Self-organizing maps as a data-driven approach to elucidate the packing motifs of perylene diimide derivatives

Marin, Francesco; Zappi, Alessandro; Melucci, Dora; Maini, Lucia

doi:10.1039/d2me00240j

“…Though not rare, only 17 out of 142 PDI-based objects retrieved in the CSD crystallize in this class. [25] Recent papers have reported on the stabilizing effect of intermolecular contacts in PDI oligomers, estimated to lie in the 65-85 kJ mol À 1 regime per dimeric contact. [26] Following Vura-Veis et al model, [27] species 2-4, which possess similar long-and shortaxis shifts (in the 1.2-1.6 Å and 2.8-3.3 Å ranges, respectively), fall far away from the highly attractive basin characterized by 75 (and higher) kJ mol À 1 binding energy value (species 1 appears slightly different in that a larger short-axis shift, 4.0 Å, is present, falling in a region not investigated in the theoretical study of ref.…”

Section: Methodsmentioning

confidence: 99%

“…Compounds 1 – 4 stack according to the tight‐long‐y description proposed by Maini and co‐workers, [25] characterized by parallel molecules piled with a larger shift in the y direction than along the molecular axis, taken as x . Though not rare, only 17 out of 142 PDI‐based objects retrieved in the CSD crystallize in this class [25] .…”

Section: Methodsmentioning

confidence: 99%

“…Compounds 1 – 4 stack according to the tight‐long‐y description proposed by Maini and co‐workers, [25] characterized by parallel molecules piled with a larger shift in the y direction than along the molecular axis, taken as x . Though not rare, only 17 out of 142 PDI‐based objects retrieved in the CSD crystallize in this class [25] . Recent papers have reported on the stabilizing effect of intermolecular contacts in PDI oligomers, estimated to lie in the 65–85 kJ mol −1 regime per dimeric contact [26] .…”

Section: Methodsmentioning

confidence: 99%

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Forcing Twisted 1,7‐Dibromoperylene Diimides to Flatten in the Solid State: What a Difference an Atom Makes

Konidaris,

Zambra,

Giannici

et al. 2023

Angew Chem Int Ed

1

0

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Perylene‐diimides (PDI) are workhorses in the field of organic electronics, owing to their appealing n‐semiconducting properties. Optimization of their performances is widely pursued by bay‐atom substitution and diverse imide functionalization. Bulk solids and thin‐films of these species crystallize in a variety of stacking configurations, depending on the geometry of the stable conformation of the polyaromatic core. We here demonstrate that 1,7‐dibromo‐substituted perylene‐diimides, PDI(H2Br2), possessing a heavily twisted conformation in the gas phase, in solution and in the solids, can be easily flattened in the solid state into centrosymmetric molecules if the polyaromatic cores form p‐p stabilized chains. This is achieved by using axial residues with low stereochemical hindrance, as guaranteed by a single CH2/NH spacer directly linked to the imide function. Structural powder diffraction and DFT calculations on four newly designed species of the PDI(H2Br2) class coherently show that, thanks to the flexibility of the N‐X‐Ar link (X = CH2/NH), flat cores are indeed obtained by overcoming the interconversion barrier between twisted atropoisomers, of only 26.5 kJ mol‐1. This strategy may then be useful to induce “anomalously flat” polyaromatic cores of different kinds (substituted acenes/rylenes) in the solid state, towards suitable crystal packing and orbital interactions for improved electronic performances.

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“…Thanks to their large electronic affinity (EA), efficient π–π intermolecular interactions, and easy functionalization, tetracarboxylic aromatic derivatives such as naphthalene dimiide (NDI) and perylene diimide (PDI) have worked as first-class n-type molecular candidates. ,− Against oxidation, their core functionalization with electron-withdrawing (EW) groups (F, CF 3 , Br, and CN) is one of the most effective strategies to raise EA (i.e., lowering the LUMO energy level) above 4.0 eV , (without exceeding 4.6 eV, to avoid nucleophilic attack or even one-electron reduction). Additionally, efforts have been spent in interpreting and optimizing intermolecular interactions (distance and offset of π–π stacked aromatic cores) in the solid state, − as a route to improve the electron mobility, although no definite recipe is to date consolidated. Finally, recent renovated interest in solution-grown (doped) NDI and PDI n-type derivatives is as organic thermoelectrics (O-TE) operating at low-to-medium temperatures (<300 °C), − an application favored by the low thermal conductivity of organic solids (as required by efficient TE materials).…”

