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A novel supramolecular electron donor-acceptor hybrid (2·1) and an electron donor-acceptor conjugate (3), both exhibiting a remarkably shifted Q band in the NIR region of the solar spectrum, were prepared. Irradiation of the supramolecular ensemble 2·1 within the visible range leads to a nanosecond lived radical-ion pair state Zn-azulenocyanine˙(+)-C(60)˙(-)., (This journal is © The Royal Society of Chemistry 2012)

The synthesis and photophysical properties of several porphyrin (P)-phthalocyanine (Pc) conjugates (P-Pc; 1-3) are described, in which the phthalocyanines are directly linked to the β-pyrrolic position of a meso-tetraphenylporphyrin. Photoinduced energy- and electron-transfer processes were studied through the preparation of H(2)P-ZnPc, ZnP-ZnPc, and PdP-ZnPc conjugates, and their assembly through metal coordination with two different pyridylfulleropyrrolidines (4 and 5). The resulting electron-donor-acceptor hybrids, which were formed by axial coordination of compounds 4 and 5 with the corresponding phthalocyanines, mimicked the fundamental processes of photosynthesis; that is, light harvesting, the transduction of excited-state energy, and unidirectional electron transfer. In particular, photophysical studies confirmed that intramolecular energy-transfer resulted from the S(2) excited state as well as from the S(1) excited state of the porphyrins to the energetically lower-lying phthalocyanines, followed by an intramolecular charge-transfer to yield P-Pc(.+)⋅C(60)(.-). This unique sequence of processes opens the way for solar-energy-conversion processes., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

In the current work, we report on the synthesis and photophysical features of supramolecular hybrid systems that are based on newly fused porphyrin-phthalocyanine (P-Pc) conjugates and a pyridylfullerene. The ZnP-ZnPc conjugate was synthesized in three steps starting with a Diels-Alder reaction between β-vinylporphyrin and fumaronitrile. The resulting mixture of isomeric adducts was then dehydrogenated to yield the corresponding benzo[b]porphyrin-2(1),2(2)-dicarbonitrile. In the final step, cyclotetramerization with 4-tert-butylphthalonitrile, in the presence of zinc acetate, afforded the bis-metalated conjugate. Selective demetallation of ZnP led to the H(2)P-ZnPc conjugate. For both conjugates steric hindrance is the inception to a bent configuration, which does, however, not preclude enlargement of the π-conjugated system, that is, the porphyrins and the phthalocyanines. The two conjugates coordinate N-(4-pyridyl)fullero[c]pyrrolidine giving rise to the corresponding supramolecular porphyrin-phthalocyanine-fullerene systems. Photophysical measurements corroborate a sequential deactivation in the excited state, namely an initial intramolecular energy transfer from ZnP or H(2)P to ZnPc followed by an intramolecular charge transfer to yield ZnP-(ZnPc)˙(+)-(C(60))˙(-) and H(2)P-(ZnPc)˙(+)-(C(60))˙(-), respectively., (This journal is © the Owner Societies 2011)

We have synthesized two different fullerene-subphthalocyanine-ferrocene conjugates. The molecules were designed so that the ferrocene unit is linked at the subphthalocyanine axial position through a phenoxy spacer while the C(60) is rigidly held close to the concave face of the macrocycle via a 3-fold C(3)-symmetrical anchoring. The Bingel trisaddition reaction leading to the final products proceeded with very high regioselectivities and full diastereoselectivity. The only difference between both systems is the length of the triple tether employed, which finely regulates the regioselectivity of the trisaddition reaction and the distance between the subphthalocyanine and the C(60) complementary π-π surfaces. Thus, when the tether is connected to the subphthalocyanine through a direct C-C bond, a short π-π distance of 3.25-3.30 Å was calculated. In contrast, when it is connected through a slightly longer C-O-C bond, the distance increases to 3.5-3.6 Å. This π-π distance has a strong influence on the ground-state electronic interactions between the subphthalocyanine and the C(60), as determined from electronic absorption and cyclic voltammetry measurements. In addition, fluorescence and time-resolved transient absorption experiments demonstrated that different mechanisms operate in the two systems after photoexcitation. Despite the similar HOMO-LUMO gaps, only when the two complementary π-π surfaces of the subphthalocyanine and the C(60) are held at a close distance, therefore showing a high degree of orbital overlap, is a multistep electron transfer process triggered, ultimately leading to the long-lived, spatially separated C(60) radical anion and ferrocenium radical cation pair. A full account of the synthesis, characterization, and studies of the ground- and excited-state electronic interactions occurring in these conjugates, as well as in their reference C(60)-subphthalocyanine and subphthalocyanine-ferrocene dyads, is presented in this article.

