Chalcogen Derivatives Research Articles

Converging optical and electrochemical detection strategies for multimodal hydrazine sensing: insights into substituent-driven diverse response.

A pair of pyrene-based chalcogen derivatives have been developed, which demonstrate multimodal ratiometric response towards hydrazine. Although these probes share a common pyrene core and differ primarily in the electronic nature of their terminal side arms, they display distinct photophysical properties. Notably, both probes undergo significant spectral changes upon the addition of hydrazine, but probe 1 exhibits a more pronounced interaction (∼5-fold fluorescence enhancement) than probe 2, attributed to the higher level of aggregation in probe 2, rendering the binding site less accessible to the incoming analyte. Additionally, we have explored electrochemical techniques, including cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), for hydrazine detection. Our molecular design strategy relies on ratiometric-responsive specific cyclization triggered by hydrazine, leading to the disruption of the π-conjugated system and the subsequent suppression of intramolecular charge transfer (ICT) processes, along with dis-assembly of the aggregated probe molecules. These probes enable the nakеd-eye detection of hydrazine, with a low detection limit of 7.33 ppb and 7.58 ppb for probe 1 and 2, respectively. Furthermore, we have investigated cost-effective probe-coatеd paper strips for the detection of hydrazine in water.

Moving on from Silicon to the Heavier Tetrels: Germyl- and Stannyl-Substituted Phosphole Derivatives

Germyl- and stannyl-substituted phospholes have been prepared and isolated. The increased reactivity of the tetrel carbon bond requires increased effort in purification by initial transformation to the chalcogen derivatives and subsequent reduction to the phosphole after subsequent to chromatographic purification for the germanium derivative. The photophysical properties of the germyl phosphole are comparable to that of its silyl analogue, whereas the stannyl phospholes turned out to be nonluminescent. All isolated compounds have been characterized by NMR spectroscopy, mass spectrometry, and elemental analysis. Furthermore, single-crystal X-ray diffraction and density functional theory (DFT) calculations have been performed on selected compounds.

Toxicological evaluation of zidovudine and novel chalcogen derivatives in Drosophila melanogaster.

Zidovudine (AZT) is the most commonly prescribed antiviral drug for the treatment of human immunodeficiency virus (HIV) infection. However, its chronic administration causes toxic side effects limiting its use. This study aimed to evaluate the toxicity of different concentrations of AZT and novel chalcogen derivatives (7A, 7D, 7G, 7K, 7M) on locomotion, mitochondrial dysfunction, acetylcholinesterase (AChE) activity, and production of reactive oxygen species (ROS) in adult Drosophila melanogaster. Our results show that AZT and its derivative 7K at a concentration of 10 μM impaired flies'locomotor behavior. Furthermore, AZT and the derivatives 7K, 7A, and 7M induced mitochondrial dysfunction observed by a decrease in oxygen flux through mitochondrial complexes I and II. Neither of the compounds tested affected AChE activity or ROS production in flies. According to these data, AZT derivatives presented the following decreasing order of toxicity: 7K > AZT > 7G > 7A > 7M > 7D. Based on the chemical structure, it is possible to infer that the presence of the seleno-phenyl group in 7A and 7G increases their toxicity compared to compounds 7D and 7M. In addition, compounds 7G, 7M, and 7K with three carbon atoms as spacer were more toxic than analogs containing one carbon atom (7A and 7D). Finally, the insertion of a p-methoxyl group enhances toxicity (7K). Based on these results, excepting 7K, all other chalcogen derivatives presented lower toxicity than AZT and are potential drug candidates.

Direct Deprotonative Functionalization of α,α-Difluoromethyl Ketones using a Catalytic Organosuperbase.

