<Abstract>

A set of three new binary-component charge transfer (CT) complexes (Ia, Ib, and Ic)

based on anthracene derivatives1-acetyl-3-naphthyl-(9-anthryl)-2-pyrazoline (ANNP)/

1-acetyl-3-(4-methoxyphenyl)-5-(9-anthryl)-2-pyrazoline (AMAP)/1-acetyl-3-thiophene-5

-(9-anthryl)-2-pyrazoline (ATAP) as donors (D) and 1,2,4,5-tetracyanobenzene (TCNB)

as acceptor (A) were fabricated via molecular self-assembly and comprehensively

characterized. Crystal structural analysis revealed that acceptor molecules become

sandwiched in a face-to-face manner between the anthracene units through charge

transfer, hydrogen bond, and π···π interactions forming CT organic co-crystals with

a unique mixed stacking of D··A··D··A··D (Ib and Ic) and DAD···DAD (Ia) arrangement.

All of these crystals displayed significant enhancement and red-shift in fluorescence

and color-tunable emission such as blue to orange in the solid state. Remarkably, the

solid state luminescence efficiency of these CT co-crystals has been improved in

comparison to pristine donors. On the basis of structural analysis, the mixed stacking

mode between π-stacked donors and acceptor results in a CT transition state that

should be responsible for these behaviors of crystals. The present study demonstrates

that using a co-crystal strategy could provide these unique mixed stacking CT assemblies,

which may have a high potential in optoelectronic applications considering their high

solid-state luminescence efficiency.

<全文連結>