A panchromatic 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene-zinc phthalocyanine conjugate (Bodipy-ZnPc) 1 was synthesized starting from phthalocyanine aldehyde 4, via dipyrromethane 3 and dipyrromethene 2. Conjugate 1 represents the first example in which a Bodipy unit is tethered to the peripheral position of a phthalocyanine core. Electrochemical and optical measurements provided evidence for strong electronic interactions between the Bodipy and ZnPc constituents in the ground state of 1. When conjugate 1 is subjected to photoexcitation in the spectral region corresponding to the Bodipy absorption, the strong fluorescence characteristic of the latter subunit is effectively quenched (i.e., > or = 97%). Excitation spectral analysis confirmed that the photoexcited Bodipy and the tethered ZnPc subunits interact and that intraconjugate singlet energy transfer occurs with an efficiency of ca. 25%. Treatment of conjugate 1 with N-pyridylfulleropyrrolidine (8), an electron-acceptor system containing a nitrogen ligand, gives rise to the novel electron donor-acceptor hybrid 1<-->8 through ligation to the ZnPc center. Irradiation of the resulting supramolecular ensemble within the visible range leads to a charge-separated Bodipy-ZnPc(*+)-C(60)(*-) radical-ion-pair state, through a sequence of excited-state and charge transfers, characterized by a remarkably long lifetime of 39.9 ns in toluene.

A novel series of double-decker lanthanide(III) bis(phthalocyaninato)-C(60) dyads [Ln(III)(Pc)(Pc')]-C(60) (M=Sm, Eu, Lu; Pc=phthalocyanine) (1 a-c) have been synthesized from unsymmetrically functionalized heteroleptic sandwich complexes [Ln(III)(Pc)(Pc')] (Ln=Sm, Eu, Lu) 3 a-c and fulleropyrrolidine carboxylic acid 2. The sandwich complexes 3 a-c were obtained by means of a stepwise procedure from unsymmetrically substituted free-base phthalocyanine 5, which was first transformed into the monophthalocyaninato intermediate [Ln(III)(acac)(Pc)] and further reacted with 1,2-dicyanobenzene in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). (1)H NMR spectra of the bis(phthalocyaninato) complexes 3 a-c and dyads 1 a-c were obtained by adding hydrazine hydrate to solutions of the complexes in [D(7)]DMF, a treatment that converts the free radical double-deckers into the protonated species, that is, [Ln(III)(Pc)(Pc')H] and [Ln(III)(Pc)(Pc')H]-C(60). The electronic absorption spectra of 3 a-c and 1 a-c in THF exhibit typical transitions of free-radical sandwich complexes. In the case of dyads 1 a-c, the spectra display the absorption bands of both constituents, but no evidence of ground-state interactions could be appreciated. When the UV/Vis spectra of 3 a-c and 1 a-c were recorded in DMF, typical features of the reduced forms were observed. Cyclic voltammetry studies for 3 a-c and 1 a-c were performed in THF. The electrochemical behavior of dyads 1 a-c is almost the exact sum of the behavior of the components, namely the double-decker [Ln(III)(Pc)(Pc')] and the C(60) fullerene, thus confirming the lack of ground-state interactions between the electroactive units. Photophysical studies on dyads 1 a-c indicate that only after irradiation at 387 nm, which excites both C(60) and [Ln(III)(Pc)(Pc')] components, a photoinduced electron transfer from the [Ln(III)(Pc)(Pc')] to C(60) occurs.

