Azadipyrromethene-Based Conjugated Oligomers with Near-IR Absorption and High Electron Affinity

Abstract

Solution-processable conjugated oligomers incorporating red-light absorbing azadipyrromethenes (aza-DIPY) within the main chain were synthesized via palladium-catalyzed Sonogashira coupling reactions. Thin films of these compounds absorbed light up to ∼1000 nm and displayed reversible reductions as ascertained by cyclic voltammetry experiments. Reactions with trifluoroboron etherate yielded materials displaying a unique combination of good solubility in organic solvents, low optical band gaps (∼1.3 eV), and high electron affinity (∼4.5 eV).

Synthesis and characterization of fluorinated azadipyrromethene complexes as acceptors for organic photovoltaics

“…The synthesis of ADP was carried out according to literature procedures [9,33]. The ADP-analogs with fluorine at the proximal or distal phenyl positions (L1-ADP and L2-ADP) were synthesized in a similar fashion with the respective fluorinated chalcones (Scheme 1).…”

“…To install phenylacetylene groups, iodination of the ADP derivatives was done according to literature procedures and purified by washing with chloroform in good yield [5,33–34]. Stille cross-coupling with the appropriate tributyltin-phenylacetylene analogs afforded the WS3 derivatives in good yield (Scheme 1).…”

“…Xylenes and tetrahydrofuran were distilled over sodium and benzophenone, degassed and stored under nitrogen. ADP, ADPI 2 , WS3, BF 2 (WS3), and Zn(WS3) 2 were synthesized and purified according to literature procedures with minor modifications [2,5,9,33–34]. (4-Fluorophenylethynyl)tributyltin (for the synthesis of L3), and [4-(trifluoromethyl)phenyl](tributyltin)acetylene (for the synthesis of L4) were synthesized according to literature procedures with minor modifications and used without purification [35–36].…”

Azadipyrromethenes: from traditional dye chemistry to leading edge applications

“…For example, Pd/Cu catalyzed reaction of iodo azadipyrromethenes 49b and 1,4-bis-(dodecyloxy)-2,5-diethynylbenzene followed by BF 2 chelation gave oligomers 53. 64 The room temperature oxidative homocoupling with FeCl 3 is a protocol for the facile dimerization of BF 2 -aza-dipyrromethene to produce 54 as reported by Bard et al (Scheme 27). 70 The coupling takes place in the -pyrrole position with no need for a previous functionalization with an activating group.…”

Boron difluoride formazanate copolymers with 9,9-di-n-hexylfluorene prepared by copper-catalyzed alkyne–azide cycloaddition chemistry

“…3,13 The resulting polymers often have high emission quantum yields, leading to their use in, for example, cell imaging (e.g., 5), [29][30][31] nanostructured dual emissive materials, 32 and as semiconductor materials for organic electronics (e.g., 6, 7). [9][10] One class of boron complexes which has yet to be incorporated into π-conjugated polymers are boron difluoride complexes of formazanate ligands. 33 Metal and boron complexes of formazanate ligands have tunable optical and electronic properties.…”