Two‐Dimensional Core‐Shelled Porous Hybrids as Highly Efficient Catalysts for the Oxygen Reduction Reaction

Two‐dimensional (2D) transition‐metal dichalcogenides (TMDs) have drawn much attention due to their unique physical and chemical properties. Using TMDs as templates for the generation of 2D sandwich‐like materials with remarkable properties still remains a great challenge due to their poor solvent processability. Herein, MoS₂‐coupled sandwich‐like conjugated microporous polymers (M‐CMPs) with high specific surface area were successfully developed by using functionalized MoS₂ nanosheets as template. As‐prepared M‐CMPs were further used as precursors for preparation of MoS₂‐embedded nitrogen‐doped porous carbon nanosheets, which were revealed as novel electrocatalysts for oxygen reduction reaction with mainly four‐electron transfer mechanism and ultralow half‐wave potential in comparison with commercial Pt/C catalyst. Our strategy to core–shelled sandwich‐like hybrids paves a way for a new class of 2D hybrids for energy conversion and storage.     

Functionalization of Two‐Dimensional MoS2: On the Reaction Between MoS2 and Organic Thiols

Two‐dimensional layered transition metal dichalcogenides (TMDs) have attracted great interest owing to their unique properties and a wide array of potential applications. However, due to their inert nature, pristine TMDs are very challenging to functionalize. We demonstrate a general route to functionalize exfoliated 2H‐MoS₂ with cysteine. Critically, MoS₂ was found to be facilitating the oxidation of the thiol cysteine to the disulfide cystine during functionalization. The resulting cystine was physisorbed on MoS₂ rather than coordinated as a thiol (cysteine) filling S‐vacancies in the 2H‐MoS₂ surface, as originally conceived. These observations were found to be true for other organic thiols and indeed other TMDs. Our findings suggest that functionalization of two‐dimensional MoS₂ using organic thiols may not yield covalently or datively tethered functionalities, rather, in this instance, they yield physisorbed disulfides that are easily removed.     

Engineering Chemically Exfoliated Large‐Area Two‐Dimensional MoS2 Nanolayers with Porphyrins for Improved Light Harvesting

Molybdenum disulfide (MoS₂) is a promising candidate for electronic and optoelectronic applications. However, its application in light harvesting has been limited in part due to crystal defects, often related to small crystallite sizes, which diminish charge separation and transfer. Here we demonstrate a surface‐engineering strategy for 2D MoS₂ to improve its photoelectrochemical properties. Chemically exfoliated large‐area MoS₂ thin films were interfaced with eight molecules from three porphyrin families: zinc(II)‐, gallium(III)‐, iron(III)‐centered, and metal‐free protoporphyrin IX (ZnPP, GaPP, FePP, H₂PP); metal‐free and zinc(II) tetra‐(N‐methyl‐4‐pyridyl)porphyrin (H₂T4, ZnT4); and metal‐free and zinc(II) tetraphenylporphyrin (H₂TPP, ZnTPP). We found that the photocurrents from MoS₂ films under visible‐light illumination are strongly dependent on the interfacial molecules and that the photocurrent enhancement is closely correlated with the highest occupied molecular orbital (HOMO) levels of the porphyrins, which suppress the recombination of electron–hole pairs in the photoexcited MoS₂ films. A maximum tenfold increase was observed for MoS₂ functionalized with ZnPP compared with pristine MoS₂ films, whereas ZnT4‐functionalized MoS₂ demonstrated small increases in photocurrent. The application of bias voltage on MoS₂ films can further promote photocurrent enhancements and control current directions. Our results suggest a facile route to render 2D MoS₂ films useful for potential high‐performance light‐harvesting applications.     

Preparation,Structural Characterization,and Antifungal Activities of Complexes of Group 12 Metals with 2‐Acetylpyridine‐ and 2‐Acetylpyridine‐N‐oxide‐4N‐phenylthiosemicarbazones