Two isomeric [5,6]-pyrrolidine-I(h)-Sc(3)N@C(80) electron donor-acceptor conjugates containing triphenylamine (TPA) as the donor system were synthesized. Electrochemical and photophysical studies of the novel conjugates were made and compared with those of their C(60) analogues, in order to determine (i) the effect of the linkage position (N-substituted versus 2-substituted pyrrolidine) of the donor system in the formation of photoinduced charge separated states, (ii) the thermal stability toward the retro-cycloaddition reaction, and (iii) the effect of changing C(60) for I(h)-Sc(3)N@C(80) as the electron acceptor. It was found that when the donor is connected to the pyrrolidine nitrogen atom, the resulting dyad produces a significantly longer lived radical pair than the corresponding 2-substituted isomer for both the C(60) and I(h)-Sc(3)N@C(80) dyads. In addition to that, the N-substituted TPA-I(h)-Sc(3)N@C(80) dyad has much better thermal stability than the 2-substituted one. Finally, the I(h)-Sc(3)N@C(80) dyads have considerably longer lived charge separated states than their C(60) analogues, thus approving the advantage of using I(h)-Sc(3)N@C(80) instead of C(60) as the acceptor for the construction of fullerene based donor-acceptor conjugates. These findings are important for the design and future application of I(h)-Sc(3)N@C(80) dyads as materials for the construction of plastic organic solar cells.

The first pyrrolidine and cyclopropane derivatives of the trimetallic nitride templated (TNT) endohedral metallofullerenes I(h)-Sc(3)N@C(80) and I(h)-Y(3)N@C(80) connected to an electron-donor unit (i.e., tetrathiafulvalene, phthalocyanine or ferrocene) were successfully prepared by 1,3-dipolar cycloaddition reactions of azomethine ylides and Bingel-Hirsch-type reactions. Electrochemical studies confirmed the formation of the [6,6] regioisomers for the Y(3)N@C(80)-based dyads and the [5,6] regioisomers in the case of Sc(3)N@C(80)-based dyads. Similar to other TNT endohedral metallofullerene systems previously synthesized, irreversible reductive behavior was observed for the [6,6]-Y(3)N@C(80)-based dyads, whereas the [5,6]-Sc(3)N@C(80)-based dyads exhibited reversible reductive electrochemistry. Density functional calculations were also carried out on these dyads confirming the importance of these structures as electron transfer model systems. Furthermore, photophysical investigations on a ferrocenyl-Sc(3)N@C(80)-fulleropyrrolidine dyad demonstrated the existence of a photoinduced electron-transfer process that yields a radical ion pair with a lifetime three times longer than that obtained for the analogous C(60) dyad.

Getting connected: The use of a bis(dipyrrinato)zinc(II)) linker allows the facile tethering of two C(60) subunits and gives rise to an electronically coupled system that allows effective charge separation following photoexcitation (see figure).

A novel dimeric phthalocyanine-C60 nanoconjugate, consisting of a bisphthalocyanine core to which two fullerenes are attached, has been prepared. The synthetic strategy implemented the preparation of a diformyl butadiynyl-bridged bisphthalocynaninato-zinc(II) complex by means of palladium-catalyzed cross-coupling reactions and subsequent dipolar cycloaddition reactions. Photophysical experiments confirm that an intramolecular electron transfer, namely, from the photoexcited ZnPc moiety to the electron-accepting C60 unit, governs the overall photoreactivity of the nanoconjugate. Through-space charge-transfer interactions facilitated by the close proximity of the ZnPc and the C60 moieties play a decisive role in determining the lifetimes of the charge-separated state which range from 10(-10) to 10(-9) seconds.

