Regioregular Phthalocyanines Substituted with Bulky Donors at Non‐Peripheral Positions

Abstract

Three regioregular phthalocyanines (1-3) were synthesized selectively by the cyclic tetramerization of phthalonitriles bearing a bulky diarylamine substituent at the next position of nitrile. The steric repulsion at the tetramerization of bulky phthalonitriles allowed for the selective formation of regioregular phthalocyanines as confirmed by NMR and single crystal X-ray structural analyses. The absorption spectrum of 1 substituted with di(4-tert-butylphenyl)amine groups at the non-peripheral positions showed a non-split Q-band at 764 nm, which was redshifted by 83 nm compared with that of metal free phthalocyanine (H Pc). The TD-DFT calculation and electrochemical studies prove that the substitution of diarylamine groups at the α-positions effectively destabilizes the HOMO energy level, which causes a large redshift of the Q-band. Moreover, 1 can generate a one-electron oxidation species through chemical oxidation. The Q-band position of 2 bearing 4,4'-dimetoxyphenylamine units was further shifted by 10 nm compared with that of 1. In addition, 3 having carbazole units showed a small redshift of the Q-band relative to H Pc. The hole-mobility of 2 in thin film was determined to be 1.1×10 cm V s by using a space charge limited current method. A perovskite solar cell employing 2 as a hole-transporting layer gave an efficiency of 5.1 % under standard global 100 Wcm AM 1.5 G illumination.

Delocalization tunable by ligand substitution in [L2Al]n−complexes highlights a mechanism for strong electronic coupling

“…Disproportionation of the MV state has been observed for MV naphthidines with ED groups, whereas EW groups, such as fluorine favored formation of the oxidized dications. 12 Although limited by synthetic challenges in many instances, the effect of ED or EW substitution on organic MV systems including phenylenediamine, 13 bis(triarylamine), 14 or naphthidine radical cations, 12 has been explored: in all cases the MV states are strongly coupled “charge resonance” compounds and the coupling is not significantly affected by substitution of ED and EW substituents on the end-groups. 13,15 The compounds are all considered Class III delocalized.…”

Near-infrared absorbing π-extended hexadeca substituted phthalocyanines

“…The Pcs exhibit a strong Q band in the near-IR region and by increasing size of the π -system, or substituting from non-peripheral positions, it can be shifted to longer wavelengths. [2,5,12,38] As shown in Figure 4…”

“…Near-infrared (near-IR) dyes are required for various advanced technologies and phthalocyanine (Pc) is one of the most important and well-studied of the near-IR absorbing dyes. [1,2] Pc derivatives have a wide array of applications, varying from their conventional use as green or blue dyes and pigments to more recent applications in photovoltaic cells [3][4][5], photodynamic therapy of cancer [2], catalysis [6], organic semiconductors [7], and nonlinear optics [8][9][10].…”

Low‐Symmetry Phthalocyanine Cobalt Bis(dicarbollide) Conjugate for Hydrogen Reduction

“…Phthalocyanines (Pcs) and their metal complexes (MPcs) have been used in a variety of contexts in both molecular science (e.g., as catalysts) and materials science to support effects such as electrochromism, sensing, and hydrogen production with modified electrodes . The advantage of these materials is that their features can be easily modified by the addition of metal ions in the central cavity and varied substituents on the periphery …”