ABSTRACT
Herein, we report the synthesis and molecular structure of the mono- and dianionic aromatic molecules [(B15C5-κ5O)2K+](LDOPTË-) (1) and [(B15C5-κ5O)2K+]2(LDOPT2-)THFsolv (2) derived from the parent aromatic polyhydrocarbon 5,6:11,12-di-o-phenylenetetracene (DOPT, LDOPT) by a controlled stepwise one and two electron chemical reduction. The effect of single and double electron charge transfer to a polycondensed aromatic hydrocarbon (PAH) without any disturbing influence of an associated metal cation has been demonstrated. This was achieved by fully sandwiching the cationic K+ counterions between two benzo-15-crown-5-ether (B15C5) ligands resulting in a fully encapsulating (κ10O) geometry which ensures a complete separation of the K+ counterions and the bare anionic PAH species [LDOPTË-] and [LDOPT2-]. The structural changes accompanied by the stepwise reduction from LDOPT to [LDOPTË-] to [LDOPT2-] are discussed and compared to earlier predictions based on density functional theory (DFT) as well as the results of previous studies of alkaline metal cationic PAH anion interactions of DOPT in which only a partial metal cation encapsulation has been achieved so far.
ABSTRACT
The molecular structure of the hydrocarbon 5,6;11,12-di-o-phenylenetetracene (DOPT), its material characterization and evaluation of electronic properties is reported for the first time. A single-crystal X-ray study reveals two different motifs of intramolecular overlap with herringbone-type arrangement displaying either face-to-edge or co-facial face-to-face packing depicting intensive π-π interactions. Density functional theory (DFT) calculations underpin that a favorable electronic transport mechanism occurs by a charge hopping process due to a π-bond overlap in the DOPT polymorph with co-facial arene orientation. The performance of polycrystalline DOPT films as active organic semiconducting layer in a state-of-the-art organic field effect transistor (OFET) device was evaluated and proves to be film thickness dependent. For 40â nm layer thickness it displays a saturation hole mobility (µhole ) of up to 0.01â cm(2) V(-1) s(-1) and an on/off-ratio (Ion /Ioff ) of 1.5×10(3) .
