scholarly journals The syntheses, structures and spectroelectrochemical properties of 6-oxo-verdazyl derivatives bearing surface anchoring groups

2021 ◽  
Author(s):  
Varshini Kumar ◽  
Jian-Zhong Wu ◽  
Martyna Judd ◽  
Elodie Rousset ◽  
Marcus Korb ◽  
...  
Keyword(s):  
Closed Shell ◽  
Coupling Reactions ◽  
Terminal Alkynes ◽  
X Ray Diffraction ◽  
Surface Anchoring ◽  
X Ray ◽  
Verdazyl Radicals ◽  
Cross Coupling Reactions ◽  
Td Dft ◽  
Anchoring Groups

A series of 6-oxo verdazyl radicals functionalised at the 1- and 5-positions by methyl, thiomethyl and iodo groups were synthesised using conventional strategies. Facile Sonogashira cross-coupling reactions of terminal alkynes with the diiodo analogue were used for synthetic elaboration of the verdazyl core structure with π-conjugated ethynyl groups. The radicals were characterised by EPR spectroscopy, single-crystal X-ray diffraction, cyclic voltammetry and optical spectroscopy. The chemically and electrochemically reversible oxidation and reduction of these radicals within a convenient redox window permitted further studies on the closed-shell cationic and anionic forms using spectroelectrochemical methods, supported by (TD-)DFT calculations.

The syntheses, structures and spectroelectrochemical properties of 6-oxo-verdazyl derivatives bearing surface anchoring groups

2022 ◽  
Author(s):  
Varshini Jayantha Kumar ◽  
Jian-Zhong Wu ◽  
Martyna Judd ◽  
Elodie ROUSSET ◽  
Marcus Korb ◽  
...  
Keyword(s):  
Cross Coupling ◽  
Coupling Reactions ◽  
Terminal Alkynes ◽  
Bearing Surface ◽  
Surface Anchoring ◽  
Verdazyl Radicals ◽  
Cross Coupling Reactions ◽  
Anchoring Groups ◽  
Spectroelectrochemical Properties

A series of 6-oxo verdazyl radicals functionalised at the 1- and 5-positions by methyl, thiomethyl and iodo groups were synthesised using conventional strategies. Facile Sonogashira cross-coupling reactions of terminal alkynes...

Improved Access to 1,8-Dichloro-10-(ethynyl)anthracene: A Useful Building Block for (Semi-)rigid Organic Frameworks

Synthesis ◽  
2018 ◽  
Vol 50 (10) ◽  
pp. 2009-2018
Author(s):  
Jan-Hendrik Lamm ◽  
Philipp Niermeier ◽  
Leif Körte ◽  
Beate Neumann ◽  
Hans-Georg Stammler ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Building Block ◽  
High Resolution Mass Spectrometry ◽  
Cross Coupling ◽  
Easy Access ◽  
Coupling Reactions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cross Coupling Reactions ◽  
Resolution Mass

An easy access to 1,8-dichloro-10-(ethynyl)anthracene is reported, which is widely applicable for building up rigid linkers between two 1,8-dichloroanthracene units. For this, 1,8-dichloroanthren-10(9H)-one was reacted with ethynylmagnesium bromide in the presence of CeCl3; the yield was 65%. This building block was used as a substrate in (cross-)coupling reactions and some examples of linked 1,8-dichloroanthracen-10-yls (e.g., 1,8-bis[(1,8-dichloroanthracen-10-yl)-ethynyl]naphthalene or 1,2-bis[(1,8-dichloroanthracen-10-yl)ethynyl]-benzene) were synthesized in good to moderate yields. Linked 1,8-dichloroanthracen-10-yl derivatives were also synthesized by cross-coupling reactions using 10-bromo-1,8-dichloroanthracene and doubly ethynyl-substituted substrates. Linkers between the 1,8-dichloroanthracene units were: butadiynediyl, dimethylsilyldiethynyl, octa-1,7-diyne-1,8-diyl, propane-1,3-diylbis(dimethylsilyl)diethynyl, benzene-1,2-diethynyl, naphthalene-1,8-diyldiethynyl, and anthracene-1,8-diyldiethynyl. The new anthracene compounds were characterized by NMR spectroscopy, high-resolution mass spectrometry, and, in part, by X-ray diffraction experiments.

