Jonathan K. Leland

Electrogenerated Chemiluminescence: An Oxidative‐Reduction Type ECL Reaction Sequence Using Tripropyl Amine

A new electrogenerated chemiluminescence (ECL) reaction which utilizes tripropyl amine and is presented. The mechanism of light generation appears general enough to include a range of amines and luminophores. An oxidative‐reduction mechanism is proposed. Upon electrochemical oxidation of both the luminophore and amine, a strong emission is observed. Voltammetric analysis reveals the potential for greatest light emission at the tripropyl amine oxidation. The emission is from the excited state of . An electron transfer reaction from the deprotonated tripropyl amine radical and is the central reaction for excited state production. An estimate of the ECL efficiency cannot be made, due to the complex nature of the reaction.

Notes. Oxidation and reduction of phosphorus–phosphorus and arsenic–arsenic double bonds. An electrochemical study of two diphosphenes and a diarsene

The diphosphenes [(Me3Si)3C]2P2(1) and (2,4,6-But3C6H2)2P2(2) and the diarsene [(Me3Si)3C]2As2(3) undergo electrochemical reduction in tetrahydrofuran (thf) solution to the corresponding anion radicals [{(Me3Si)2C}2P2]˙–(4), [(2,4,6-But3C6H2)2P2]˙–(5), and [{(Me3Si)3C}2As2]˙–(6), respectively. Anion radicals (4) and (5) were sufficiently stable to permit the acquisition of e.s.r. data. The products of oxidation of (1), (2), and (3) were much more difficult to characterise. The oxidation of (1) in CH2Cl2, is irreversible at 25 °C; however, at –75 °C a one-electron oxidation occurs to the unstable cation radical [{(Me3Si)3C}2P2]˙+. The oxidation of both (2) and (3) is irreversible even at –75 °C.

Synthesis, structures, and reactivities of some pentamethylcyclopentadienyl–sulphur compounds

The pentamethylcyclopentadienyl–sulphur compounds S(C5Me5)2(1) and S2(C5Me5)2(2) have been prepared by the reaction of Li(C5Me5) with SCL2 and S2Cl2, respectively. Compounds (1) and (2) were characterised by n.m.r. and mass spectroscopy. The X-ray crystal structure of (1) has been determined. Compound (1) crystallises in the monoclinic space group P21/c(no. 14), with a= 10.375(2), b= 11.274(2), c= 16.132(9)A, β= 91.92(3)°, and Z= 4. The reaction of (1) with [Fe2(CO)9] results in the known cluster compound, [Fe3S2(CO)9](3), the identity of which was confirmed by X-ray crystallography. Unsuccessful attempts were made to prepare cations of the type [S(C5Me5)2]n+ by (i) oxidation of (1) and (2), or (ii) the reaction of S(C5Me5)Cl (prepared in situ) with Al2Cl6. Cyclic voltammetric experiments on (1) and C5Me5H suggest that oxidation occurs at the carbocyclic ring rather than at the sulphur atom.

Semiconductor Electrodes LXI . Photoelectrochemistry of in Aqueous Solutions

The photoelectrochemical response of electrodes of single crystals of the layer-type compound n-ZrS/sub 2/ prepared by vapor transport in Fe/sup 3+//Fe/sup 2+/, ferrocyanide/ferricyanide, and iodide solutions was investigated. The flatband potential (V/sub FB/) of the electrode in 1M NaCl and 0.032M HCl solutions, estimated from impedance measurements, was -0.40V vs. SCE at pH 1.5 and shifted towards more negative values by 54 mV/unit pH change to pH 12. A two-electrode photoelectrochemical cell with a n-ZrS/sub 2/ anode and Pt gauze cathode in a 0.10M FeCl/sub 2/, 0.10M FeCl/sub 3/, and 1.0M HCl electrolyte gave a short-circuit photocurrent of 15 mA/cm/sup 2/ and an open-circuit photovoltage of 0.4V under xenon lamp illumination (ca. 100 mW/cm/sup 2/).

Preparation and electronic properties of monolayer tungsten oxide on silica particles

Abstract Monolayer tungsten oxide on silica particles was prepared by a controlled hydrolysis technique. The material displays a bandgap which is 0.3 eV higher in energy than that for bulk WO 3 . The quasi-Fermi level for electrons, in this material, as determined by electrochemical measurements, is 170 mV more negative for SiO 2 /WO 3 than that for particulate WO 3 .