Selective Detection of Ethylene by MoS2-Carbon Nanotube Networks Coated with Cu(I)-Pincer Complexes

The plant hormone ethylene (C2) can induce premature fruit ripening and flower senescence at levels below 1 ppm, which has motivated efforts to develop cost-effective methods for C2 monitoring during the transport and storage of climacteric fruits. Here, we describe a nanocomposite film composed of exfoliated MoS₂, single-walled carbon nanotubes (SCNTs), and Cu(I)-tris(mercaptoimidazolyl)borate complexes (Cu-Tm) for real-time detection of C2 at levels down to 100 ppb. A copercolation network of MoS₂ and SCNTs was deposited onto interdigitated Ag electrodes printed on plastic substrates and then coated with Cu-Tm with a final conductance in the 0.5 mS range. Reversible changes in relative conductance (-ΔG/G₀) were measured upon C2 exposure with a linear response at sub-ppm levels. The thin-film sensors were highly selective toward C2, and they responded weakly to other volatile organic compounds or water at similar partial pressures. A mechanism is proposed in which Cu-Tm behaves as a chemically sensitive n-type dopant for MoS₂, based on spectroscopic characterization and density functional theory modeling. Cu-Tm-coated MoS₂/SCNT sensors were also connected to a battery-powered wireless transmitter and used to monitor C2 production from various fruit samples, validating their utility as practical, field-deployable sensors.

Copper(i)-based oxidation of polycyclic aromatic hydrocarbons and product elucidation using vacuum ultraviolet spectroscopy and theoretical spectral calculations

Fluorinated 1,3,5-triazapentadienyl complexes of copper catalyze the oxidation PAHs to quinones using H₂O₂as an oxidant under mild conditions.

The silver(I) complex [HB{3-(CF3),5-(CH3)Pz}3]AgNCCH3 supported by a partially fluorinated scorpionate ligand

Tris(pyrazolyl)borates are used extensively in metal coordination chemistry and belong to a class of ligands generally referred to as scorpionates. The steric and electronic properties of these ligands can be modified quite easily by varying the substituents on the 3-, 4-, and 5-positions of the pyrazolyl moieties on the B atom. Fluorinated tris(pyrazolyl)borates are useful in the stabilization of rare silver(I) complexes. The silver(I) adduct (acetonitrile-κN){tris[5-methyl-3-(trifluoromethyl)pyrazol-1-yl-κN²]hydroborato}silver(I), [Ag(C₁₅H₁₃BF₉N₆)(CH₃CN)] or [HB{3-(CF₃),5-(CH₃)Pz}₃]AgNCCH₃, was obtained by treating [HB{3-(CF₃),5-(CH₃)Pz}₃]Na with CF₃SO₃Ag in the presence of acetonitrile, and was isolated in 85% yield. Single-crystal X-ray diffraction analysis reveals that the Ag^I center has a pseudo-tetrahedral all-nitrogen coordination sphere, and is supported by a tris(pyrazolyl)borate ligand that binds to the Ag^I center in a κ³-fashion.

An unusual bis-heteroscorpionate complex with anomalous ligands: [tris(3,4-dibromo-5-phenylpyrazolyl)hydroborato][hydrotris(3-neopentylpyrazolyl)borato]nickel(II)

Tridentate trispyrazolylborate (Tp) ligands, introduced by Trofimenko in 1966, have been widely utilized in metal coordination chemistry because of the relatively facile synthetic modification of their electronic and steric factors. The title heteroscorpionate, [Ni(C27H16BBr6N6)(C24H40BN6)], features one ligand, namely hydrotris(3-neopentylpyrazolyl)borate, that has previously displayed variable steric effects, and a brominated ligand, namely tris(3,4-dibromo-5-phenylpyrazolyl)hydroborate, that, atypical in trispyrazolylborate chemistry, coordinates such that the less bulky pyrazole substituent is oriented facing toward the metal ion. The potential molecular threefold symmetry in scorpionates can allow axial chirality. Although crystallized in the centrosymmetricP\overline{1} space group, a closer inspection of the structure of the title compound reveals axial diastereomers.

Zinc(II)-Mediated Carbene Insertion into C-H Bonds in Alkanes

The cationic zinc adduct {[HB(3,5-(CF3)2Pz)3]Zn(NCMe)2}ClO4 catalyzes the functionalization of tertiary, secondary, and primary C-H bonds of alkanes via carbene insertion. Ethyl diazoacetate serves as the :CHCO2Et carbene precursor. The counteranion, supporting ligand, and coordinating solvents affect the catalytic activity. An in situ generated {[HB(3,5-(CF3)2Pz)3]Zn}(+) species containing a bulkier {B[3,5-(CF3)2C6H3]4}(-) anion gives the best results among the zinc catalysts used.