Novel hydrogen bond network topologies in complexes of the ditopic ligand 5-amino-3-(pyrid-2-yl)-1H-pyrazole

Abstract

The syntheses and crystal structures of [MnCl₂L₂]·2CH₃OH (1·2CH₃OH), [FeCl₂L₂]Cl·4CH₃OH (2·4CH₃OH), [Cu(ClO₄)L₂]ClO₄·CH₃OH (3·CH₃OH), [Cu(NCMe)L₂][ClO₄]₂ (4), [Cu(NO₃)L₂]NO₃·xH₂O (5·xH₂O), [Zn(NO₃)L₂]NO₃·xH₂O (6·xH₂O) and [Cu(μ-{L–H})(L–H)]₂·xH₂O (7·xH₂O) are presented, where L = 5{3}-amino-3{5}-(pyrid-2-yl)-1H-pyrazole. In each case the ligand ‘L’ chelates to the metal cation through its pyridinyl and pyrazolyl N-donors, while the aminopyrazole moiety hydrogen bonds to coordinated or non-coordinated anions or solvent in the structure. This bifunctionality leads to extended hydrogen-bond networks. Of particular interest are 2·4CH₃OH, whose six, four-connected network can be understood as a heavily modified derivative of the boron nitride topology; 3·CH₃OH, which forms a network of linked ladders containing alternating five- and three-connected nodes; and, isostructural 5·xH₂O and 6·xH₂O, which form an extremely complicated network of four distinct nodes with connectivities of up to nine, depending on the presence or absence of a partially occupied water molecule.