Synthesis and structural characterization of substituted phenols with a m-terphenyl backbone 2,4,6-R3C6H2OH (R=2,4,6-Me3C6H2, Me5C6)

2015 ◽  
Vol 70 (1) ◽  
pp. 77-81 ◽  
Author(s):  
Atena B. Şolea ◽  
Marian Olaru ◽  
Cristian Silvestru ◽  
Ciprian I. Raţ
Keyword(s):  
Grignard Reagent ◽  
Cross Coupling ◽  
Molecular Structures ◽  
Coupling Reactions ◽  
X Ray Diffraction ◽  
Substituted Phenols ◽  
X Ray ◽  
Cross Coupling Reactions ◽  
C Nmr

AbstractSubstituted phenols with a m-terphenyl backbone 2,4,6-R3C6H2OH [R=2,4,6-Me3C6H2 (1), Me5C6 (2)] were synthesized using Kumada cross-coupling reactions between 2,4,6-I3C6H2OH and the corresponding Grignard reagent. Both compounds were structurally characterized in solution by 1H and 13C NMR spectroscopy and HRMS. The molecular structures of 1 and 2 were determined by single-crystal X-ray diffraction.

Pd-catalyzed synthesis of C-C (Sonogashira, Suzuki, Heck, Stille), C-P and C-S linked products using gem -dibromovinyl BODIPY

2021 ◽  
pp. A-O
Author(s):  
Hasrat Ali ◽  
Brigitte Guérin ◽  
Johan E. van Lier
Keyword(s):  
Absorption Maximum ◽  
Palladium Catalysis ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Cross Coupling Reactions ◽  
Derivatives Of ◽  
C Nmr

The chemistry of gem-dibromovinyl derivatives has undergone a renaissance through the application of palladium catalysis and has been applied to pyrrole substituted gem-dibromovinyl BODIPY. gem-Dibromovinyl BODIPYs (substituted at either the [Formula: see text]-position of 8-phenyl or the [Formula: see text]-position of the pyrrole rings) were studied for cross-coupling reactions using Sonogashira, Suzuki, Heck and Stille conditions, and with phosphonates and thiols. The assigned structures were supported by MS and 1H NMR, [Formula: see text]C NMR, X-ray diffraction analysis as well as optical spectroscopy. The conjugates were investigated for their absorption, fluorescence and solvatochromic properties in different solvents. Substitution at the [Formula: see text]-position of 8-phenyl derivatives of gem-diethynyl BODIPYs did not induce any shift in the absorption maximum, while the [Formula: see text]-position pyrrole substituted derivatives showed a red shift. Aromatic compounds gave larger red shifts as compared to the aliphatic substituted analogs.

scholarly journals Synthesis and X-ray Diffraction Study of thiosemicarbazone Palladacycles with dppm

Proceedings ◽  
2021 ◽  
Vol 62 (1) ◽  
pp. 13
Author(s):  
Marcos Rúa-Sueiro ◽  
Paula Munin-Cruz ◽  
Francisco Reigosa ◽  
José M. Vila ◽  
Juan M. Ortigueira
Keyword(s):  
Nmr Spectroscopy ◽  
31P Nmr ◽  
Antimicrobial Agents ◽  
Cross Coupling ◽  
31P Nmr Spectroscopy ◽  
Coupling Reactions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cross Coupling Reactions ◽  
Platinum Salt

Cyclometallated compounds have been extensively studied, in particular those with palladium and platinum. This is because of their possible applications in medicinal chemistry, as anticancer or antimicrobial agents; in some cases, with similar results as cisplatin, carboplatin or oxaliplatin. What is also remarkable is their use as homogeneous catalysts, for example, in cross coupling reactions such as Suzuki–Miyaura or Mizoroki–Heck. Herein, we report the synthesis of different thiosemicarbazone ligands, which will be reacted with a palladium or platinum salt, to give the corresponding cyclometallated compounds; in addition, their reactivity with bis(diphenylphosphino)methane (dppm) will be studied. Characterization has been carried out by elemental analysis, IR spectroscopy, 1H and 31P NMR spectroscopy. Additionally, 1c has been studied by X-ray diffraction.

