Transition metal salts of 2-amino-3,5-dihalopyridine - dimers: syntheses, structures and magnetic properties of (3,5-diCAPH)<sub>2</sub>Cu<sub>2</sub>Br<sub>6</sub> and (3,5-diBAPH)<sub>2</sub>Cu<sub>2</sub>X<sub>6</sub>

<p>Three dimeric copper(II) complexes have been prepared with the general formula bis(2-amino-3,5-dihalopyridinium)hexahalodicuprate cuprate(II): (3,5-diCAPH)<sub>2</sub>Cu<sub>2</sub>Br<sub>6</sub> (<b>1</b>), (3,5-diBAPH)<sub>2</sub>Cu<sub>2</sub>Cl<sub>6</sub> (<b>2</b>) and (3,5-diBAPH)<sub>2</sub>Cu<sub>2</sub>Br<sub>6</sub> (<b>3</b>) [3,5-diCAPH = 2-amino-3,5-dichloropyridinium; 3,5-diBAPH = 2-amino-3,5-dibromopyridinium]. The compounds have been characterized via single crystal X-ray diffraction and temperature dependent magnetic susceptibility measurements. All three compounds crystallize in monoclinic space groups (<b>1</b>, <i>C</i>2/<i>c</i>; <b>2</b> and <b>3</b>, <i>P</i>2<sub>1</sub>/<i>c</i>) and exhibit alternating layers of hexahalodicuprate ions and organic cations. The hexahalodicuprate ions exhibit short X⋯Cu and X⋯X contacts which link the dimers into a square array. Variable temperature magnetic susceptibility data reveal strong intradimer antiferromagnetic exchange (<i>J</i> = −153, −65, −122 K for <b>1</b>–<b>3</b>, respectively), but negligible inter-dimer magnetic exchange.</p>