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CONTENTS

Modifications of the porphyrin core results in porphyrinoids with novel and unique physical and electronic properties. Recent improvements in synthetic protocols allow the easy replacement of pyrrolic units in the porphyirn core — just like puzzle pieces in a jigsaw. In this review, the various possible core modified porphyrins and their syntheses along with their electronic and spectroscopic properties are summarized.

This micro review focuses on covalently linked phthalocyanine-fullerene conjugates in solutions and solid nanostructures. The covalent bonding enables sufficient degree of control over mutual organization of the donor and acceptor parts, and makes possible to investigate the relationships between molecular structure and functioning of single molecules and molecular assemblies.

Structural features, synthesis and properties of conjugated di- and trinuclear phthalocyanines and their analogs are described. Annulated systems sharing a common benzene ring, condensed ones of fused phthalocyanine ligands and examples of di- and trinuclear phthalocyanines linked via one or two carbon atoms of each macrocycle are discussed.

This review provides an overview of methods for the synthesis of corroles, and a comprehensive description of the chemical reactivity and functionalization of corroles, focusing especially on reactions at the periphery of the macrocycle.

This highlight presents a synopsis of the reported studies on the functionalization of porphyrins using diazo compounds as reagents.

Porphyrinic [2]catenanes were synthesized by using Cu(I)–N interactions to assemble acyclic complexes and the central porphyrinic metal and pyridyl groups to generate rings. The metal can be a substitution-labile metal center such as Zn²⁺ thus favoring reactions performed under thermodynamic control, or substitution inert metals carried out with kinetic control.

The photophysical properties of [22]π-conjugated pentapyrrolic systems, sapphyrin, N-confused and N-fused sapphyrins were investigated. The absorption spectra of N-confused and N-fused sapphyrins was found to exhibit relatively red-shifted features compared to sapphyrin.

The mono nitration of 2,7,12,17-tetraphenylporhycene (TPPo) has been optimized. The resulting 9-nitro-2,7,12,17-tetraphenylporhycene is a versatile derivative useful to prepare TPPo conjugates. With this aim, 9-(glutaric methylesteramide)-2,7,12,17-tetraphenylporphycene was synthetized. Extending the reaction time of the nitration, the dini tration of TPPo can be achieved providing 9,20-dinitro and 9,19-dinitro-2, 7,12,17-tetraphenylporphycenes in a ratio of 3 to 1.

Two zinc(II)porphyrin oligopeptide conjugates (zinc(II)-5,10,15,20-bis[4- (peptide)phenyl]porphyrin and -tetrakis[3,5-di(peptide)phenyl]porphyrin (peptide = -CH₂(CO)Gly-Phe-Ala-CNH₂) were prepared, their photophysical pro perties examined, and their structures addressed by modeling.

Synthesis, characterization and electrochemical redox properties of free-base β-tetrabromo-meso-tetrakis(4′-substituted phenyl)porphyrins and their metal complexes are reported. These derivatives revealed fairly linear trend in the redox potentials with the increase in Hammett parameter of the substituents.

The preparation and characterisation of a number of metallated derivatives of 1,4,8,11,15,18,22,25-octaalkyltetrabenzotriazaporphyrins (TBTAPs) are reported. The mesophase behavior exhibited by compounds has been characterised by differential scanning calorimetry (DSC) and polarized light optical miscoscopy. A parallel was drawn with molecular reorganizations detected in spin coated films of examples of the compounds using variable temperature UV-vis spectroscopy.

A novel approach towards extended phthalocyanines was developed and applied in the synthesis of an octaatriazole-fused naphthalocyanine. This method employs the fusion of an ortho-bis(iodotriazole) system by using the intramolecular homocoupling procedure (orange). Due to the extended core size (by four benzene and eight triazole rings compared with phthalocyanines), this class of materials is predicted to possess strong aggregation properties, which can be modified upon doping of four functional cavities (purple) with metals or guest molecules.

A novel class of sensors based on Langmuir-Blodgett (LB) films a composite lutetium bisphthalocyaninate/carbon nanotube is reported. The influence of the carbon naonotube in the structure of the LB films and in their spectroscopic, chemical, electrochromic and gas sensing properties has been evaluated.

b-Bilene hydrochlorides give zinc(II) and copper(II) isoporphyrin salts upon macrocyclization with a carbonyl-containing linker. Metal-free isoporphyrins were also isolated. In vitro studies using human carcinoma HEp2 cells show that all metallo-isoporphyrins accumulate within cells and localize partially in the mitochondria. The zinc-isoporphyrins were found to be moderately phototoxic while the copper complex showed the lowest phototoxicity.

Benzoporphycenes and naphthoporphycenes were prepared by retro-Diels-Alder reaction of bicyclo[2.2.2]octadiene-fused precursors. The crystal structures of free-base tetrabenzoporhycene showed a herringbone structure, while zinc tetrabenzoporphycene showed a hexagonal box-structure with six pyridine ligands inside. Tetrabenzo-, dibenzo-, and dinaphthoporphycenes showed fluorescence with quantum yields of 0.32, 0.42, and 0.31, respectively, although their precursors were non-fluorescent. Supplementary Material

A series of octabutoxy axial phenoxy silicon phthalocyanines have been prepared from the corresponding phenols. The phenols bear either carboxylic ester or phosphonate groups which, upon deprotection, can serve as anchoring groups for attaching the phthalocyanines to semiconducting metal oxides used in dye sensitized solar cells (DSSCs). All the phthalocyanines of the series absorb in the near infra-red region, 758–776 nm. Based on the first oxidation potential for each phenoxy derivative, these dyes should be able to photosensitize TiO₂.