Reaction of group 12 metal dihalides in ethanolic media with 2‐acetylpyridine ⁴N‐phenylthiosemicarbazone ( H4PL ) and 2‐acetylpyridine‐N‐oxide ⁴N‐phenylthiosemicarbazone ( H4PLO ) afforded the compounds [M(H4PL)X₂] (X = Cl, Br, M = Zn, Cd, Hg; X = I, M = Zn, Cd) ( 1–8 ), [Hg(4PL)I]₂ ( 9 ) and [M(H4PLO)X₂] (X = Cl, Br, I, M = Zn, Cd, Hg) ( 10–18 ). H4PL , H4PLO and their complexes were characterized by elemental analysis and by IR and ¹H and ¹³C NMR spectroscopy (and the cadmium complexes by ¹¹³Cd NMR spectroscopy), and H4PL , H4PLO , ( 5 · DMSO) and ( 9 ) were additionally studied by X‐ray diffraction. H4PL is N,N,S‐tridentate in all its complexes, including 9 , in which it is deprotonated, and H4PLO is in all cases O,N,S‐tridentate. In all the complexes, the metal atoms are pentacoordinate and the coordination polyhedra are redistorted tetragonal pyramids. In assays of antifungal activity against Aspergillus niger and Paecilomyces variotii, the only compound to show any activity was [Hg(H4PLO)I₂] ( 18 ).     

NaY Zeolite Functionalized by Sulfamic Acid/Cu(OAc)2 as a Novel and Reusable Heterogeneous Hybrid Catalyst in Efficient Synthesis of Bis,Tris, and Tetrakis(indolyl)methanes, 3,4‐Dihydropyrimidin‐2(1H)‐ones,and 2‐Aryl‐1H‐benzothiazoles

An efficient acid‐catalyzed synthesis of some bis, tris, and tetrakis(indolyl)methanes, 3,4‐dihydropyrimidin‐2(1H )‐ones, and 2‐aryl‐1H ‐benzothiazoles is reported using NaY zeolite functionalized by sulfamic acid/Cu(OAc )₂ (NaY zeolite‐NHSO₃H /Cu(OAc )₂) in excellent yield. The heterogeneous catalyst has a simple work‐up procedure and could be recycled and reused for six reaction cycles.     

Metal Derivatives of 1,3‐Imidazolidine‐2‐thione with Divalent d10 Metal Ions (Zn–Hg) : Synthesis and Structures

Reactions of divalent Zn‐Hg metal ions with 1,3‐imidazolidine‐2‐thione (imdtH₂) in 1 : 2 molar ratio have formed monomeric complexes, [Zn(η¹‐S‐imdtH₂)₂(OAc)₂] ( 1 ), [Cd((η¹‐SimdtH₂)₂I₂] ( 2 ), [Cd(η¹‐S‐imdtH₂)₂Br₂] ( 3 ), and [Hg(η¹‐S‐imdtH₂)₂I₂] ( 4 ). Complexes 1 – 4 , have been characterized by elemental analysis (C, H, N), spectroscopy (IR, ¹H, NMR) and x‐ray crystallography ( 1 ‐ 4 ). Hydrogen bonding between oxygen of acetate and imino hydrogen of ligand, {N(2)–H(2C)···O(2)^#} in 1 , ring CH and imino hydrogen, {C(2A)–H(2A)···Br(2)^#} in 3 have formed H‐bonded dimers. Similarly, the interactions between molecular units of complexes 2 and 4 have yielded 2D polymers. The polymerization occurs via intermolecular interactions between thione sulfur and imino hydrogen, {N(2)–H(2)···S(1)^#}, imino hydrogen and the iodine atom, {NH(1)···I(2)^#} in 2 and imino hydrogen – iodine atom {N(2A)–H(2A)···I(2)} and I···I interaction in 4 . Crystal data: [Zn(η¹‐S‐imdtH₂)₂(OAc)₂] ( 1 ), C₁₀H₁₈N₄O₄S₂Zn, orthorhombic, Pbcn, a = 9.3854(7) Å, b = 12.4647(10) Å, c = 13.2263(11) Å; V = 1547.3(2) ų, Z = 4, R = 0.0280 [Cd((η¹‐S‐imdtH₂)₂I₂] ( 2 ), C₆H₁₂CdI₂N₄S₂, orthorhombic, Pnma, a = 13.8487(10) Å, b = 14.4232(11) Å, c = 7.0659(5) Å; Z = 4, V = 1411.36(18) ų, R = 0.0186.     