A series of three novel ZnPc-C60 conjugates (Pc=phthalocyanine) 1 a-c bearing different spacers (single, double, and triple bond) between the two electroactive moieties was synthesized and compared to that of ZnPc-C60 conjugate 2, in which the two electroactive moieties are linked directly. The synthetic strategy- towards the preparation of 1 a-c- involved palladium-catalyzed cross-coupling reactions over a monoiodophthalocyanine precursor 4 to introduce the corresponding spacer, and subsequent dipolar cycloaddition reaction to C60. Detailed photophysical investigations of 1 a-c and 2 prompted an intramolecular electron transfer that evolves from the photoexcited ZnPc to the electron-accepting C60. In particular, with the help of femtosecond laser photolysis charge separation was indeed confirmed as the major deactivation channel. Complementary time-dependent density functional calculations supported the spectral assignment, namely, the spectral identity of the ZnPc(*+) radical cation and the C60 (*-) radical anion as seen in the differential absorption spectra. The lifetimes of the correspondingly formed radical ion-pair states depend markedly on the solvent polarity: they increase as polarity decreases. Similarly, although to a lesser extent, the nature of the linker impacts the lifetime of the radical ion-pair states. In general, the lifetimes of these states tend to be shortest in the system that lacks any spacer at all (2), whereas the longest lifetimes were found in the system that carries the triple-bond spacer (1 a).

We have prepared two complementary series of SubPc-C(60) (SubPc=subphthalocyanine) electron/energy donor-acceptor systems, in which the two constituents are linked through ortho-, meta-, or para-substituted phenoxy spacers. In one of the series (1 a) the SubPc units bear iodine atoms, while in the other series (1 b) diphenylamino groups are linked to the SubPc macrocycles. The iodine atoms and diphenylamino groups both influence the resulting oxidation potentials of the electron-donating SubPc. They also modulate the outcome of excited state interactions, namely, energy and/or charge transfer. In addition, we have studied the impact that the substitution pattern in the phenoxy spacer exerts onto intramolecular processes in the ground and excited states. Although some of these processes are governed by the spatial separation between both components, the different electronic coupling through ortho-, meta-, or para- connections also plays decisive roles in some cases.

Herein we report the first example of a supramolecular cage that works as a catalytic molecular reactor to perform transformations over fullerenes in aqueous medium. Taking advantage of the ability of metallo–organic Pd(II)‐subphthalocyanine (SubPc) capsules to form stable host:guest complexes with C60, we have prepared a water‐soluble cage that provides a hydrophobic environment for conducting cycloadditions over encapsulated C60, namely, Diels–Alder reactions with anthracene. Indeed, the presence of catalytic amounts of SubPc cage dissolved in water promotes co‐encapsulation of insoluble C60 and anthracene substrates, allowing the reaction to occur inside the cavity under mild conditions. The lower stability of the host:guest complex with the resulting C60 cycloadduct facilitates its displacement by pristine C60, which grants catalytic turnover. Moreover, bis‐addition compounds are regioselectively formed inside the cage when using excess anthracene. [ABSTRACT FROM AUTHOR]

Subphthalocyanine (SubPc) chemistry has been limited so far by their high sensitivity toward strong nucleophiles. In particular, the substitution of the axial chlorine atom by a nucleophilic group in the case of less‐reactive SubPcs, such as those bearing electron‐withdrawing peripheral substituents, presents some limitations and requires harsh conditions. By taking advantage of the electrophilic character of DIBAL‐H, it has been possible to prepare for the first time SubPc‐hydride derivatives that exhibit high reactivity as hydroboration reagents of aldehydes. This hydride transfer requires using a typical carbonyl activator (trimethylsilyl triflate) and only one equivalent of aldehyde, affording SubPcs with an axial benzyloxy group in good yield. This transformation has proven to be a useful alternative method for the axial functionalisation of dodecafluoroSubPc, a paradigmatic SubPc derivative, by using electrophiles for the first time. Considering the increasing interest in SubPcs as electron‐acceptor semiconductors with remarkable absorption in the visible range to replace fullerene in organic photovoltaic (OPV) devices, it is of the utmost importance to develop new synthetic methodologies for their axial functionalisation. [ABSTRACT FROM AUTHOR]