Section: Introductionmentioning

confidence: 99%

Polyfluorinated Naphthalene-bis-hydrazimide for Solution-Grown n-Type Semiconducting Films

Zambra,

Abbinante,

García-Espejo

et al. 2023

ACS Omega

1

0

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Naphthalene tetracarboxylic diimides (NDIs), possessing low-lying and tunable LUMO levels, are of wide interest for their aptitude to provide cost-effective, flexible, and environmentally stable n-type organic semiconductors through simple solution processing. NDI-based aromatic hydrazidimides are herein studied in relation to their chemical and environmental stability and as spin-coated stable thin films. In the case of the pentafluorinated residue, these were found to be crystalline, highly oriented, and molecularly flat (roughness = 0.3 nm), based on optical and atomic force microscopy, X-ray diffraction in specular and grazing incidence geometry, and X-ray reflectivity measurements. A new polymorph, previously undetected during the isolation of bulk powders or in their controlled thermal treatments, is found in the thin film and was metrically and structurally characterized from 2D GIWAXS patterns (monoclinic, P2/c, a = 17.50; b = 4.56; c = 14.24 Å; β = 84.8°). This new thin-film phase, TF-F5, is formed no matter whether silicon, glass, or polymethylmethacrylate substrates are used, thus opening the way to the preparation of solution-grown flexible semiconducting films. The TF-F5 films exhibit a systematic and rigorous molecular alignment with both orientation and packing favorable to electron mobility (μ = 0.02 cm 2 V −1 s −1 ). Structural and morphological differences are deemed responsible for the absence of measurable conductivity in thin films of polyfluorinated analogues bearing −CF 3 residues on the hydrazidimide aromatic rings.

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Forcing Twisted 1,7‐Dibromoperylene Diimides to Flatten in the Solid State: What a Difference an Atom Makes

Konidaris,

Zambra,

Giannici

et al. 2023

Angewandte Chemie

0

View full text Add to dashboard Cite

Perylene‐diimides (PDI) are workhorses in the field of organic electronics, owing to their appealing n‐semiconducting properties. Optimization of their performances is widely pursued by bay‐atom substitution and diverse imide functionalization. Bulk solids and thin‐films of these species crystallize in a variety of stacking configurations, depending on the geometry of the stable conformation of the polyaromatic core. We here demonstrate that 1,7‐dibromo‐substituted perylene‐diimides, PDI(H2Br2), possessing a heavily twisted conformation in the gas phase, in solution and in the solids, can be easily flattened in the solid state into centrosymmetric molecules if the polyaromatic cores form p‐p stabilized chains. This is achieved by using axial residues with low stereochemical hindrance, as guaranteed by a single CH2/NH spacer directly linked to the imide function. Structural powder diffraction and DFT calculations on four newly designed species of the PDI(H2Br2) class coherently show that, thanks to the flexibility of the N‐X‐Ar link (X = CH2/NH), flat cores are indeed obtained by overcoming the interconversion barrier between twisted atropoisomers, of only 26.5 kJ mol‐1. This strategy may then be useful to induce “anomalously flat” polyaromatic cores of different kinds (substituted acenes/rylenes) in the solid state, towards suitable crystal packing and orbital interactions for improved electronic performances.

show abstract

Self-organizing maps as a data-driven approach to elucidate the packing motifs of perylene diimide derivatives

Abstract: The efficient classification or prediction of crystal structures into a small number of families of related structures can be extremely important in the design of materials with specific packing and properties.

Cited by 3 publications

References 69 publications

Forcing Twisted 1,7‐Dibromoperylene Diimides to Flatten in the Solid State: What a Difference an Atom Makes

Forcing Twisted 1,7‐Dibromoperylene Diimides to Flatten in the Solid State: What a Difference an Atom Makes

Polyfluorinated Naphthalene-bis-hydrazimide for Solution-Grown n-Type Semiconducting Films

Forcing Twisted 1,7‐Dibromoperylene Diimides to Flatten in the Solid State: What a Difference an Atom Makes

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