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A series of homoleptic monoanionic nickel dithiolene complexes [Ni(bdt)2](NBu4), [Ni(tdt)2](NBu4), and [Ni(mnt)2](NBu4) containing the ligands benzene-1,2-dithiolate (bdt2−), toluene-3,4-dithiolate (tdt2−), and maleonitriledithiolate (mnt2−), respectively, were employed as electrocatalysts in the hydrogen-evolution reaction with trifluoroacetic acid as the proton source in acetonitrile. All complexes are active catalysts with TONs reaching 113, 158, and 6 for [Ni(bdt)2](NBu4), [Ni(tdt)2](NBu4), and [Ni(mnt)2](NBu4), respectively. The Faradaic yield for the hydrogen evolution reaction reaches 88 % for 2−, which also displays the minimal overpotential requirement value (467 mV) within the series. Two pathways for H2 evolution can be hypothesized that differ in the sequence of protonation and reduction steps. DFT calculations are in agreement with experimental data and indicate that protonation at sulfur follows the reduction to the dianion. Hydrogen evolves from the direduced–diprotonated form via a highly distorted nickel hydride intermediate. The effects of acid strength and concentration in the hydrogen-evolving mechanism are also discussed. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

A series of neutral and monoanionic nickel dithiolene complexes with p-methoxyphenyl-substituted 1,2-dithiolene ligands have been prepared and characterized with physicochemical methods. Two of the complexes, the monoanion of the symmetric [Ni{S2C2(Ph-p-OCH3)2}2] (3-) with NBu4+ as a counterion and the neutral asymmetric [Ni{S2C2(Ph)(Ph-p-OCH3)}2] (2), have been structurally characterized by single-crystal X-ray crystallography. All complexes have been employed as proton-reducing catalysts in N,N-dimethylformamide with trifluoroacetic acid as the proton source. The complexes are active catalysts with good faradaic yields, reaching 83% for 2 but relatively high overpotential requirements (0.91 and 1.55 V measured at the middle of the catalytic wave for two processes observed depending on the different routes of the mechanism). The similarity of the experimental data regardless of whether the neutral or anionic form of the complexes is used indicates that the neutral form acts as a precatalyst. On the basis of detailed density functional theory calculations, the proposed mechanism reveals two different main routes after protonation of the dianion of the catalyst in accordance with the experimental data, indicating the role of the concentration of the acid and the influence of the methoxy groups. Protonation at sulfur seems be more favorable than that at the metal, which is in marked contrast with the catalytic mechanism proposed for analogous cobalt dithiolene complexes. © 2015 American Chemical Society.

Objective: We conducted a randomised controlled trial to compare the effects of three types of internet delivered Inhibitory Control Training (ICT) with each other and with an active control intervention on alcohol consumption in a community sample of problem drinkers. Methods: Two-hundred and forty-six heavy drinkers, who were motivated to reduce their alcohol consumption (mean age 41.32, 130 female) self-monitored their alcohol consumption for one week before being randomised to receive one of three variants of ICT (Associative No-Go, Associative Stop Signal, General Inhibition) or an active control. Participants then completed up to 14 ICT / control sessions on the internet over a four-week period, whilst \ud \ud regularly recording their alcohol consumption. Results: There were significant reductions in alcohol consumption across all groups over the four week training period (main effect of time, F(2, 402) = 77.12, p < .01, ηp2 =.28, BF10 > 99), however there were no differences between ICT groups, or between ICT groups and the active control group (group x time interaction, F(6, 402) = 1.10, p = .36, ηp2 = .02, BF10 = 0.03). Contrary to hypotheses, there were no changes in general inhibitory control, the disinhibiting \ud \ud effects of alcohol cues, or alcohol affective associations after ICT. Conclusions: In this study which attempted to translate findings from proof-of-concept laboratory studies into a viable behaviour change \ud \ud intervention, we found that multiple sessions of ICT delivered over the internet did not help heavy drinkers to reduce their alcohol consumption beyond non-specific effects associated with taking part in a trial.