In the scientific race to build up photoactive electron donor‐acceptor systems with increasing efficiencies, little is known about the interplay of their building blocks when integrated into supramolecular nanoscale arrays, particularly in aqueous environments. Here, we describe an aqueous donor‐acceptor ensemble whose emergence as a nanoscale material renders it remarkably stable and efficient. We have focused on a tetracationic zinc phthalocyanine (ZnPc) featuring pyrenes, which shows an unprecedented mode of aggregation, driven by subtle cooperation between electrostatic and π–π interactions. Our studies demonstrate monocrystalline growth in solution and a symmetry‐breaking intermolecular charge transfer between adjacent ZnPcs upon photoexcitation. Immobilizing a negatively charged fullerene (C60) as electron acceptor onto the monocrystalline ZnPc assemblies was found to enhance the overall stability, and to suppress the energy‐wasting charge recombination found in the absence of C60. Overall, the resulting artificial photosynthetic model system exhibits a high degree of preorganization, which facilitates efficient charge separation and subsequent charge transport. [ABSTRACT FROM AUTHOR]

The regio- and stereocontrolled synthesis of fullerene bisadducts is a topic of increasing interest in fullerene chemistry and a key point for the full exploitation of these derivatives in materials science. In this context, while the tether-directed remote functionalization strategy offers a valid approach to this synthetic challenge, no examples of such control have yet been reported using nontethered species. Presented here is a conceptually novel, supramolecular-directed functionalization approach in which noncovalent interactions between untethered residues have been used, for the first time, to amplify (>2800-fold) the regio-, stereo-, and atropselective formation of a C60 fullerene bisadduct racemate from a complex mixture of 130 bisadducts. Remarkably, both enantiomers, which present a sterically demanding cis-1 C60 addition pattern, represent the first examples of fullerene derivatives which combine central, axial, and helical chirality. [ABSTRACT FROM AUTHOR]

A zinc phthalocyanine endowed with four [18]-crown-6 moieties, ZnPcTeCr, has been prepared and self-assembled with either pyridyl-functionalized perylenebisimides (PDI-Py) or fullerenes (C60-Py) to afford a set of novel electron donor-acceptor hybrids. In the case of ZnPcTeCr, aggregation has been circumvented by the addition of potassium or rubidium ions to lead to the formation of monomers and cofacial dimers, respectively. From fluorescence titration experiments, which gave rise to mutual interactions between the electron donors and the acceptors in the excited state, the association constants of the respective ZnPcTeCr monomers and/or dimers with the corresponding electron acceptors were derived. Complementary transient-absorption experiments not only corroborated photoinduced electron transfer from ZnPcTeCr to either PDI-Py or C60-Py within the electron donor-acceptor hybrids, but also the unexpected photoinduced electron transfer within ZnPcTeCr dimers. In the electron donor-acceptor hybrids, the charge-separated-state lifetimes were elucidated to be close to 337 ps and 3.4 ns for the two PDI-Pys, whereas the longest lifetime for the photoactive system that contains C60-Py was calculated to be approximately 5.1 ns. [ABSTRACT FROM AUTHOR]

Invited for this month's cover are the collaborating groups of Prof. Ángela Sastre‐Santos, Universidad Miguel Hernández, Prof. Lluis F. Marsal, Universitat Rovira i Virgili and Prof. Tomás Torres, Universidad Autónoma de Madrid, Spain. The cover shows a toy doll holding an umbrella which represents a non‐planar, highly conjugated subphthalocyanine‐diketopyrrolopyrrole hybrid molecule for non‐fullerene organic solar cells. When the sun shines on the umbrella, it absorbs the light, and the doll slides down a polymeric flexible solar cell like a slide, where electrons are produced and electricity flows into the magic wand to illuminate the room. More information can be found in theFull Paper by Ángela Sastre‐Santos, Lluis F. Marsal, Tomás Torres, and co‐workers. [ABSTRACT FROM AUTHOR]