Facing zinc bisporphyrins connected with diethanoanthracene and diethano naphthacene contain large clefts with different sizes capable for complexation with fullerenes such as C₆₀ and C₇₀. These designed syn-oriented bisporphyrins serve as effective and selective molecular tweezers for C₇₀.

DFT calculations revealed the effect of peripheral substituents on tuning the nature of phthalocyaninato zinc semiconductor: introduction of eight weak electron-donating methoxy groups onto the peripheral positions of ZnPc induces a better p-type semiconductor material while peripheral methoxycarbonyl substitution changes the semiconductor nature from p-type to n-type. Supplementary Material

Two porphyrins of high boron content were synthesized in high yields. Both were found to have low cytotoxicity toward HEp2 cells, and to localize mainly in the cell lysosomes. Animal toxicity studies revealed maximum tolerated doses for these porphyrins of 160 mg/kg and 320 mg/kg, respectively.

Synthesis, IR/UV-visible spectral properties and photoactivity for the generation of singlet oxygen, ¹O₂, were investigated for three related platinated compounds—[(PtCl₂)₄LPt], [LPt] (L = tetrakis-2,3-[5,6-di-(2-pyridyl)pyrazino]porphyrazinato dianion) and [L′Pt](I₈) (L′ = octamethylated L).

The incorporation of metal ions into the chelating tetrapyrrolic ring of a chiral porphyrin of molecular weight around 2000 Daltons makes dramatic changes on both the stability and type of aggregate, even in the absence of very specific non-covalent interactions. The changes can influence both the optical activity, the gelling ability — which is a direct reflection of the capacity for forming linear aggregates — as well as the morphology of the gel-derived materials. Supplementary Material

Two new silicon phthalocyanines (SiPcs 1 and 2) axially substituted with carboxylic acid appends have been synthesized and chemically characterized. DSC devices using SiPcs as sensitizers have been prepared for the first time. Although similar HOMO–LUMO values were obtained for both SiPcs, the device prepared with the SiPc 2 gives both higher open circuit voltage (V_oc) and also higher injection (j_sc), so the overall conversion efficiency is longer than for the one where SiPc 1 is used as a dye.

Diverse set of coumarin-corroles has been synthesized via both direct condensation of formyl-coumarins with dipyrranes and post-functionalization of simple trans-A₂B-corroles. Second approach was proved to be overall more effective. The optical properties of synthesized bichromophoric sytems were evaluated and suggest that the linked components are weakly electronically coupled.

This paper reports on the synthesis and characterization of the 2,3,7,8, 12,13,17,18-octakis-[6-(2-(1′-methyl-1′,2′-dicarba-closo-dodecaboran-2′-yl)-hexyl)-1,2-dicarba-closo-dodecaboran-1-yl)hexylthio] 5,10,15,20 (21H, 23H) porphyrazine, (H₂(MCHE)CHESPz), a nanosized molecule bearing height dicarboranyl-substituted carborarod-like alkyl pendants.

Self-assembly, photoinduced electron transfer, photocatalysis to accumulate one-electron reduced product, and photoelectrochemical behavior of nanohybrids comprised of zinc porphyrin (ZnP) or zinc phthalocyanine (ZnPc) with semiconducting (7,6)- and (6,5)-enriched SWCNTs are described. Supplementary Material

It is shown that both the lack of one meso-atom and the increase of the extent of the π-system cause the balance between intermolecular interactions (AP-AP) —(AP-water) to shift to the latter and lead to formation of stable monolayers with the most open face-on structure of nanoaggregates instead of the edge-on one, all other factors being equal, in Langmuir layers prepared from solutions in aromatic solvents. The micro-level structural difference of copper tetra-tert-butylsubstituted porphyrazine (CuPaztBu4) and phthalocyanine (CuPctBu4) resulted from the structural difference of two-dimensional nanoaggregates forming the layers was shown using Brewster angle microscopy.

The cationic water soluble complex [Pt(terpy)]₄(TpyP)⁸⁺ has been synthesized and fully characterized. The introduction of the Pt(II) terpy molecular fragments allows to extend the aromatic surface promoting aggregation in solutions, as well as on glass surface. Kinetics of Cu(II) insertion have been carried out on anionic (SDS) micellar phase.

Zinc phthalocyanines bearing different number of quinoxaline units containing terminal azide were prepared and fully characterized. Adjacent and opposite isomers were also separated. All compounds showed singlet oxygen quantum yields over 0.60 and fluorescence quantum yield in a range 0.03–0.06. All compounds absorbed strongly over 700 nm. Supplementary Material

In this study an easy and flexible synthetic access to porphyrin and chlorin phosphonic acids starting from the red blood pigment hemin chloride is presented. Phosphonic acid functions were linked to the porphyrinoids via appropriate spacer moieties. Self-assembled monolayers of the phosphonic acid terminated porphyrins and clorins on mesoporous TiO₂ electrodes of 3 μm thickness were formed as indicated by change in color. Surface concentrations range from 1 to 4 × 10^-8 mol.cm^-2.

Complexes 1 and 2 were loaded on the surface of silica gel by use of an electrostatic interaction with deprotonated silanol groups of silica gel. While complex 1 formed its dimer species with increase in the amount of the complex in the composite, complex 2 hardly formed the dimer in the composite due to the steric hindrance of its peripheral substituents. 1,3-Diphenylisobenzofuran was more effectively photo-oxidized using the composite of complex 2 in aerated methanol. Bilirubinditaurate was also photo-oxidized using the composites in an aerated aqueous solution.

Nitration of free base meso-triphenylcorrole was investigated using two different nitrating systems, based on NaNO₂ in acidic medium. These protocols led to the formation of corrole derivatives nitrated at their β-pyrrolic positions, characterized as their Co triphenylphosphino complexes.