The deprotonative functionalization of α,α-difluoromethyl ketones is described herein. Using a catalytic organosuperbase and a silane additive, the corresponding difluoroenolate could be generated and trapped with aldehydes to deliver various α,α-difluoro-β-hydroxy ketones in high yields. This new strategy tolerates numerous functional groups and represents the access to the difluoroenolate by direct deprotonation of the difluoromethyl unit. The diastereoselective version of the reaction was also investigated with d.r. up to 93 : 7. Several transformations were performed to demonstrate the synthetic potential of these α,α-difluoro-β-hydroxy ketones. In addition, this method has been extended to the use of other electrophiles such as imines and chalcogen derivatives, and a difluoromethyl sulfoxide as nucleophile, thus leading to a diversity of difluoromethylene compounds.

Direct Deprotonative Functionalization of α,α‐Difluoromethyl Ketones using a Catalytic Organosuperbase

AbstractThe deprotonative functionalization of α,α‐difluoromethyl ketones is described herein. Using a catalytic organosuperbase and a silane additive, the corresponding difluoroenolate could be generated and trapped with aldehydes to deliver various α,α‐difluoro‐β‐hydroxy ketones in high yields. This new strategy tolerates numerous functional groups and represents the access to the difluoroenolate by direct deprotonation of the difluoromethyl unit. The diastereoselective version of the reaction was also investigated with d.r. up to 93 : 7. Several transformations were performed to demonstrate the synthetic potential of these α,α‐difluoro‐β‐hydroxy ketones. In addition, this method has been extended to the use of other electrophiles such as imines and chalcogen derivatives, and a difluoromethyl sulfoxide as nucleophile, thus leading to a diversity of difluoromethylene compounds.

Simple Synthesis of 1,3‐Dialkylimidazole‐2‐chalcogenones (E=S, Se, Te) from NHC−CO2 Adducts

AbstractWe present a high yield synthesis of 1‐ethyl‐3‐methyl‐imidazole‐2‐chalcogenones from readily available imidazolium‐2‐carboxylate zwitterions NHC−CO2 and elemental chalcogens. In sharp contrast to previous syntheses for corresponding thiones and selones from imidazolium salts and bases our reactions proceed fast with full instead of low conversion and selectivity, decarboxylation is the driving force. Furthermore, this strategy is applicable to all heavier chalcogens including tellurium. Vacuum sublimation of imidazole‐2‐chalcogenones is implemented as convenient method of purification leading to solid instead of liquid products reported in literature. Newly prepared 1‐ethyl‐3‐methyl‐imidazole‐2‐tellone was characterized by XRD analysis and a correlation study of 125Te NMR and 13C NMR shifts with respect to known representatives. The reaction of NHC−CO2 with TMS2S leads to NHC−COS, characterized by XRD analysis, whereas heavier chalcogen derivatives TMS2E (E=Se, Te) did not react with NHC activated CO2.

Recent advances in the synthesis of diazaporphyrins and their chalcogen derivatives.

Porphyrins are highly influential functional materials in the field of science owing to their fascinating colors and diverse electrochemical and optical properties. Peripheral modification of porphyrin rings with nitrogen is an attractive approach for imparting unprecedented functions to both natural and artificial pophyrins. Diazaporphyrins (DAPs) are a class of compounds that have two meso-nitrogen atoms. DAPs exhibit characteristic redox and optical properties that differ significantly from those of porphyrins. The preparation and chemical functionalization of DAP-based sensitizers, catalysts, and materials have gained significant attention in various fields such as medical science, organic synthesis, and materials chemistry. This review focuses on recent advances in the synthesis of diazaporphyrins and their chalcogen derivatives, including historically important examples.

Structures of the Most Twisted Thioamide and Selenoamide: Effect of Higher Chalcogens of Twisted Amides on N-C(X) Resonance.