In this communication, encapsulation studies between metallosupramolecular capsule 1, formed by 2 subphthalocyanines (SubPcs) coordinated to 3 metallic centers, and phthalocyanine (Pc)-C60 fullerene conjugates 2-5 have been carried out. It was shown that the encapsulation of the C60 moiety by the SubPc cage occurred exclusively for dyads 2-4, whereas it was not observed in the case of triad 5. The rigidity of the linker between the Pc and the fullerene unit proved to have an important impact in the complex formation. Complex formation was tested in 2 different solvents, where the importance of solvophobic effects was highlighted. The resulting multicomponent supramolecular systems represent a unique combination of photoactive moieties where covalent and supramolecular chemistry coexist. [ABSTRACT FROM AUTHOR]

Diketopyrrolopyrroles, non-fullerene acceptor, organic solar cells, -systems, subphthalocyanines Front Cover: Subphthalocyanine-Diketopyrrolopyrrole Conjugates: 3D Star-Shaped Systems as Non-Fullerene Acceptors in Polymer Solar Cells with High Open-Circuit Voltage (ChemPlusChem 10/2021) Keywords: diketopyrrolopyrroles; non-fullerene acceptor; organic solar cells; -systems; subphthalocyanines EN diketopyrrolopyrroles non-fullerene acceptor organic solar cells -systems subphthalocyanines 1357 1357 1 10/29/21 20211001 NES 211001 B The Cover shows b a toy doll holding an umbrella which represents a non-planar, highly conjugated subphthalocyanine-diketopyrrolopyrrole hybrid molecule for non-fullerene organic solar cells. [Extracted from the article]

We report on the remarkable organization properties of a covalently-linked phthalocyanine–C60fullerene conjugate which is able to self-organize by means of non-covalent interactions on the outer wall of single-walled carbon nanotubes (SWCNTs). [ABSTRACT FROM AUTHOR]

A correction to the article "Porphyrin-Phthalocyanine/Pyridylfullerene Supramolecular Assemblies" that was publsihed in the 2012 issue is presented.

Abstract: A photo- and redoxactive system ZnPc-oPPV-C60 2, in which the photoexcited state electron donor – zinc phthalocyanine – and the ground state electron acceptor – C60 – are connected by a oligo(p-phenylenevinylene) (oPPV) spacer, has been synthesized in a multi-step synthesis by means of two consecutive Wadsworth–Horner–Emmons and a dipolar 1,3-cycloaddition reactions as key steps. The simpler system ZnPc-C60 1 has also been prepared as a reference model for photophysical studies. In this regards, the photophysical investigations by means of fluorescence, flash photolysis, and transient-absorption spectroscopy have manifested a clear dependence between charge transfer kinetics and spatial arrangement. In both systems, intramolecular charge separation evolves from the photoexcited ZnPc and yields the ZnPc·+/C60 ·- radical ion pairs. Interestingly, the ZnPc·+/C60 ·- radical ion pair lifetimes and quantum yields are strongly impacted by the solvent polarity and the distance. To this end, maximum radical ion pair lifetimes of 2900 and 5530ps were found in anisol for 1 and 2, respectively. [Copyright &y& Elsevier]

