Synthesis and Characterization of Monoisomeric 1,8,15,22-Substituted (A₃B and A₂B₂) Phthalocyanines and Phthalocyanine−Fullerene Dyads

Abstract

Synthesis and characterization of three phthalocyanine-fullerene (Pc-C(60)) dyads, corresponding monoisomeric phthalocyanines (Pc), and building blocks, phthalonitriles, are described. Six novel bisaryl phthalonitriles were prepared by the Suzuki-Miyaura coupling reaction from trifluoromethanesulfonic acid 2,3-dicyanophenyl ester and various oxaborolanes. Two phthalonitriles were selected for the synthesis of A(3)B- and A(2)B(2)-type phthalocyanines. Phthalonitrile 4 has a bulky 3,5-di-tert-butylphenyl substituent at the alpha-phthalo position, which forces only one regioisomer to form and greatly increases the solubility of phthalocyanine. Phthalonitrile 8 has a 3-phenylpropanol side chain at the alpha-position making further modifications of the side group possible. Synthesized monoisomeric A(3)B- and A(2)B(2)-type phthalocyanines are modified by attachment of malonic residues. Finally, fullerene is covalently linked to phthalocyanine with one or two malonic bridges to produce Pc-C(60) dyads. Due to the monoisomeric structure and increased solubility of phthalocyanines, the quality of NMR spectra of the compounds is enhanced significantly, making detailed NMR analysis of the structures possible. The synthesized dyads have different orientations of phthalocyanine and fullerene, which strongly influence the electron transfer (ET) from phthalocyanine to fullerene moiety. Fluorescence quenchings of the dyads were measured in both polar and nonpolar solvents, and in all cases, the quenching was more efficient in the polar environment. As expected, most efficient fluorescence quenching was observed for dyad 20b, with two linkers and phthalocyanine and fullerene in face-to-face orientation.

Regioregular Phthalocyanines Substituted with Bulky Donors at Non‐Peripheral Positions

“…Tetra‐α‐substituted phthalocyanine ( 1 ) was successfully synthesized in a 41 % yield in presence of n ‐hexOLi (Scheme ) . When as‐synthesized Pc 1 was obtained from the quenching of the reaction by the addition of methanol, the as‐synthesized 1 showed a simple 1 H NMR spectrum, suggesting that one isomer was formed by the regioselective tetramerization of 4 .…”

Synthesis and properties of bis(pyrrolidino)fullerenes bridged by a flexible alkyl-tether

“…9 As such, there was a need to improve the selectivity of multiaddition reactions in aim to get pure bisadducts in higher yields. Significant breakthroughs in selectivity were made with rigid tether templated bisaddition 10e14 dfrom selective synthesis of the equatorial mixed BingeleDielseAlder bisadduct in 50% yield, 15 over targeted preparation of a single or major isomer of bis(methano)fullerenes bridged with different poorly flexible spacers (xylenes, 16 Tr€ oger bases, 17 porphyrins, 18,19 crown ethers 20 ) to Prato's bisaddition with bridged bisaldehydes. 21,22 In all cases the spacer geometry strongly influenced the distribution of regioisomers, i.e., its rigidity favoured some of the addition patterns.…”

Fullerene-Based Photoactive Layers for Heterojunction Solar Cells: Structure, Absorption Spectra and Charge Transfer Process

“…Therefore, to construct an efficient artificial photoactive layer, the following characteristics [5,6] are required: (a) the capture of absorption light obtained by antenna molecules; and (b) the absorption of light must lead to direct electron transfer from D to A; and (c) the charge transfer rate must be larger than the charge recombination rate. Usually, the candidates of an electron transfer system with high-efficiency are covalently linked donor and acceptor moieties; for example, some photosensitizing electron donors such as porphyrin, phthalocyanine and ruthenium phthalocyanine, were covalently linked to fullerene [7,8,9]. Another approach is a mixture of fullerene with an electron donor, such as poly(3-hexylthiophene) (P3HT): [60]PCBM, Poly(p-phenylene vinylene) (PPV): [60]PCBM, metallophthalocyanine: fullerene [10,11,12,13,14], etc .…”