2D/2D h‐BN/N‐doped MoS2 Heterostructure Catalyst with Enhanced Peroxidase‐like Performance for Visual Colorimetric Determination of H2O2

Recently, nanozymes have attracted extensive attention because of their advantages of combining nanomaterials with enzymes. Herein, hexagonal boron nitride (h‐BN) and nitride‐doped molybdenum disulfide (N?MoS₂) nano‐composites (h‐BN/N?MoS₂) were synthesized by facile and cost‐effective liquid exfoliation with a solvothermal method in nontoxic ethanol solution. The results show that h‐BN, as a co‐catalyst, can not only dope into the lattice of MoS₂ but also form a heterogeneous structure with MoS₂NSs. It expanded the layer spacing and specific surface area of MoS₂NSs, which was beneficial to the contact between the catalyst and the substrate, and resulted in a synergistic enhancement of the catalytic activity of hydrogen peroxide (H₂O₂) with MoS₂. A colorimetric determination platform of h‐BN/N?MoS₂‐TMB‐H₂O₂ was constructed. It exhibited a wide linear range of 1–1000 μM with a low limit of detection (LOD) of 0.4 μM under optimal conditions, high sensitivity and stability, as well as good reliability (99.4–110.0%) in practice, making the measurement system more widely applicable.1. Introduction     

Production and isolation of ligated metal(IV)‐oxo ions by tandem mass spectrometry

High valent metal(IV)‐oxo species, [M(?O)(MeIm)_n(OAc)]⁺ (M = Mn–Ni, MeIm = 1‐methylimidazole, n = 1–2), which are relevant to biology and oxidative catalysis, were produced and isolated in gas‐phase reactions of the metal(II) precursor ions [M(MeIm)_n(OAc)]⁺ (M = Mn–Zn, n = 1–3) with ozone. The precursor ions [M(MeIm)(OAc)]⁺ and [M(MeIm)₂(OAc)]⁺ were generated via collision‐induced dissociation of the corresponding [M(MeIm)₃(OAc)]⁺ ion. The dependence of ozone reactivity on metal and coordination number is discussed. Copyright © 2010 John Wiley & Sons, Ltd.     

Pd(OAc)2@SBA‐15/PrEn nanoreactor: a highly active,reusable and selective phosphine‐free catalyst for Suzuki–Miyaura cross‐coupling reaction in aqueous media

A series of ordered mesoporous organic–inorganic hybrid material was designed by using the amine‐functionalized SBA‐15 (PdX₂@SBA‐15/N_Y, Y = 1, 2) as solid support for palladium complexes. Among them, the Pd(OAc)₂/ethylenediamine complex encapsulated into SBA‐15 (Pd(OAc)₂@SBA‐15/PrEn or Pd(OAc)₂@SBA‐15/PrNHEtNH₂) exhibits higher activity and selectivity toward Suzuki cross‐coupling reaction under aerobic conditions and water solvent mixture. The SBA‐15/PrEn supported palladium pre‐catalyst could be separated easily from reaction products and used repetitively several times, showing its superiority over homogeneous catalysts for industrial and chemical applications. Copyright © 2013 John Wiley & Sons, Ltd.     

Cationic nitrile‐functionalized Ag(I)‐ and Hg(II)‐N‐heterocyclic carbene complexes of CCC,CNC, and NCN pincer‐type carbene ligands: Synthesis,crystal structures,and characterization

Three nitrile‐functionalized (benz)imid‐ zaolium derivatives with CCC, CNC, and NCN coordination pockets have been synthesized and isolated as the bromide salts and are converted into their hexafluorophosphate counterparts ( 5–7 ) by ligand metathesis. N‐heterocyclic carbene Ag(I)‐ and Hg(II)‐complexes ( 8–10 and 11–13 ) are readily formed in good to excellent yields from ligand precursors 5–7 and Ag₂O and Hg(OAc)₂, respectively. All reported compounds have been characterized by various spectral and analytical techniques, such as FTIR, ¹H, and ¹³C NMR spectroscopy and X‐ray diffraction studies. Solid‐state structures of carbene precursors 5 , 7 , and an Ag(I)–carbene complex 10 have been determined crystallographically. Single crystal X‐ray crystallography of complex 10 reveals the chelation of carbene carbons to metal center in almost a linear manner. © 2012 Wiley Periodicals, Inc. Heteroatom Chem 23:486–497, 2012; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.21041     

Highly Efficient,Green, and Scalable β‐Cyclodextrin‐Assisted Aqueous Exfoliation of Transition‐Metal Dichalcogenides: MoS2 and ReS2 Nanoflakes

The β‐cyclodextrin‐assisted aqueous‐exfoliation method was used to prepare transition‐metal dichalcogenide (TMD) nanosheets, in a cheap, highly efficient, scalable and environmentally friendly manner. As study cases, MoS₂ and ReS₂ nanoflakes were prepared according to this method. Particularly, the effective exfoliation of ReS₂ crystals in an aqueous environment was observed for the first time. Moreover, exfoliated nanomaterials can be readily utilized in hydrogen evolution reactions (HERs) as noble‐metal‐free catalysts. This work provides new opportunities for highly efficient exfoliation of TMDs and other 2D nanomaterials into few‐layer nanosheets in aqueous media. Their production process showed high biocompatibility, broad applicability and excellent sustainability.     