scholarly journals Double N-arylation reaction of polyhalogenated 4,4’-bipyridines. Expedious synthesis of functionalized 2,7-diazacarbazoles

2012 ◽  
Vol 8 ◽  
pp. 253-258 ◽  
Author(s):  
Mohamed Abboud ◽  
Emmanuel Aubert ◽  
Victor Mamane
Keyword(s):  
Cross Coupling ◽  
Catalyst System ◽  
Coupling Reactions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cross Coupling Reactions ◽  
Π Stacking ◽  
Phenyl Rings ◽  
One Step ◽  
Site Selective

Unusual 2,7-diazacarbazoles were prepared in one step from readily available tetra-halogenated 4,4’-bipyridines by using a double N-arylation reaction in the presence of the Pd–XPhos catalyst system. Moderate to good yields were obtained in this site-selective Buchwald–Hartwig double amination. The functionalization of these tricyclic derivatives was performed by using Pd-catalyzed cross-coupling reactions such as the Stille and Suzuki couplings. Two compounds were analyzed by X-ray diffraction and show π–π stacking involving the diazacarbazole moieties and the phenyl rings of functionalized groups.

scholarly journals Toward the synthesis of thiadiazole-based therapeutic agents: synthesis, spectroscopic study, X-ray analysis, and cross-coupling reactions of the key intermediate 3,5-diiodo-1,2,4-thiadiazole

2019 ◽  
Vol 46 (2) ◽  
pp. 1507-1519
Author(s):  
Mohammed Boulhaoua ◽  
Ana Torvisco ◽  
Tibor Pasinszki
Keyword(s):  
Solid Phase ◽  
Cross Coupling ◽  
Therapeutic Agents ◽  
Biologically Active ◽  
Coupling Reactions ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
X Ray ◽  
Cross Coupling Reactions ◽  
First Time

AbstractThe 1,2,4-thiadiazole moiety is an important component of several biologically active compounds, and varying substituents on this aromatic ring is one of the possible methods to develop novel thiadiazole-based drugs for medicine. A key building block to this end, namely 3,5-diiodo-1,2,4-thiadiazole (1), has been synthesized and characterized in this work for the first time. 1 has exhibited high selectivity for the replacement of iodine atom at position C5 (carbon next to sulfur) in Sonogashira-type cross-coupling reactions with phenylacetylene. Therefore, 3-iodo-5-(phenylethynyl)-1,2,4-thiadiazole (4) or 3,5-bis(phenylethynyl)-1,2,4-thiadiazole (5) could be synthesized selectively depending on reaction conditions. All three novel molecules have been characterized by NMR, IR, Raman, mass, and UV spectroscopies, and their solid phase structures have been determined by single-crystal X-ray diffraction. 1 is expected to be a key starting material for producing thiadiazole-based therapeutic agents using cross-coupling reactions.

Functionalized Pyrazoles as Agents in C–C Cross-Coupling Reactions

2014 ◽  
Vol 69 (1) ◽  
pp. 83-97 ◽  
Author(s):  
Marijana Pejic ◽  
Sebastian Popp ◽  
Michael Bolte ◽  
Matthias Wagner ◽  
Hans-Wolfram Lerner
Keyword(s):  
Cross Coupling ◽  
Boronic Acids ◽  
Aryl Halides ◽  
Second Step ◽  
Coupling Reactions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Suzuki Reactions ◽  
Microwave Assisted ◽  
Cross Coupling Reactions