Amide bond replacement with planar isosteric chalcogen analogues has an important implication for the properties of the N-C(X) linkage in structural chemistry, biochemistry and organic synthesis. Herein, we report the first higher chalcogen derivatives of non-planar twisted amides. The synthesis of twisted thioamide in a versatile system has been accomplished by direct thionation without cleavage of the σ N-C bond. The synthesis of twisted selenoamide has been accomplished by selenation with Woollins' reagent. The structures of higher chalcogen analogues of non-planar amides were unambiguously confirmed by X-ray crystallography. Reactivity studies were conducted to determine the effect of isologous N-C(O) to N-C(X) replacement on the properties of the amide linkage. Computational studies were employed to evaluate structural and energetic parameters of amide bond alteration in higher chalcogen amides. The study provides the first experimental evidence on the effect of chalcogen isologues on the structural and electronic properties of the non-planar amide N-C(X) linkage.

Structures of the Most Twisted Thioamide and Selenoamide: Effect of Higher Chalcogens of Twisted Amides on N−C(X) Resonance

AbstractAmide bond replacement with planar isosteric chalcogen analogues has an important implication for the properties of the N−C(X) linkage in structural chemistry, biochemistry and organic synthesis. Herein, we report the first higher chalcogen derivatives of non‐planar twisted amides. The synthesis of twisted thioamide in a versatile system has been accomplished by direct thionation without cleavage of the σ N−C bond. The synthesis of twisted selenoamide has been accomplished by selenation with Woollins’ reagent. The structures of higher chalcogen analogues of non‐planar amides were unambiguously confirmed by X‐ray crystallography. Reactivity studies were conducted to determine the effect of isologous N−C(O) to N−C(X) replacement on the properties of the amide linkage. Computational studies were employed to evaluate structural and energetic parameters of amide bond alteration in higher chalcogen amides. The study provides the first experimental evidence on the effect of chalcogen isologues on the structural and electronic properties of the non‐planar amide N−C(X) linkage.

Synthesis of benzo[b]chalcogenophenes fused to selenophenes via intramolecular electrophilic cyclization of 1,3-diynes.

We describe herein an alternative and transition-metal-free procedure for the access of benzo[b]chalcogenophenes fused to selenophenes via intramolecular cyclization of 1,3-diynes. This efficient protocol involves a double cyclization of 1,3-diynyl chalcogen derivatives promoted by the electrophilic species of organoselenium generated in situ by the oxidative cleavage of the Se-Se bond of dibutyl diselenide using Oxone® in acetonitrile as solvent in an open-flask at 80 °C. In this study, 15 selenophenes with broad substrate scope were prepared in moderate to excellent yields (55-98%) with short reaction times (0.5-3.0 h).

Corannulene Chalcogenides.

The introduction of chalcogen atoms into a polycyclic aromatic hydrocarbon structure is an established method to tune material properties. In the context of corannulene (C20 H10 ), a fragment of fullerene C60 , such structural adjustments have given rise to an emerging class of functional and responsive molecular materials. In this minireview, our aim is to discuss the synthesis and properties of such chalcogen (sulfur, selenium, and tellurium) derivatives of corannulene.

Activating Chalcogen Bonding (ChB) in Alkylseleno/Alkyltelluroacetylenes toward Chalcogen Bonding Directionality Control.

Activation of a deep electron-deficient area on chalcogen atoms (Ch=Se, Te) is demonstrated in alkynyl chalcogen derivatives, in the prolongation of the (C≡)C-Ch bond. The solid-state structures of 1,4-bis(methylselenoethynyl)perfluorobenzene (1Se) show the formation of recurrent chalcogen-bonded (ChB) motifs. Association of 1Se and the tellurium analogue 1Te with 4,4'-bipyridine and with the stronger Lewis base 1,4-di(4-pyridyl)piperazine gives 1:1 co-crystals with 1D extended structures linked by short and directional ChB interactions, comparable to those observed with the corresponding halogen bond (XB) donor, 1,4-bis(iodoethynyl)-perfluorobenzene. This "alkynyl" approach for chalcogen activation provides the crystal-engineering community with efficient, and neutral ChB donors for the elaboration of supramolecular 1D (and potentially 2D or 3D) architectures, with a degree of strength and predictability comparable to that of halogen bonding in iodoacetylene derivatives.

