Convergent Strategy for the Regioselective Synthesis of Nonaggregated α-Triaryl-β-carboxy Zinc Phthalocyanines

The windmill, the dragon, and the frog: geometry control over the spectral, magnetic, and electrochemical properties of cobalt phthalocyanine regioisomers

For the first time, we have prepared non-aggregating phthalocyanine cobalt complexes as a set of resolved positional isomers. These compounds comprise a unique test bed for the structure-properties studies, as their optical and electrochemical properties are influenced by the planarity of the phthalocyanine macrocycle, which can be controlled by the positional isomerism of the bulky aromatic substituents at the α-phthalo sites. We support our conclusions with molecular modelling studies, which show a perfect match between the calculated and experimentally determined spectral/electrochemical values. We challenge a common perception that the NMR spectra of cobalt phthalocyanines cannot be measured due to the paramagnetic nature of Co(II). We suggest instead that the key factors affecting the NMR spectral resolution are molecular aggregation and π-π stacking. These interactions are suppressed by the bulky peripheral substituents on the cobalt phthalocyanines prepared, making these isomeric compounds an excellent tool for paramagnetic NMR studies.

Quantum-Classical Protocol for Efficient Characterization of Absorption Lineshape and Fluorescence Quenching upon Aggregation: The Case of Zinc Phthalocyanine Dyes

A quantum-classical protocol that incorporates Jahn-Teller vibronic coupling effects and cluster analysis of molecular dynamics simulations is reported, providing a tool for simulations of absorption spectra and ultrafast nonadiabatic dynamics in large molecular photosystems undergoing aggregation in solution. Employing zinc phthalocyanine dyes as target systems, we demonstrated that the proposed protocol provided fundamental information on vibronic, electronic couplings and thermal dynamical effects that mostly contribute to the absorption spectra lineshape and the fluorescence quenching processes upon dye aggregation. Decomposing the various effects arising upon dimer formation, the structure-property relations associated with their optical responses have been deciphered at atomistic resolution.

Low-Symmetry Phthalocyanines Bearing Carboxy-Groups: Synthesis, Spectroscopic and Quantum-Chemical Characterization

The synthesis and characterization of A₃B-type phthalocyanines, ZnPc1–4, bearing bulky 2,6-diisopropylphenoxy-groups or chlorine atoms on isoindoline units “A” and either one or two carboxylic anchors on isoindoline unit “B” are reported. A comparison of molecular modelling with the conventional time dependent—density functional theory (TD-DFT) approach and its simplified sTD-DFT approximation provides further evidence that the latter method accurately reproduces the key trends in the spectral properties, providing colossal savings in computer time for quite large molecules. This demonstrates that it is a valuable tool for guiding the rational design of new phthalocyanines for practical applications.

A new sterically hindered asymmetric zinc phthalocyanine as an efficient sensitizer for dye-sensitized solar cells

A novel push–pull zinc phthalocyanine dye (KH1) containing 2,6-di-tert-butyl-4-methylphenoxy donor groups was synthesized for DSSCs. The DSSC based on the dye exhibited a PCE of 3.12%.

Metal-free regioselective C5-cyanoalkylation of the 8-aminoquinolineamides/sulfonamides via oxidative cross-dehydrogenative coupling with alkylnitriles

A practical, versatile and Metal-free regioselective C5-cyanoalkylation of the 8-aminoquinolineamides/sulfonamides with acetonitrile has been described.

Iridium-catalysed 3,5-bis-borylation of phthalonitrile enables access to a family of C4h octaarylphthalocyanines

Ir-catalysed borylation of phthalonitrile produces both 4-(Bpin)phthalonitrile (1) and 3,5-bis(Bpin)phthalonitrile (2), which are potential divergent intermediates for the synthesis of functionalized phthalocyanines. To exemplify the utility of 2, we have prepared a series of 3,5-bis-arylphthalonitriles that in turn undergo sterically controlled regioselective cyclotetramization to give previously unknown C4h 1,3,8,10,15,17,22,24-octaarylphthalocyanines.

The peripheral and non-peripheral 2H-benzotriazole substituted phthalocyanines: Synthesis, characterization, photophysical and photochemical studies of zinc derivatives

In this study, the novel 3-(1H-benzo[d][1,2,3]triazol-1-yl)methoxy substituted novel phthalonitrile compounds (2 and 6) were synthesized. Their non-peripheral and peripheral zinc (II) (3 and 7), manganese (III) (4 and 8) and copper (II) (5 and 9) phthalocyanine complexes were synthesized for the first time. These novel compounds were characterized by elemental analysis and different spectroscopic techniques such as FT-IR, UV-Vis, ¹H NMR, ¹³C NMR and MALDI-TOF mass. Also, photochemical and photophysical properties of non-peripheral and peripheral substituted zinc (II) phthalocyanines (3 and 7) were investigated for determination of photodynamic therapy applications of these phthalocyanines.

Introducing rigid π-conjugated peripheral substituents in phthalocyanines for DSSCs

A new carboxy-Zn(II)phthalocyanine bearing rigid 2,6-diarylphenyl peripheral substituents linked to the macrocycle through alkynyl spacers has been prepared by a convergent approach, which implies a triple Sonogashira coupling between the formyltriiodoZnPc and the corresponding terminal alkyne. Indeed, the introduction of this type of [Formula: see text]-conjugated peripheral substituents accounts for a remarkable red shift of the phthalocyanine Q-band until ca. 700 nm. However, aggregation phenomena could not be supressed and may explain the moderate overall efficiencies achieved with these devices.