The 1-tetrahydropyranyl-(THP-)protected pyrazoles 4-R-pz(THP) (R=pinacolatoboryl=Bpin (3a(THP)), Me3Si (4a(THP)), Me3Sn (5a(THP)), and 4-R-3,5-Ph2pz (R=Bpin (3b(THP)), Me3Si (4b(THP)), Me3Sn (5b(THP)) were obtained by the following syntheses: i) In a first step, 4-X-pz (X=Br (1a), I (2a)) and 4-X-3,5-Ph2pz (X=Br (1b), I (2b)) were reacted with 3,4-dihydro-2Hpyran (DHP) to give the related THP-protected bromo- or iodopyrazole derivatives. ii) In a second step these THP derivatives were metalated by treatment with nBuLi or iPrMgCl. Subsequent reactions of the THP-protected metallopyrazoles 4-M-pz(THP) and 4-M-3,5-Ph2pz(THP) (M=Li, MgBr) with Bpin(OiPr), Me3SiCl, and Me3SnCl yielded the pyrazole derivatives 3a(THP), 3b(THP), 4a(THP), 4b(THP), 5a(THP), and 5b(THP). In contrast to the stannylated pyrazoles 5a(THP) and 5b(THP), the corresponding borylated and silylated derivatives could be easily deprotected: treatment of 3a(THP), 3b(THP), and 4a(THP) with HCl yielded the parent pyrazoles 3a, 3b and 4a. The microwave-assisted C-C cross-coupling reactions of these pyrazoles with aryl halides were examined, e. g. Suzuki reactions of 3a with p-pentylphenylbromide, p-hexylphenylbromide, and p- (2-ethylhexyl)phenylbromide. Similar reactions were also performed with 1a, 1b, 2a, and 2b and aryl-substituted pinacolatoboranes or boronic acids. Crystals of 5b(THP) suitable for X-ray diffraction were grown (monoclinic P21/c) and their structure determined. The crystal structures of 1a·HBr (monoclinic P21/n), 1b (triclinic P̄1̄), (1c)2·HBr (monoclinic P2/c), 1c·HBr·(Br2)0.5 (triclinic P̄1̄), (2a)3·H2SO4 (triclinic P̄1̄), 3a (orthorhombic P212121), (3a)3·H2O (trigonal R3c), 3b (orthorhombic Pna21), and 4a (monoclinic Pc) reveal interesting hydrogen bonding networks.

Hidden superlattice in Tl2(SC6H4S) and Tl2(SeC6H4Se) solved from powder X-ray diffraction

2011 ◽  
Vol 67 (5) ◽  
pp. 409-415 ◽  
Author(s):  
Kevin H. Stone ◽  
Dayna L. Turner ◽  
Mayank Pratap Singh ◽  
Thomas P. Vaid ◽  
Peter W. Stephens
Keyword(s):  
Additional Data ◽  
Sulfur Compound ◽  
Closed Shell ◽  
Initial Structure ◽  
X Ray Diffraction ◽  
Rietveld Refinements ◽  
X Ray ◽  
Additional Data Collection ◽  
Superlattice Structures ◽  
Counting Statistics

The crystal structures of the isostructural title compounds poly[(μ-benzene-1,4-dithiolato)dithallium], Tl2(SC6H4S), and poly[(μ-benzene-1,4-diselenolato)dithallium], Tl2(SeC6H4Se), were solved by simulated annealing from high-resolution synchrotron X-ray powder diffraction. Rietveld refinements of an initial structure with one formula unit per triclinic cell gave satisfactory agreement with the data, but led to a structure with impossibly close non-bonded contacts. A disordered model was proposed to alleviate this problem, but an alternative supercell structure leads to slightly improved agreement with the data. The isostructural superlattice structures were confirmed for both compounds through additional data collection, with substantially better counting statistics, which revealed the presence of very weak superlattice peaks not previously seen. Overall, each structure contains Tl—S or Tl—Se two-dimensional networks, connected by phenylene bridges. The sulfur (or selenium) coordination sphere around each thallium is a highly distorted square pyramid or a `see-saw' shape, depending upon how many Tl—S or Tl—Se interactions are considered to be bonds. In addition, the two compounds contain pairs of TlI ions that interact through a closed-shell `thallophilic' interaction: in the sulfur compound there are two inequivalent pairs of Tl atoms with Tl—Tl distances of 3.49 and 3.58 Å, while in the selenium compound those Tl—Tl interactions are at 3.54 and 3.63 Å.

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