A voyage into the synthesis and photophysics of homo- and heterobinuclear ensembles of phthalocyanines and porphyrins

Abstract

The remarkable properties of both phthalocyanines and porphyrins as individual building blocks have motivated the synthesis and study of homo- and heterobinuclear conjugates as light-harvesting systems. These planar chromophores share important electronic features such as high molar absorption coefficients, rich redox chemistry and interesting photoinduced energy and/or electron transfer abilities. In addition, some of these properties can be tuned by the introduction of different peripheral substituents and metal centres. In this review, we present relevant synthetic strategies for the preparation of covalent and supramolecular, homo- and heterobinuclear systems based on phthalocyanine and porphyrin chromophores, leading to a variety of architectures. In such systems, the degree of electronic interaction between the components is highly dependent on the electronic features of the two macrocycles, their linkage, and the molecular topology of the ensemble. In addition, incorporation of electroactive units into these binuclear systems has been pursued, affording multicomponent, donor-acceptor conjugates. In-depth photophysical characterization of the ground- and excited-state features of many of these homo- and heterobinuclear phthalocyanine and/or porphyrin ensembles has also been presented. Particular attention has been paid to understand the fundamental dynamics of the energy transfer and charge separation processes of these systems. This review intends to offer a general overview of the preparation of this class of compounds and the study of their photophysical properties which clearly show their potentiality as model compounds of light-harvesting complexes.

Versatile Bisethynyl[60]fulleropyrrolidine Scaffolds for Mimicking Artificial Light‐Harvesting Photoreaction Centers

“…In particular, depending on the chemical nature of the carbonyl (aldehyde or ketone) and amino acid derivatives, different functional groups can be introduced on the three different positions of the pyrrolidine ring, and a large variety of [60]fullerene dyads and triads can be synthesized a priori. [7,11,17,[32][33][34][35][36] By taking advantage of the versatile 1,3-dipolar cycloaddition of azomethine ylides to C 60 , [23] we found that ketones could be the precursors of choice to form tetrads. Nevertheless, only a limited number of reports describe the 1,3-dipolar cycloaddition of azomethine ylides using ketones, [37][38][39][40][41][42][43][44][45][46][47] and in most cases with modest yields (< 40 %).…”

“…[6,7] In particular, their use in donor-acceptor systems for photovoltaic devices has impressively expanded. [8,9] To this end, a variety of [60]fullerene derivatives linked to electron-donating units such as, among others, porphyrins, [10][11][12][13][14] tetrathiafulvalenes (TTFs), [15] ferrocene, [16] phthalocyanines, [17] oligophenylenevinylenes, [18] and transition-metal complexes [19][20][21] have been prepared. The mechanisms of photoinduced electron and energy transfer have been elucidated by means of timeresolved spectroscopic methods, thus showing a strong intramolecular quenching of the excited singlet and triplet states of C 60 through the formation of charge-separated (CS) radical ion pairs.…”

“Anti-Michael addition” of Grignard reagents to sulfonylacetylenes: synthesis of alkynes

“…1, 2 The triple bond is extremely important in the assembly of different nano-scale molecules, such as fullerenes, nano-tubes or porphyrins. Moreover, the triple bond moiety has been employed as a starting material for a large number of different reactions, such as click chemistry, 3 alkyne hydroamination, 4 Pd-catalyzed cross-coupling, 5 olefin metathesis, 6 and [2 + 2 + 2] cycloaddition arene formation.…”

“…In the literature, a wide variety of new approaches for incorporating alkyne moieties into organic molecules using metals (formation of C sp -C sp 2 or C sp -C sp 3 bonds) have appeared.…”

Elucidating the Ultrafast Dynamics of Photoinduced Charge Separation in Metalloporphyrin-Fullerene Dyads Across the Electromagnetic Spectrum

“…1 Their ubiquity is also related to strongly coupled electronic and geometric structures that display highly selective responsivity towards the environment. Since their physicochemical attributes are readily modulated by synthetic substitutions on the planar π-conjugated porphyrinring and by the nature of the central metal ion, 2,3 MPs constitute a versatile class of building blocks, which can be incorporated into Donor-Acceptor (D-A) assemblies. These molecular complexes provide a wide range of fullyfunctional systems for photovoltaic [4][5][6] and photocatalytic applications, 7 as well as biomimetic models for disentangling in-vivo working mechanisms.…”