Novel Chiral Pyromellitdiimide (1,2,4,5-Benzenetetracarboxydiimide) Dimers and Trimers: Exploring Their Structure, Electronic Transitions, and Exciton Coupling

Abstract

The chiral but highly symmetrical acyclic and cyclic pyromellitic diimide dimers and trimers 2–5 have been obtained and characterized for the first time. The pyromellitdiimide chromophores in these molecules are linked by a rigid diequatorially 1,2‐disubstituted cyclohexane skeleton. The structures of the compounds have been determined in detail by molecular modeling and, in the case of cyclic dimer 4 and trimer 5, by means of X‐ray diffraction analysis. The electronically excited states of the pyromellitdiimide chromophore (1 a) have been studied in these and other model compounds by means of linear dichroism (LD), magnetic circular dichroism (MCD), and circular dichroism (CD) spectroscopy. CD spectra of the rigid cyclic trimer 5 have provided the most detailed information on the excited states of the pyromellitdiimide chromophore. The low‐energy tail (340–360 nm) of the absorption envelope can be assigned to out‐of‐plane polarized n–π* transitions (I, II). The higher energy bands are due to contributions from up to six π–π* transitions, these being polarized either along the long (IV–VI, VIII) or short axis (III, VII). The results of ab initio CIS/cc‐pVDZ and semiempirical INDO/S‐CI calculations have been compared with the experimental data. CD Cotton effects in the region 200–260 nm, which result from exciton interactions between electric dipole allowed transitions of two pyromellitdiimide chromophores in compounds 2–5, provide reliable and useful information concerning the conformation and absolute configuration of these molecules, which may be extrapolated to other oligoimide systems.

Redox-Active Macrocycles for Organic Rechargeable Batteries

“…Our investigation suggests that the intrinsic properties of the redox unit itself and the mutual arrangement of individual redox units within the active material are equally critical to designing organic electrodes for rechargeable batteries. While PMDI-Ref and (-)-2PMDI were synthesized according to previously reported 16 procedures, the synthesis of (-)-3PMDI-∆ has been optimized for multi-gram scale production without the use of column chromatography. X-Ray crystal structures of the PMDI macrocycles exhibit minor differences from those reported 16 in the previous study, apparently reflecting the influence of the solvents used in crystallizations.…”

“…16 The first two compounds were purified using automated column chromatography on a Teledyne Isco Combiflash RF 200 system, while the triangular macrocycle was purified according to the procedures described in Section B without the use of column chromatography. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 …”

Local dipole interactions induce helicity of (S)-2-butyl-N-(1,8-naphthaloyl)-2-aminobenzoate molecules containing 1,8-naphthalimide rings utilized as a column building blocks: X-ray and quantum mechanical studies

“…Aromatic amides such as 1,2,4,5-benzenetetracarboxydiimides (pyrromellitic diimides) and 1,4,5,8-naphthalenetetracarboxydiimides (NDI) are neutral, planar, electron deficient molecules whose synthetic potential has been used in construction of oligomeric molecules [1][2][3], new fluorophors [4], and catenanes [5], and whose structural and electronic properties have been utilized in many different areas, to mention medicinal chemistry [6] and photophysics [7]. Monoimides, like phtalimides and 1,8-naphtalimides, have been used successfully in crystal engineering [8] and as chromophores in stereochemical studies [9][10][11].…”

Electron Sharing and Anion–π Recognition in Molecular Triangular Prisms

“…The high symmetry of both (−)‐ and (+)‐NDI‐Δ is reflected by the relative simplicity of the 1 H NMR spectra for the compounds, which show only two sets of signals for the 12 NDI protons (Supporting Information). The rigid molecular structures of (−)‐ and (+)‐NDI‐Δ also lead to strong peaks (Figure 1 b) in the circular dichroism (CD) spectra 17. Both enantiomers of NDI‐Δ formed crystals from MeOH/CH 2 Cl 2 solutions suitable for single‐crystal X‐ray diffraction analyses.…”