Activating Chalcogen Bonding (ChB) in Alkylseleno/Alkyltelluroacetylenes toward Chalcogen Bonding Directionality Control

AbstractActivation of a deep electron‐deficient area on chalcogen atoms (Ch=Se, Te) is demonstrated in alkynyl chalcogen derivatives, in the prolongation of the (C≡)C−Ch bond. The solid‐state structures of 1,4‐bis(methylselenoethynyl)perfluorobenzene (1Se) show the formation of recurrent chalcogen‐bonded (ChB) motifs. Association of 1Se and the tellurium analogue 1Te with 4,4′‐bipyridine and with the stronger Lewis base 1,4‐di(4‐pyridyl)piperazine gives 1:1 co‐crystals with 1D extended structures linked by short and directional ChB interactions, comparable to those observed with the corresponding halogen bond (XB) donor, 1,4‐bis(iodoethynyl)‐perfluorobenzene. This “alkynyl” approach for chalcogen activation provides the crystal‐engineering community with efficient, and neutral ChB donors for the elaboration of supramolecular 1D (and potentially 2D or 3D) architectures, with a degree of strength and predictability comparable to that of halogen bonding in iodoacetylene derivatives.

A physiological examination of the antioxidant ability of super tocopherol derivatives

A quantum-chemical study on some super tocopherol derivatives and their heavier chalcogen derivatives has been undertaken to evaluate the antioxidant abilities through different mechanistic pathways. The effect of different solvent media, including the lipid environment, on their antioxidant ability has also been explored. This study reveals that the incorporation of heavier chalcogen not only increases the antioxidant abilities of the super tocopherol derivatives but also makes them physiologically more active. The heavier analogs can scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical through H-atom transfer. The stability of the antioxidant free radicals is due to the presence of non-covalent chalcogen–chalcogen interactions, which increase with the incorporation of heavier chalcogen atoms into the super tocopherol derivatives.

The Synthesis and Investigation of Liquid-Liquid Extraction Capability of N-Diphenylphosphino-N-ethylaniline and Its Chalcogenide Derivatives

The aminophosphine ligand was synthesized by the reaction of N-ethylaniline with chlorodiphenylphosphine in the presence of triethylamine at low temperature. Oxidation of the ligand with elemental sulfur or selenium afforded the corresponding aminophosphine sulfide and selenide. The compounds were characterized by elemental analyses, IR, 1H and 31P NMR. N-diphenylphosphino-N-ethylaniline and its chalcogen derivatives were used as ligands in solvent extraction of metal picrates such as Cd2+ and Ni2+ from the aqueous to the organic phase. Influences of parameters such as pH of the aqueous phase, solvent, extraction time, and extradant concentration were investigated to determine the extraction ability of ligands for metal ions. Results of the experiments showed that an extractability of 95.5 and 97.8%, respectively for Ni2+, and Cd2+ at pH 2 could be achieved.

Development of a methodology for reversible chemical modification of silicon surfaces with application in nanomechanical biosensors

Hypervalent tellurium compounds have a particular reactivity towards thiol compounds which are related to their biological properties. In this work, this property was assembled to tellurium-functionalized surfaces. These compounds were used as linkers in the immobilization process of thiolated biomolecules (such as DNA) on microcantilever surfaces. The telluride derivatives acted as reversible binding agents due to their redox properties, providing the regeneration of microcantilever surfaces and allowing their reuse for further biomolecules immobilizations, recycling the functional surface. Initially, we started from the synthesis of 4-((3-((4-methoxyphenyl) tellanyl) phenyl) amino)-4-oxobutanoic acid, a new compound, which was immobilized on a silicon surface. In nanomechanical systems, the detection involved a hybridization study of thiolated DNA sequences. Fluorescence microscopy technique was used to confirm the immobilization and removal of the telluride-DNA system and provided revealing results about the potentiality of applying redox properties to chalcogen derivatives at surfaces.

