
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In: European Journal of Organic Chemistry. - : John Wiley & Sons. - 1434-193X .- 1099-0690. ; 26:4
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Journal article (peer-reviewed)abstract
- The first examples of a pi-conjugated benzo[b]phosphole P-oxide in which two phosphole P-oxide units are connected by a carbon-carbon double bond are described. The molecules are synthesized as E isomers with respect to the carbon-carbon double bond and exist as stable cis and trans isomers (chiral and meso one respectively) relatively to the two stereogenic P atoms. The optical and electrochemical properties of both isomers have been investigated by experiment and computations.
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| 9. |
- Esfandiarfard, Keyhan, et al.
(author)
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Precursors for the Development of π-Conjugated Low-Coordinate Phosphorus Compounds
- 2023
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In: ChemPlusChem. - : Wiley-VCH Verlagsgesellschaft. - 2192-6506. ; 88:6
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Journal article (peer-reviewed)abstract
- The synthesis of a novel monomeric precursor and its butadiyne-bridged dimeric form for the preparation of novel π-conjugated organophosphorus compounds is presented. The precursors are synthesized from commercially available starting materials, and based on a Dmp (2,6-dimesitylphenyl) group for kinetic stabilization of the P-functionality, a bromo substituent for the introduction of the phosphorus center, and an acetylene unit at the para position of the Dmp moiety. Such acetylenic units are synthetically versatile, and can be explored for the construction of larger phosphorus-containing π-conjugates. The precursors are utilized to prepare Dmp-stabilized C,C-dibromophosphaalkenes, and butadiyne-bridged dimeric species thereof. The effect of the low-coordinate phosphorus centers and the extent of π-conjugation on the spectroscopic and electronic properties is evaluated by NMR and UV/Vis spectroscopy, as well as cyclic voltammetry. In addition to the phosphaalkenes, the successful syntheses of two new diphosphenes are presented, indicating a broad applicability of the precursor.
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| 10. |
- Ferreira, Ricardo J., et al.
(author)
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Pedrolane, a Polycyclic Diterpene Scaffold Containing a Bicyclo[2.2.1]heptane System, from Euphorbia pedroi
- 2021
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In: Organic Letters. - : American Chemical Society (ACS). - 1523-7060 .- 1523-7052. ; 23:2, s. 274-278
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Journal article (peer-reviewed)abstract
- Pedrolide (1), a diterpenoid with an unprecedented carbon skeleton, pedrolane, containing a bicycle[2.2.1]heptane system, is reported. This structural feature is hypothesized to involve an intramolecular cyclization, via Michael addition, and a ring contraction, via 1,2-alkyl shift or a Pinacol rearrangement of rings A and B, from a tigliane-type 5/7/6/3-tetracyclic ring precursor. The structure of 1 was established using spectroscopic techniques, single-crystal X-ray diffraction, and ab initio calculations. Pedrolide reversed multidrug resistance mediated by P-glycoprotein.
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