Palladium‐catalyzed Suzuki reaction using 1,3‐dialkylbenzimidazol‐2‐ylidene ligands in aqueous media

From readily available starting compounds, six functionalized 1,3‐dialkylbenzimidazolium salts ( 2a–c and 4a–c ) have been prepared and characterized by conventional spectroscopic methods and elemental analyses. A highly effective, easy to handle, and environmentally benign process for palladium‐mediated Suzuki cross‐coupling was developed. The in situ prepared three‐component systems Pd(OAc)₂/1,3‐dialkylbenzimidazolium chlorides and Cs₂CO₃ catalyze quantitatively the Suzuki cross‐coupling of deactivated aryl chlorides. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:419–423, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20034     

In-situ formation of 2H phase MoS2/cerium-zirconium oxide nanohybrid for potential electrochemical detection of an anticancer drug flutamide

The developing field of sensors is highly motivated and attracted by two-dimensional transition metal dichalcogenides (TMDs) with transition metal oxide integration. Initially, molybdenum disulfide (MoS₂), one among the TMDs with cerium-zirconium oxide (CZO), was one-pot synthesized via hydrothermal method for sensing flutamide (FLD). The as-synthesized hybrid nanocomposite was characterized to understand their physical and chemical presence. MoS₂-CZO was well assigned with crystalline nature observed from X-ray powder diffraction and X-ray photoelectron spectroscopy. High-resolution transmission electron microscopy confirms the irregularly arranged nanoparticles wrapped with MoS₂ sheets. The wide surface area with more electroactive sites has provided higher conductance of the MoS₂-CZO/glassy carbon electrode. The limit of detection was 0.005 μM with a linear range of 0.019 μM to 668.5 μM, sensitivity 0.353 μA μM?1 cm^?2. The practical feasibility was analyzed with human urine and river water samples, whereas the obtained results showed excellent FLD detection. The fabricated MoS₂-CZO with all these distinguished analyses will be an outbreak in the field of electrochemical sensors.     

Allylic Peroxidations with Bis(2‐pyridylimino)isoindolato‐Cobalt and ‐Iron Complexes

Several novel substituted bis(2‐pyridylimino)isoindolato (BPI) cobalt(II) and iron(II) complexes [M(BPI)(OAc)(H₂O)] (M = Co: 1 ‐ 6, Fe: 7) have been synthesized by reaction of bis(2‐pyridylimino)isoindole derivatives with the corresponding metal(II) acetates. Reaction of 1‐6 with 1.5 ‐ 2 molar equivalents of t‐BuOOH gave the corresponding alkylperoxocobalt(III) complexes [Co(BPI)(OAc)(OOtBu)] (10 ‐ 15). Using an aqueous solution of t‐BuOOH (70 %), cyclohexene was selectively catalytically oxidized to the dialkylperoxide cyclohex‐2‐ene‐1‐t‐butylperoxide.     

Orthopalladated complexes of phosphorus ylide: Poly(N‐vinyl‐2‐pyrrolidone)‐stabilized palladium nanoparticles as reusable heterogeneous catalyst for Suzuki and Heck cross‐coupling reactions