Studies on diverse chemical species derived from chalcogen atoms ~ The Footprint of Professor Naomichi Furukawa in Heteroatom Chemistry ~

AbstractThis account summarizes representative contributions of Prof. Naomichi Furukawa to the field of heteroatom chemistry. Ligand‐coupling reactions (LCRs) and ligand‐exchange reactions (LERs) of chalcogen derivatives were developed from reactions of trivalent chalcogen species with organometallic reagents. Prof. Furukawa has also reported a large number of mono‐ and dicationic compounds generated via transannular and intermolecular interactions. Furthermore, the detection and isolation of hypercoordinated chalcogen species bearing only carbon ligands and an efficient method for the synthesis of thiophene S‐oxides and their reactivity are described.

Synthesis and Applications of 5‐Membered Chalcogen‐Nitrogen π‐Heterocycles with Three Heteroatoms

AbstractThe recent progress in the synthesis of the title heterocycles exemplified by closed‐ and open‐shell 1,2,5‐chalcogenadiazoles, 1,2,3‐dichalcogenazoles and their hybrids (chalcogens: S, Se, and Te), and in actual or potential applications of these compounds in materials science and biomedicine, is discussed. The synthetic importance of the chalcogen exchange, both direct and indirect, is emphasized, as well as the significance of the heavier chalcogen derivatives in the design and synthesis of smart molecular materials.

Thermodynamics of Anion Binding by Chalcogen Bonding Receptors.

The application of chalcogen bonding (ChB) to anion recognition is an underdeveloped area of host-guest supramolecular chemistry. The chemical instability of heavier chalcogen derivatives may in part be responsible for the lack of progress. Herein, the synthesis of a new structurally simple, tellurium-based ChB binding motif is reported, the robust stability of which has enabled the thermodynamic properties for ChB halide anion binding in polar aprotic and wet protic organic solvent media to be elucidated. The thermodynamic data reveals how the subtle interplay between ChB host, anion guest and solvent dictates halide binding selectivity and affinity trends. These findings help to provide a deeper insight into the nature of the ChB-anion interaction.

Reactivity of LGe–NR2 and LGe(E)–NR2 over LGe–Cl and LGe(E)–Cl toward Me3SiX (L = Aminotroponiminate; NR2 = N(SiMe3)2/NC4H4; E = S/Se; X = Br/CN)

The halogen exchange reaction of either germylene monochloride [LGeCl] (1) or germachalcogenoacid chlorides [LGe(E)Cl] (L = (i-Bu)2ATI; ATI = aminotroponiminate; E = S (V)/Se (VI)) with Me3SiX (X = Br/CN) did not occur. Therefore, the reactions of germanium compounds containing Ge–N bonds with Me3SiBr/CN were tried. Germylene amide [LGeN(SiMe3)2] (2) reacted with Me3SiBr to afford the aminotroponiminatogermylene monobromide [LGeBr] (3). Similarly, the chalcogen derivatives of compound 2, viz., germachalcogenoamides [LGe(E)N(SiMe3)2] (E = S 4 and Se 5) reacted with Me3SiBr and resulted in germachalcogenoacid bromides [LGe(E)Br] (E = S 6 and Se 7), respectively. N-Germylene pyrrole [LGeNC4H4] (2a) and N-germachalcogenoacylpyrroles [LGe(E)NC4H4] (E = S 4a, Se 5a) also reacted with Me3SiBr and afforded compounds 3, and 6−7 in excellent yields, respectively. Interestingly, the reaction of compound 2a with Me3SiCN afforded germanium(II) cyanide [LGeCN] (8). The difference in the reactivity of compounds (1, V, and VI) with Ge–Cl bonds against the compounds (2, 4, and 5) with Ge–N bonds was analyzed theoretically.