Reactivity of α,ω-dibromoalkanes at copper and silver cathodes: (I) Behaviour of 1,3-dibromopropane

Evidence is presented that copper, silver, and their alloys with palladium, may display an exceptional reactivity in the contact of α,ω-alkanes [Br–(CH2)n–Br]. Thus, the use of coppered surfaces as cathode materials shows a spectacular potential shift (ΔE ≈ 1 V) for the main reduction step when compared to glassy carbon taken as a standard interface. Such cathodic reactions are particularly easy and fast with 1,3-dibromopropane (DB3). Thus, it is expected that a preliminarily transient [(CH2)3Cu(II),2Br−] monomer or polymer, is formed: the indirect reduction by use of 3D electrodes from copper powder in suspension may produce at electrified surfaces (made of glassy carbon, platinum, or nickel) fine deposits of copper nano-particles. Oppositely, silver (essentially by means of Ag–Pd alloy employed as cathode material) reacts with each C–Br bond and the observed cathodic behaviour is uniform with all α,ω-alkanes. A special attention is drawn on the nature of modified surfaces and the enhancement of catalysis kinetics brought by the use of copperized and silverized electrodes.