Synthesis, crystal structures and semiconductor properties of 2-(thiopyran-4-ylidene)-1,3-benzodithioles with an aryl substituent

Abstract

Three 2-(thiopyran-4-ylidene)-1,3-benzodithiole (TP-BT) derivatives containing phenyl (1), 2-pyridyl (2) or 4-pyridyl (3) group on the benzene moiety were synthesized to investigate the relationship between molecular structure and their semiconductor properties....

Semiconductor Properties of π‐Extended 2‐(Thiopyran‐4‐ylidene)‐1,3‐benzodithiole (TP‐BT) Analogs

“…1000 times (Figure 12b), which corresponds to a photoresponse behavior similar to that of Ph-TP-BT. [39] These results indicate that D-A type molecules in which the HOMO and LUMO are separated exhibit more remarkable photo-response properties.…”

“…Ph-TP-BT, compound 1, and dithiolium salt 2 were prepared according to previously reported methods. [39,41,42] Nap-TP-BT and Ant-TP-BT were synthesized via the Suzuki-Miyaura coupling of compound 1 with the corresponding boronic acids in 60 % and 47 % yields, respectively. The reaction of dithiolium salt 2 with triethylphosphite (P(OEt) 3 ) afforded phosphonate 3 in 81 % yield.…”

“…Cyclic voltammograms of the TP-BT analogs are shown in Figure 3. The first oxidation potentials (E 1 ) of TP-NT, Ph-TP-BT, Nap-TP-BT, and Ant-TP-BT were À 0.009, À 0.045, [39] À 0.069, and À 0.059 V (vs. Fc/Fc + ), respectively, and their HOMO levels were estimated to be similar to that of the parent TP-BT (À 4.76 eV), [38] i. e., À 4.79, À 4.75, À 4.73, and À 4.74 eV, respectively. This result indicated that the HOMOs were mainly dominated by the TP-BT moieties and not affected by π-extension.…”

“…In this study, a fused-type π-extended analog, i. e., 2-(thiopyran-4-ylidene)-1,3-naphtho [2,3-d]dithiole (TP-NT), and three σ-bonded-type π-extended analogs, i. e., 5-phenyl-, [39] 2) were synthesized. The σ-bonded-type TP-BT analogs were prepared by introducing simple linear conjugated units such as naphthalene and anthracene into the aromatic ring moiety of our previously reported TP-BT derivatives bearing 2pyridyl (2Py) or 4-pyridyl (4Py) rings (Figure 2).…”

“…The σ-bonded-type TP-BT analogs were prepared by introducing simple linear conjugated units such as naphthalene and anthracene into the aromatic ring moiety of our previously reported TP-BT derivatives bearing 2pyridyl (2Py) or 4-pyridyl (4Py) rings (Figure 2). [39] Since the anthracene-substituted structure contains stronger CÀ H•••π interactions [40] and S•••S contacts between the terminal S atoms, the formation of a bilayer-type layered herringbone (b-LHB) arrangement [36] was expected. The formation of such a structure was confirmed by an X-ray crystal structure analysis of Ant-TP-BT.…”