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The role of C–H⋯O hydrogen-bonding interactions in the solid-state packing networks of squaraine dyes has been investigated by re-examining the nine previously published X-ray crystal structures of these materials. In addition, two new compounds, 2,4-bis(1-hexyl-3,3-dimethyl-2-indolinylidenemethyl)cyclobutenebis(ylium)-1,3-diolate and 2,4-bis(1-(ethan-2-ol)-3,3-dimethyl-2-indolinylidenemethyl)cyclobutenebis(ylium)-1,3-diolate, have had their structures determined and lattice packings discussed with respect to their hydrogen-bonding networks. Analysis of the eleven structures shows, in seven cases, two emergent packing motifs. All structures exhibit molecules in stacked columns, but the two differing patterns arise from specific intermolecular C–H⋯O associations which are directed at the molecules of either an adjacent parallel column or a column of opposing direction. In the four structures which do not exhibit either of these two packing arrangements, hydrogen-bonding associations are still important in the analysis of the overall lattice network. |
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