Tuning N,N-Diarylanilinosquaraine Crystal Packing: n-Hexylaryl and Fluoroaryl Substitution

Abstract

X-ray diffraction results for single crystals of N,N-diarylanilinosquaraines (SQ-TAAs) 2,4-bis(4-bis(p-R-phenyl)amino)-2,6-dihydroxyphenyl)cyclobuta-1,3-diene-1,3-bis(olate) for R = F (SQ-TAA-F) and R = n-hexyl (SQ-TAA-C6) are reported. SQ-TAA-F (an ambipolar charge transporter) forms π-stacked dyads intercolated by cross-stacked molecules, a unique motif among the systems studied. Its [C]–H···F contacts induce this intermolecular packing and may account for its ambipolar charge transport behavior. SQ-TAA-C6 (a hole charge transporter) forms strongly slip-stacked 1-D chains aligned along molecular long axes. SQ-TAA-C6 exhibits packing of its conjugated core structure that is similar to those for SQ-TAAs with R = H and R = OH, which also exhibit qualitative hole transport properties. SQ-TAA-C6 has one n-hexyl group that is not fully extended, but all of its alkyl groups pack into alkyl rich planes that alternate with SQ-TAA core rich planes to form the overall lattice.