π-Extended benzo[1,2:4,5]di[7]annulene bis(dicarboximide)s – a new class of non-alternant polycyclic aromatic dicarboximides

Aromatic dicarboximides are a class of molecules represented by the well-known rylene bis(dicarboximide)s, in particular perylene or naphthalene bis(dicarboximide)s, which show pronounced optoelectronic properties and are applied as color pigments, fluorescent dyes and organic semiconductors. Herein we extend the family of aromatic bis(dicarboximide)s and report the synthesis of the first series of non-alternant aromatic dicarboximides by twofold Pd-catalyzed [5 + 2] annulation. Characterization by UV/vis spectroscopy and cyclic voltammetry (CV) measurements give insight into the optoelectronic characteristics of the hitherto unexplored substance class of heptagon-containing imides. Theoretical studies by nucleus independent chemical shift (NICS) XY-scans and anisotropy of the induced current density (ACID) plots demonstrate the influence of both the non-alternant carbon framework and the imide moieties on aromaticity of the synthesized bisimides.


Table of Contents
General remarks: The chemicals were purchased from commercial suppliers and were used without further purification.Flash column chromatography was performed with silica-gel from Macherey-Nagel (particle size 40-63 μm) as stationary phase or on an interchim PuriFlash 420 system with prepacked PF-30SIHPFOO25 columns (silica-gel).The identification via thin layer chromatography (TLC) was performed on aluminum plates coated with 0.20 mm silica-gel containing a fluorescent indicator (Macherey-Nagel, ALUGRAM ® , SIL G/UV254).Dry methylene chloride was obtained from a solvent purification system PS-M6-6/7 from inert technologies.All reactions involving oxygen-or moisture-sensitive compounds were performed by standard Schlenk technique under an inert atmosphere of nitrogen.1,3-Diisopropylimidazol-2ylidene borane was prepared by an adapted literature method. 1 UV/Vis absorption spectroscopy was measured on a Jasco V-670 spectrophotometer with 1 cm Hellma quartz glass cuvettes.
NMR spectroscopy was measured on Bruker Avance III HD 400 spectrometers at 298 K with deuterated methylene chloride as solvent.Chemical shifts are reported in  units relative to tetramethylsilane and calibrated to the residual solvent signal (CHDCl2 in CD2Cl2 at  = 5.32 ppm). 2 Multiplicity is designated by the following abbreviations: s (singlet), d (doublet), dd (doublet of doublets) or m (multiplet).
Coupling constants are reported as observed and given in Hz.All NMR spectra were analyzed and processed with MestReNova v14.2.1.

Cyclic and differential pulse voltammetry
Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) measurements were carried out with a BASi Epsilon potentiostat connected to a microcell apparatus from rhd instruments involving a 1.6 mL sample container, a platinum counter-and pseudoreference electrode as well as a glassy carbon working electrode.
Tetrabutylammonium hexafluorophosphate ((n-Bu)4NPF6) was applied as the supporting electrolyte with ferrocene (Fc) as an internal standard for the calibration of potentials.
Single crystal X-ray analysis was carried out on Bruker D8 Quest Kappa diffractometers with a PhotonII CMOS detector and multilayered mirror monochromated CuKα radiation (λ = 1.54178Å).The structure was solved using SHELXT 3 expanded with Fourier techniques and refined using the SHELX software package. 4Hydrogen atoms were assigned at idealized positions and were included in the calculation of structure factors.All non-hydrogen atoms in the main residue were refined anisotropically.Standard SHELX restraints RIGU, DELU, ISOR, SAME, and SIMU were applied to model disordered chloroform solvates.
Melting points were determined with a Stuart SMP50 automatic digital melting point apparatus or a polarization microscope BX41 from Olympus in conjunction with a temperature control element TP-94 by Linkam.All given melting points are uncorrected.

Bond Lengths
G,H 1.415

5. 6
Figure S19: Representation of the NICS-XY-scan trajectories of bisimide 3. Shown on the left is the unchanged molecule from which the contribution of the σ-skeleton obtained by the σ-only model (right) is subtracted, yielding uncontaminated NICSπ,zz values.

Figure S20 :
Figure S20: Subtraction of the NICS values of the σ-only model (NICSσ-only) from those of the unmodified molecule (NICSzz) yields NICSπ,zz values free of σ-contamination.

Figure S21 :
Figure S21: ACID plots (isovalue: 0.05) of the synthesized bisimides calculated at the B3LYP/6-31+G(d) level of theory.Diamagnetic ring currents are denoted by red, clockwise pointing arrows and paramagnetic ring currents by blue, anticlockwise pointing arrows.

Table S1 :
Crystal data and structure refinement for bisimide 1.

Table S7 :
Cartesian coordinates of the transoid optimized geometry of bisimide 1 at the

Table S12 :
Cartesian coordinates of the cisoid optimized geometry of PAH 2a at the B3LYP/6-31+G(d) level of theory.

Table S13 :
Cartesian coordinates of the cisoid optimized geometry of PAH 3a at the B3LYP/6-31+G(d) level of theory.

Table S14 :
Cartesian coordinates of the cisoid optimized geometry of PAH 4a at the B3LYP/6-31+G(d) level of theory.