The convergent synthesis, electrochemical characterization, and photophysical studies of phthalocyanine-fullerene hybrids 3-5 bearing an orthogonal geometry (Chart 2) are reported. These donor-acceptor arrays have been assembled through metal coordination of linear fullerene mono- and bispyridyl ligands to ruthenium(ll) phthalocyanines. The hybrid [Ru(CO)(C60Py)Pc] (3) and the triad [Ru2(CO)2(C60Py2)Pc2] (5) were prepared by treatment of the phthalocyanine 6 with the mono- and hexakis-substituted C60-pyridyl ligands 1 and 2, respectively. The triad [Ru(C60Py)2Pc] (4) was prepared in a similar manner from the monosubstituted C60-pyridyl ligand 1 and the phthalocyanine precursor 7. The simplicity of this versatile synthetic approach allows to determine the influence of the donor and acceptor ratio in the radical ion pair state lifetime. The chemical, electrochemical, and photophysical characterization of the phthalocyanine-fullerene hybrids 3-5 was conducted using ¹H and 13C NMR, UV/vis, and IR spectroscopies, as well as mass spectrometry, cyclic voltammetry, femtosecond transient absorption studies, and nanosecond laser flash photolysis experiments. Arrays 3-5 exhibit electronic coupling between the two electroactive components in the ground state, which is modulated by the axial CO and 4-pyridylfulleropyrrolidine ligands. With respect to the excited state, we have demonstrated that RuPc/C60 electron donor-acceptor hybrids are a versatile platform to fine-tune the outcome and dynamics of charge transfer processes. The use of ruthenium(ll) phthalocyanines instead of the corresponding zinc(ll) complexes allows the suppression of energy wasting and unwanted charge recombination, affording radical ion pair state lifetimes on the order of hundreds of nanoseconds for the C60-monoadduct-based complexes 3 and 4. For the hexakis-substituted C60 unit 2, the reduction potential is shifted cathodically, thus raising the radical ion pair state energy. However, the location of the RuPc triplet excited state is not high enough, and still offers a rapid deactivation of the radical ion pair state. [ABSTRACT FROM AUTHOR]

Within the present work, two series of novel ruthenium(ll) phthalocyanine (RuPc) complexes with one [RuPcCOPy-nT] or two [RuPc(Py-nT)[sub2]] dendritic oligothiophene (DOT) ligands in the axial positions are reported. The ability of Ru" for axial coordination in RuPcs allowed the attachment of the Pc through the metal site to the DOT-ligands bearing pyridine at the core position of the dendrons. These extended pyridine functionalized conjugated DOT-ligands (Py-nT) were chosen to cover the spectral window between 380 and 550 nm, where the RuPc does not exhibit a strong absorption, in order to improve the light- absorption of these complexes and hence enhance the efficiency of the corresponding solar cells. Good efficiencies of up to 1.6% have been achieved when blended together with a fullerene acceptor in solution- processed photovoltaic devices, providing by far the best phthalocyanine-based bulk heterojunction solar cells reported to-date. [ABSTRACT FROM AUTHOR]

The use of blends in which a mesogen induces mesomorphism into a non-mesogenic compound has made possible the self-organization of phthalocyanine—[60]fullerene (Pc-C60) dyads into liquid crystals. Pc-C60 dyads 1, 2, or 3, in which two photoactive units are brought together by a phenylenevinylene spacer, have been synthesized through a Heck reaction that links 4-vinylbenzaldehyde to a monoiodoph- thalocyanine precursor, followed by standard cycloaddition of azomethine ylides—generated from the formylPc derivative and N-methylglycine—to one of the double bonds of C60. The mesomorphic and thermal properties of different mixtures formed by the liquid-crystalline phthalocyanine 4 and dyads 1, 2, or 3 were examined using polarizing optical microscopy (POM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). DSC diagrams of the blends show clear transitions from the crystalline state to a mesophase, and the measured structural parameters obtained from the powder diffraction experiments are consistent with a discotic hexagonal columnar (Colh) structure. Considering that segregation in domains of separated molecules of Pc-C60 dyad and phthalocyanine 4 would preclude mesomorphism due to the mismatch in the column diameter and to the lack of mesogenic character of the pure dyads, a predominance of alternating stacking is proposed. Additionally, the observed decrease in the calculated density of the blend mesophases relative to the mesophase of pure compound 4 is important evidence in this direction. [ABSTRACT FROM AUTHOR]

