Synthesis and Photophysical Properties of Fullerene–Phthalocyanine–Porphyrin Triads and Pentads

Abstract

The synthesis and photophysical properties of several fullerene-phthalocyanine-porphyrin triads (1-3) and pentads (4-6) are described. The three photoactive moieties were covalently connected in an one-step synthesis through 1,3-dipolar cycloaddition to C(60) of the corresponding azomethine ylides generated in situ by condensation reaction of a substituted N-porphyrinylmethylglycine derivative and an appropriated formyl phthalocyanine or a diformyl phthalocyanine derivative, respectively. ZnP-C(60)-ZnPc (3), (ZnP)(2)-ZnPc-(C(60))(2) (6), and (H(2)P)(2)-ZnPc-(C(60))(2) (5) give rise upon excitation of their ZnP or H(2)P components to a sequence of energy and charge-transfer reactions with, however, fundamentally different outcomes. With (ZnP)(2)-ZnPc-(C(60))(2) (6) the major pathway is an highly exothermic charge transfer to afford (ZnP)(ZnP(.+))-ZnPc-(C(60)(.-))(C(60)). The lower singlet excited state energy of H(2)P (i.e., ca. 0.2 eV) and likewise its more anodic oxidation (i.e., ca. 0.2 V) renders the direct charge transfer in (H(2)P)(2)-ZnPc-(C(60))(2) (5) not competitive. Instead, a transduction of singlet excited state energy prevails to form the ZnPc singlet excited state. This triggers then an intramolecular charge transfer reaction to form exclusively (H(2)P)(2)-ZnPc(.+)-(C(60)(.-))(C(60)). A similar sequence is found for ZnP-C(60)-ZnPc (3).

Convergent Synthesis of Near‐Infrared Absorbing, “Push–Pull”, Bisthiophene‐Substituted, Zinc(II) Phthalocyanines and their Application in Dye‐Sensitized Solar Cells

“…Scheme 1 shows the synthetic route followed. The statistical cross condensation of 4-iodophthalonitrile [16] and 4-hydroxymethyl-phthalonitrile [17] yielded a mixture of two main Pc products, namely, the desired, unsymmetrically substituted, ZnPc 4 and the symmetrically substituted Zn II tetraiodophthalocyanine. [14] After purification by column chromatography, ZnPc 4 was subjected to oxidation in the presence of the periodinane derivative…”

Push–Pull Zinc Phthalocyanine Bearing Hexa-Tertiary Substituted Carbazolyl Donor Groups for Dye-Sensitized Solar Cells

“…bis(3,6-di-tert-butyl-9H-carbazol-9-yl)phthalonitrile(1) and 4-(hydroxymethyl)phthalonitrile(2),[37] have been prepared according to published procedures.Tri-tert-butylcarbazolyl-hydroxymethylphthalocyaninatozinc(II) (3): A mixture of 4,5-bis(3,6-di-tert-butyl-9H-carbazol-9-yl)phthalonitrile (1) (737 mg, 4 mmol), 4-hydroxymethylphthalonitrile (2) [37] (158 mg, 1 mmol) and Zn(AcO) 2 (330 mg, 1.5 mmol) in DMAE (4 mL) was refluxed during 24 h. The solvent was evaporated under reduced pressure, and the crude product was purified by column chromatography (SiO2, ethyl acetate/cyclohexane 9:1) to afford 3 as a deep green solid (130 mg, 14%); m.p. > 300 • C; 1 H NMR (600 MHz, DMSO-d 6 ) δ = 9.82 (d, 6H), 9.82 (s, 1H), 9.43 (d, 2H), 8.58 (s, 1H), 7.96-7.79 (m, 12H), 7.39-7.30 (m, 12H), 7.13-7.05 (m, 12H), 6.07 (bs, 3H), 1.37-1.30 (brs, 108H).…”

Chemical physics behind formation of efficient charge-separated state for complexation between PC70BM and designed diporphyrin in solution

“…In particular, their unique electronic and optical properties make these complexes as promising donors for photovoltaic devices [6] and to mimic the photosynthetic system [7][8][9][10][11][12]. The covalently connected fullerene/porphyrin dyads and triads were extensively investigated with the purpose of generating photocurrent, in addition to their unique photophysical and photochemical properties [13,14]. Supramolecular donor-acceptor hybrids consisting fullerene and porphyrin finds potential application in sensing, switching and catalysis other than electron transfer [15].…”