The phosphorus ylide [Ph₃PCHC(O)C₆H₄‐NO₂–4] reacted with Pd(OAc)₂ to give the C,C‐orthometallated complex [Pd{κ²(C,C)‐C₆H₄PPh₂C(H)CO(C₆H₄‐NO₂–4)}(μ‐OAc)]₂, which underwent bridge exchange reaction with NaN₃, NaCl, KBr and KI, respectively, to afford the binuclear C,C‐orthopalladated complexes [Pd{κ²(C,C)‐C₆H₄PPh₂C(H)CO(C₆H₄‐NO₂–4)}(μ‐X)]₂ (X = N₃ ( 1 ), Cl ( 2 ), Br ( 3 ) and I ( 4 )). The complexes were identified using spectroscopy (infrared and NMR), CHNS technique and single‐crystal X‐ray structure analysis. Thereafter, palladium nanoparticles with narrow size distribution were easily prepared using the refluxing reaction of iodo‐bridged orthopalladated complex 4 with poly(N ‐vinyl‐2‐pyrrolidone) (PVP) as the protecting group. The PVP‐stabilized palladium nanoparticles were characterized using a variety of techniques including X‐ray diffraction, transmission and scanning electron microscopies, energy‐dispersive X‐ray spectroscopy, inductively coupled plasma analysis and Fourier transform infrared spectroscopy. The catalytic activity of the PVP‐stabilized palladium nanoparticles was evaluated in the Suzuki reaction of phenylboronic acid and the Heck reaction of styrene with aryl halides of varying electron densities. This catalyst exhibited excellent catalytic activity for Suzuki cross‐coupling reactions in ethanol–water. Notably, aryl chlorides which are cheaper and more accessible than their bromide and iodide counterparts also reacted satisfactorily using this catalyst. After completion of reactions, the catalyst could be separated using a simple method and used many times in repeat cycles without considerable loss in its activity.     

Cytotoxicity of Exfoliated Transition‐Metal Dichalcogenides (MoS2, WS2, and WSe2) is Lower Than That of Graphene and its Analogues

Studies involving transition‐metal dichalcogenides (TMDs) have been around for many decades and in recent years, many were focused on using TMDs to synthesize inorganic analogues of carbon nanotubes, fullerene, as well as graphene and its derivatives with the ultimate aim of employing these materials into consumer products. In view of this rising trend, we investigated the cytotoxicity of three common exfoliated TMDs (exTMDs), namely MoS₂, WS₂, and WSe₂, and compared their toxicological effects with graphene oxides and halogenated graphenes to find out whether these inorganic analogues of graphenes and derivatives would show improved biocompatibility. Based on the cell viability assessments using methylthiazolyldiphenyl‐tetrazolium bromide (MTT) and water‐soluble tetrazolium salt (WST‐8) assays on human lung carcinoma epithelial cells (A549) following a 24 h exposure to varying concentrations of the three exTMDs, it was concluded that MoS₂ and WS₂ nanosheets induced very low cytotoxicity to A549 cells, even at high concentrations. On the other hand, WSe₂ exhibited dose‐dependent toxicological effects on A549 cells, reducing cell viability to 31.8 % at the maximum concentration of 400 μg mL^?1; the higher cytotoxicity displayed by WSe₂ might be linked to the identity of the chalcogen. In comparison with graphene oxides and halogenated graphenes, MoS₂ and WS₂ were much less hazardous, whereas WSe₂ showed similar degree of cytotoxicity. Future in‐depth studies should be built upon this first work on the in vitro cytotoxicity of MoS₂ and WS₂ to ensure that they do not pose acute toxicity. Lastly, nanomaterial‐induced interference control experiments revealed that exTMDs were capable of reacting with MTT assay viability markers in the absence of cells, but not with WST‐8 assay. This suggests that the MTT assay is not suitable for measuring the cytotoxicity of exTMDs because inflated results will be obtained, giving false impressions that the materials are less toxic.     

Covalent Modification of MoS2 with Poly(N‐vinylcarbazole) for Solid‐State Broadband Optical Limiters

New soluble MoS₂ nanosheets covalently functionalized with poly(N‐vinylcarbazole) (MoS₂–PVK) were in situ synthesized for the first time. In contrast to MoS₂ and MoS₂/PVK blends, both the solution of MoS₂–PVK in DMF and MoS₂–PVK/poly(methyl methacrylate) (PMMA) film show superior nonlinear optical and optical limiting responses. The MoS₂–PVK/PMMA film shows the largest nonlinear coefficients (β_eff) of about 917 cm GW^?1 at λ=532 nm (cf. 100.69 cm GW^?1 for MoS₂/PMMA and 125.12 cm GW^?1 for MoS₂/PVK/PMMA) and about 461 cm GW^?1 at λ=1064 nm (cf. ?48.92 cm GW^?1 for MoS₂/PMMA and 147.56 cm GW^?1 for MoS₂/PVK/PMMA). A larger optical limiting effect, with thresholds of about 0.3 GW cm^?2 at λ=532 nm and about 0.5 GW cm^?2 at λ=1064 nm, was also achieved from the MoS₂–PVK/PMMA film. These values are among the highest reported for MoS₂‐based nonlinear optical materials. These results show that covalent functionalization of MoS₂ with polymers is an effective way to improve nonlinear optical responses for efficient optical limiting devices.     

