Development of non-symmetric thiophene-fused BODIPYs

A series of non-symmetric BODIPYs containing thieno[3,2-b]pyrrole moiety were synthesized in 21-63% yields. The absorption and emission maxima covered from the visible green to red region (lambda(abs)=532-647 nm: lambda(em)=547-664 nm; Phi(f)=0.19-0.45). X-ray analysis indicated that the S-C bond lengths were shorter than those of thienopyrrole and thienohelicene by 0.03-0.05 angstrom. The crystal packing pattern suggested that strong pi-pi interaction, intermolecular C-H center dot center dot center dot F interaction, and weak S center dot center dot center dot pi interaction existed. The tunable emission was achieved by structure modifications. Oxidation of BODIPY (lambda(em)=547 nm) with m-CPBA generated thiophene-1,1-dioxide derived BODIPY (lambda(em)=528 nm). Knoevenagel-type condensation of BODIPY with N,N-dimethylaminobenzaldehyde led to BODIPY (lambda(em)=693 nm) with extended conjugation. (C) 2012 Elsevier Ltd. All rights reserved.