Structure–Assembly–Property Relationships of Simple Ditopic Hydrogen-Bonding-Capable π-Conjugated Oligomers

Abstract

A series of simple ditopic hydrogen bonding capable molecules functionalized with 2,4-diamino-1,3,5-triazine (DAT), barbiturate (B), and phthalhydrazide (PH) on both termini of a 2,2′-bithiophene linker were designed and synthesized. The intrinsic electronic structures of the ditopic DAT, PH, and B molecules were investigated with ground-state DFT calculations. Their solution absorbance was investigated with UV-vis, where it was found that increasing size of R group substituent on the bithiophene linker resulted in a general blue-shift in solution absorbance maximum. The solid-state optical properties of ditopic DAT and B thin films were evaluated by UV-vis, and it was found that the solid-state absorbance was red-shifted with respect to solution absorbance in all cases. The three DAT molecules were vacuum thermal deposited onto Au(111) substrates and the morphologies were examined using STM. (DAT-T)2 was observed to organize into six-membered rosettes on the surface, whereas (DAT-TMe)2 formed linear assemblies before and after thermal annealing. For (DAT-Toct)2 , an irregular arrangement was observed, while (B-TMe)2 showed several co-existent assembly patterns. The work presented here provides fundamental molecular-supramolecular relationships useful for semiconductive materials design based on ditopic hydrogen bonding capable building blocks.

Synthesis and Aggregation Behavior of Novel Linear and Branched Oligothiophene‐Containing Organosilicon Multipods

“…At room temperature the elongation of the conjugated part of the molecule causes a gradual shift of the maximum of absorption from 400 nm for 4T to 454 nm for 7T [18] . At the same time, as the temperature decreases, the absorption maxima of each of these molecules undergo a 3–5 nm shift towards the red spectral region, accompanied by the appearance of additional maxima at higher wavelengths, suggesting the formation of aggregates in the solution [20] . It should be noted that this wavelength shift increases with the conjugation length due to reduced solubility and thus a higher degree of aggregation (e. g., for molecules containing 6–7 thiophene rings).…”

“…[18] At the same time, as the temperature decreases, the absorption maxima of each of these molecules undergo a 3-5 nm shift towards the red spectral region, accompanied by the appearance of additional maxima at higher wavelengths, suggesting the formation of aggregates in the solution. [20] It should be noted that this wavelength shift increases with the conjugation length due to reduced solubility and thus a higher degree of aggregation (e. g., for molecules containing 6-7 thiophene rings). Therefore, within the compounds with the same conjugation length, the temperature decrease leads to an additional (slight) red shift (by 3-5 nm).…”

“…1,1,3,3-tetramethyl-1-[3-(2,2':5',2''-terthien-5-yl)propyl]disiloxane (20). 5-allyl-2,2':5',2''-terthiophene 18 (2.00 g, 6.93 mmol) was dissolved in 1,1,3,3-tetramethyldisiloxane (50 mL) under argon, after which Karstedt's catalyst (Pt o with [ViMe 2 Si] 2 O) (63 mkL) was added.…”

Regulating the Content of Donor Unit in Donor–Acceptor Covalent Triazine Frameworks for Promoting Photocatalytic H2Production

“…The authors have cited additional references within the Supporting Information. [39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56]…”

Structure–property relationships in dicyanopyrazinoquinoxalines and their hydrogen-bonding-capable dihydropyrazinoquinoxalinedione derivatives

“…These compounds demonstrated a power conversion efficiency (PCE) twice as high as that of non-hydrogen bonding controls upon photovoltaic device fabrication with the electron acceptor C 60 . Subsequently, the design was extended to “ditopic” systems with diverse HB-capable units such as PH, 2,4-diamino-1,3,5-triazine (DAT), and barbiturate (B) that can form trimeric and hexameric “rosettes”, respectively [ 16 ].…”