Synthesis and Structural Characterization of Metal Complexes of 2‐Formylpyrrole‐4N‐ethylthiosemicarbazone (4 EL1) and 2‐Acetylpyrrole‐4N‐ethylthiosemicarbazone (4 EL2)

The reactions of ⁴N‐ethyl‐2‐[1‐(pyrrol‐2‐yl)methylidene(hydrazine carbothioamide ( 4 EL₁ ) and ⁴N‐ethyl‐2[1‐(pyrrol‐2‐yl)ethylidene(hydrazine carbothioamide ( 4 EL₂ ) with Group 12 metal halides afforded complexes of types [M(L)₂X₂] (M = Zn, Cd; L = 4 EL₁, 4 EL₂; X = Cl, Br, I; 1 – 6 , 14 – 19 ) and [M(L)X₂] (M = Hg; L = 4 EL₁, 4 EL₂; X = Cl, Br, I; 7 – 9 , 20 – 22 ). In addition, reaction of 4 EL₁ with salts of Cu^II, Ni^II, Pd^II and Pt^II afforded compounds of type [M(4 EL₁–H)₂] ( 10 – 13 ). The new compounds were characterized by elemental analysis, FAB mass spectrometry, IR and electronic spectroscopy and, for sufficiently soluble compounds, ¹H, ¹³C and, when appropriate, ¹¹³Cd or ¹⁹⁹Hg NMR spectrometry. The spectral data suggest that in their complexes with Group 12 metal cations, both thiosemicarbazones are neutral and S‐monodentate; and for [Zn(4 EL₁)₂I₂] ( 3 ), [Cd(4 EL₁)₂Br₂] ( 5 ) and [Hg(4 EL₁)Cl₂]₂ ( 7 ) this was confirmed by X‐ray diffractometry. By contrast, in its complexes with Cu^II and Group 10 metal cations, 4 EL₁ is monodeprotonated and S,N‐bidentate, as was confirmed by X‐ray diffractometry for [Ni(4 EL₁–H)₂] ( 11 ) and [Pd(4 EL₁–H)₂] ( 12 ).     

Variable Bonding Modes of Pyrimidine‐2‐thione in PdII/PtII Complexes [M(η2‐N,S‐pymS)(η1‐S‐pymS)(PPh3)] and [M(η1‐S‐pymS)2(L‐L)] (L‐L = dppm,dppe)

Reactions of pyrimidine‐2‐thione (HpymS) with Pd^II/Pt^IV salts in the presence of triphenyl phosphine and bis(diphenylphosphino)alkanes, Ph₂P‐(CH₂)_m‐PPh₂ (m = 1, 2) have yielded two types of complexes, viz. a) [M(η²‐N, S‐ pymS)(η¹‐S‐ pymS)(PPh₃)] (M = Pd, 1 ; Pt, 2 ), and (b) [M(η¹‐S‐pymS)₂(L‐L)] {L‐L, M = dppm (m = 1) Pd, 3 ; Pt, 4 ; dppe (m = 2), Pd, 5 ; Pt, 6 }. Complexes have been characterized by elemental analysis (C, H, N), NMR spectroscopy (¹H, ¹³C, ³¹P), and single crystal X‐ray crystallography ( 1 , 2 , 4 , and 5 ). Complexes 1 and 2 have terminal η¹‐S and chelating η²‐N, S‐modes of pymS⁻, while other Pd/Pt complexes have only terminal η¹‐S modes. The solution state ³¹P NMR spectral data reveal dynamic equilibrium for the complexes 3 , 5 and 6 , whereas the complexes 1 , 2 and 4 are static in solution state.     

Superior Performance of a MoS2‐RGO Composite and a Borocarbonitride in the Electrochemical Detection of Dopamine,Uric Acid and Adenine

A MoS₂‐RGO composite and borocarbonitride (BC₅N) have been used as electrodes to selectively detect dopamine and uric acid in the presence of ascorbic acid. Both the electrodes show excellent eletrocatalytic activity towards the detection of dopamine, the detection limits being 0.55 μM and 2.1 μM in the case of MoS₂‐RGO and BCN respectively. MoS₂‐RGO shows a linear range of current over the 1–110 μM concentrations of dopamine, while BCN shows over the 2.3–20 μM range. BCN also exhibits satisfactory performance in the oxidation of uric acid with a detection limit of 3.8 μM and the linear range from 4 to 40 μM. The MoS₂‐RGO has also been used to detect adenine as well.