Random exchange in the spin ladder Cu(quinoxaline)X2 (X = Cl, Br)

Mixed halide versions of the spin ladder copper quinoxaline dihalide (X = Cl, Br) have been synthesized. X-ray crystallographic analysis shows the structures of the mixed halide versions are the same as those as the pure halide compounds; in the mixed-halide compounds, the larger bromide ions are preferentially found in the terminal, rather than the bridging, sites of the Cu2X4 dimeric units. Susceptibility studies show the rung interactions (within the dimeric units) remain unchanged upon mixing but the rail interactions (through the quinoxaline molecules) change systematically.

Mixed halide versions of the spin ladder Cu(quinoxaline)X2 (X = Cl, Br) have been synthesized. X-ray analysis shows preference for the bromide ions to occupy the terminal halide sites. Susceptibility studies show the rung interactions (within the dimers) remain unchanged with doping, but the rail interactions (through quinoxaline) change systematically.Figure optionsDownload as PowerPoint slideResearch highlights
► Synthesis of mixed halide complexes (Cl,Br) allows the study of randomness in magnetic ladders.
► The rails of the ladders occur via quinoxaline molecules; the rungs are formed by halide ions.
► Bromide ions occupy the terminal halide positions of the Cu2X4 dimeric rung units ∼2:1 at low doping.
► Surprisingly, doping the halide ions (rungs) changes in the exchange through the quinoxalines (rails).