HiPco single-walled carbon nanotubes (SWNTs) have been sidewall-functionalized with phtha- locyanine addends following two different approaches: a straightforward Prato reaction with N-octylglycine and a formyl-containing phthalocyanine, and a stepwise approach that involves a former Prato cycloaddition to the double bonds of SWNTs using p-formyl benzoic acid followed by esterification of the derivatized nanotubes with an appropriate phthalocyanine molecule. The two materials obtained by these routes comprise different carbon/Pc-addenda ratios, as evidenced by Raman, TGA, and photophysical studies. The occurrence of electron transfer from photoexcited phthalocyanines to the nanotube framework in these ZnPc-SWNT ensembles is observed in transient absorption experiments, which confirm the absorption of the one-electron oxidized ZnPc cation and the concomitant bleaching of the van Hove singularities typical from SWNTs. Charge-separation (i.e., 2.0 × 1010 -1) and charge-recombination (i.e., 1.5 × 106 s-1) dynamics reveal a notable stabilization of the radical ion pair product in dimethylformamide. [ABSTRACT FROM AUTHOR]

Abstract: Z-scan experiments have been performed on solutions of tBu4PcTiO2-C60 (2) in order to explore a plausible synergistic effect. For comparative purposes we have also measured C60 and tBu4PcTiO (1) derivatives. The results indicate poorer excited-state absorption of dyad 2 than those of the corresponding individual phthalocyanine and fullerene components. [Copyright &y& Elsevier]

Abstract: Electronic absorption and emission properties of a new cytidine tethered zinc phthalocyanine 2 were used to probe the aggregation and guanosine/C60 derived de-aggregation of this nucleobase linked phthalocyanine. These experiments revealed that 2 aggregates even at low concentrations in a competitive solvent system (1.1×10−6 M in 20% DCM/toluene). Nucleobase–metal coordination and slipped co-facial π-stacking interactions are both important in aggregate formation. Guanosine 5 , C60 6 , and a guanosine-C60 chimera 4 were employed as potential aggregate disruptors. These experiments revealed that both guanosine and fullerene subunits are effective in disrupting the aggregate formed by 2 . Such findings support the conclusion that base-pairing, π-stacking, as well as nucleobase–metal coordination interactions play important roles in the de-aggregation of 2 . [Copyright &y& Elsevier]

• Porphyrinoid-based photo- and electro-active systems within the Torres-Guldi collaboration are reviewed. • Covalent and non-covalent electron donor–acceptor systems based on phthalocyanines/subphthalocyanines and fullerenes. • Covalent and non-covalent electron donor–acceptor systems based on porphyrinoids and non-fullerenic electroactive moieties. • Phthalocyanines for solar cell applications. • Porphyrinoids for sensing, biochemical, and biomedical applications. This review highlights the combined effort of the Torres and Guldi groups in the preparation and study of porphyrinoid-based photo- and electro-active systems. The perfect synergy between the deep knowledge on the chemistry of porphyrinoids and advanced carbon allotropes possessed by the Spanish team, and the profound expertise in the advanced photophysical characterization and photon- and charge-management held by the German group represents the real asset of this transnational collaboration. Along the last twenty years, the two groups have developed a plethora of electron donor–acceptor architectures based mainly on phthalocyanines and subphthalocyanines, but also porphyrins and other porphyrinoids, connected, either covalently or through supramolecular interactions, to several electroactive units such as advanced carbon allotropes, that is, fullerenes, carbon nanotubes, and graphene, among others. Important guidelines relating the structural and electronic features of such photo- and electro-active species with physical aspects such as the dynamics of charge separation, charge transport, charge shift, and charge recombination processes have been obtained. This knowledge has resulted crucial for the implementation of many of these systems into applied research fields such as optoelectronics, solar energy conversion, and biomedicine. [ABSTRACT FROM AUTHOR]